| /* |
| * |
| * Copyright 2016, Google Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| /** 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 |
| * glb_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 <errno.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/client_channel/client_channel.h" |
| #include "src/core/ext/client_channel/client_channel_factory.h" |
| #include "src/core/ext/client_channel/lb_policy_factory.h" |
| #include "src/core/ext/client_channel/lb_policy_registry.h" |
| #include "src/core/ext/client_channel/parse_address.h" |
| #include "src/core/ext/lb_policy/grpclb/grpclb.h" |
| #include "src/core/ext/lb_policy/grpclb/load_balancer_api.h" |
| #include "src/core/lib/channel/channel_args.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_internal.h" |
| #include "src/core/lib/slice/slice_string_helpers.h" |
| #include "src/core/lib/support/backoff.h" |
| #include "src/core/lib/support/string.h" |
| #include "src/core/lib/surface/call.h" |
| #include "src/core/lib/surface/channel.h" |
| #include "src/core/lib/transport/static_metadata.h" |
| |
| #define GRPC_GRPCLB_MIN_CONNECT_TIMEOUT_SECONDS 20 |
| #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 |
| |
| int grpc_lb_glb_trace = 0; |
| |
| /* add lb_token of selected subchannel (address) to the call's initial |
| * metadata */ |
| static void 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 != NULL); |
| GPR_ASSERT(lb_token != NULL); |
| grpc_metadata_batch_add_tail(initial_metadata, lb_token_mdelem_storage, |
| lb_token); |
| } |
| |
| typedef struct wrapped_rr_closure_arg { |
| /* the closure instance using this struct as argument */ |
| grpc_closure wrapper_closure; |
| |
| /* the original closure. Usually a on_complete/notify cb for pick() and ping() |
| * calls against the internal RR instance, respectively. */ |
| grpc_closure *wrapped_closure; |
| |
| /* the pick's initial metadata, kept in order to append the LB token for the |
| * pick */ |
| grpc_metadata_batch *initial_metadata; |
| |
| /* the picked target, used to determine which LB token to add to the pick's |
| * initial metadata */ |
| grpc_connected_subchannel **target; |
| |
| /* the LB token associated with the pick */ |
| grpc_mdelem *lb_token; |
| |
| /* storage for the lb token initial metadata mdelem */ |
| grpc_linked_mdelem *lb_token_mdelem_storage; |
| |
| /* The RR instance related to the closure */ |
| grpc_lb_policy *rr_policy; |
| |
| /* heap memory to be freed upon closure execution. */ |
| void *free_when_done; |
| } wrapped_rr_closure_arg; |
| |
| /* 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 wrapped_rr_closure(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error) { |
| wrapped_rr_closure_arg *wc_arg = arg; |
| |
| GPR_ASSERT(wc_arg->wrapped_closure != NULL); |
| grpc_closure_sched(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_REF(error)); |
| |
| if (wc_arg->rr_policy != NULL) { |
| /* if *target is NULL, no pick has been made by the RR policy (eg, all |
| * addresses failed to connect). There won't be any user_data/token |
| * available */ |
| if (*wc_arg->target != NULL) { |
| if (wc_arg->lb_token != NULL) { |
| initial_metadata_add_lb_token(wc_arg->initial_metadata, |
| wc_arg->lb_token_mdelem_storage, |
| GRPC_MDELEM_REF(wc_arg->lb_token)); |
| } else { |
| gpr_log(GPR_ERROR, |
| "No LB token for connected subchannel pick %p (from RR " |
| "instance %p).", |
| (void *)*wc_arg->target, (void *)wc_arg->rr_policy); |
| abort(); |
| } |
| } |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Unreffing RR %p", (void *)wc_arg->rr_policy); |
| } |
| GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "wrapped_rr_closure"); |
| } |
| GPR_ASSERT(wc_arg->free_when_done != NULL); |
| gpr_free(wc_arg->free_when_done); |
| } |
| |
| /* 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/updated. |
| * |
| * One particularity is the wrapping of the user-provided \a on_complete closure |
| * (in \a wrapped_on_complete and \a wrapped_on_complete_arg). This is needed in |
| * order to correctly unref the RR policy instance upon completion of the pick. |
| * See \a wrapped_rr_closure for details. */ |
| typedef struct pending_pick { |
| struct pending_pick *next; |
| |
| /* original pick()'s arguments */ |
| grpc_lb_policy_pick_args pick_args; |
| |
| /* output argument where to store the pick()ed connected subchannel, or NULL |
| * upon error. */ |
| grpc_connected_subchannel **target; |
| |
| /* args for wrapped_on_complete */ |
| wrapped_rr_closure_arg wrapped_on_complete_arg; |
| } pending_pick; |
| |
| static void add_pending_pick(pending_pick **root, |
| const grpc_lb_policy_pick_args *pick_args, |
| grpc_connected_subchannel **target, |
| grpc_closure *on_complete) { |
| pending_pick *pp = gpr_malloc(sizeof(*pp)); |
| memset(pp, 0, sizeof(pending_pick)); |
| memset(&pp->wrapped_on_complete_arg, 0, sizeof(wrapped_rr_closure_arg)); |
| pp->next = *root; |
| pp->pick_args = *pick_args; |
| pp->target = target; |
| pp->wrapped_on_complete_arg.wrapped_closure = on_complete; |
| pp->wrapped_on_complete_arg.target = target; |
| pp->wrapped_on_complete_arg.initial_metadata = pick_args->initial_metadata; |
| pp->wrapped_on_complete_arg.lb_token_mdelem_storage = |
| pick_args->lb_token_mdelem_storage; |
| pp->wrapped_on_complete_arg.free_when_done = pp; |
| grpc_closure_init(&pp->wrapped_on_complete_arg.wrapper_closure, |
| wrapped_rr_closure, &pp->wrapped_on_complete_arg, |
| grpc_schedule_on_exec_ctx); |
| *root = pp; |
| } |
| |
| /* Same as the \a pending_pick struct but for ping operations */ |
| typedef struct pending_ping { |
| struct pending_ping *next; |
| |
| /* args for wrapped_notify */ |
| wrapped_rr_closure_arg wrapped_notify_arg; |
| } pending_ping; |
| |
| static void add_pending_ping(pending_ping **root, grpc_closure *notify) { |
| pending_ping *pping = gpr_malloc(sizeof(*pping)); |
| memset(pping, 0, sizeof(pending_ping)); |
| memset(&pping->wrapped_notify_arg, 0, sizeof(wrapped_rr_closure_arg)); |
| pping->wrapped_notify_arg.wrapped_closure = notify; |
| pping->wrapped_notify_arg.free_when_done = pping; |
| pping->next = *root; |
| grpc_closure_init(&pping->wrapped_notify_arg.wrapper_closure, |
| wrapped_rr_closure, &pping->wrapped_notify_arg, |
| grpc_schedule_on_exec_ctx); |
| *root = pping; |
| } |
| |
| /* |
| * glb_lb_policy |
| */ |
| typedef struct rr_connectivity_data rr_connectivity_data; |
| static const grpc_lb_policy_vtable glb_lb_policy_vtable; |
| typedef struct glb_lb_policy { |
| /** base policy: must be first */ |
| grpc_lb_policy base; |
| |
| /** mutex protecting remaining members */ |
| gpr_mu mu; |
| |
| /** who the client is trying to communicate with */ |
| const char *server_name; |
| grpc_client_channel_factory *cc_factory; |
| grpc_channel_args *args; |
| |
| /** deadline for the LB's call */ |
| gpr_timespec deadline; |
| |
| /** for communicating with the LB server */ |
| grpc_channel *lb_channel; |
| |
| /** the RR policy to use of the backend servers returned by the LB server */ |
| grpc_lb_policy *rr_policy; |
| |
| bool started_picking; |
| |
| /** our connectivity state tracker */ |
| grpc_connectivity_state_tracker state_tracker; |
| |
| /** stores the deserialized response from the LB. May be NULL until one such |
| * response has arrived. */ |
| grpc_grpclb_serverlist *serverlist; |
| |
| /** 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; |
| |
| /************************************************************/ |
| /* client data associated with the LB server communication */ |
| /************************************************************/ |
| /* Status from the LB server has been received. This signals the end of the LB |
| * call. */ |
| grpc_closure lb_on_server_status_received; |
| |
| /* A response from the LB server has been received. Process it */ |
| grpc_closure lb_on_response_received; |
| |
| /* LB call retry timer callback. */ |
| grpc_closure lb_on_call_retry; |
| |
| grpc_call *lb_call; /* streaming call to the LB server, */ |
| |
| grpc_metadata_array lb_initial_metadata_recv; /* initial MD from LB server */ |
| grpc_metadata_array |
| lb_trailing_metadata_recv; /* trailing MD from LB server */ |
| |
| /* what's being sent to the LB server. Note that its value may vary if the LB |
| * server indicates a redirect. */ |
| grpc_byte_buffer *lb_request_payload; |
| |
| /* response the LB server, if any. Processed in lb_on_response_received() */ |
| grpc_byte_buffer *lb_response_payload; |
| |
| /* call status code and details, set in lb_on_server_status_received() */ |
| grpc_status_code lb_call_status; |
| char *lb_call_status_details; |
| size_t lb_call_status_details_capacity; |
| |
| /** LB call retry backoff state */ |
| gpr_backoff lb_call_backoff_state; |
| |
| /** LB call retry timer */ |
| grpc_timer lb_call_retry_timer; |
| } glb_lb_policy; |
| |
| /* Keeps track and reacts to changes in connectivity of the RR instance */ |
| struct rr_connectivity_data { |
| grpc_closure on_change; |
| grpc_connectivity_state state; |
| glb_lb_policy *glb_policy; |
| }; |
| |
| static bool is_server_valid(const grpc_grpclb_server *server, size_t idx, |
| bool log) { |
| 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 == NULL ? NULL : GRPC_MDELEM_REF(token); |
| } |
| static void lb_token_destroy(grpc_exec_ctx *exec_ctx, void *token) { |
| if (token != NULL) GRPC_MDELEM_UNREF(exec_ctx, 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) { |
| 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; |
| memset(addr, 0, sizeof(*addr)); |
| 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( |
| grpc_exec_ctx *exec_ctx, 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; |
| } |
| if (num_valid == 0) return NULL; |
| |
| 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) { |
| GPR_ASSERT(addr_idx < num_valid); |
| const grpc_grpclb_server *server = serverlist->servers[sl_idx]; |
| if (!is_server_valid(serverlist->servers[sl_idx], sl_idx, false)) continue; |
| |
| /* 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_mdstr *lb_token_mdstr = grpc_mdstr_from_buffer( |
| (uint8_t *)server->load_balance_token, lb_token_length); |
| user_data = grpc_mdelem_from_metadata_strings( |
| exec_ctx, GRPC_MDSTR_LB_TOKEN, lb_token_mdstr); |
| } 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 = GRPC_MDELEM_LB_TOKEN_EMPTY; |
| } |
| |
| grpc_lb_addresses_set_address(lb_addresses, addr_idx, &addr.addr, addr.len, |
| false /* is_balancer */, |
| NULL /* balancer_name */, user_data); |
| ++addr_idx; |
| } |
| GPR_ASSERT(addr_idx == num_valid); |
| return lb_addresses; |
| } |
| |
| /* returns true if the new RR policy should replace the current one, if any */ |
| static bool update_lb_connectivity_status_locked( |
| grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy, |
| grpc_connectivity_state new_rr_state, grpc_error *new_rr_state_error) { |
| grpc_error *curr_state_error; |
| const grpc_connectivity_state curr_glb_state = grpc_connectivity_state_check( |
| &glb_policy->state_tracker, &curr_state_error); |
| |
| /* 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 (new_rr_state) { |
| case GRPC_CHANNEL_TRANSIENT_FAILURE: |
| case GRPC_CHANNEL_SHUTDOWN: |
| GPR_ASSERT(new_rr_state_error != GRPC_ERROR_NONE); |
| return false; /* don't replace the RR policy */ |
| case GRPC_CHANNEL_INIT: |
| case GRPC_CHANNEL_IDLE: |
| case GRPC_CHANNEL_CONNECTING: |
| case GRPC_CHANNEL_READY: |
| GPR_ASSERT(new_rr_state_error == GRPC_ERROR_NONE); |
| } |
| |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, |
| "Setting grpclb's state to %s from new RR policy %p state.", |
| grpc_connectivity_state_name(new_rr_state), |
| (void *)glb_policy->rr_policy); |
| } |
| grpc_connectivity_state_set(exec_ctx, &glb_policy->state_tracker, |
| new_rr_state, GRPC_ERROR_REF(new_rr_state_error), |
| "update_lb_connectivity_status_locked"); |
| return true; |
| } |
| |
| /* perform a pick over \a rr_policy. Given that a pick can return immediately |
| * (ignoring its completion callback) we need to perform the cleanups this |
| * callback would be otherwise resposible for */ |
| static bool pick_from_internal_rr_locked( |
| grpc_exec_ctx *exec_ctx, grpc_lb_policy *rr_policy, |
| const grpc_lb_policy_pick_args *pick_args, |
| grpc_connected_subchannel **target, wrapped_rr_closure_arg *wc_arg) { |
| GPR_ASSERT(rr_policy != NULL); |
| const bool pick_done = |
| grpc_lb_policy_pick(exec_ctx, rr_policy, pick_args, target, |
| (void **)&wc_arg->lb_token, &wc_arg->wrapper_closure); |
| if (pick_done) { |
| /* synchronous grpc_lb_policy_pick call. Unref the RR policy. */ |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Unreffing RR (0x%" PRIxPTR ")", |
| (intptr_t)wc_arg->rr_policy); |
| } |
| GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync"); |
| |
| /* add the load reporting initial metadata */ |
| initial_metadata_add_lb_token(pick_args->initial_metadata, |
| pick_args->lb_token_mdelem_storage, |
| GRPC_MDELEM_REF(wc_arg->lb_token)); |
| |
| gpr_free(wc_arg); |
| } |
| /* 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 *create_rr_locked( |
| grpc_exec_ctx *exec_ctx, const grpc_grpclb_serverlist *serverlist, |
| glb_lb_policy *glb_policy) { |
| GPR_ASSERT(serverlist != NULL && serverlist->num_servers > 0); |
| |
| grpc_lb_policy_args args; |
| memset(&args, 0, sizeof(args)); |
| args.client_channel_factory = glb_policy->cc_factory; |
| grpc_lb_addresses *addresses = |
| process_serverlist_locked(exec_ctx, serverlist); |
| |
| // 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_policy *rr = grpc_lb_policy_create(exec_ctx, "round_robin", &args); |
| GPR_ASSERT(rr != NULL); |
| grpc_lb_addresses_destroy(exec_ctx, addresses); |
| grpc_channel_args_destroy(exec_ctx, args.args); |
| return rr; |
| } |
| |
| static void glb_rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error); |
| /* glb_policy->rr_policy may be NULL (initial handover) */ |
| static void rr_handover_locked(grpc_exec_ctx *exec_ctx, |
| glb_lb_policy *glb_policy) { |
| GPR_ASSERT(glb_policy->serverlist != NULL && |
| glb_policy->serverlist->num_servers > 0); |
| |
| if (glb_policy->shutting_down) return; |
| |
| grpc_lb_policy *new_rr_policy = |
| create_rr_locked(exec_ctx, glb_policy->serverlist, glb_policy); |
| if (new_rr_policy == NULL) { |
| gpr_log(GPR_ERROR, |
| "Failure creating a RoundRobin policy for serverlist update with " |
| "%lu entries. The previous RR instance (%p), if any, will continue " |
| "to be used. Future updates from the LB will attempt to create new " |
| "instances.", |
| (unsigned long)glb_policy->serverlist->num_servers, |
| (void *)glb_policy->rr_policy); |
| return; |
| } |
| |
| grpc_error *new_rr_state_error = NULL; |
| const grpc_connectivity_state new_rr_state = |
| grpc_lb_policy_check_connectivity(exec_ctx, new_rr_policy, |
| &new_rr_state_error); |
| /* Connectivity state is a function of the new RR policy just created */ |
| const bool replace_old_rr = update_lb_connectivity_status_locked( |
| exec_ctx, glb_policy, new_rr_state, new_rr_state_error); |
| |
| if (!replace_old_rr) { |
| /* dispose of the new RR policy that won't be used after all */ |
| GRPC_LB_POLICY_UNREF(exec_ctx, new_rr_policy, "rr_handover_no_replace"); |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, |
| "Keeping old RR policy (%p) despite new serverlist: new RR " |
| "policy was in %s connectivity state.", |
| (void *)glb_policy->rr_policy, |
| grpc_connectivity_state_name(new_rr_state)); |
| } |
| return; |
| } |
| |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Created RR policy (%p) to replace old RR (%p)", |
| (void *)new_rr_policy, (void *)glb_policy->rr_policy); |
| } |
| |
| if (glb_policy->rr_policy != NULL) { |
| /* if we are phasing out an existing RR instance, unref it. */ |
| GRPC_LB_POLICY_UNREF(exec_ctx, glb_policy->rr_policy, "rr_handover"); |
| } |
| |
| /* Finally update the RR policy to the newly created one */ |
| glb_policy->rr_policy = new_rr_policy; |
| |
| /* 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(exec_ctx, |
| glb_policy->rr_policy->interested_parties, |
| glb_policy->base.interested_parties); |
| |
| /* Allocate the data for the tracking of the new RR policy's connectivity. |
| * It'll be deallocated in glb_rr_connectivity_changed() */ |
| rr_connectivity_data *rr_connectivity = |
| gpr_malloc(sizeof(rr_connectivity_data)); |
| memset(rr_connectivity, 0, sizeof(rr_connectivity_data)); |
| grpc_closure_init(&rr_connectivity->on_change, glb_rr_connectivity_changed, |
| rr_connectivity, grpc_schedule_on_exec_ctx); |
| rr_connectivity->glb_policy = glb_policy; |
| rr_connectivity->state = new_rr_state; |
| |
| /* Subscribe to changes to the connectivity of the new RR */ |
| GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "rr_connectivity_cb"); |
| grpc_lb_policy_notify_on_state_change(exec_ctx, glb_policy->rr_policy, |
| &rr_connectivity->state, |
| &rr_connectivity->on_change); |
| grpc_lb_policy_exit_idle(exec_ctx, glb_policy->rr_policy); |
| |
| /* Update picks and pings in wait */ |
| pending_pick *pp; |
| while ((pp = glb_policy->pending_picks)) { |
| glb_policy->pending_picks = pp->next; |
| GRPC_LB_POLICY_REF(glb_policy->rr_policy, "rr_handover_pending_pick"); |
| pp->wrapped_on_complete_arg.rr_policy = glb_policy->rr_policy; |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Pending pick about to PICK from 0x%" PRIxPTR "", |
| (intptr_t)glb_policy->rr_policy); |
| } |
| pick_from_internal_rr_locked(exec_ctx, glb_policy->rr_policy, |
| &pp->pick_args, pp->target, |
| &pp->wrapped_on_complete_arg); |
| } |
| |
| pending_ping *pping; |
| while ((pping = glb_policy->pending_pings)) { |
| glb_policy->pending_pings = pping->next; |
| GRPC_LB_POLICY_REF(glb_policy->rr_policy, "rr_handover_pending_ping"); |
| pping->wrapped_notify_arg.rr_policy = glb_policy->rr_policy; |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Pending ping about to PING from 0x%" PRIxPTR "", |
| (intptr_t)glb_policy->rr_policy); |
| } |
| grpc_lb_policy_ping_one(exec_ctx, glb_policy->rr_policy, |
| &pping->wrapped_notify_arg.wrapper_closure); |
| } |
| } |
| |
| static void glb_rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error) { |
| rr_connectivity_data *rr_connectivity = arg; |
| glb_lb_policy *glb_policy = rr_connectivity->glb_policy; |
| |
| gpr_mu_lock(&glb_policy->mu); |
| const bool shutting_down = glb_policy->shutting_down; |
| bool unref_needed = false; |
| GRPC_ERROR_REF(error); |
| |
| if (rr_connectivity->state == GRPC_CHANNEL_SHUTDOWN || shutting_down) { |
| /* RR policy shutting down. Don't renew subscription and free the arg of |
| * this callback. In addition we need to stash away the current policy to |
| * be UNREF'd after releasing the lock. Otherwise, if the UNREF is the last |
| * one, the policy would be destroyed, alongside the lock, which would |
| * result in a use-after-free */ |
| unref_needed = true; |
| gpr_free(rr_connectivity); |
| } else { /* rr state != SHUTDOWN && !shutting down: biz as usual */ |
| update_lb_connectivity_status_locked(exec_ctx, glb_policy, |
| rr_connectivity->state, error); |
| /* Resubscribe. Reuse the "rr_connectivity_cb" weak ref. */ |
| grpc_lb_policy_notify_on_state_change(exec_ctx, glb_policy->rr_policy, |
| &rr_connectivity->state, |
| &rr_connectivity->on_change); |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| if (unref_needed) { |
| GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, |
| "rr_connectivity_cb"); |
| } |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx, |
| grpc_lb_policy_factory *factory, |
| grpc_lb_policy_args *args) { |
| /* Count the number of gRPC-LB addresses. There must be at least one. |
| * TODO(roth): For now, we ignore non-balancer addresses, but in the |
| * future, we may change the behavior such that we fall back to using |
| * the non-balancer addresses if we cannot reach any balancers. At that |
| * time, this should be changed to allow a list with no balancer addresses, |
| * since the resolver might fail to return a balancer address even when |
| * this is the right LB policy to use. */ |
| const grpc_arg *arg = |
| grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES); |
| GPR_ASSERT(arg != NULL && arg->type == GRPC_ARG_POINTER); |
| grpc_lb_addresses *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 NULL; |
| |
| glb_lb_policy *glb_policy = gpr_malloc(sizeof(*glb_policy)); |
| memset(glb_policy, 0, sizeof(*glb_policy)); |
| |
| /* Get server name. */ |
| arg = grpc_channel_args_find(args->args, GRPC_ARG_SERVER_URI); |
| GPR_ASSERT(arg != NULL); |
| 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) { |
| gpr_log(GPR_INFO, "Will use '%s' as the server name for LB request.", |
| glb_policy->server_name); |
| } |
| grpc_uri_destroy(uri); |
| |
| /* All input addresses in 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. |
| * |
| * Create a client channel over them to communicate with a LB service */ |
| glb_policy->cc_factory = args->client_channel_factory; |
| glb_policy->args = grpc_channel_args_copy(args->args); |
| GPR_ASSERT(glb_policy->cc_factory != NULL); |
| |
| /* construct a target from the addresses in args, given in the form |
| * ipvX://ip1:port1,ip2:port2,... |
| * TODO(dgq): support mixed ip version */ |
| char **addr_strs = gpr_malloc(sizeof(char *) * num_grpclb_addrs); |
| size_t addr_index = 0; |
| for (size_t i = 0; i < addresses->num_addresses; i++) { |
| if (addresses->addresses[i].user_data != NULL) { |
| gpr_log(GPR_ERROR, |
| "This LB policy doesn't support user data. It will be ignored"); |
| } |
| if (addresses->addresses[i].is_balancer) { |
| if (addr_index == 0) { |
| addr_strs[addr_index++] = |
| grpc_sockaddr_to_uri(&addresses->addresses[i].address); |
| } else { |
| GPR_ASSERT(grpc_sockaddr_to_string(&addr_strs[addr_index++], |
| &addresses->addresses[i].address, |
| true) > 0); |
| } |
| } |
| } |
| size_t uri_path_len; |
| char *target_uri_str = gpr_strjoin_sep((const char **)addr_strs, |
| num_grpclb_addrs, ",", &uri_path_len); |
| |
| /* Create a channel to talk to the LBs. |
| * |
| * We strip out the channel arg for the LB policy name, since we want |
| * to use the default (pick_first) in this case. |
| * |
| * We also strip out the channel arg for the resolved addresses, since |
| * that will be generated by the name resolver used in the LB channel. |
| * Note that the LB channel will use the sockaddr resolver, so this |
| * won't actually generate a query to DNS (or some other name service). |
| * However, the addresses returned by the sockaddr resolver will have |
| * is_balancer=false, whereas our own addresses have is_balancer=true. |
| * We need the LB channel to return addresses with is_balancer=false |
| * so that it does not wind up recursively using the grpclb LB policy, |
| * as per the special case logic in client_channel.c. |
| * |
| * Finally, we also strip out the channel arg for the server URI, |
| * since that will be different for the LB channel than for the parent |
| * channel. (The client channel factory will re-add this arg with |
| * the right value.) |
| */ |
| static const char *keys_to_remove[] = { |
| GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI}; |
| grpc_channel_args *new_args = grpc_channel_args_copy_and_remove( |
| args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove)); |
| glb_policy->lb_channel = grpc_client_channel_factory_create_channel( |
| exec_ctx, glb_policy->cc_factory, target_uri_str, |
| GRPC_CLIENT_CHANNEL_TYPE_LOAD_BALANCING, new_args); |
| grpc_channel_args_destroy(exec_ctx, new_args); |
| |
| gpr_free(target_uri_str); |
| for (size_t i = 0; i < num_grpclb_addrs; i++) { |
| gpr_free(addr_strs[i]); |
| } |
| gpr_free(addr_strs); |
| |
| if (glb_policy->lb_channel == NULL) { |
| gpr_free(glb_policy); |
| return NULL; |
| } |
| |
| grpc_lb_policy_init(&glb_policy->base, &glb_lb_policy_vtable); |
| gpr_mu_init(&glb_policy->mu); |
| grpc_connectivity_state_init(&glb_policy->state_tracker, GRPC_CHANNEL_IDLE, |
| "grpclb"); |
| |
| return &glb_policy->base; |
| } |
| |
| static void glb_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| GPR_ASSERT(glb_policy->pending_picks == NULL); |
| GPR_ASSERT(glb_policy->pending_pings == NULL); |
| gpr_free((void *)glb_policy->server_name); |
| grpc_channel_args_destroy(exec_ctx, glb_policy->args); |
| grpc_channel_destroy(glb_policy->lb_channel); |
| glb_policy->lb_channel = NULL; |
| grpc_connectivity_state_destroy(exec_ctx, &glb_policy->state_tracker); |
| if (glb_policy->serverlist != NULL) { |
| grpc_grpclb_destroy_serverlist(glb_policy->serverlist); |
| } |
| gpr_mu_destroy(&glb_policy->mu); |
| gpr_free(glb_policy); |
| } |
| |
| static void glb_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| gpr_mu_lock(&glb_policy->mu); |
| glb_policy->shutting_down = true; |
| |
| pending_pick *pp = glb_policy->pending_picks; |
| glb_policy->pending_picks = NULL; |
| pending_ping *pping = glb_policy->pending_pings; |
| glb_policy->pending_pings = NULL; |
| if (glb_policy->rr_policy) { |
| GRPC_LB_POLICY_UNREF(exec_ctx, glb_policy->rr_policy, "glb_shutdown"); |
| } |
| grpc_connectivity_state_set( |
| exec_ctx, &glb_policy->state_tracker, GRPC_CHANNEL_SHUTDOWN, |
| GRPC_ERROR_CREATE("Channel Shutdown"), "glb_shutdown"); |
| /* We need a copy of the lb_call pointer because we can't cancell the call |
| * while holding glb_policy->mu: lb_on_server_status_received, invoked due to |
| * the cancel, needs to acquire that same lock */ |
| grpc_call *lb_call = glb_policy->lb_call; |
| gpr_mu_unlock(&glb_policy->mu); |
| |
| /* glb_policy->lb_call and this local lb_call must be consistent at this point |
| * because glb_policy->lb_call is only assigned in lb_call_init_locked as part |
| * of query_for_backends_locked, which can only be invoked while |
| * glb_policy->shutting_down is false. */ |
| if (lb_call != NULL) { |
| grpc_call_cancel(lb_call, NULL); |
| /* lb_on_server_status_received will pick up the cancel and clean up */ |
| } |
| while (pp != NULL) { |
| pending_pick *next = pp->next; |
| *pp->target = NULL; |
| grpc_closure_sched(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure, |
| GRPC_ERROR_NONE); |
| pp = next; |
| } |
| |
| while (pping != NULL) { |
| pending_ping *next = pping->next; |
| grpc_closure_sched(exec_ctx, &pping->wrapped_notify_arg.wrapper_closure, |
| GRPC_ERROR_NONE); |
| pping = next; |
| } |
| } |
| |
| static void glb_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, |
| grpc_connected_subchannel **target, |
| grpc_error *error) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| gpr_mu_lock(&glb_policy->mu); |
| pending_pick *pp = glb_policy->pending_picks; |
| glb_policy->pending_picks = NULL; |
| while (pp != NULL) { |
| pending_pick *next = pp->next; |
| if (pp->target == target) { |
| *target = NULL; |
| grpc_closure_sched( |
| exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure, |
| GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1)); |
| } else { |
| pp->next = glb_policy->pending_picks; |
| glb_policy->pending_picks = pp; |
| } |
| pp = next; |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| static void glb_cancel_picks(grpc_exec_ctx *exec_ctx, 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; |
| gpr_mu_lock(&glb_policy->mu); |
| pending_pick *pp = glb_policy->pending_picks; |
| glb_policy->pending_picks = NULL; |
| while (pp != NULL) { |
| pending_pick *next = pp->next; |
| if ((pp->pick_args.initial_metadata_flags & initial_metadata_flags_mask) == |
| initial_metadata_flags_eq) { |
| grpc_closure_sched( |
| exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure, |
| GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1)); |
| } else { |
| pp->next = glb_policy->pending_picks; |
| glb_policy->pending_picks = pp; |
| } |
| pp = next; |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| static void query_for_backends_locked(grpc_exec_ctx *exec_ctx, |
| glb_lb_policy *glb_policy); |
| static void start_picking_locked(grpc_exec_ctx *exec_ctx, |
| glb_lb_policy *glb_policy) { |
| glb_policy->started_picking = true; |
| gpr_backoff_reset(&glb_policy->lb_call_backoff_state); |
| query_for_backends_locked(exec_ctx, glb_policy); |
| } |
| |
| static void glb_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| gpr_mu_lock(&glb_policy->mu); |
| if (!glb_policy->started_picking) { |
| start_picking_locked(exec_ctx, glb_policy); |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| } |
| |
| static int glb_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, |
| const grpc_lb_policy_pick_args *pick_args, |
| grpc_connected_subchannel **target, void **user_data, |
| grpc_closure *on_complete) { |
| if (pick_args->lb_token_mdelem_storage == NULL) { |
| *target = NULL; |
| grpc_closure_sched( |
| exec_ctx, on_complete, |
| GRPC_ERROR_CREATE("No mdelem storage for the LB token. Load reporting " |
| "won't work without it. Failing")); |
| return 0; |
| } |
| |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| gpr_mu_lock(&glb_policy->mu); |
| glb_policy->deadline = pick_args->deadline; |
| bool pick_done; |
| |
| if (glb_policy->rr_policy != NULL) { |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "grpclb %p about to PICK from RR %p", |
| (void *)glb_policy, (void *)glb_policy->rr_policy); |
| } |
| GRPC_LB_POLICY_REF(glb_policy->rr_policy, "glb_pick"); |
| |
| wrapped_rr_closure_arg *wc_arg = gpr_malloc(sizeof(wrapped_rr_closure_arg)); |
| memset(wc_arg, 0, sizeof(wrapped_rr_closure_arg)); |
| |
| grpc_closure_init(&wc_arg->wrapper_closure, wrapped_rr_closure, wc_arg, |
| grpc_schedule_on_exec_ctx); |
| wc_arg->rr_policy = glb_policy->rr_policy; |
| wc_arg->target = target; |
| wc_arg->wrapped_closure = on_complete; |
| wc_arg->lb_token_mdelem_storage = pick_args->lb_token_mdelem_storage; |
| wc_arg->initial_metadata = pick_args->initial_metadata; |
| wc_arg->free_when_done = wc_arg; |
| pick_done = pick_from_internal_rr_locked(exec_ctx, glb_policy->rr_policy, |
| pick_args, target, wc_arg); |
| } else { |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_DEBUG, |
| "No RR policy in grpclb instance %p. Adding to grpclb's pending " |
| "picks", |
| (void *)(glb_policy)); |
| } |
| add_pending_pick(&glb_policy->pending_picks, pick_args, target, |
| on_complete); |
| |
| if (!glb_policy->started_picking) { |
| start_picking_locked(exec_ctx, glb_policy); |
| } |
| pick_done = false; |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| return pick_done; |
| } |
| |
| static grpc_connectivity_state glb_check_connectivity( |
| grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, |
| grpc_error **connectivity_error) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| grpc_connectivity_state st; |
| gpr_mu_lock(&glb_policy->mu); |
| st = grpc_connectivity_state_check(&glb_policy->state_tracker, |
| connectivity_error); |
| gpr_mu_unlock(&glb_policy->mu); |
| return st; |
| } |
| |
| static void glb_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, |
| grpc_closure *closure) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| gpr_mu_lock(&glb_policy->mu); |
| if (glb_policy->rr_policy) { |
| grpc_lb_policy_ping_one(exec_ctx, glb_policy->rr_policy, closure); |
| } else { |
| add_pending_ping(&glb_policy->pending_pings, closure); |
| if (!glb_policy->started_picking) { |
| start_picking_locked(exec_ctx, glb_policy); |
| } |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| } |
| |
| static void glb_notify_on_state_change(grpc_exec_ctx *exec_ctx, |
| grpc_lb_policy *pol, |
| grpc_connectivity_state *current, |
| grpc_closure *notify) { |
| glb_lb_policy *glb_policy = (glb_lb_policy *)pol; |
| gpr_mu_lock(&glb_policy->mu); |
| grpc_connectivity_state_notify_on_state_change( |
| exec_ctx, &glb_policy->state_tracker, current, notify); |
| |
| gpr_mu_unlock(&glb_policy->mu); |
| } |
| |
| static void lb_on_server_status_received(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error); |
| static void lb_on_response_received(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error); |
| static void lb_call_init_locked(grpc_exec_ctx *exec_ctx, |
| glb_lb_policy *glb_policy) { |
| GPR_ASSERT(glb_policy->server_name != NULL); |
| GPR_ASSERT(glb_policy->server_name[0] != '\0'); |
| GPR_ASSERT(!glb_policy->shutting_down); |
| |
| /* Note the following LB call progresses every time there's activity in \a |
| * glb_policy->base.interested_parties, which is comprised of the polling |
| * entities from \a client_channel. */ |
| glb_policy->lb_call = grpc_channel_create_pollset_set_call( |
| exec_ctx, glb_policy->lb_channel, NULL, GRPC_PROPAGATE_DEFAULTS, |
| glb_policy->base.interested_parties, |
| "/grpc.lb.v1.LoadBalancer/BalanceLoad", glb_policy->server_name, |
| glb_policy->deadline, NULL); |
| |
| grpc_metadata_array_init(&glb_policy->lb_initial_metadata_recv); |
| grpc_metadata_array_init(&glb_policy->lb_trailing_metadata_recv); |
| |
| grpc_grpclb_request *request = |
| grpc_grpclb_request_create(glb_policy->server_name); |
| grpc_slice request_payload_slice = grpc_grpclb_request_encode(request); |
| glb_policy->lb_request_payload = |
| grpc_raw_byte_buffer_create(&request_payload_slice, 1); |
| grpc_slice_unref_internal(exec_ctx, request_payload_slice); |
| grpc_grpclb_request_destroy(request); |
| |
| glb_policy->lb_call_status_details = NULL; |
| glb_policy->lb_call_status_details_capacity = 0; |
| |
| grpc_closure_init(&glb_policy->lb_on_server_status_received, |
| lb_on_server_status_received, glb_policy, |
| grpc_schedule_on_exec_ctx); |
| grpc_closure_init(&glb_policy->lb_on_response_received, |
| lb_on_response_received, glb_policy, |
| grpc_schedule_on_exec_ctx); |
| |
| gpr_backoff_init(&glb_policy->lb_call_backoff_state, |
| GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS, |
| GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER, |
| GRPC_GRPCLB_RECONNECT_JITTER, |
| GRPC_GRPCLB_MIN_CONNECT_TIMEOUT_SECONDS * 1000, |
| GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS * 1000); |
| } |
| |
| static void lb_call_destroy_locked(glb_lb_policy *glb_policy) { |
| GPR_ASSERT(glb_policy->lb_call != NULL); |
| grpc_call_destroy(glb_policy->lb_call); |
| glb_policy->lb_call = NULL; |
| |
| grpc_metadata_array_destroy(&glb_policy->lb_initial_metadata_recv); |
| grpc_metadata_array_destroy(&glb_policy->lb_trailing_metadata_recv); |
| |
| grpc_byte_buffer_destroy(glb_policy->lb_request_payload); |
| gpr_free(glb_policy->lb_call_status_details); |
| } |
| |
| /* |
| * Auxiliary functions and LB client callbacks. |
| */ |
| static void query_for_backends_locked(grpc_exec_ctx *exec_ctx, |
| glb_lb_policy *glb_policy) { |
| GPR_ASSERT(glb_policy->lb_channel != NULL); |
| if (glb_policy->shutting_down) return; |
| |
| lb_call_init_locked(exec_ctx, glb_policy); |
| |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Query for backends (grpclb: %p, lb_call: %p)", |
| (void *)glb_policy, (void *)glb_policy->lb_call); |
| } |
| GPR_ASSERT(glb_policy->lb_call != NULL); |
| |
| grpc_call_error call_error; |
| grpc_op ops[4]; |
| memset(ops, 0, sizeof(ops)); |
| |
| grpc_op *op = ops; |
| op->op = GRPC_OP_SEND_INITIAL_METADATA; |
| op->data.send_initial_metadata.count = 0; |
| op->flags = 0; |
| op->reserved = NULL; |
| op++; |
| |
| op->op = GRPC_OP_RECV_INITIAL_METADATA; |
| op->data.recv_initial_metadata = &glb_policy->lb_initial_metadata_recv; |
| op->flags = 0; |
| op->reserved = NULL; |
| op++; |
| |
| GPR_ASSERT(glb_policy->lb_request_payload != NULL); |
| op->op = GRPC_OP_SEND_MESSAGE; |
| op->data.send_message = glb_policy->lb_request_payload; |
| op->flags = 0; |
| op->reserved = NULL; |
| op++; |
| |
| op->op = GRPC_OP_RECV_STATUS_ON_CLIENT; |
| op->data.recv_status_on_client.trailing_metadata = |
| &glb_policy->lb_trailing_metadata_recv; |
| op->data.recv_status_on_client.status = &glb_policy->lb_call_status; |
| op->data.recv_status_on_client.status_details = |
| &glb_policy->lb_call_status_details; |
| op->data.recv_status_on_client.status_details_capacity = |
| &glb_policy->lb_call_status_details_capacity; |
| op->flags = 0; |
| op->reserved = NULL; |
| op++; |
| /* take a weak ref (won't prevent calling of \a glb_shutdown if the strong ref |
| * count goes to zero) to be unref'd in lb_on_server_status_received */ |
| GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "lb_on_server_status_received"); |
| call_error = grpc_call_start_batch_and_execute( |
| exec_ctx, glb_policy->lb_call, ops, (size_t)(op - ops), |
| &glb_policy->lb_on_server_status_received); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| |
| op = ops; |
| op->op = GRPC_OP_RECV_MESSAGE; |
| op->data.recv_message = &glb_policy->lb_response_payload; |
| op->flags = 0; |
| op->reserved = NULL; |
| op++; |
| /* take another weak ref to be unref'd in lb_on_response_received */ |
| GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "lb_on_response_received"); |
| call_error = grpc_call_start_batch_and_execute( |
| exec_ctx, glb_policy->lb_call, ops, (size_t)(op - ops), |
| &glb_policy->lb_on_response_received); |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| } |
| |
| static void lb_on_response_received(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error) { |
| glb_lb_policy *glb_policy = arg; |
| |
| grpc_op ops[2]; |
| memset(ops, 0, sizeof(ops)); |
| grpc_op *op = ops; |
| gpr_mu_lock(&glb_policy->mu); |
| if (glb_policy->lb_response_payload != NULL) { |
| gpr_backoff_reset(&glb_policy->lb_call_backoff_state); |
| /* Received data from the LB server. Look inside |
| * glb_policy->lb_response_payload, for a serverlist. */ |
| grpc_byte_buffer_reader bbr; |
| grpc_byte_buffer_reader_init(&bbr, glb_policy->lb_response_payload); |
| grpc_slice response_slice = grpc_byte_buffer_reader_readall(&bbr); |
| grpc_byte_buffer_destroy(glb_policy->lb_response_payload); |
| grpc_grpclb_serverlist *serverlist = |
| grpc_grpclb_response_parse_serverlist(response_slice); |
| if (serverlist != NULL) { |
| GPR_ASSERT(glb_policy->lb_call != NULL); |
| grpc_slice_unref_internal(exec_ctx, response_slice); |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Serverlist with %lu servers received", |
| (unsigned long)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, "Serverlist[%lu]: %s", (unsigned long)i, ipport); |
| gpr_free(ipport); |
| } |
| } |
| |
| /* update serverlist */ |
| if (serverlist->num_servers > 0) { |
| if (grpc_grpclb_serverlist_equals(glb_policy->serverlist, serverlist)) { |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, |
| "Incoming server list identical to current, ignoring."); |
| } |
| grpc_grpclb_destroy_serverlist(serverlist); |
| } else { /* new serverlist */ |
| if (glb_policy->serverlist != NULL) { |
| /* dispose of the old serverlist */ |
| grpc_grpclb_destroy_serverlist(glb_policy->serverlist); |
| } |
| /* 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; |
| |
| rr_handover_locked(exec_ctx, glb_policy); |
| } |
| } else { |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, |
| "Received empty server list. Picks will stay pending until a " |
| "response with > 0 servers is received"); |
| } |
| } |
| } else { /* serverlist == NULL */ |
| gpr_log(GPR_ERROR, "Invalid LB response received: '%s'. Ignoring.", |
| grpc_dump_slice(response_slice, GPR_DUMP_ASCII | GPR_DUMP_HEX)); |
| grpc_slice_unref_internal(exec_ctx, response_slice); |
| } |
| |
| if (!glb_policy->shutting_down) { |
| /* keep listening for serverlist updates */ |
| op->op = GRPC_OP_RECV_MESSAGE; |
| op->data.recv_message = &glb_policy->lb_response_payload; |
| op->flags = 0; |
| op->reserved = NULL; |
| op++; |
| /* reuse the "lb_on_response_received" weak ref taken in |
| * query_for_backends_locked() */ |
| const grpc_call_error call_error = grpc_call_start_batch_and_execute( |
| exec_ctx, glb_policy->lb_call, ops, (size_t)(op - ops), |
| &glb_policy->lb_on_response_received); /* loop */ |
| GPR_ASSERT(GRPC_CALL_OK == call_error); |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| } else { /* empty payload: call cancelled. */ |
| /* dispose of the "lb_on_response_received" weak ref taken in |
| * query_for_backends_locked() and reused in every reception loop */ |
| gpr_mu_unlock(&glb_policy->mu); |
| GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, |
| "lb_on_response_received_empty_payload"); |
| } |
| } |
| |
| static void lb_call_on_retry_timer(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error) { |
| glb_lb_policy *glb_policy = arg; |
| gpr_mu_lock(&glb_policy->mu); |
| |
| if (!glb_policy->shutting_down) { |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_INFO, "Restaring call to LB server (grpclb %p)", |
| (void *)glb_policy); |
| } |
| GPR_ASSERT(glb_policy->lb_call == NULL); |
| query_for_backends_locked(exec_ctx, glb_policy); |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, |
| "grpclb_on_retry_timer"); |
| } |
| |
| static void lb_on_server_status_received(grpc_exec_ctx *exec_ctx, void *arg, |
| grpc_error *error) { |
| glb_lb_policy *glb_policy = arg; |
| gpr_mu_lock(&glb_policy->mu); |
| |
| GPR_ASSERT(glb_policy->lb_call != NULL); |
| |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_DEBUG, |
| "Status from LB server received. Status = %d, Details = '%s', " |
| "(call: %p)", |
| glb_policy->lb_call_status, glb_policy->lb_call_status_details, |
| (void *)glb_policy->lb_call); |
| } |
| |
| /* We need to performe cleanups no matter what. */ |
| lb_call_destroy_locked(glb_policy); |
| |
| if (!glb_policy->shutting_down) { |
| /* if we aren't shutting down, restart the LB client call after some time */ |
| gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC); |
| gpr_timespec next_try = |
| gpr_backoff_step(&glb_policy->lb_call_backoff_state, now); |
| if (grpc_lb_glb_trace) { |
| gpr_log(GPR_DEBUG, "Connection to LB server lost (grpclb: %p)...", |
| (void *)glb_policy); |
| gpr_timespec timeout = gpr_time_sub(next_try, now); |
| if (gpr_time_cmp(timeout, gpr_time_0(timeout.clock_type)) > 0) { |
| gpr_log(GPR_DEBUG, "... retrying in %" PRId64 ".%09d seconds.", |
| timeout.tv_sec, timeout.tv_nsec); |
| } else { |
| gpr_log(GPR_DEBUG, "... retrying immediately."); |
| } |
| } |
| GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_retry_timer"); |
| grpc_closure_init(&glb_policy->lb_on_call_retry, lb_call_on_retry_timer, |
| glb_policy, grpc_schedule_on_exec_ctx); |
| grpc_timer_init(exec_ctx, &glb_policy->lb_call_retry_timer, next_try, |
| &glb_policy->lb_on_call_retry, now); |
| } |
| gpr_mu_unlock(&glb_policy->mu); |
| GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, |
| "lb_on_server_status_received"); |
| } |
| |
| /* Code wiring the policy with the rest of the core */ |
| static const grpc_lb_policy_vtable glb_lb_policy_vtable = { |
| glb_destroy, glb_shutdown, glb_pick, |
| glb_cancel_pick, glb_cancel_picks, glb_ping_one, |
| glb_exit_idle, glb_check_connectivity, glb_notify_on_state_change}; |
| |
| 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 */ |
| void grpc_lb_policy_grpclb_init() { |
| grpc_register_lb_policy(grpc_glb_lb_factory_create()); |
| grpc_register_tracer("glb", &grpc_lb_glb_trace); |
| } |
| |
| void grpc_lb_policy_grpclb_shutdown() {} |