| /* |
| * |
| * Copyright 2016 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| /** Implementation of the gRPC LB policy. |
| * |
| * This policy takes as input a set of resolved addresses {a1..an} for which the |
| * LB set was set (it's the resolver's responsibility to ensure this). That is |
| * to say, {a1..an} represent a collection of LB servers. |
| * |
| * An internal channel (\a glb_lb_policy.lb_channel) is created over {a1..an}. |
| * This channel behaves just like a regular channel. In particular, the |
| * constructed URI over the addresses a1..an will use the default pick first |
| * policy to select from this list of LB server backends. |
| * |
| * The first time the policy gets a request for a pick, a ping, or to exit the |
| * idle state, \a query_for_backends_locked() is called. This function sets up |
| * and initiates the internal communication with the LB server. In particular, |
| * it's responsible for instantiating the internal *streaming* call to the LB |
| * server (whichever address from {a1..an} pick-first chose). This call is |
| * serviced by two callbacks, \a lb_on_server_status_received and \a |
| * lb_on_response_received. The former will be called when the call to the LB |
| * server completes. This can happen if the LB server closes the connection or |
| * if this policy itself cancels the call (for example because it's shutting |
| * down). If the internal call times out, the usual behavior of pick-first |
| * applies, continuing to pick from the list {a1..an}. |
| * |
| * Upon sucesss, the incoming \a LoadBalancingResponse is processed by \a |
| * res_recv. An invalid one results in the termination of the streaming call. A |
| * new streaming call should be created if possible, failing the original call |
| * otherwise. For a valid \a LoadBalancingResponse, the server list of actual |
| * backends is extracted. A Round Robin policy will be created from this list. |
| * There are two possible scenarios: |
| * |
| * 1. This is the first server list received. There was no previous instance of |
| * the Round Robin policy. \a rr_handover_locked() will instantiate the RR |
| * policy and perform all the pending operations over it. |
| * 2. There's already a RR policy instance active. We need to introduce the new |
| * one build from the new serverlist, but taking care not to disrupt the |
| * operations in progress over the old RR instance. This is done by |
| * decreasing the reference count on the old policy. The moment no more |
| * references are held on the old RR policy, it'll be destroyed and \a |
| * on_rr_connectivity_changed notified with a \a GRPC_CHANNEL_SHUTDOWN |
| * state. At this point we can transition to a new RR instance safely, which |
| * is done once again via \a rr_handover_locked(). |
| * |
| * |
| * Once a RR policy instance is in place (and getting updated as described), |
| * calls to for a pick, a ping or a cancellation will be serviced right away by |
| * forwarding them to the RR instance. Any time there's no RR policy available |
| * (ie, right after the creation of the gRPCLB policy, if an empty serverlist is |
| * received, etc), pick/ping requests are added to a list of pending picks/pings |
| * to be flushed and serviced as part of \a rr_handover_locked() the moment the |
| * RR policy instance becomes available. |
| * |
| * \see https://github.com/grpc/grpc/blob/master/doc/load-balancing.md for the |
| * high level design and details. */ |
| |
| /* TODO(dgq): |
| * - Implement LB service forwarding (point 2c. in the doc's diagram). |
| */ |
| |
| /* With the addition of a libuv endpoint, sockaddr.h now includes uv.h when |
| using that endpoint. Because of various transitive includes in uv.h, |
| including windows.h on Windows, uv.h must be included before other system |
| headers. Therefore, sockaddr.h must always be included first */ |
| #include "src/core/lib/iomgr/sockaddr.h" |
| |
| #include <inttypes.h> |
| #include <limits.h> |
| #include <string.h> |
| |
| #include <grpc/byte_buffer_reader.h> |
| #include <grpc/grpc.h> |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/host_port.h> |
| #include <grpc/support/string_util.h> |
| #include <grpc/support/time.h> |
| |
| #include "src/core/ext/filters/client_channel/client_channel.h" |
| #include "src/core/ext/filters/client_channel/client_channel_factory.h" |
| #include "src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h" |
| #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h" |
| #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h" |
| #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h" |
| #include "src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h" |
| #include "src/core/ext/filters/client_channel/lb_policy_factory.h" |
| #include "src/core/ext/filters/client_channel/lb_policy_registry.h" |
| #include "src/core/ext/filters/client_channel/parse_address.h" |
| #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h" |
| #include "src/core/ext/filters/client_channel/subchannel_index.h" |
| #include "src/core/lib/backoff/backoff.h" |
| #include "src/core/lib/channel/channel_args.h" |
| #include "src/core/lib/channel/channel_stack.h" |
| #include "src/core/lib/gpr/string.h" |
| #include "src/core/lib/gprpp/manual_constructor.h" |
| #include "src/core/lib/iomgr/combiner.h" |
| #include "src/core/lib/iomgr/sockaddr.h" |
| #include "src/core/lib/iomgr/sockaddr_utils.h" |
| #include "src/core/lib/iomgr/timer.h" |
| #include "src/core/lib/slice/slice_hash_table.h" |
| #include "src/core/lib/slice/slice_internal.h" |
| #include "src/core/lib/slice/slice_string_helpers.h" |
| #include "src/core/lib/surface/call.h" |
| #include "src/core/lib/surface/channel.h" |
| #include "src/core/lib/surface/channel_init.h" |
| #include "src/core/lib/transport/static_metadata.h" |
| |
| #define GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS 1 |
| #define GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER 1.6 |
| #define GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS 120 |
| #define GRPC_GRPCLB_RECONNECT_JITTER 0.2 |
| #define GRPC_GRPCLB_DEFAULT_FALLBACK_TIMEOUT_MS 10000 |
| |
| grpc_core::TraceFlag grpc_lb_glb_trace(false, "glb"); |
| |
| struct glb_lb_policy; |
| |
| namespace { |
| |
| /// Linked list of pending pick requests. It stores all information needed to |
| /// eventually call (Round Robin's) pick() on them. They mainly stay pending |
| /// waiting for the RR policy to be created. |
| /// |
| /// Note that when a pick is sent to the RR policy, we inject our own |
| /// on_complete callback, so that we can intercept the result before |
| /// invoking the original on_complete callback. This allows us to set the |
| /// LB token metadata and add client_stats to the call context. |
| /// See \a pending_pick_complete() for details. |
| struct pending_pick { |
| // Our on_complete closure and the original one. |
| grpc_closure on_complete; |
| grpc_closure* original_on_complete; |
| // The original pick. |
| grpc_lb_policy_pick_state* pick; |
| // Stats for client-side load reporting. Note that this holds a |
| // reference, which must be either passed on via context or unreffed. |
| grpc_grpclb_client_stats* client_stats; |
| // The LB token associated with the pick. This is set via user_data in |
| // the pick. |
| grpc_mdelem lb_token; |
| // The grpclb instance that created the wrapping. This instance is not owned, |
| // reference counts are untouched. It's used only for logging purposes. |
| glb_lb_policy* glb_policy; |
| // Next pending pick. |
| struct pending_pick* next; |
| }; |
| |
| /// A linked list of pending pings waiting for the RR policy to be created. |
| struct pending_ping { |
| grpc_closure* on_initiate; |
| grpc_closure* on_ack; |
| struct pending_ping* next; |
| }; |
| |
| } // namespace |
| |
| typedef struct glb_lb_call_data { |
| struct glb_lb_policy* glb_policy; |
| // TODO(juanlishen): c++ize this struct. |
| gpr_refcount refs; |
| |
| /** The streaming call to the LB server. Always non-NULL. */ |
| grpc_call* lb_call; |
| |
| /** The initial metadata received from the LB server. */ |
| grpc_metadata_array lb_initial_metadata_recv; |
| |
| /** The message sent to the LB server. It's used to query for backends (the |
| * value may vary if the LB server indicates a redirect) or send client load |
| * report. */ |
| grpc_byte_buffer* send_message_payload; |
| /** The callback after the initial request is sent. */ |
| grpc_closure lb_on_sent_initial_request; |
| |
| /** The response received from the LB server, if any. */ |
| grpc_byte_buffer* recv_message_payload; |
| /** The callback to process the response received from the LB server. */ |
| grpc_closure lb_on_response_received; |
| bool seen_initial_response; |
| |
| /** The callback to process the status received from the LB server, which |
| * signals the end of the LB call. */ |
| grpc_closure lb_on_server_status_received; |
| /** The trailing metadata from the LB server. */ |
| grpc_metadata_array lb_trailing_metadata_recv; |
| /** The call status code and details. */ |
| grpc_status_code lb_call_status; |
| grpc_slice lb_call_status_details; |
| |
| /** The stats for client-side load reporting associated with this LB call. |
| * Created after the first serverlist is received. */ |
| grpc_grpclb_client_stats* client_stats; |
| /** The interval and timer for next client load report. */ |
| grpc_millis client_stats_report_interval; |
| grpc_timer client_load_report_timer; |
| bool client_load_report_timer_callback_pending; |
| bool last_client_load_report_counters_were_zero; |
| bool client_load_report_is_due; |
| /** The closure used for either the load report timer or the callback for |
| * completion of sending the load report. */ |
| grpc_closure client_load_report_closure; |
| } glb_lb_call_data; |
| |
| typedef struct glb_lb_policy { |
| /** Base policy: must be first. */ |
| grpc_lb_policy base; |
| |
| /** Who the client is trying to communicate with. */ |
| const char* server_name; |
| |
| /** Channel related data that will be propagated to the internal RR policy. */ |
| grpc_client_channel_factory* cc_factory; |
| grpc_channel_args* args; |
| |
| /** Timeout in milliseconds for before using fallback backend addresses. |
| * 0 means not using fallback. */ |
| int lb_fallback_timeout_ms; |
| |
| /** The channel for communicating with the LB server. */ |
| grpc_channel* lb_channel; |
| |
| /** The data associated with the current LB call. It holds a ref to this LB |
| * policy. It's initialized every time we query for backends. It's reset to |
| * NULL whenever the current LB call is no longer needed (e.g., the LB policy |
| * is shutting down, or the LB call has ended). A non-NULL lb_calld always |
| * contains a non-NULL lb_call. */ |
| glb_lb_call_data* lb_calld; |
| |
| /** response generator to inject address updates into \a lb_channel */ |
| grpc_fake_resolver_response_generator* response_generator; |
| |
| /** the RR policy to use of the backend servers returned by the LB server */ |
| grpc_lb_policy* rr_policy; |
| |
| /** the connectivity state of the embedded RR policy */ |
| grpc_connectivity_state rr_connectivity_state; |
| |
| bool started_picking; |
| |
| /** our connectivity state tracker */ |
| grpc_connectivity_state_tracker state_tracker; |
| |
| /** connectivity state of the LB channel */ |
| grpc_connectivity_state lb_channel_connectivity; |
| |
| /** stores the deserialized response from the LB. May be nullptr until one |
| * such response has arrived. */ |
| grpc_grpclb_serverlist* serverlist; |
| |
| /** Index into serverlist for next pick. |
| * If the server at this index is a drop, we return a drop. |
| * Otherwise, we delegate to the RR policy. */ |
| size_t serverlist_index; |
| |
| /** stores the backend addresses from the resolver */ |
| grpc_lb_addresses* fallback_backend_addresses; |
| |
| /** list of picks that are waiting on RR's policy connectivity */ |
| pending_pick* pending_picks; |
| |
| /** list of pings that are waiting on RR's policy connectivity */ |
| pending_ping* pending_pings; |
| |
| bool shutting_down; |
| |
| /** are we already watching the LB channel's connectivity? */ |
| bool watching_lb_channel; |
| |
| /** is the callback associated with \a lb_call_retry_timer pending? */ |
| bool retry_timer_callback_pending; |
| |
| /** is the callback associated with \a lb_fallback_timer pending? */ |
| bool fallback_timer_callback_pending; |
| |
| /** called upon changes to the LB channel's connectivity. */ |
| grpc_closure lb_channel_on_connectivity_changed; |
| |
| /** called upon changes to the RR's connectivity. */ |
| grpc_closure rr_on_connectivity_changed; |
| |
| /** called upon reresolution request from the RR policy. */ |
| grpc_closure rr_on_reresolution_requested; |
| |
| /************************************************************/ |
| /* client data associated with the LB server communication */ |
| /************************************************************/ |
| |
| /** LB call retry backoff state */ |
| grpc_core::ManualConstructor<grpc_core::BackOff> lb_call_backoff; |
| |
| /** timeout in milliseconds for the LB call. 0 means no deadline. */ |
| int lb_call_timeout_ms; |
| |
| /** LB call retry timer */ |
| grpc_timer lb_call_retry_timer; |
| /** LB call retry timer callback */ |
| grpc_closure lb_on_call_retry; |
| |
| /** LB fallback timer */ |
| grpc_timer lb_fallback_timer; |
| /** LB fallback timer callback */ |
| grpc_closure lb_on_fallback; |
| } glb_lb_policy; |
| |
| static void glb_lb_call_data_ref(glb_lb_call_data* lb_calld, |
| const char* reason) { |
| gpr_ref_non_zero(&lb_calld->refs); |
| if (grpc_lb_glb_trace.enabled()) { |
| const gpr_atm count = gpr_atm_acq_load(&lb_calld->refs.count); |
| gpr_log(GPR_DEBUG, "[%s %p] lb_calld %p REF %lu->%lu (%s)", |
| grpc_lb_glb_trace.name(), lb_calld->glb_policy, lb_calld, |
| (unsigned long)(count - 1), (unsigned long)count, reason); |
| } |
| } |
| |
| static void glb_lb_call_data_unref(glb_lb_call_data* lb_calld, |
| const char* reason) { |
| const bool done = gpr_unref(&lb_calld->refs); |
| if (grpc_lb_glb_trace.enabled()) { |
| const gpr_atm count = gpr_atm_acq_load(&lb_calld->refs.count); |
| gpr_log(GPR_DEBUG, "[%s %p] lb_calld %p UNREF %lu->%lu (%s)", |
| grpc_lb_glb_trace.name(), lb_calld->glb_policy, lb_calld, |
| (unsigned long)(count + 1), (unsigned long)count, reason); |
| } |
| if (done) { |
| GPR_ASSERT(lb_calld->lb_call != nullptr); |
| grpc_call_unref(lb_calld->lb_call); |
| grpc_metadata_array_destroy(&lb_calld->lb_initial_metadata_recv); |
| grpc_metadata_array_destroy(&lb_calld->lb_trailing_metadata_recv); |
| grpc_byte_buffer_destroy(lb_calld->send_message_payload); |
| grpc_byte_buffer_destroy(lb_calld->recv_message_payload); |
| grpc_slice_unref_internal(lb_calld->lb_call_status_details); |
| if (lb_calld->client_stats != nullptr) { |
| grpc_grpclb_client_stats_unref(lb_calld->client_stats); |
| } |
| GRPC_LB_POLICY_UNREF(&lb_calld->glb_policy->base, "lb_calld"); |
| gpr_free(lb_calld); |
| } |
| } |
| |
| static void lb_call_data_shutdown(glb_lb_policy* glb_policy) { |
| GPR_ASSERT(glb_policy->lb_calld != nullptr); |
| GPR_ASSERT(glb_policy->lb_calld->lb_call != nullptr); |
| // lb_on_server_status_received will complete the cancellation and clean up. |
| grpc_call_cancel(glb_policy->lb_calld->lb_call, nullptr); |
| if (glb_policy->lb_calld->client_load_report_timer_callback_pending) { |
| grpc_timer_cancel(&glb_policy->lb_calld->client_load_report_timer); |
| } |
| glb_policy->lb_calld = nullptr; |
| } |
| |
| /* add lb_token of selected subchannel (address) to the call's initial |
| * metadata */ |
| static grpc_error* initial_metadata_add_lb_token( |
| grpc_metadata_batch* initial_metadata, |
| grpc_linked_mdelem* lb_token_mdelem_storage, grpc_mdelem lb_token) { |
| GPR_ASSERT(lb_token_mdelem_storage != nullptr); |
| GPR_ASSERT(!GRPC_MDISNULL(lb_token)); |
| return grpc_metadata_batch_add_tail(initial_metadata, lb_token_mdelem_storage, |
| lb_token); |
| } |
| |
| static void destroy_client_stats(void* arg) { |
| grpc_grpclb_client_stats_unref((grpc_grpclb_client_stats*)arg); |
| } |
| |
| static void pending_pick_set_metadata_and_context(pending_pick* pp) { |
| /* if connected_subchannel is nullptr, no pick has been made by the RR |
| * policy (e.g., all addresses failed to connect). There won't be any |
| * user_data/token available */ |
| if (pp->pick->connected_subchannel != nullptr) { |
| if (!GRPC_MDISNULL(pp->lb_token)) { |
| initial_metadata_add_lb_token(pp->pick->initial_metadata, |
| &pp->pick->lb_token_mdelem_storage, |
| GRPC_MDELEM_REF(pp->lb_token)); |
| } else { |
| gpr_log(GPR_ERROR, |
| "[grpclb %p] No LB token for connected subchannel pick %p", |
| pp->glb_policy, pp->pick); |
| abort(); |
| } |
| // Pass on client stats via context. Passes ownership of the reference. |
| if (pp->client_stats != nullptr) { |
| pp->pick->subchannel_call_context[GRPC_GRPCLB_CLIENT_STATS].value = |
| pp->client_stats; |
| pp->pick->subchannel_call_context[GRPC_GRPCLB_CLIENT_STATS].destroy = |
| destroy_client_stats; |
| } |
| } else { |
| if (pp->client_stats != nullptr) { |
| grpc_grpclb_client_stats_unref(pp->client_stats); |
| } |
| } |
| } |
| |
| /* The \a on_complete closure passed as part of the pick requires keeping a |
| * reference to its associated round robin instance. We wrap this closure in |
| * order to unref the round robin instance upon its invocation */ |
| static void pending_pick_complete(void* arg, grpc_error* error) { |
| pending_pick* pp = (pending_pick*)arg; |
| pending_pick_set_metadata_and_context(pp); |
| GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_REF(error)); |
| gpr_free(pp); |
| } |
| |
| static pending_pick* pending_pick_create(glb_lb_policy* glb_policy, |
| grpc_lb_policy_pick_state* pick) { |
| pending_pick* pp = (pending_pick*)gpr_zalloc(sizeof(*pp)); |
| pp->pick = pick; |
| pp->glb_policy = glb_policy; |
| GRPC_CLOSURE_INIT(&pp->on_complete, pending_pick_complete, pp, |
| grpc_schedule_on_exec_ctx); |
| pp->original_on_complete = pick->on_complete; |
| pp->pick->on_complete = &pp->on_complete; |
| return pp; |
| } |
| |
| static void pending_pick_add(pending_pick** root, pending_pick* new_pp) { |
| new_pp->next = *root; |
| *root = new_pp; |
| } |
| |
| static void pending_ping_add(pending_ping** root, grpc_closure* on_initiate, |
| grpc_closure* on_ack) { |
| pending_ping* pping = (pending_ping*)gpr_zalloc(sizeof(*pping)); |
| pping->on_initiate = on_initiate; |
| pping->on_ack = on_ack; |
| pping->next = *root; |
| *root = pping; |
| } |
| |
| static bool is_server_valid(const grpc_grpclb_server* server, size_t idx, |
| bool log) { |
| if (server->drop) return false; |
| const grpc_grpclb_ip_address* ip = &server->ip_address; |
| if (server->port >> 16 != 0) { |
| if (log) { |
| gpr_log(GPR_ERROR, |
| "Invalid port '%d' at index %lu of serverlist. Ignoring.", |
| server->port, (unsigned long)idx); |
| } |
| return false; |
| } |
| if (ip->size != 4 && ip->size != 16) { |
| if (log) { |
| gpr_log(GPR_ERROR, |
| "Expected IP to be 4 or 16 bytes, got %d at index %lu of " |
| "serverlist. Ignoring", |
| ip->size, (unsigned long)idx); |
| } |
| return false; |
| } |
| return true; |
| } |
| |
| /* vtable for LB tokens in grpc_lb_addresses. */ |
| static void* lb_token_copy(void* token) { |
| return token == nullptr |
| ? nullptr |
| : (void*)GRPC_MDELEM_REF(grpc_mdelem{(uintptr_t)token}).payload; |
| } |
| static void lb_token_destroy(void* token) { |
| if (token != nullptr) { |
| GRPC_MDELEM_UNREF(grpc_mdelem{(uintptr_t)token}); |
| } |
| } |
| static int lb_token_cmp(void* token1, void* token2) { |
| if (token1 > token2) return 1; |
| if (token1 < token2) return -1; |
| return 0; |
| } |
| static const grpc_lb_user_data_vtable lb_token_vtable = { |
| lb_token_copy, lb_token_destroy, lb_token_cmp}; |
| |
| static void parse_server(const grpc_grpclb_server* server, |
| grpc_resolved_address* addr) { |
| memset(addr, 0, sizeof(*addr)); |
| if (server->drop) return; |
| const uint16_t netorder_port = htons((uint16_t)server->port); |
| /* the addresses are given in binary format (a in(6)_addr struct) in |
| * server->ip_address.bytes. */ |
| const grpc_grpclb_ip_address* ip = &server->ip_address; |
| if (ip->size == 4) { |
| addr->len = sizeof(struct sockaddr_in); |
| struct sockaddr_in* addr4 = (struct sockaddr_in*)&addr->addr; |
| addr4->sin_family = AF_INET; |
| memcpy(&addr4->sin_addr, ip->bytes, ip->size); |
| addr4->sin_port = netorder_port; |
| } else if (ip->size == 16) { |
| addr->len = sizeof(struct sockaddr_in6); |
| struct sockaddr_in6* addr6 = (struct sockaddr_in6*)&addr->addr; |
| addr6->sin6_family = AF_INET6; |
| memcpy(&addr6->sin6_addr, ip->bytes, ip->size); |
| addr6->sin6_port = netorder_port; |
| } |
| } |
| |
| /* Returns addresses extracted from \a serverlist. */ |
| static grpc_lb_addresses* process_serverlist_locked( |
| const grpc_grpclb_serverlist* serverlist) { |
| size_t num_valid = 0; |
| /* first pass: count how many are valid in order to allocate the necessary |
| * memory in a single block */ |
| for (size_t i = 0; i < serverlist->num_servers; ++i) { |
| if (is_server_valid(serverlist->servers[i], i, true)) ++num_valid; |
| } |
| grpc_lb_addresses* lb_addresses = |
| grpc_lb_addresses_create(num_valid, &lb_token_vtable); |
| /* second pass: actually populate the addresses and LB tokens (aka user data |
| * to the outside world) to be read by the RR policy during its creation. |
| * Given that the validity tests are very cheap, they are performed again |
| * instead of marking the valid ones during the first pass, as this would |
| * incurr in an allocation due to the arbitrary number of server */ |
| size_t addr_idx = 0; |
| for (size_t sl_idx = 0; sl_idx < serverlist->num_servers; ++sl_idx) { |
| const grpc_grpclb_server* server = serverlist->servers[sl_idx]; |
| if (!is_server_valid(serverlist->servers[sl_idx], sl_idx, false)) continue; |
| GPR_ASSERT(addr_idx < num_valid); |
| /* address processing */ |
| grpc_resolved_address addr; |
| parse_server(server, &addr); |
| /* lb token processing */ |
| void* user_data; |
| if (server->has_load_balance_token) { |
| const size_t lb_token_max_length = |
| GPR_ARRAY_SIZE(server->load_balance_token); |
| const size_t lb_token_length = |
| strnlen(server->load_balance_token, lb_token_max_length); |
| grpc_slice lb_token_mdstr = grpc_slice_from_copied_buffer( |
| server->load_balance_token, lb_token_length); |
| user_data = |
| (void*)grpc_mdelem_from_slices(GRPC_MDSTR_LB_TOKEN, lb_token_mdstr) |
| .payload; |
| } else { |
| char* uri = grpc_sockaddr_to_uri(&addr); |
| gpr_log(GPR_INFO, |
| "Missing LB token for backend address '%s'. The empty token will " |
| "be used instead", |
| uri); |
| gpr_free(uri); |
| user_data = (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload; |
| } |
| grpc_lb_addresses_set_address(lb_addresses, addr_idx, &addr.addr, addr.len, |
| false /* is_balancer */, |
| nullptr /* balancer_name */, user_data); |
| ++addr_idx; |
| } |
| GPR_ASSERT(addr_idx == num_valid); |
| return lb_addresses; |
| } |
| |
| /* Returns the backend addresses extracted from the given addresses */ |
| static grpc_lb_addresses* extract_backend_addresses_locked( |
| const grpc_lb_addresses* addresses) { |
| /* first pass: count the number of backend addresses */ |
| size_t num_backends = 0; |
| for (size_t i = 0; i < addresses->num_addresses; ++i) { |
| if (!addresses->addresses[i].is_balancer) { |
| ++num_backends; |
| } |
| } |
| /* second pass: actually populate the addresses and (empty) LB tokens */ |
| grpc_lb_addresses* backend_addresses = |
| grpc_lb_addresses_create(num_backends, &lb_token_vtable); |
| size_t num_copied = 0; |
| for (size_t i = 0; i < addresses->num_addresses; ++i) { |
| if (addresses->addresses[i].is_balancer) continue; |
| const grpc_resolved_address* addr = &addresses->addresses[i].address; |
| grpc_lb_addresses_set_address(backend_addresses, num_copied, &addr->addr, |
| addr->len, false /* is_balancer */, |
| nullptr /* balancer_name */, |
| (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload); |
| ++num_copied; |
| } |
| return backend_addresses; |
| } |
| |
| static void update_lb_connectivity_status_locked(glb_lb_policy* glb_policy, |
| grpc_error* rr_state_error) { |
| const grpc_connectivity_state curr_glb_state = |
| grpc_connectivity_state_check(&glb_policy->state_tracker); |
| /* The new connectivity status is a function of the previous one and the new |
| * input coming from the status of the RR policy. |
| * |
| * current state (grpclb's) |
| * | |
| * v || I | C | R | TF | SD | <- new state (RR's) |
| * ===++====+=====+=====+======+======+ |
| * I || I | C | R | [I] | [I] | |
| * ---++----+-----+-----+------+------+ |
| * C || I | C | R | [C] | [C] | |
| * ---++----+-----+-----+------+------+ |
| * R || I | C | R | [R] | [R] | |
| * ---++----+-----+-----+------+------+ |
| * TF || I | C | R | [TF] | [TF] | |
| * ---++----+-----+-----+------+------+ |
| * SD || NA | NA | NA | NA | NA | (*) |
| * ---++----+-----+-----+------+------+ |
| * |
| * A [STATE] indicates that the old RR policy is kept. In those cases, STATE |
| * is the current state of grpclb, which is left untouched. |
| * |
| * In summary, if the new state is TRANSIENT_FAILURE or SHUTDOWN, stick to |
| * the previous RR instance. |
| * |
| * Note that the status is never updated to SHUTDOWN as a result of calling |
| * this function. Only glb_shutdown() has the power to set that state. |
| * |
| * (*) This function mustn't be called during shutting down. */ |
| GPR_ASSERT(curr_glb_state != GRPC_CHANNEL_SHUTDOWN); |
| switch (glb_policy->rr_connectivity_state) { |
| case GRPC_CHANNEL_TRANSIENT_FAILURE: |
| case GRPC_CHANNEL_SHUTDOWN: |
| GPR_ASSERT(rr_state_error != GRPC_ERROR_NONE); |
| break; |
| case GRPC_CHANNEL_IDLE: |
| case GRPC_CHANNEL_CONNECTING: |
| case GRPC_CHANNEL_READY: |
| GPR_ASSERT(rr_state_error == GRPC_ERROR_NONE); |
| } |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log( |
| GPR_INFO, |
| "[grpclb %p] Setting grpclb's state to %s from new RR policy %p state.", |
| glb_policy, |
| grpc_connectivity_state_name(glb_policy->rr_connectivity_state), |
| glb_policy->rr_policy); |
| } |
| grpc_connectivity_state_set(&glb_policy->state_tracker, |
| glb_policy->rr_connectivity_state, rr_state_error, |
| "update_lb_connectivity_status_locked"); |
| } |
| |
| /* Perform a pick over \a glb_policy->rr_policy. Given that a pick can return |
| * immediately (ignoring its completion callback), we need to perform the |
| * cleanups this callback would otherwise be responsible for. |
| * If \a force_async is true, then we will manually schedule the |
| * completion callback even if the pick is available immediately. */ |
| static bool pick_from_internal_rr_locked(glb_lb_policy* glb_policy, |
| bool force_async, pending_pick* pp) { |
| // Check for drops if we are not using fallback backend addresses. |
| if (glb_policy->serverlist != nullptr) { |
| // Look at the index into the serverlist to see if we should drop this call. |
| grpc_grpclb_server* server = |
| glb_policy->serverlist->servers[glb_policy->serverlist_index++]; |
| if (glb_policy->serverlist_index == glb_policy->serverlist->num_servers) { |
| glb_policy->serverlist_index = 0; // Wrap-around. |
| } |
| if (server->drop) { |
| // Update client load reporting stats to indicate the number of |
| // dropped calls. Note that we have to do this here instead of in |
| // the client_load_reporting filter, because we do not create a |
| // subchannel call (and therefore no client_load_reporting filter) |
| // for dropped calls. |
| if (glb_policy->lb_calld != nullptr && |
| glb_policy->lb_calld->client_stats != nullptr) { |
| grpc_grpclb_client_stats_add_call_dropped_locked( |
| server->load_balance_token, glb_policy->lb_calld->client_stats); |
| } |
| if (force_async) { |
| GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_NONE); |
| gpr_free(pp); |
| return false; |
| } |
| gpr_free(pp); |
| return true; |
| } |
| } |
| // Set client_stats and user_data. |
| if (glb_policy->lb_calld != nullptr && |
| glb_policy->lb_calld->client_stats != nullptr) { |
| pp->client_stats = |
| grpc_grpclb_client_stats_ref(glb_policy->lb_calld->client_stats); |
| } |
| GPR_ASSERT(pp->pick->user_data == nullptr); |
| pp->pick->user_data = (void**)&pp->lb_token; |
| // Pick via the RR policy. |
| bool pick_done = grpc_lb_policy_pick_locked(glb_policy->rr_policy, pp->pick); |
| if (pick_done) { |
| pending_pick_set_metadata_and_context(pp); |
| if (force_async) { |
| GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_NONE); |
| pick_done = false; |
| } |
| gpr_free(pp); |
| } |
| /* else, the pending pick will be registered and taken care of by the |
| * pending pick list inside the RR policy (glb_policy->rr_policy). |
| * Eventually, wrapped_on_complete will be called, which will -among other |
| * things- add the LB token to the call's initial metadata */ |
| return pick_done; |
| } |
| |
| static grpc_lb_policy_args* lb_policy_args_create(glb_lb_policy* glb_policy) { |
| grpc_lb_addresses* addresses; |
| if (glb_policy->serverlist != nullptr) { |
| GPR_ASSERT(glb_policy->serverlist->num_servers > 0); |
| addresses = process_serverlist_locked(glb_policy->serverlist); |
| } else { |
| // If rr_handover_locked() is invoked when we haven't received any |
| // serverlist from the balancer, we use the fallback backends returned by |
| // the resolver. Note that the fallback backend list may be empty, in which |
| // case the new round_robin policy will keep the requested picks pending. |
| GPR_ASSERT(glb_policy->fallback_backend_addresses != nullptr); |
| addresses = grpc_lb_addresses_copy(glb_policy->fallback_backend_addresses); |
| } |
| GPR_ASSERT(addresses != nullptr); |
| grpc_lb_policy_args* args = (grpc_lb_policy_args*)gpr_zalloc(sizeof(*args)); |
| args->client_channel_factory = glb_policy->cc_factory; |
| args->combiner = glb_policy->base.combiner; |
| // Replace the LB addresses in the channel args that we pass down to |
| // the subchannel. |
| static const char* keys_to_remove[] = {GRPC_ARG_LB_ADDRESSES}; |
| const grpc_arg arg = grpc_lb_addresses_create_channel_arg(addresses); |
| args->args = grpc_channel_args_copy_and_add_and_remove( |
| glb_policy->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &arg, |
| 1); |
| grpc_lb_addresses_destroy(addresses); |
| return args; |
| } |
| |
| static void lb_policy_args_destroy(grpc_lb_policy_args* args) { |
| grpc_channel_args_destroy(args->args); |
| gpr_free(args); |
| } |
| |
| static void rr_on_reresolution_requested_locked(void* arg, grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)arg; |
| if (glb_policy->shutting_down || error != GRPC_ERROR_NONE) { |
| GRPC_LB_POLICY_UNREF(&glb_policy->base, |
| "rr_on_reresolution_requested_locked"); |
| return; |
| } |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log( |
| GPR_DEBUG, |
| "[grpclb %p] Re-resolution requested from the internal RR policy (%p).", |
| glb_policy, glb_policy->rr_policy); |
| } |
| // If we are talking to a balancer, we expect to get updated addresses form |
| // the balancer, so we can ignore the re-resolution request from the RR |
| // policy. Otherwise, handle the re-resolution request using glb's original |
| // re-resolution closure. |
| if (glb_policy->lb_calld == nullptr || |
| !glb_policy->lb_calld->seen_initial_response) { |
| grpc_lb_policy_try_reresolve(&glb_policy->base, &grpc_lb_glb_trace, |
| GRPC_ERROR_NONE); |
| } |
| // Give back the wrapper closure to the RR policy. |
| grpc_lb_policy_set_reresolve_closure_locked( |
| glb_policy->rr_policy, &glb_policy->rr_on_reresolution_requested); |
| } |
| |
| static void create_rr_locked(glb_lb_policy* glb_policy, |
| grpc_lb_policy_args* args) { |
| GPR_ASSERT(glb_policy->rr_policy == nullptr); |
| grpc_lb_policy* new_rr_policy = grpc_lb_policy_create("round_robin", args); |
| if (new_rr_policy == nullptr) { |
| gpr_log(GPR_ERROR, |
| "[grpclb %p] Failure creating a RoundRobin policy for serverlist " |
| "update with %" PRIuPTR |
| " entries. The previous RR instance (%p), if any, will continue to " |
| "be used. Future updates from the LB will attempt to create new " |
| "instances.", |
| glb_policy, glb_policy->serverlist->num_servers, |
| glb_policy->rr_policy); |
| return; |
| } |
| GRPC_LB_POLICY_REF(&glb_policy->base, "rr_on_reresolution_requested_locked"); |
| grpc_lb_policy_set_reresolve_closure_locked( |
| new_rr_policy, &glb_policy->rr_on_reresolution_requested); |
| glb_policy->rr_policy = new_rr_policy; |
| grpc_error* rr_state_error = nullptr; |
| glb_policy->rr_connectivity_state = grpc_lb_policy_check_connectivity_locked( |
| glb_policy->rr_policy, &rr_state_error); |
| /* Connectivity state is a function of the RR policy updated/created */ |
| update_lb_connectivity_status_locked(glb_policy, rr_state_error); |
| /* Add the gRPC LB's interested_parties pollset_set to that of the newly |
| * created RR policy. This will make the RR policy progress upon activity on |
| * gRPC LB, which in turn is tied to the application's call */ |
| grpc_pollset_set_add_pollset_set(glb_policy->rr_policy->interested_parties, |
| glb_policy->base.interested_parties); |
| /* Subscribe to changes to the connectivity of the new RR */ |
| GRPC_LB_POLICY_REF(&glb_policy->base, "rr_on_connectivity_changed_locked"); |
| grpc_lb_policy_notify_on_state_change_locked( |
| glb_policy->rr_policy, &glb_policy->rr_connectivity_state, |
| &glb_policy->rr_on_connectivity_changed); |
| grpc_lb_policy_exit_idle_locked(glb_policy->rr_policy); |
| // Send pending picks to RR policy. |
| pending_pick* pp; |
| while ((pp = glb_policy->pending_picks)) { |
| glb_policy->pending_picks = pp->next; |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Pending pick about to (async) PICK from RR %p", |
| glb_policy, glb_policy->rr_policy); |
| } |
| pick_from_internal_rr_locked(glb_policy, true /* force_async */, pp); |
| } |
| // Send pending pings to RR policy. |
| pending_ping* pping; |
| while ((pping = glb_policy->pending_pings)) { |
| glb_policy->pending_pings = pping->next; |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, "[grpclb %p] Pending ping about to PING from RR %p", |
| glb_policy, glb_policy->rr_policy); |
| } |
| grpc_lb_policy_ping_one_locked(glb_policy->rr_policy, pping->on_initiate, |
| pping->on_ack); |
| gpr_free(pping); |
| } |
| } |
| |
| /* glb_policy->rr_policy may be nullptr (initial handover) */ |
| static void rr_handover_locked(glb_lb_policy* glb_policy) { |
| if (glb_policy->shutting_down) return; |
| grpc_lb_policy_args* args = lb_policy_args_create(glb_policy); |
| GPR_ASSERT(args != nullptr); |
| if (glb_policy->rr_policy != nullptr) { |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_DEBUG, "[grpclb %p] Updating RR policy %p", glb_policy, |
| glb_policy->rr_policy); |
| } |
| grpc_lb_policy_update_locked(glb_policy->rr_policy, args); |
| } else { |
| create_rr_locked(glb_policy, args); |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_DEBUG, "[grpclb %p] Created new RR policy %p", glb_policy, |
| glb_policy->rr_policy); |
| } |
| } |
| lb_policy_args_destroy(args); |
| } |
| |
| static void rr_on_connectivity_changed_locked(void* arg, grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)arg; |
| if (glb_policy->shutting_down) { |
| GRPC_LB_POLICY_UNREF(&glb_policy->base, |
| "rr_on_connectivity_changed_locked"); |
| return; |
| } |
| update_lb_connectivity_status_locked(glb_policy, GRPC_ERROR_REF(error)); |
| // Resubscribe. Reuse the "rr_on_connectivity_changed_locked" ref. |
| grpc_lb_policy_notify_on_state_change_locked( |
| glb_policy->rr_policy, &glb_policy->rr_connectivity_state, |
| &glb_policy->rr_on_connectivity_changed); |
| } |
| |
| static void destroy_balancer_name(void* balancer_name) { |
| gpr_free(balancer_name); |
| } |
| |
| static grpc_slice_hash_table_entry targets_info_entry_create( |
| const char* address, const char* balancer_name) { |
| grpc_slice_hash_table_entry entry; |
| entry.key = grpc_slice_from_copied_string(address); |
| entry.value = gpr_strdup(balancer_name); |
| return entry; |
| } |
| |
| static int balancer_name_cmp_fn(void* a, void* b) { |
| const char* a_str = (const char*)a; |
| const char* b_str = (const char*)b; |
| return strcmp(a_str, b_str); |
| } |
| |
| /* Returns the channel args for the LB channel, used to create a bidirectional |
| * stream for the reception of load balancing updates. |
| * |
| * Inputs: |
| * - \a addresses: corresponding to the balancers. |
| * - \a response_generator: in order to propagate updates from the resolver |
| * above the grpclb policy. |
| * - \a args: other args inherited from the grpclb policy. */ |
| static grpc_channel_args* build_lb_channel_args( |
| const grpc_lb_addresses* addresses, |
| grpc_fake_resolver_response_generator* response_generator, |
| const grpc_channel_args* args) { |
| size_t num_grpclb_addrs = 0; |
| for (size_t i = 0; i < addresses->num_addresses; ++i) { |
| if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs; |
| } |
| /* All input addresses come from a resolver that claims they are LB services. |
| * It's the resolver's responsibility to make sure this policy is only |
| * instantiated and used in that case. Otherwise, something has gone wrong. */ |
| GPR_ASSERT(num_grpclb_addrs > 0); |
| grpc_lb_addresses* lb_addresses = |
| grpc_lb_addresses_create(num_grpclb_addrs, nullptr); |
| grpc_slice_hash_table_entry* targets_info_entries = |
| (grpc_slice_hash_table_entry*)gpr_zalloc(sizeof(*targets_info_entries) * |
| num_grpclb_addrs); |
| |
| size_t lb_addresses_idx = 0; |
| for (size_t i = 0; i < addresses->num_addresses; ++i) { |
| if (!addresses->addresses[i].is_balancer) continue; |
| if (addresses->addresses[i].user_data != nullptr) { |
| gpr_log(GPR_ERROR, |
| "This LB policy doesn't support user data. It will be ignored"); |
| } |
| char* addr_str; |
| GPR_ASSERT(grpc_sockaddr_to_string( |
| &addr_str, &addresses->addresses[i].address, true) > 0); |
| targets_info_entries[lb_addresses_idx] = targets_info_entry_create( |
| addr_str, addresses->addresses[i].balancer_name); |
| gpr_free(addr_str); |
| |
| grpc_lb_addresses_set_address( |
| lb_addresses, lb_addresses_idx++, addresses->addresses[i].address.addr, |
| addresses->addresses[i].address.len, false /* is balancer */, |
| addresses->addresses[i].balancer_name, nullptr /* user data */); |
| } |
| GPR_ASSERT(num_grpclb_addrs == lb_addresses_idx); |
| grpc_slice_hash_table* targets_info = |
| grpc_slice_hash_table_create(num_grpclb_addrs, targets_info_entries, |
| destroy_balancer_name, balancer_name_cmp_fn); |
| gpr_free(targets_info_entries); |
| |
| grpc_channel_args* lb_channel_args = |
| grpc_lb_policy_grpclb_build_lb_channel_args(targets_info, |
| response_generator, args); |
| |
| grpc_arg lb_channel_addresses_arg = |
| grpc_lb_addresses_create_channel_arg(lb_addresses); |
| |
| grpc_channel_args* result = grpc_channel_args_copy_and_add( |
| lb_channel_args, &lb_channel_addresses_arg, 1); |
| grpc_slice_hash_table_unref(targets_info); |
| grpc_channel_args_destroy(lb_channel_args); |
| grpc_lb_addresses_destroy(lb_addresses); |
| return result; |
| } |
| |
| static void glb_destroy(grpc_lb_policy* pol) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| GPR_ASSERT(glb_policy->pending_picks == nullptr); |
| GPR_ASSERT(glb_policy->pending_pings == nullptr); |
| gpr_free((void*)glb_policy->server_name); |
| grpc_channel_args_destroy(glb_policy->args); |
| grpc_connectivity_state_destroy(&glb_policy->state_tracker); |
| if (glb_policy->serverlist != nullptr) { |
| grpc_grpclb_destroy_serverlist(glb_policy->serverlist); |
| } |
| if (glb_policy->fallback_backend_addresses != nullptr) { |
| grpc_lb_addresses_destroy(glb_policy->fallback_backend_addresses); |
| } |
| grpc_fake_resolver_response_generator_unref(glb_policy->response_generator); |
| grpc_subchannel_index_unref(); |
| gpr_free(glb_policy); |
| } |
| |
| static void glb_shutdown_locked(grpc_lb_policy* pol, |
| grpc_lb_policy* new_policy) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown"); |
| glb_policy->shutting_down = true; |
| if (glb_policy->lb_calld != nullptr) { |
| lb_call_data_shutdown(glb_policy); |
| } |
| if (glb_policy->retry_timer_callback_pending) { |
| grpc_timer_cancel(&glb_policy->lb_call_retry_timer); |
| } |
| if (glb_policy->fallback_timer_callback_pending) { |
| grpc_timer_cancel(&glb_policy->lb_fallback_timer); |
| } |
| if (glb_policy->rr_policy != nullptr) { |
| grpc_lb_policy_shutdown_locked(glb_policy->rr_policy, nullptr); |
| GRPC_LB_POLICY_UNREF(glb_policy->rr_policy, "glb_shutdown"); |
| } |
| // We destroy the LB channel here because |
| // glb_lb_channel_on_connectivity_changed_cb needs a valid glb_policy |
| // instance. Destroying the lb channel in glb_destroy would likely result in |
| // a callback invocation without a valid glb_policy arg. |
| if (glb_policy->lb_channel != nullptr) { |
| grpc_channel_destroy(glb_policy->lb_channel); |
| glb_policy->lb_channel = nullptr; |
| } |
| grpc_connectivity_state_set(&glb_policy->state_tracker, GRPC_CHANNEL_SHUTDOWN, |
| GRPC_ERROR_REF(error), "glb_shutdown"); |
| grpc_lb_policy_try_reresolve(pol, &grpc_lb_glb_trace, GRPC_ERROR_CANCELLED); |
| // Clear pending picks. |
| pending_pick* pp = glb_policy->pending_picks; |
| glb_policy->pending_picks = nullptr; |
| while (pp != nullptr) { |
| pending_pick* next = pp->next; |
| if (new_policy != nullptr) { |
| // Hand pick over to new policy. |
| if (pp->client_stats != nullptr) { |
| grpc_grpclb_client_stats_unref(pp->client_stats); |
| } |
| pp->pick->on_complete = pp->original_on_complete; |
| if (grpc_lb_policy_pick_locked(new_policy, pp->pick)) { |
| // Synchronous return; schedule callback. |
| GRPC_CLOSURE_SCHED(pp->pick->on_complete, GRPC_ERROR_NONE); |
| } |
| gpr_free(pp); |
| } else { |
| pp->pick->connected_subchannel.reset(); |
| GRPC_CLOSURE_SCHED(&pp->on_complete, GRPC_ERROR_REF(error)); |
| } |
| pp = next; |
| } |
| // Clear pending pings. |
| pending_ping* pping = glb_policy->pending_pings; |
| glb_policy->pending_pings = nullptr; |
| while (pping != nullptr) { |
| pending_ping* next = pping->next; |
| GRPC_CLOSURE_SCHED(pping->on_initiate, GRPC_ERROR_REF(error)); |
| GRPC_CLOSURE_SCHED(pping->on_ack, GRPC_ERROR_REF(error)); |
| gpr_free(pping); |
| pping = next; |
| } |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| // Cancel a specific pending pick. |
| // |
| // A grpclb pick progresses as follows: |
| // - If there's a Round Robin policy (glb_policy->rr_policy) available, it'll be |
| // handed over to the RR policy (in create_rr_locked()). From that point |
| // onwards, it'll be RR's responsibility. For cancellations, that implies the |
| // pick needs also be cancelled by the RR instance. |
| // - Otherwise, without an RR instance, picks stay pending at this policy's |
| // level (grpclb), inside the glb_policy->pending_picks list. To cancel these, |
| // we invoke the completion closure and set *target to nullptr right here. |
| static void glb_cancel_pick_locked(grpc_lb_policy* pol, |
| grpc_lb_policy_pick_state* pick, |
| grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| pending_pick* pp = glb_policy->pending_picks; |
| glb_policy->pending_picks = nullptr; |
| while (pp != nullptr) { |
| pending_pick* next = pp->next; |
| if (pp->pick == pick) { |
| pick->connected_subchannel.reset(); |
| GRPC_CLOSURE_SCHED(&pp->on_complete, |
| GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( |
| "Pick Cancelled", &error, 1)); |
| } else { |
| pp->next = glb_policy->pending_picks; |
| glb_policy->pending_picks = pp; |
| } |
| pp = next; |
| } |
| if (glb_policy->rr_policy != nullptr) { |
| grpc_lb_policy_cancel_pick_locked(glb_policy->rr_policy, pick, |
| GRPC_ERROR_REF(error)); |
| } |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| // Cancel all pending picks. |
| // |
| // A grpclb pick progresses as follows: |
| // - If there's a Round Robin policy (glb_policy->rr_policy) available, it'll be |
| // handed over to the RR policy (in create_rr_locked()). From that point |
| // onwards, it'll be RR's responsibility. For cancellations, that implies the |
| // pick needs also be cancelled by the RR instance. |
| // - Otherwise, without an RR instance, picks stay pending at this policy's |
| // level (grpclb), inside the glb_policy->pending_picks list. To cancel these, |
| // we invoke the completion closure and set *target to nullptr right here. |
| static void glb_cancel_picks_locked(grpc_lb_policy* pol, |
| uint32_t initial_metadata_flags_mask, |
| uint32_t initial_metadata_flags_eq, |
| grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| pending_pick* pp = glb_policy->pending_picks; |
| glb_policy->pending_picks = nullptr; |
| while (pp != nullptr) { |
| pending_pick* next = pp->next; |
| if ((pp->pick->initial_metadata_flags & initial_metadata_flags_mask) == |
| initial_metadata_flags_eq) { |
| GRPC_CLOSURE_SCHED(&pp->on_complete, |
| GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( |
| "Pick Cancelled", &error, 1)); |
| } else { |
| pp->next = glb_policy->pending_picks; |
| glb_policy->pending_picks = pp; |
| } |
| pp = next; |
| } |
| if (glb_policy->rr_policy != nullptr) { |
| grpc_lb_policy_cancel_picks_locked( |
| glb_policy->rr_policy, initial_metadata_flags_mask, |
| initial_metadata_flags_eq, GRPC_ERROR_REF(error)); |
| } |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| static void lb_on_fallback_timer_locked(void* arg, grpc_error* error); |
| static void query_for_backends_locked(glb_lb_policy* glb_policy); |
| static void start_picking_locked(glb_lb_policy* glb_policy) { |
| /* start a timer to fall back */ |
| if (glb_policy->lb_fallback_timeout_ms > 0 && |
| glb_policy->serverlist == nullptr && |
| !glb_policy->fallback_timer_callback_pending) { |
| grpc_millis deadline = |
| grpc_core::ExecCtx::Get()->Now() + glb_policy->lb_fallback_timeout_ms; |
| GRPC_LB_POLICY_REF(&glb_policy->base, "grpclb_fallback_timer"); |
| GRPC_CLOSURE_INIT(&glb_policy->lb_on_fallback, lb_on_fallback_timer_locked, |
| glb_policy, |
| grpc_combiner_scheduler(glb_policy->base.combiner)); |
| glb_policy->fallback_timer_callback_pending = true; |
| grpc_timer_init(&glb_policy->lb_fallback_timer, deadline, |
| &glb_policy->lb_on_fallback); |
| } |
| glb_policy->started_picking = true; |
| glb_policy->lb_call_backoff->Reset(); |
| query_for_backends_locked(glb_policy); |
| } |
| |
| static void glb_exit_idle_locked(grpc_lb_policy* pol) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| if (!glb_policy->started_picking) { |
| start_picking_locked(glb_policy); |
| } |
| } |
| |
| static int glb_pick_locked(grpc_lb_policy* pol, |
| grpc_lb_policy_pick_state* pick) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| pending_pick* pp = pending_pick_create(glb_policy, pick); |
| bool pick_done = false; |
| if (glb_policy->rr_policy != nullptr) { |
| const grpc_connectivity_state rr_connectivity_state = |
| grpc_lb_policy_check_connectivity_locked(glb_policy->rr_policy, |
| nullptr); |
| // The glb_policy->rr_policy may have transitioned to SHUTDOWN but the |
| // callback registered to capture this event |
| // (on_rr_connectivity_changed_locked) may not have been invoked yet. We |
| // need to make sure we aren't trying to pick from a RR policy instance |
| // that's in shutdown. |
| if (rr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) { |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] NOT picking from from RR %p: RR conn state=%s", |
| glb_policy, glb_policy->rr_policy, |
| grpc_connectivity_state_name(rr_connectivity_state)); |
| } |
| pending_pick_add(&glb_policy->pending_picks, pp); |
| pick_done = false; |
| } else { // RR not in shutdown |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, "[grpclb %p] about to PICK from RR %p", glb_policy, |
| glb_policy->rr_policy); |
| } |
| pick_done = |
| pick_from_internal_rr_locked(glb_policy, false /* force_async */, pp); |
| } |
| } else { // glb_policy->rr_policy == NULL |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_DEBUG, |
| "[grpclb %p] No RR policy. Adding to grpclb's pending picks", |
| glb_policy); |
| } |
| pending_pick_add(&glb_policy->pending_picks, pp); |
| if (!glb_policy->started_picking) { |
| start_picking_locked(glb_policy); |
| } |
| pick_done = false; |
| } |
| return pick_done; |
| } |
| |
| static grpc_connectivity_state glb_check_connectivity_locked( |
| grpc_lb_policy* pol, grpc_error** connectivity_error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| return grpc_connectivity_state_get(&glb_policy->state_tracker, |
| connectivity_error); |
| } |
| |
| static void glb_ping_one_locked(grpc_lb_policy* pol, grpc_closure* on_initiate, |
| grpc_closure* on_ack) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| if (glb_policy->rr_policy) { |
| grpc_lb_policy_ping_one_locked(glb_policy->rr_policy, on_initiate, on_ack); |
| } else { |
| pending_ping_add(&glb_policy->pending_pings, on_initiate, on_ack); |
| if (!glb_policy->started_picking) { |
| start_picking_locked(glb_policy); |
| } |
| } |
| } |
| |
| static void glb_notify_on_state_change_locked(grpc_lb_policy* pol, |
| grpc_connectivity_state* current, |
| grpc_closure* notify) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)pol; |
| grpc_connectivity_state_notify_on_state_change(&glb_policy->state_tracker, |
| current, notify); |
| } |
| |
| static void lb_call_on_retry_timer_locked(void* arg, grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)arg; |
| glb_policy->retry_timer_callback_pending = false; |
| if (!glb_policy->shutting_down && error == GRPC_ERROR_NONE && |
| glb_policy->lb_calld == nullptr) { |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, "[grpclb %p] Restarting call to LB server", glb_policy); |
| } |
| query_for_backends_locked(glb_policy); |
| } |
| GRPC_LB_POLICY_UNREF(&glb_policy->base, "grpclb_retry_timer"); |
| } |
| |
| static void start_lb_call_retry_timer_locked(glb_lb_policy* glb_policy) { |
| grpc_millis next_try = glb_policy->lb_call_backoff->NextAttemptTime(); |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_DEBUG, "[grpclb %p] Connection to LB server lost...", |
| glb_policy); |
| grpc_millis timeout = next_try - grpc_core::ExecCtx::Get()->Now(); |
| if (timeout > 0) { |
| gpr_log(GPR_DEBUG, |
| "[grpclb %p] ... retry_timer_active in %" PRIuPTR "ms.", |
| glb_policy, timeout); |
| } else { |
| gpr_log(GPR_DEBUG, "[grpclb %p] ... retry_timer_active immediately.", |
| glb_policy); |
| } |
| } |
| GRPC_LB_POLICY_REF(&glb_policy->base, "grpclb_retry_timer"); |
| GRPC_CLOSURE_INIT(&glb_policy->lb_on_call_retry, |
| lb_call_on_retry_timer_locked, glb_policy, |
| grpc_combiner_scheduler(glb_policy->base.combiner)); |
| glb_policy->retry_timer_callback_pending = true; |
| grpc_timer_init(&glb_policy->lb_call_retry_timer, next_try, |
| &glb_policy->lb_on_call_retry); |
| } |
| |
| static void maybe_send_client_load_report_locked(void* arg, grpc_error* error); |
| |
| static void schedule_next_client_load_report(glb_lb_call_data* lb_calld) { |
| const grpc_millis next_client_load_report_time = |
| grpc_core::ExecCtx::Get()->Now() + lb_calld->client_stats_report_interval; |
| GRPC_CLOSURE_INIT( |
| &lb_calld->client_load_report_closure, |
| maybe_send_client_load_report_locked, lb_calld, |
| grpc_combiner_scheduler(lb_calld->glb_policy->base.combiner)); |
| grpc_timer_init(&lb_calld->client_load_report_timer, |
| next_client_load_report_time, |
| &lb_calld->client_load_report_closure); |
| lb_calld->client_load_report_timer_callback_pending = true; |
| } |
| |
| static void client_load_report_done_locked(void* arg, grpc_error* error) { |
| glb_lb_call_data* lb_calld = (glb_lb_call_data*)arg; |
| glb_lb_policy* glb_policy = lb_calld->glb_policy; |
| grpc_byte_buffer_destroy(lb_calld->send_message_payload); |
| lb_calld->send_message_payload = nullptr; |
| if (error != GRPC_ERROR_NONE || lb_calld != glb_policy->lb_calld) { |
| glb_lb_call_data_unref(lb_calld, "client_load_report"); |
| return; |
| } |
| schedule_next_client_load_report(lb_calld); |
| } |
| |
| static bool load_report_counters_are_zero(grpc_grpclb_request* request) { |
| grpc_grpclb_dropped_call_counts* drop_entries = |
| (grpc_grpclb_dropped_call_counts*) |
| request->client_stats.calls_finished_with_drop.arg; |
| return request->client_stats.num_calls_started == 0 && |
| request->client_stats.num_calls_finished == 0 && |
| request->client_stats.num_calls_finished_with_client_failed_to_send == |
| 0 && |
| request->client_stats.num_calls_finished_known_received == 0 && |
| (drop_entries == nullptr || drop_entries->num_entries == 0); |
| } |
| |
| static void send_client_load_report_locked(glb_lb_call_data* lb_calld) { |
| glb_lb_policy* glb_policy = lb_calld->glb_policy; |
| // Construct message payload. |
| GPR_ASSERT(lb_calld->send_message_payload == nullptr); |
| grpc_grpclb_request* request = |
| grpc_grpclb_load_report_request_create_locked(lb_calld->client_stats); |
| // Skip client load report if the counters were all zero in the last |
| // report and they are still zero in this one. |
| if (load_report_counters_are_zero(request)) { |
| if (lb_calld->last_client_load_report_counters_were_zero) { |
| grpc_grpclb_request_destroy(request); |
| schedule_next_client_load_report(lb_calld); |
| return; |
| } |
| lb_calld->last_client_load_report_counters_were_zero = true; |
| } else { |
| lb_calld->last_client_load_report_counters_were_zero = false; |
| } |
| grpc_slice request_payload_slice = grpc_grpclb_request_encode(request); |
| lb_calld->send_message_payload = |
| grpc_raw_byte_buffer_create(&request_payload_slice, 1); |
| grpc_slice_unref_internal(request_payload_slice); |
| grpc_grpclb_request_destroy(request); |
| // Send the report. |
| grpc_op op; |
| memset(&op, 0, sizeof(op)); |
| op.op = GRPC_OP_SEND_MESSAGE; |
| op.data.send_message.send_message = lb_calld->send_message_payload; |
| GRPC_CLOSURE_INIT(&lb_calld->client_load_report_closure, |
| client_load_report_done_locked, lb_calld, |
| grpc_combiner_scheduler(glb_policy->base.combiner)); |
| grpc_call_error call_error = grpc_call_start_batch_and_execute( |
| lb_calld->lb_call, &op, 1, &lb_calld->client_load_report_closure); |
| if (call_error != GRPC_CALL_OK) { |
| gpr_log(GPR_ERROR, "[grpclb %p] call_error=%d", glb_policy, call_error); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| } |
| } |
| |
| static void maybe_send_client_load_report_locked(void* arg, grpc_error* error) { |
| glb_lb_call_data* lb_calld = (glb_lb_call_data*)arg; |
| glb_lb_policy* glb_policy = lb_calld->glb_policy; |
| lb_calld->client_load_report_timer_callback_pending = false; |
| if (error != GRPC_ERROR_NONE || lb_calld != glb_policy->lb_calld) { |
| glb_lb_call_data_unref(lb_calld, "client_load_report"); |
| return; |
| } |
| // If we've already sent the initial request, then we can go ahead and send |
| // the load report. Otherwise, we need to wait until the initial request has |
| // been sent to send this (see lb_on_sent_initial_request_locked()). |
| if (lb_calld->send_message_payload == nullptr) { |
| send_client_load_report_locked(lb_calld); |
| } else { |
| lb_calld->client_load_report_is_due = true; |
| } |
| } |
| |
| static void lb_on_sent_initial_request_locked(void* arg, grpc_error* error); |
| static void lb_on_server_status_received_locked(void* arg, grpc_error* error); |
| static void lb_on_response_received_locked(void* arg, grpc_error* error); |
| static glb_lb_call_data* lb_call_data_create_locked(glb_lb_policy* glb_policy) { |
| GPR_ASSERT(!glb_policy->shutting_down); |
| // Init the LB call. Note that the LB call will progress every time there's |
| // activity in glb_policy->base.interested_parties, which is comprised of the |
| // polling entities from client_channel. |
| GPR_ASSERT(glb_policy->server_name != nullptr); |
| GPR_ASSERT(glb_policy->server_name[0] != '\0'); |
| grpc_slice host = grpc_slice_from_copied_string(glb_policy->server_name); |
| grpc_millis deadline = |
| glb_policy->lb_call_timeout_ms == 0 |
| ? GRPC_MILLIS_INF_FUTURE |
| : grpc_core::ExecCtx::Get()->Now() + glb_policy->lb_call_timeout_ms; |
| glb_lb_call_data* lb_calld = (glb_lb_call_data*)gpr_zalloc(sizeof(*lb_calld)); |
| lb_calld->lb_call = grpc_channel_create_pollset_set_call( |
| glb_policy->lb_channel, nullptr, GRPC_PROPAGATE_DEFAULTS, |
| glb_policy->base.interested_parties, |
| GRPC_MDSTR_SLASH_GRPC_DOT_LB_DOT_V1_DOT_LOADBALANCER_SLASH_BALANCELOAD, |
| &host, deadline, nullptr); |
| grpc_slice_unref_internal(host); |
| // Init the LB call request payload. |
| grpc_grpclb_request* request = |
| grpc_grpclb_request_create(glb_policy->server_name); |
| grpc_slice request_payload_slice = grpc_grpclb_request_encode(request); |
| lb_calld->send_message_payload = |
| grpc_raw_byte_buffer_create(&request_payload_slice, 1); |
| grpc_slice_unref_internal(request_payload_slice); |
| grpc_grpclb_request_destroy(request); |
| // Init other data associated with the LB call. |
| lb_calld->glb_policy = glb_policy; |
| gpr_ref_init(&lb_calld->refs, 1); |
| grpc_metadata_array_init(&lb_calld->lb_initial_metadata_recv); |
| grpc_metadata_array_init(&lb_calld->lb_trailing_metadata_recv); |
| GRPC_CLOSURE_INIT(&lb_calld->lb_on_sent_initial_request, |
| lb_on_sent_initial_request_locked, lb_calld, |
| grpc_combiner_scheduler(glb_policy->base.combiner)); |
| GRPC_CLOSURE_INIT(&lb_calld->lb_on_response_received, |
| lb_on_response_received_locked, lb_calld, |
| grpc_combiner_scheduler(glb_policy->base.combiner)); |
| GRPC_CLOSURE_INIT(&lb_calld->lb_on_server_status_received, |
| lb_on_server_status_received_locked, lb_calld, |
| grpc_combiner_scheduler(glb_policy->base.combiner)); |
| // Hold a ref to the glb_policy. |
| GRPC_LB_POLICY_REF(&glb_policy->base, "lb_calld"); |
| return lb_calld; |
| } |
| |
| /* |
| * Auxiliary functions and LB client callbacks. |
| */ |
| |
| static void query_for_backends_locked(glb_lb_policy* glb_policy) { |
| GPR_ASSERT(glb_policy->lb_channel != nullptr); |
| if (glb_policy->shutting_down) return; |
| // Init the LB call data. |
| GPR_ASSERT(glb_policy->lb_calld == nullptr); |
| glb_policy->lb_calld = lb_call_data_create_locked(glb_policy); |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Query for backends (lb_channel: %p, lb_calld: %p, " |
| "lb_call: %p)", |
| glb_policy, glb_policy->lb_channel, glb_policy->lb_calld, |
| glb_policy->lb_calld->lb_call); |
| } |
| GPR_ASSERT(glb_policy->lb_calld->lb_call != nullptr); |
| // Create the ops. |
| grpc_call_error call_error; |
| grpc_op ops[3]; |
| memset(ops, 0, sizeof(ops)); |
| // Op: send initial metadata. |
| grpc_op* op = ops; |
| op->op = GRPC_OP_SEND_INITIAL_METADATA; |
| op->data.send_initial_metadata.count = 0; |
| op->flags = 0; |
| op->reserved = nullptr; |
| op++; |
| // Op: send request message. |
| GPR_ASSERT(glb_policy->lb_calld->send_message_payload != nullptr); |
| op->op = GRPC_OP_SEND_MESSAGE; |
| op->data.send_message.send_message = |
| glb_policy->lb_calld->send_message_payload; |
| op->flags = 0; |
| op->reserved = nullptr; |
| op++; |
| glb_lb_call_data_ref(glb_policy->lb_calld, |
| "lb_on_sent_initial_request_locked"); |
| call_error = grpc_call_start_batch_and_execute( |
| glb_policy->lb_calld->lb_call, ops, (size_t)(op - ops), |
| &glb_policy->lb_calld->lb_on_sent_initial_request); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| // Op: recv initial metadata. |
| op = ops; |
| op->op = GRPC_OP_RECV_INITIAL_METADATA; |
| op->data.recv_initial_metadata.recv_initial_metadata = |
| &glb_policy->lb_calld->lb_initial_metadata_recv; |
| op->flags = 0; |
| op->reserved = nullptr; |
| op++; |
| // Op: recv response. |
| op->op = GRPC_OP_RECV_MESSAGE; |
| op->data.recv_message.recv_message = |
| &glb_policy->lb_calld->recv_message_payload; |
| op->flags = 0; |
| op->reserved = nullptr; |
| op++; |
| glb_lb_call_data_ref(glb_policy->lb_calld, "lb_on_response_received_locked"); |
| call_error = grpc_call_start_batch_and_execute( |
| glb_policy->lb_calld->lb_call, ops, (size_t)(op - ops), |
| &glb_policy->lb_calld->lb_on_response_received); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| // Op: recv server status. |
| op = ops; |
| op->op = GRPC_OP_RECV_STATUS_ON_CLIENT; |
| op->data.recv_status_on_client.trailing_metadata = |
| &glb_policy->lb_calld->lb_trailing_metadata_recv; |
| op->data.recv_status_on_client.status = &glb_policy->lb_calld->lb_call_status; |
| op->data.recv_status_on_client.status_details = |
| &glb_policy->lb_calld->lb_call_status_details; |
| op->flags = 0; |
| op->reserved = nullptr; |
| op++; |
| // This callback signals the end of the LB call, so it relies on the initial |
| // ref instead of a new ref. When it's invoked, it's the initial ref that is |
| // unreffed. |
| call_error = grpc_call_start_batch_and_execute( |
| glb_policy->lb_calld->lb_call, ops, (size_t)(op - ops), |
| &glb_policy->lb_calld->lb_on_server_status_received); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| } |
| |
| static void lb_on_sent_initial_request_locked(void* arg, grpc_error* error) { |
| glb_lb_call_data* lb_calld = (glb_lb_call_data*)arg; |
| grpc_byte_buffer_destroy(lb_calld->send_message_payload); |
| lb_calld->send_message_payload = nullptr; |
| // If we attempted to send a client load report before the initial request was |
| // sent (and this lb_calld is still in use), send the load report now. |
| if (lb_calld->client_load_report_is_due && |
| lb_calld == lb_calld->glb_policy->lb_calld) { |
| send_client_load_report_locked(lb_calld); |
| lb_calld->client_load_report_is_due = false; |
| } |
| glb_lb_call_data_unref(lb_calld, "lb_on_sent_initial_request_locked"); |
| } |
| |
| static void lb_on_response_received_locked(void* arg, grpc_error* error) { |
| glb_lb_call_data* lb_calld = (glb_lb_call_data*)arg; |
| glb_lb_policy* glb_policy = lb_calld->glb_policy; |
| // Empty payload means the LB call was cancelled. |
| if (lb_calld != glb_policy->lb_calld || |
| lb_calld->recv_message_payload == nullptr) { |
| glb_lb_call_data_unref(lb_calld, "lb_on_response_received_locked"); |
| return; |
| } |
| grpc_op ops[2]; |
| memset(ops, 0, sizeof(ops)); |
| grpc_op* op = ops; |
| glb_policy->lb_call_backoff->Reset(); |
| grpc_byte_buffer_reader bbr; |
| grpc_byte_buffer_reader_init(&bbr, lb_calld->recv_message_payload); |
| grpc_slice response_slice = grpc_byte_buffer_reader_readall(&bbr); |
| grpc_byte_buffer_reader_destroy(&bbr); |
| grpc_byte_buffer_destroy(lb_calld->recv_message_payload); |
| lb_calld->recv_message_payload = nullptr; |
| grpc_grpclb_initial_response* initial_response; |
| grpc_grpclb_serverlist* serverlist; |
| if (!lb_calld->seen_initial_response && |
| (initial_response = grpc_grpclb_initial_response_parse(response_slice)) != |
| nullptr) { |
| // Have NOT seen initial response, look for initial response. |
| if (initial_response->has_client_stats_report_interval) { |
| lb_calld->client_stats_report_interval = GPR_MAX( |
| GPR_MS_PER_SEC, grpc_grpclb_duration_to_millis( |
| &initial_response->client_stats_report_interval)); |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Received initial LB response message; " |
| "client load reporting interval = %" PRIdPTR " milliseconds", |
| glb_policy, lb_calld->client_stats_report_interval); |
| } |
| } else if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Received initial LB response message; client load " |
| "reporting NOT enabled", |
| glb_policy); |
| } |
| grpc_grpclb_initial_response_destroy(initial_response); |
| lb_calld->seen_initial_response = true; |
| } else if ((serverlist = grpc_grpclb_response_parse_serverlist( |
| response_slice)) != nullptr) { |
| // Have seen initial response, look for serverlist. |
| GPR_ASSERT(lb_calld->lb_call != nullptr); |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Serverlist with %" PRIuPTR " servers received", |
| glb_policy, serverlist->num_servers); |
| for (size_t i = 0; i < serverlist->num_servers; ++i) { |
| grpc_resolved_address addr; |
| parse_server(serverlist->servers[i], &addr); |
| char* ipport; |
| grpc_sockaddr_to_string(&ipport, &addr, false); |
| gpr_log(GPR_INFO, "[grpclb %p] Serverlist[%" PRIuPTR "]: %s", |
| glb_policy, i, ipport); |
| gpr_free(ipport); |
| } |
| } |
| /* update serverlist */ |
| if (serverlist->num_servers > 0) { |
| // Start sending client load report only after we start using the |
| // serverlist returned from the current LB call. |
| if (lb_calld->client_stats_report_interval > 0 && |
| lb_calld->client_stats == nullptr) { |
| lb_calld->client_stats = grpc_grpclb_client_stats_create(); |
| glb_lb_call_data_ref(lb_calld, "client_load_report"); |
| schedule_next_client_load_report(lb_calld); |
| } |
| if (grpc_grpclb_serverlist_equals(glb_policy->serverlist, serverlist)) { |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Incoming server list identical to current, " |
| "ignoring.", |
| glb_policy); |
| } |
| grpc_grpclb_destroy_serverlist(serverlist); |
| } else { /* new serverlist */ |
| if (glb_policy->serverlist != nullptr) { |
| /* dispose of the old serverlist */ |
| grpc_grpclb_destroy_serverlist(glb_policy->serverlist); |
| } else { |
| /* or dispose of the fallback */ |
| grpc_lb_addresses_destroy(glb_policy->fallback_backend_addresses); |
| glb_policy->fallback_backend_addresses = nullptr; |
| if (glb_policy->fallback_timer_callback_pending) { |
| grpc_timer_cancel(&glb_policy->lb_fallback_timer); |
| glb_policy->fallback_timer_callback_pending = false; |
| } |
| } |
| /* and update the copy in the glb_lb_policy instance. This |
| * serverlist instance will be destroyed either upon the next |
| * update or in glb_destroy() */ |
| glb_policy->serverlist = serverlist; |
| glb_policy->serverlist_index = 0; |
| rr_handover_locked(glb_policy); |
| } |
| } else { |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, "[grpclb %p] Received empty server list, ignoring.", |
| glb_policy); |
| } |
| grpc_grpclb_destroy_serverlist(serverlist); |
| } |
| } else { |
| // No valid initial response or serverlist found. |
| gpr_log(GPR_ERROR, |
| "[grpclb %p] Invalid LB response received: '%s'. Ignoring.", |
| glb_policy, |
| grpc_dump_slice(response_slice, GPR_DUMP_ASCII | GPR_DUMP_HEX)); |
| } |
| grpc_slice_unref_internal(response_slice); |
| if (!glb_policy->shutting_down) { |
| // Keep listening for serverlist updates. |
| op->op = GRPC_OP_RECV_MESSAGE; |
| op->data.recv_message.recv_message = &lb_calld->recv_message_payload; |
| op->flags = 0; |
| op->reserved = nullptr; |
| op++; |
| // Reuse the "lb_on_response_received_locked" ref taken in |
| // query_for_backends_locked(). |
| const grpc_call_error call_error = grpc_call_start_batch_and_execute( |
| lb_calld->lb_call, ops, (size_t)(op - ops), |
| &lb_calld->lb_on_response_received); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| } else { |
| glb_lb_call_data_unref(lb_calld, |
| "lb_on_response_received_locked+glb_shutdown"); |
| } |
| } |
| |
| static void lb_on_server_status_received_locked(void* arg, grpc_error* error) { |
| glb_lb_call_data* lb_calld = (glb_lb_call_data*)arg; |
| glb_lb_policy* glb_policy = lb_calld->glb_policy; |
| GPR_ASSERT(lb_calld->lb_call != nullptr); |
| if (grpc_lb_glb_trace.enabled()) { |
| char* status_details = |
| grpc_slice_to_c_string(lb_calld->lb_call_status_details); |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Status from LB server received. Status = %d, details " |
| "= '%s', (lb_calld: %p, lb_call: %p), error '%s'", |
| lb_calld->glb_policy, lb_calld->lb_call_status, status_details, |
| lb_calld, lb_calld->lb_call, grpc_error_string(error)); |
| gpr_free(status_details); |
| } |
| grpc_lb_policy_try_reresolve(&glb_policy->base, &grpc_lb_glb_trace, |
| GRPC_ERROR_NONE); |
| // If this lb_calld is still in use, this call ended because of a failure so |
| // we want to retry connecting. Otherwise, we have deliberately ended this |
| // call and no further action is required. |
| if (lb_calld == glb_policy->lb_calld) { |
| glb_policy->lb_calld = nullptr; |
| if (lb_calld->client_load_report_timer_callback_pending) { |
| grpc_timer_cancel(&lb_calld->client_load_report_timer); |
| } |
| GPR_ASSERT(!glb_policy->shutting_down); |
| if (lb_calld->seen_initial_response) { |
| // If we lose connection to the LB server, reset the backoff and restart |
| // the LB call immediately. |
| glb_policy->lb_call_backoff->Reset(); |
| query_for_backends_locked(glb_policy); |
| } else { |
| // If this LB call fails establishing any connection to the LB server, |
| // retry later. |
| start_lb_call_retry_timer_locked(glb_policy); |
| } |
| } |
| glb_lb_call_data_unref(lb_calld, "lb_call_ended"); |
| } |
| |
| static void lb_on_fallback_timer_locked(void* arg, grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)arg; |
| glb_policy->fallback_timer_callback_pending = false; |
| /* If we receive a serverlist after the timer fires but before this callback |
| * actually runs, don't fall back. */ |
| if (glb_policy->serverlist == nullptr && !glb_policy->shutting_down && |
| error == GRPC_ERROR_NONE) { |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Falling back to use backends from resolver", |
| glb_policy); |
| } |
| GPR_ASSERT(glb_policy->fallback_backend_addresses != nullptr); |
| rr_handover_locked(glb_policy); |
| } |
| GRPC_LB_POLICY_UNREF(&glb_policy->base, "grpclb_fallback_timer"); |
| } |
| |
| static void fallback_update_locked(glb_lb_policy* glb_policy, |
| const grpc_lb_addresses* addresses) { |
| GPR_ASSERT(glb_policy->fallback_backend_addresses != nullptr); |
| grpc_lb_addresses_destroy(glb_policy->fallback_backend_addresses); |
| glb_policy->fallback_backend_addresses = |
| extract_backend_addresses_locked(addresses); |
| if (glb_policy->lb_fallback_timeout_ms > 0 && |
| glb_policy->rr_policy != nullptr) { |
| rr_handover_locked(glb_policy); |
| } |
| } |
| |
| static void glb_update_locked(grpc_lb_policy* policy, |
| const grpc_lb_policy_args* args) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)policy; |
| const grpc_arg* arg = |
| grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES); |
| if (arg == nullptr || arg->type != GRPC_ARG_POINTER) { |
| if (glb_policy->lb_channel == nullptr) { |
| // If we don't have a current channel to the LB, go into TRANSIENT |
| // FAILURE. |
| grpc_connectivity_state_set( |
| &glb_policy->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE, |
| GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing update in args"), |
| "glb_update_missing"); |
| } else { |
| // otherwise, keep using the current LB channel (ignore this update). |
| gpr_log( |
| GPR_ERROR, |
| "[grpclb %p] No valid LB addresses channel arg in update, ignoring.", |
| glb_policy); |
| } |
| return; |
| } |
| const grpc_lb_addresses* addresses = |
| (const grpc_lb_addresses*)arg->value.pointer.p; |
| // If a non-empty serverlist hasn't been received from the balancer, |
| // propagate the update to fallback_backend_addresses. |
| if (glb_policy->serverlist == nullptr) { |
| fallback_update_locked(glb_policy, addresses); |
| } |
| GPR_ASSERT(glb_policy->lb_channel != nullptr); |
| // Propagate updates to the LB channel (pick_first) through the fake |
| // resolver. |
| grpc_channel_args* lb_channel_args = build_lb_channel_args( |
| addresses, glb_policy->response_generator, args->args); |
| grpc_fake_resolver_response_generator_set_response( |
| glb_policy->response_generator, lb_channel_args); |
| grpc_channel_args_destroy(lb_channel_args); |
| // Start watching the LB channel connectivity for connection, if not |
| // already doing so. |
| if (!glb_policy->watching_lb_channel) { |
| glb_policy->lb_channel_connectivity = grpc_channel_check_connectivity_state( |
| glb_policy->lb_channel, true /* try to connect */); |
| grpc_channel_element* client_channel_elem = grpc_channel_stack_last_element( |
| grpc_channel_get_channel_stack(glb_policy->lb_channel)); |
| GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter); |
| glb_policy->watching_lb_channel = true; |
| GRPC_LB_POLICY_REF(&glb_policy->base, "watch_lb_channel_connectivity"); |
| grpc_client_channel_watch_connectivity_state( |
| client_channel_elem, |
| grpc_polling_entity_create_from_pollset_set( |
| glb_policy->base.interested_parties), |
| &glb_policy->lb_channel_connectivity, |
| &glb_policy->lb_channel_on_connectivity_changed, nullptr); |
| } |
| } |
| |
| // Invoked as part of the update process. It continues watching the LB channel |
| // until it shuts down or becomes READY. It's invoked even if the LB channel |
| // stayed READY throughout the update (for example if the update is identical). |
| static void glb_lb_channel_on_connectivity_changed_cb(void* arg, |
| grpc_error* error) { |
| glb_lb_policy* glb_policy = (glb_lb_policy*)arg; |
| if (glb_policy->shutting_down) goto done; |
| // Re-initialize the lb_call. This should also take care of updating the |
| // embedded RR policy. Note that the current RR policy, if any, will stay in |
| // effect until an update from the new lb_call is received. |
| switch (glb_policy->lb_channel_connectivity) { |
| case GRPC_CHANNEL_CONNECTING: |
| case GRPC_CHANNEL_TRANSIENT_FAILURE: { |
| // Keep watching the LB channel. |
| grpc_channel_element* client_channel_elem = |
| grpc_channel_stack_last_element( |
| grpc_channel_get_channel_stack(glb_policy->lb_channel)); |
| GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter); |
| grpc_client_channel_watch_connectivity_state( |
| client_channel_elem, |
| grpc_polling_entity_create_from_pollset_set( |
| glb_policy->base.interested_parties), |
| &glb_policy->lb_channel_connectivity, |
| &glb_policy->lb_channel_on_connectivity_changed, nullptr); |
| break; |
| } |
| // The LB channel may be IDLE because it's shut down before the update. |
| // Restart the LB call to kick the LB channel into gear. |
| case GRPC_CHANNEL_IDLE: |
| case GRPC_CHANNEL_READY: |
| if (glb_policy->lb_calld != nullptr) { |
| lb_call_data_shutdown(glb_policy); |
| } |
| if (glb_policy->started_picking) { |
| if (glb_policy->retry_timer_callback_pending) { |
| grpc_timer_cancel(&glb_policy->lb_call_retry_timer); |
| } |
| glb_policy->lb_call_backoff->Reset(); |
| query_for_backends_locked(glb_policy); |
| } |
| // Fall through. |
| case GRPC_CHANNEL_SHUTDOWN: |
| done: |
| glb_policy->watching_lb_channel = false; |
| GRPC_LB_POLICY_UNREF(&glb_policy->base, |
| "watch_lb_channel_connectivity_cb_shutdown"); |
| } |
| } |
| |
| /* Code wiring the policy with the rest of the core */ |
| static const grpc_lb_policy_vtable glb_lb_policy_vtable = { |
| glb_destroy, |
| glb_shutdown_locked, |
| glb_pick_locked, |
| glb_cancel_pick_locked, |
| glb_cancel_picks_locked, |
| glb_ping_one_locked, |
| glb_exit_idle_locked, |
| glb_check_connectivity_locked, |
| glb_notify_on_state_change_locked, |
| glb_update_locked}; |
| |
| static grpc_lb_policy* glb_create(grpc_lb_policy_factory* factory, |
| grpc_lb_policy_args* args) { |
| /* Count the number of gRPC-LB addresses. There must be at least one. */ |
| const grpc_arg* arg = |
| grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES); |
| if (arg == nullptr || arg->type != GRPC_ARG_POINTER) { |
| return nullptr; |
| } |
| grpc_lb_addresses* addresses = (grpc_lb_addresses*)arg->value.pointer.p; |
| size_t num_grpclb_addrs = 0; |
| for (size_t i = 0; i < addresses->num_addresses; ++i) { |
| if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs; |
| } |
| if (num_grpclb_addrs == 0) return nullptr; |
| |
| glb_lb_policy* glb_policy = (glb_lb_policy*)gpr_zalloc(sizeof(*glb_policy)); |
| |
| /* Get server name. */ |
| arg = grpc_channel_args_find(args->args, GRPC_ARG_SERVER_URI); |
| GPR_ASSERT(arg != nullptr); |
| GPR_ASSERT(arg->type == GRPC_ARG_STRING); |
| grpc_uri* uri = grpc_uri_parse(arg->value.string, true); |
| GPR_ASSERT(uri->path[0] != '\0'); |
| glb_policy->server_name = |
| gpr_strdup(uri->path[0] == '/' ? uri->path + 1 : uri->path); |
| if (grpc_lb_glb_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "[grpclb %p] Will use '%s' as the server name for LB request.", |
| glb_policy, glb_policy->server_name); |
| } |
| grpc_uri_destroy(uri); |
| |
| glb_policy->cc_factory = args->client_channel_factory; |
| GPR_ASSERT(glb_policy->cc_factory != nullptr); |
| |
| arg = grpc_channel_args_find(args->args, GRPC_ARG_GRPCLB_CALL_TIMEOUT_MS); |
| glb_policy->lb_call_timeout_ms = |
| grpc_channel_arg_get_integer(arg, {0, 0, INT_MAX}); |
| |
| arg = grpc_channel_args_find(args->args, GRPC_ARG_GRPCLB_FALLBACK_TIMEOUT_MS); |
| glb_policy->lb_fallback_timeout_ms = grpc_channel_arg_get_integer( |
| arg, {GRPC_GRPCLB_DEFAULT_FALLBACK_TIMEOUT_MS, 0, INT_MAX}); |
| |
| // Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args, |
| // since we use this to trigger the client_load_reporting filter. |
| grpc_arg new_arg = grpc_channel_arg_string_create( |
| (char*)GRPC_ARG_LB_POLICY_NAME, (char*)"grpclb"); |
| static const char* args_to_remove[] = {GRPC_ARG_LB_POLICY_NAME}; |
| glb_policy->args = grpc_channel_args_copy_and_add_and_remove( |
| args->args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1); |
| |
| /* Extract the backend addresses (may be empty) from the resolver for |
| * fallback. */ |
| glb_policy->fallback_backend_addresses = |
| extract_backend_addresses_locked(addresses); |
| |
| /* Create a client channel over them to communicate with a LB service */ |
| glb_policy->response_generator = |
| grpc_fake_resolver_response_generator_create(); |
| grpc_channel_args* lb_channel_args = build_lb_channel_args( |
| addresses, glb_policy->response_generator, args->args); |
| char* uri_str; |
| gpr_asprintf(&uri_str, "fake:///%s", glb_policy->server_name); |
| glb_policy->lb_channel = grpc_lb_policy_grpclb_create_lb_channel( |
| uri_str, args->client_channel_factory, lb_channel_args); |
| |
| /* Propagate initial resolution */ |
| grpc_fake_resolver_response_generator_set_response( |
| glb_policy->response_generator, lb_channel_args); |
| grpc_channel_args_destroy(lb_channel_args); |
| gpr_free(uri_str); |
| if (glb_policy->lb_channel == nullptr) { |
| gpr_free((void*)glb_policy->server_name); |
| grpc_channel_args_destroy(glb_policy->args); |
| gpr_free(glb_policy); |
| return nullptr; |
| } |
| grpc_subchannel_index_ref(); |
| GRPC_CLOSURE_INIT(&glb_policy->rr_on_connectivity_changed, |
| rr_on_connectivity_changed_locked, glb_policy, |
| grpc_combiner_scheduler(args->combiner)); |
| GRPC_CLOSURE_INIT(&glb_policy->rr_on_reresolution_requested, |
| rr_on_reresolution_requested_locked, glb_policy, |
| grpc_combiner_scheduler(args->combiner)); |
| GRPC_CLOSURE_INIT(&glb_policy->lb_channel_on_connectivity_changed, |
| glb_lb_channel_on_connectivity_changed_cb, glb_policy, |
| grpc_combiner_scheduler(args->combiner)); |
| grpc_lb_policy_init(&glb_policy->base, &glb_lb_policy_vtable, args->combiner); |
| grpc_connectivity_state_init(&glb_policy->state_tracker, GRPC_CHANNEL_IDLE, |
| "grpclb"); |
| // Init LB call backoff option. |
| grpc_core::BackOff::Options backoff_options; |
| backoff_options |
| .set_initial_backoff(GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS * 1000) |
| .set_multiplier(GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER) |
| .set_jitter(GRPC_GRPCLB_RECONNECT_JITTER) |
| .set_max_backoff(GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS * 1000); |
| glb_policy->lb_call_backoff.Init(backoff_options); |
| return &glb_policy->base; |
| } |
| |
| static void glb_factory_ref(grpc_lb_policy_factory* factory) {} |
| |
| static void glb_factory_unref(grpc_lb_policy_factory* factory) {} |
| |
| static const grpc_lb_policy_factory_vtable glb_factory_vtable = { |
| glb_factory_ref, glb_factory_unref, glb_create, "grpclb"}; |
| |
| static grpc_lb_policy_factory glb_lb_policy_factory = {&glb_factory_vtable}; |
| |
| grpc_lb_policy_factory* grpc_glb_lb_factory_create() { |
| return &glb_lb_policy_factory; |
| } |
| |
| /* Plugin registration */ |
| |
| // Only add client_load_reporting filter if the grpclb LB policy is used. |
| static bool maybe_add_client_load_reporting_filter( |
| grpc_channel_stack_builder* builder, void* arg) { |
| const grpc_channel_args* args = |
| grpc_channel_stack_builder_get_channel_arguments(builder); |
| const grpc_arg* channel_arg = |
| grpc_channel_args_find(args, GRPC_ARG_LB_POLICY_NAME); |
| if (channel_arg != nullptr && channel_arg->type == GRPC_ARG_STRING && |
| strcmp(channel_arg->value.string, "grpclb") == 0) { |
| return grpc_channel_stack_builder_append_filter( |
| builder, (const grpc_channel_filter*)arg, nullptr, nullptr); |
| } |
| return true; |
| } |
| |
| void grpc_lb_policy_grpclb_init() { |
| grpc_register_lb_policy(grpc_glb_lb_factory_create()); |
| grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL, |
| GRPC_CHANNEL_INIT_BUILTIN_PRIORITY, |
| maybe_add_client_load_reporting_filter, |
| (void*)&grpc_client_load_reporting_filter); |
| } |
| |
| void grpc_lb_policy_grpclb_shutdown() {} |