Implement grpclb drop support.
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
index b7c0e92..d2a2856 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
@@ -327,6 +327,11 @@
* 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;
+
/** list of picks that are waiting on RR's policy connectivity */
pending_pick *pending_picks;
@@ -402,6 +407,9 @@
static bool is_server_valid(const grpc_grpclb_server *server, size_t idx,
bool log) {
+ if (server->drop_for_rate_limiting || server->drop_for_load_balancing) {
+ return false;
+ }
const grpc_grpclb_ip_address *ip = &server->ip_address;
if (server->port >> 16 != 0) {
if (log) {
@@ -411,7 +419,6 @@
}
return false;
}
-
if (ip->size != 4 && ip->size != 16) {
if (log) {
gpr_log(GPR_ERROR,
@@ -445,11 +452,12 @@
static void parse_server(const grpc_grpclb_server *server,
grpc_resolved_address *addr) {
+ memset(addr, 0, sizeof(*addr));
+ if (server->drop_for_rate_limiting || server->drop_for_load_balancing) 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;
- memset(addr, 0, sizeof(*addr));
if (ip->size == 4) {
addr->len = sizeof(struct sockaddr_in);
struct sockaddr_in *addr4 = (struct sockaddr_in *)&addr->addr;
@@ -586,16 +594,51 @@
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 */
+/* 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 resposible 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(
- grpc_exec_ctx *exec_ctx, grpc_lb_policy *rr_policy,
- const grpc_lb_policy_pick_args *pick_args,
+ grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
+ const grpc_lb_policy_pick_args *pick_args, bool force_async,
grpc_connected_subchannel **target, wrapped_rr_closure_arg *wc_arg) {
- GPR_ASSERT(rr_policy != NULL);
+ // 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_for_rate_limiting || server->drop_for_load_balancing) {
+ // Not using the RR policy, so unref it.
+ if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+ gpr_log(GPR_INFO, "Unreffing RR for drop (0x%" PRIxPTR ")",
+ (intptr_t)wc_arg->rr_policy);
+ }
+ GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync");
+ // 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.
+ grpc_grpclb_client_stats_add_call_started(wc_arg->client_stats);
+ grpc_grpclb_client_stats_add_call_finished(
+ server->drop_for_rate_limiting, server->drop_for_load_balancing,
+ false /* failed_to_send */, false /* known_received */,
+ wc_arg->client_stats);
+ grpc_grpclb_client_stats_unref(wc_arg->client_stats);
+ if (force_async) {
+ GPR_ASSERT(wc_arg->wrapped_closure != NULL);
+ grpc_closure_sched(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_NONE);
+ gpr_free(wc_arg->free_when_done);
+ return false;
+ }
+ gpr_free(wc_arg->free_when_done);
+ return true;
+ }
+ // Pick via the RR policy.
const bool pick_done = grpc_lb_policy_pick_locked(
- exec_ctx, rr_policy, pick_args, target, wc_arg->context,
+ exec_ctx, wc_arg->rr_policy, pick_args, target, wc_arg->context,
(void **)&wc_arg->lb_token, &wc_arg->wrapper_closure);
if (pick_done) {
/* synchronous grpc_lb_policy_pick call. Unref the RR policy. */
@@ -604,17 +647,20 @@
(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(exec_ctx, pick_args->initial_metadata,
pick_args->lb_token_mdelem_storage,
GRPC_MDELEM_REF(wc_arg->lb_token));
-
// Pass on client stats via context. Passes ownership of the reference.
GPR_ASSERT(wc_arg->client_stats != NULL);
wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].value = wc_arg->client_stats;
wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].destroy = destroy_client_stats;
-
+ if (force_async) {
+ GPR_ASSERT(wc_arg->wrapped_closure != NULL);
+ grpc_closure_sched(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_NONE);
+ gpr_free(wc_arg->free_when_done);
+ return false;
+ }
gpr_free(wc_arg->free_when_done);
}
/* else, the pending pick will be registered and taken care of by the
@@ -744,8 +790,8 @@
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,
+ pick_from_internal_rr_locked(exec_ctx, glb_policy, &pp->pick_args,
+ true /* force_async */, pp->target,
&pp->wrapped_on_complete_arg);
}
@@ -1115,8 +1161,9 @@
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);
+ pick_done =
+ pick_from_internal_rr_locked(exec_ctx, glb_policy, pick_args,
+ false /* force_async */, target, wc_arg);
} else {
if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
gpr_log(GPR_DEBUG,
@@ -1517,7 +1564,7 @@
* 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(exec_ctx, glb_policy);
}
} else {