diff --git a/src/core/ext/filters/client_channel/client_channel.cc b/src/core/ext/filters/client_channel/client_channel.cc index 58496dc2468..aced9adf9f1 100644 --- a/src/core/ext/filters/client_channel/client_channel.cc +++ b/src/core/ext/filters/client_channel/client_channel.cc @@ -210,6 +210,14 @@ typedef struct client_channel_channel_data { char* info_service_config_json; } channel_data; +typedef struct { + channel_data* chand; + /** used as an identifier, don't dereference it because the LB policy may be + * non-existing when the callback is run */ + grpc_lb_policy* lb_policy; + grpc_closure closure; +} reresolution_request_args; + /** We create one watcher for each new lb_policy that is returned from a resolver, to watch for state changes from the lb_policy. When a state change is seen, we update the channel, and create a new watcher. */ @@ -258,21 +266,13 @@ static void set_channel_connectivity_state_locked(grpc_exec_ctx* exec_ctx, static void on_lb_policy_state_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) { lb_policy_connectivity_watcher* w = (lb_policy_connectivity_watcher*)arg; - grpc_connectivity_state publish_state = w->state; /* check if the notification is for the latest policy */ if (w->lb_policy == w->chand->lb_policy) { if (grpc_client_channel_trace.enabled()) { gpr_log(GPR_DEBUG, "chand=%p: lb_policy=%p state changed to %s", w->chand, w->lb_policy, grpc_connectivity_state_name(w->state)); } - if (publish_state == GRPC_CHANNEL_SHUTDOWN && - w->chand->resolver != nullptr) { - publish_state = GRPC_CHANNEL_TRANSIENT_FAILURE; - grpc_resolver_channel_saw_error_locked(exec_ctx, w->chand->resolver); - GRPC_LB_POLICY_UNREF(exec_ctx, w->chand->lb_policy, "channel"); - w->chand->lb_policy = nullptr; - } - set_channel_connectivity_state_locked(exec_ctx, w->chand, publish_state, + set_channel_connectivity_state_locked(exec_ctx, w->chand, w->state, GRPC_ERROR_REF(error), "lb_changed"); if (w->state != GRPC_CHANNEL_SHUTDOWN) { watch_lb_policy_locked(exec_ctx, w->chand, w->lb_policy, w->state); @@ -369,6 +369,27 @@ static void parse_retry_throttle_params(const grpc_json* field, void* arg) { } } +static void request_reresolution_locked(grpc_exec_ctx* exec_ctx, void* arg, + grpc_error* error) { + reresolution_request_args* args = (reresolution_request_args*)arg; + channel_data* chand = args->chand; + // If this invocation is for a stale LB policy, treat it as an LB shutdown + // signal. + if (args->lb_policy != chand->lb_policy || error != GRPC_ERROR_NONE || + chand->resolver == nullptr) { + GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "re-resolution"); + gpr_free(args); + return; + } + if (grpc_client_channel_trace.enabled()) { + gpr_log(GPR_DEBUG, "chand=%p: started name re-resolving", chand); + } + grpc_resolver_channel_saw_error_locked(exec_ctx, chand->resolver); + // Give back the closure to the LB policy. + grpc_lb_policy_set_reresolve_closure_locked(exec_ctx, chand->lb_policy, + &args->closure); +} + static void on_resolver_result_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) { channel_data* chand = (channel_data*)arg; @@ -385,100 +406,114 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx* exec_ctx, grpc_server_retry_throttle_data* retry_throttle_data = nullptr; grpc_slice_hash_table* method_params_table = nullptr; if (chand->resolver_result != nullptr) { - // Find LB policy name. - const char* lb_policy_name = nullptr; - const grpc_arg* channel_arg = - grpc_channel_args_find(chand->resolver_result, GRPC_ARG_LB_POLICY_NAME); - if (channel_arg != nullptr) { - GPR_ASSERT(channel_arg->type == GRPC_ARG_STRING); - lb_policy_name = channel_arg->value.string; - } - // Special case: If at least one balancer address is present, we use - // the grpclb policy, regardless of what the resolver actually specified. - channel_arg = - grpc_channel_args_find(chand->resolver_result, GRPC_ARG_LB_ADDRESSES); - if (channel_arg != nullptr && channel_arg->type == GRPC_ARG_POINTER) { - grpc_lb_addresses* addresses = - (grpc_lb_addresses*)channel_arg->value.pointer.p; - bool found_balancer_address = false; - for (size_t i = 0; i < addresses->num_addresses; ++i) { - if (addresses->addresses[i].is_balancer) { - found_balancer_address = true; - break; + if (chand->resolver != nullptr) { + // Find LB policy name. + const char* lb_policy_name = nullptr; + const grpc_arg* channel_arg = grpc_channel_args_find( + chand->resolver_result, GRPC_ARG_LB_POLICY_NAME); + if (channel_arg != nullptr) { + GPR_ASSERT(channel_arg->type == GRPC_ARG_STRING); + lb_policy_name = channel_arg->value.string; + } + // Special case: If at least one balancer address is present, we use + // the grpclb policy, regardless of what the resolver actually specified. + channel_arg = + grpc_channel_args_find(chand->resolver_result, GRPC_ARG_LB_ADDRESSES); + if (channel_arg != nullptr && channel_arg->type == GRPC_ARG_POINTER) { + grpc_lb_addresses* addresses = + (grpc_lb_addresses*)channel_arg->value.pointer.p; + bool found_balancer_address = false; + for (size_t i = 0; i < addresses->num_addresses; ++i) { + if (addresses->addresses[i].is_balancer) { + found_balancer_address = true; + break; + } + } + if (found_balancer_address) { + if (lb_policy_name != nullptr && + strcmp(lb_policy_name, "grpclb") != 0) { + gpr_log(GPR_INFO, + "resolver requested LB policy %s but provided at least one " + "balancer address -- forcing use of grpclb LB policy", + lb_policy_name); + } + lb_policy_name = "grpclb"; } } - if (found_balancer_address) { - if (lb_policy_name != nullptr && - strcmp(lb_policy_name, "grpclb") != 0) { - gpr_log(GPR_INFO, - "resolver requested LB policy %s but provided at least one " - "balancer address -- forcing use of grpclb LB policy", + // Use pick_first if nothing was specified and we didn't select grpclb + // above. + if (lb_policy_name == nullptr) lb_policy_name = "pick_first"; + grpc_lb_policy_args lb_policy_args; + lb_policy_args.args = chand->resolver_result; + lb_policy_args.client_channel_factory = chand->client_channel_factory; + lb_policy_args.combiner = chand->combiner; + // Check to see if we're already using the right LB policy. + // Note: It's safe to use chand->info_lb_policy_name here without + // taking a lock on chand->info_mu, because this function is the + // only thing that modifies its value, and it can only be invoked + // once at any given time. + lb_policy_name_changed = + chand->info_lb_policy_name == nullptr || + gpr_stricmp(chand->info_lb_policy_name, lb_policy_name) != 0; + if (chand->lb_policy != nullptr && !lb_policy_name_changed) { + // Continue using the same LB policy. Update with new addresses. + lb_policy_updated = true; + grpc_lb_policy_update_locked(exec_ctx, chand->lb_policy, + &lb_policy_args); + } else { + // Instantiate new LB policy. + new_lb_policy = + grpc_lb_policy_create(exec_ctx, lb_policy_name, &lb_policy_args); + if (new_lb_policy == nullptr) { + gpr_log(GPR_ERROR, "could not create LB policy \"%s\"", lb_policy_name); + } else { + reresolution_request_args* args = + (reresolution_request_args*)gpr_zalloc(sizeof(*args)); + args->chand = chand; + args->lb_policy = new_lb_policy; + GRPC_CLOSURE_INIT(&args->closure, request_reresolution_locked, args, + grpc_combiner_scheduler(chand->combiner)); + GRPC_CHANNEL_STACK_REF(chand->owning_stack, "re-resolution"); + grpc_lb_policy_set_reresolve_closure_locked(exec_ctx, new_lb_policy, + &args->closure); } - lb_policy_name = "grpclb"; - } - } - // Use pick_first if nothing was specified and we didn't select grpclb - // above. - if (lb_policy_name == nullptr) lb_policy_name = "pick_first"; - grpc_lb_policy_args lb_policy_args; - lb_policy_args.args = chand->resolver_result; - lb_policy_args.client_channel_factory = chand->client_channel_factory; - lb_policy_args.combiner = chand->combiner; - // Check to see if we're already using the right LB policy. - // Note: It's safe to use chand->info_lb_policy_name here without - // taking a lock on chand->info_mu, because this function is the - // only thing that modifies its value, and it can only be invoked - // once at any given time. - lb_policy_name_changed = - chand->info_lb_policy_name == nullptr || - gpr_stricmp(chand->info_lb_policy_name, lb_policy_name) != 0; - if (chand->lb_policy != nullptr && !lb_policy_name_changed) { - // Continue using the same LB policy. Update with new addresses. - lb_policy_updated = true; - grpc_lb_policy_update_locked(exec_ctx, chand->lb_policy, &lb_policy_args); - } else { - // Instantiate new LB policy. - new_lb_policy = - grpc_lb_policy_create(exec_ctx, lb_policy_name, &lb_policy_args); - if (new_lb_policy == nullptr) { - gpr_log(GPR_ERROR, "could not create LB policy \"%s\"", lb_policy_name); } - } - // Find service config. - channel_arg = - grpc_channel_args_find(chand->resolver_result, GRPC_ARG_SERVICE_CONFIG); - if (channel_arg != nullptr) { - GPR_ASSERT(channel_arg->type == GRPC_ARG_STRING); - service_config_json = gpr_strdup(channel_arg->value.string); - grpc_service_config* service_config = - grpc_service_config_create(service_config_json); - if (service_config != nullptr) { - channel_arg = - grpc_channel_args_find(chand->resolver_result, GRPC_ARG_SERVER_URI); - GPR_ASSERT(channel_arg != nullptr); + // Find service config. + channel_arg = grpc_channel_args_find(chand->resolver_result, + GRPC_ARG_SERVICE_CONFIG); + if (channel_arg != nullptr) { GPR_ASSERT(channel_arg->type == GRPC_ARG_STRING); - grpc_uri* uri = - grpc_uri_parse(exec_ctx, channel_arg->value.string, true); - GPR_ASSERT(uri->path[0] != '\0'); - service_config_parsing_state parsing_state; - memset(&parsing_state, 0, sizeof(parsing_state)); - parsing_state.server_name = - uri->path[0] == '/' ? uri->path + 1 : uri->path; - grpc_service_config_parse_global_params( - service_config, parse_retry_throttle_params, &parsing_state); - grpc_uri_destroy(uri); - retry_throttle_data = parsing_state.retry_throttle_data; - method_params_table = grpc_service_config_create_method_config_table( - exec_ctx, service_config, method_parameters_create_from_json, - method_parameters_ref_wrapper, method_parameters_unref_wrapper); - grpc_service_config_destroy(service_config); + service_config_json = gpr_strdup(channel_arg->value.string); + grpc_service_config* service_config = + grpc_service_config_create(service_config_json); + if (service_config != nullptr) { + channel_arg = grpc_channel_args_find(chand->resolver_result, + GRPC_ARG_SERVER_URI); + GPR_ASSERT(channel_arg != nullptr); + GPR_ASSERT(channel_arg->type == GRPC_ARG_STRING); + grpc_uri* uri = + grpc_uri_parse(exec_ctx, channel_arg->value.string, true); + GPR_ASSERT(uri->path[0] != '\0'); + service_config_parsing_state parsing_state; + memset(&parsing_state, 0, sizeof(parsing_state)); + parsing_state.server_name = + uri->path[0] == '/' ? uri->path + 1 : uri->path; + grpc_service_config_parse_global_params( + service_config, parse_retry_throttle_params, &parsing_state); + grpc_uri_destroy(uri); + retry_throttle_data = parsing_state.retry_throttle_data; + method_params_table = grpc_service_config_create_method_config_table( + exec_ctx, service_config, method_parameters_create_from_json, + method_parameters_ref_wrapper, method_parameters_unref_wrapper); + grpc_service_config_destroy(service_config); + } } + // Before we clean up, save a copy of lb_policy_name, since it might + // be pointing to data inside chand->resolver_result. + // The copy will be saved in chand->lb_policy_name below. + lb_policy_name_dup = gpr_strdup(lb_policy_name); } - // Before we clean up, save a copy of lb_policy_name, since it might - // be pointing to data inside chand->resolver_result. - // The copy will be saved in chand->lb_policy_name below. - lb_policy_name_dup = gpr_strdup(lb_policy_name); grpc_channel_args_destroy(exec_ctx, chand->resolver_result); chand->resolver_result = nullptr; } @@ -515,11 +550,11 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx* exec_ctx, } chand->method_params_table = method_params_table; // If we have a new LB policy or are shutting down (in which case - // new_lb_policy will be NULL), swap out the LB policy, unreffing the - // old one and removing its fds from chand->interested_parties. - // Note that we do NOT do this if either (a) we updated the existing - // LB policy above or (b) we failed to create the new LB policy (in - // which case we want to continue using the most recent one we had). + // new_lb_policy will be NULL), swap out the LB policy, unreffing the old one + // and removing its fds from chand->interested_parties. Note that we do NOT do + // this if either (a) we updated the existing LB policy above or (b) we failed + // to create the new LB policy (in which case we want to continue using the + // most recent one we had). if (new_lb_policy != nullptr || error != GRPC_ERROR_NONE || chand->resolver == nullptr) { if (chand->lb_policy != nullptr) { diff --git a/src/core/ext/filters/client_channel/lb_policy.cc b/src/core/ext/filters/client_channel/lb_policy.cc index 6276c3e952b..db566f1b562 100644 --- a/src/core/ext/filters/client_channel/lb_policy.cc +++ b/src/core/ext/filters/client_channel/lb_policy.cc @@ -161,3 +161,30 @@ void grpc_lb_policy_update_locked(grpc_exec_ctx* exec_ctx, const grpc_lb_policy_args* lb_policy_args) { policy->vtable->update_locked(exec_ctx, policy, lb_policy_args); } + +void grpc_lb_policy_set_reresolve_closure_locked( + grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, + grpc_closure* request_reresolution) { + policy->vtable->set_reresolve_closure_locked(exec_ctx, policy, + request_reresolution); +} + +void grpc_lb_policy_try_reresolve(grpc_exec_ctx* exec_ctx, + grpc_lb_policy* policy, + grpc_core::TraceFlag* grpc_lb_trace, + grpc_error* error) { + if (policy->request_reresolution != nullptr) { + GRPC_CLOSURE_SCHED(exec_ctx, policy->request_reresolution, error); + policy->request_reresolution = nullptr; + if (grpc_lb_trace->enabled()) { + gpr_log(GPR_DEBUG, + "%s %p: scheduling re-resolution closure with error=%s.", + grpc_lb_trace->name(), policy, grpc_error_string(error)); + } + } else { + if (grpc_lb_trace->enabled() && error == GRPC_ERROR_NONE) { + gpr_log(GPR_DEBUG, "%s %p: re-resolution already in progress.", + grpc_lb_trace->name(), policy); + } + } +} diff --git a/src/core/ext/filters/client_channel/lb_policy.h b/src/core/ext/filters/client_channel/lb_policy.h index 72d027995a1..d3159eebf3b 100644 --- a/src/core/ext/filters/client_channel/lb_policy.h +++ b/src/core/ext/filters/client_channel/lb_policy.h @@ -38,6 +38,8 @@ struct grpc_lb_policy { grpc_pollset_set* interested_parties; /* combiner under which lb_policy actions take place */ grpc_combiner* combiner; + /* callback to force a re-resolution */ + grpc_closure* request_reresolution; }; /** Extra arguments for an LB pick */ @@ -96,6 +98,11 @@ struct grpc_lb_policy_vtable { void (*update_locked)(grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, const grpc_lb_policy_args* args); + + /** \see grpc_lb_policy_set_reresolve_closure */ + void (*set_reresolve_closure_locked)(grpc_exec_ctx* exec_ctx, + grpc_lb_policy* policy, + grpc_closure* request_reresolution); }; #ifndef NDEBUG @@ -202,4 +209,16 @@ void grpc_lb_policy_update_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, const grpc_lb_policy_args* lb_policy_args); +/** Set the re-resolution closure to \a request_reresolution. */ +void grpc_lb_policy_set_reresolve_closure_locked( + grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, + grpc_closure* request_reresolution); + +/** Try to request a re-resolution. It's NOT a public API; it's only for use by + the LB policy implementations. */ +void grpc_lb_policy_try_reresolve(grpc_exec_ctx* exec_ctx, + grpc_lb_policy* policy, + grpc_core::TraceFlag* grpc_lb_trace, + grpc_error* error); + #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_H */ diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc index 2f8e0c93b24..a65f897a2f6 100644 --- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc +++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc @@ -637,7 +637,7 @@ static void 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 resposible for. + * 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( @@ -766,6 +766,9 @@ static void create_rr_locked(grpc_exec_ctx* exec_ctx, glb_lb_policy* glb_policy, glb_policy->rr_policy); return; } + grpc_lb_policy_set_reresolve_closure_locked( + exec_ctx, new_rr_policy, glb_policy->base.request_reresolution); + glb_policy->base.request_reresolution = nullptr; glb_policy->rr_policy = new_rr_policy; grpc_error* rr_state_error = nullptr; const grpc_connectivity_state rr_state = @@ -991,6 +994,7 @@ static void glb_destroy(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { static void glb_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { 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; /* We need a copy of the lb_call pointer because we can't cancell the call @@ -1021,6 +1025,9 @@ static void glb_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { glb_policy->pending_pings = nullptr; if (glb_policy->rr_policy != nullptr) { GRPC_LB_POLICY_UNREF(exec_ctx, glb_policy->rr_policy, "glb_shutdown"); + } else { + grpc_lb_policy_try_reresolve(exec_ctx, pol, &grpc_lb_glb_trace, + GRPC_ERROR_CANCELLED); } // We destroy the LB channel here because // glb_lb_channel_on_connectivity_changed_cb needs a valid glb_policy @@ -1030,28 +1037,27 @@ static void glb_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { grpc_channel_destroy(glb_policy->lb_channel); glb_policy->lb_channel = nullptr; } - grpc_connectivity_state_set( - exec_ctx, &glb_policy->state_tracker, GRPC_CHANNEL_SHUTDOWN, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown"), "glb_shutdown"); + grpc_connectivity_state_set(exec_ctx, &glb_policy->state_tracker, + GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_REF(error), + "glb_shutdown"); while (pp != nullptr) { pending_pick* next = pp->next; *pp->target = nullptr; - GRPC_CLOSURE_SCHED( - exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown")); + GRPC_CLOSURE_SCHED(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure, + GRPC_ERROR_REF(error)); gpr_free(pp); pp = next; } while (pping != nullptr) { pending_ping* next = pping->next; - GRPC_CLOSURE_SCHED( - exec_ctx, &pping->wrapped_notify_arg.wrapper_closure, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown")); + GRPC_CLOSURE_SCHED(exec_ctx, &pping->wrapped_notify_arg.wrapper_closure, + GRPC_ERROR_REF(error)); gpr_free(pping); pping = next; } + GRPC_ERROR_UNREF(error); } // Cancel a specific pending pick. @@ -1754,8 +1760,8 @@ static void fallback_update_locked(grpc_exec_ctx* exec_ctx, grpc_lb_addresses_destroy(exec_ctx, glb_policy->fallback_backend_addresses); glb_policy->fallback_backend_addresses = extract_backend_addresses_locked(exec_ctx, addresses); - if (glb_policy->started_picking && glb_policy->lb_fallback_timeout_ms > 0 && - !glb_policy->fallback_timer_active) { + if (glb_policy->lb_fallback_timeout_ms > 0 && + glb_policy->rr_policy != nullptr) { rr_handover_locked(exec_ctx, glb_policy); } } @@ -1870,6 +1876,20 @@ static void glb_lb_channel_on_connectivity_changed_cb(grpc_exec_ctx* exec_ctx, } } +static void glb_set_reresolve_closure_locked( + grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, + grpc_closure* request_reresolution) { + glb_lb_policy* glb_policy = (glb_lb_policy*)policy; + GPR_ASSERT(!glb_policy->shutting_down); + GPR_ASSERT(glb_policy->base.request_reresolution == nullptr); + if (glb_policy->rr_policy != nullptr) { + grpc_lb_policy_set_reresolve_closure_locked(exec_ctx, glb_policy->rr_policy, + request_reresolution); + } else { + glb_policy->base.request_reresolution = request_reresolution; + } +} + /* Code wiring the policy with the rest of the core */ static const grpc_lb_policy_vtable glb_lb_policy_vtable = { glb_destroy, @@ -1881,7 +1901,8 @@ static const grpc_lb_policy_vtable glb_lb_policy_vtable = { glb_exit_idle_locked, glb_check_connectivity_locked, glb_notify_on_state_change_locked, - glb_update_locked}; + glb_update_locked, + glb_set_reresolve_closure_locked}; static grpc_lb_policy* glb_create(grpc_exec_ctx* exec_ctx, grpc_lb_policy_factory* factory, diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc index 6cfc37e9d10..228a77d9db7 100644 --- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc +++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc @@ -70,8 +70,9 @@ static void pf_destroy(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { } } -static void shutdown_locked(grpc_exec_ctx* exec_ctx, pick_first_lb_policy* p, - grpc_error* error) { +static void pf_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { + pick_first_lb_policy* p = (pick_first_lb_policy*)pol; + grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown"); if (grpc_lb_pick_first_trace.enabled()) { gpr_log(GPR_DEBUG, "Pick First %p Shutting down", p); } @@ -96,14 +97,11 @@ static void shutdown_locked(grpc_exec_ctx* exec_ctx, pick_first_lb_policy* p, exec_ctx, p->latest_pending_subchannel_list, "pf_shutdown"); p->latest_pending_subchannel_list = nullptr; } + grpc_lb_policy_try_reresolve(exec_ctx, &p->base, &grpc_lb_pick_first_trace, + GRPC_ERROR_CANCELLED); GRPC_ERROR_UNREF(error); } -static void pf_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { - shutdown_locked(exec_ctx, (pick_first_lb_policy*)pol, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown")); -} - static void pf_cancel_pick_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol, grpc_connected_subchannel** target, grpc_error* error) { @@ -157,10 +155,15 @@ static void start_picking_locked(grpc_exec_ctx* exec_ctx, if (p->subchannel_list != nullptr && p->subchannel_list->num_subchannels > 0) { p->subchannel_list->checking_subchannel = 0; - grpc_lb_subchannel_list_ref_for_connectivity_watch( - p->subchannel_list, "connectivity_watch+start_picking"); - grpc_lb_subchannel_data_start_connectivity_watch( - exec_ctx, &p->subchannel_list->subchannels[0]); + for (size_t i = 0; i < p->subchannel_list->num_subchannels; ++i) { + if (p->subchannel_list->subchannels[i].subchannel != nullptr) { + grpc_lb_subchannel_list_ref_for_connectivity_watch( + p->subchannel_list, "connectivity_watch+start_picking"); + grpc_lb_subchannel_data_start_connectivity_watch( + exec_ctx, &p->subchannel_list->subchannels[i]); + break; + } + } } } @@ -404,6 +407,9 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, if (sd->curr_connectivity_state != GRPC_CHANNEL_READY && p->latest_pending_subchannel_list != nullptr) { p->selected = nullptr; + grpc_lb_subchannel_data_stop_connectivity_watch(exec_ctx, sd); + grpc_lb_subchannel_list_unref_for_connectivity_watch( + exec_ctx, sd->subchannel_list, "selected_not_ready+switch_to_update"); grpc_lb_subchannel_list_shutdown_and_unref( exec_ctx, p->subchannel_list, "selected_not_ready+switch_to_update"); p->subchannel_list = p->latest_pending_subchannel_list; @@ -412,21 +418,35 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE, GRPC_ERROR_REF(error), "selected_not_ready+switch_to_update"); } else { - if (sd->curr_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) { - /* if the selected channel goes bad, we're done */ - sd->curr_connectivity_state = GRPC_CHANNEL_SHUTDOWN; + // TODO(juanlishen): we re-resolve when the selected subchannel goes to + // TRANSIENT_FAILURE because we used to shut down in this case before + // re-resolution is introduced. But we need to investigate whether we + // really want to take any action instead of waiting for the selected + // subchannel reconnecting. + if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN || + sd->curr_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) { + // If the selected channel goes bad, request a re-resolution. + grpc_connectivity_state_set(exec_ctx, &p->state_tracker, + GRPC_CHANNEL_IDLE, GRPC_ERROR_NONE, + "selected_changed+reresolve"); + p->started_picking = false; + grpc_lb_policy_try_reresolve( + exec_ctx, &p->base, &grpc_lb_pick_first_trace, GRPC_ERROR_NONE); + } else { + grpc_connectivity_state_set(exec_ctx, &p->state_tracker, + sd->curr_connectivity_state, + GRPC_ERROR_REF(error), "selected_changed"); } - grpc_connectivity_state_set(exec_ctx, &p->state_tracker, - sd->curr_connectivity_state, - GRPC_ERROR_REF(error), "selected_changed"); if (sd->curr_connectivity_state != GRPC_CHANNEL_SHUTDOWN) { // Renew notification. grpc_lb_subchannel_data_start_connectivity_watch(exec_ctx, sd); } else { + p->selected = nullptr; grpc_lb_subchannel_data_stop_connectivity_watch(exec_ctx, sd); grpc_lb_subchannel_list_unref_for_connectivity_watch( exec_ctx, sd->subchannel_list, "pf_selected_shutdown"); - shutdown_locked(exec_ctx, p, GRPC_ERROR_REF(error)); + grpc_lb_subchannel_data_unref_subchannel(exec_ctx, sd, + "pf_selected_shutdown"); } } return; @@ -531,24 +551,37 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, } while (sd->subchannel == nullptr && sd != original_sd); if (sd == original_sd) { grpc_lb_subchannel_list_unref_for_connectivity_watch( - exec_ctx, sd->subchannel_list, "pf_candidate_shutdown"); - shutdown_locked(exec_ctx, p, - GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( - "Pick first exhausted channels", &error, 1)); - break; - } - if (sd->subchannel_list == p->subchannel_list) { - grpc_connectivity_state_set(exec_ctx, &p->state_tracker, - GRPC_CHANNEL_TRANSIENT_FAILURE, - GRPC_ERROR_REF(error), "subchannel_failed"); + exec_ctx, sd->subchannel_list, "pf_exhausted_subchannels"); + if (sd->subchannel_list == p->subchannel_list) { + grpc_connectivity_state_set(exec_ctx, &p->state_tracker, + GRPC_CHANNEL_IDLE, GRPC_ERROR_NONE, + "exhausted_subchannels+reresolve"); + p->started_picking = false; + grpc_lb_policy_try_reresolve( + exec_ctx, &p->base, &grpc_lb_pick_first_trace, GRPC_ERROR_NONE); + } + } else { + if (sd->subchannel_list == p->subchannel_list) { + grpc_connectivity_state_set( + exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE, + GRPC_ERROR_REF(error), "subchannel_failed"); + } + // Reuses the connectivity refs from the previous watch. + grpc_lb_subchannel_data_start_connectivity_watch(exec_ctx, sd); } - // Reuses the connectivity refs from the previous watch. - grpc_lb_subchannel_data_start_connectivity_watch(exec_ctx, sd); - break; } } } +static void pf_set_reresolve_closure_locked( + grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, + grpc_closure* request_reresolution) { + pick_first_lb_policy* p = (pick_first_lb_policy*)policy; + GPR_ASSERT(!p->shutdown); + GPR_ASSERT(policy->request_reresolution == nullptr); + policy->request_reresolution = request_reresolution; +} + static const grpc_lb_policy_vtable pick_first_lb_policy_vtable = { pf_destroy, pf_shutdown_locked, @@ -559,7 +592,8 @@ static const grpc_lb_policy_vtable pick_first_lb_policy_vtable = { pf_exit_idle_locked, pf_check_connectivity_locked, pf_notify_on_state_change_locked, - pf_update_locked}; + pf_update_locked, + pf_set_reresolve_closure_locked}; static void pick_first_factory_ref(grpc_lb_policy_factory* factory) {} diff --git a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc index 23a4cc4a5a3..f68daba474c 100644 --- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc +++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc @@ -20,9 +20,9 @@ * * Before every pick, the \a get_next_ready_subchannel_index_locked function * returns the p->subchannel_list->subchannels index for next subchannel, - * respecting the relative - * order of the addresses provided upon creation or updates. Note however that - * updates will start picking from the beginning of the updated list. */ + * respecting the relative order of the addresses provided upon creation or + * updates. Note however that updates will start picking from the beginning of + * the updated list. */ #include @@ -167,8 +167,9 @@ static void rr_destroy(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { gpr_free(p); } -static void shutdown_locked(grpc_exec_ctx* exec_ctx, round_robin_lb_policy* p, - grpc_error* error) { +static void rr_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { + round_robin_lb_policy* p = (round_robin_lb_policy*)pol; + grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown"); if (grpc_lb_round_robin_trace.enabled()) { gpr_log(GPR_DEBUG, "[RR %p] Shutting down", p); } @@ -194,15 +195,11 @@ static void shutdown_locked(grpc_exec_ctx* exec_ctx, round_robin_lb_policy* p, "sl_shutdown_pending_rr_shutdown"); p->latest_pending_subchannel_list = nullptr; } + grpc_lb_policy_try_reresolve(exec_ctx, &p->base, &grpc_lb_round_robin_trace, + GRPC_ERROR_CANCELLED); GRPC_ERROR_UNREF(error); } -static void rr_shutdown_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol) { - round_robin_lb_policy* p = (round_robin_lb_policy*)pol; - shutdown_locked(exec_ctx, p, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown")); -} - static void rr_cancel_pick_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* pol, grpc_connected_subchannel** target, grpc_error* error) { @@ -255,10 +252,12 @@ static void start_picking_locked(grpc_exec_ctx* exec_ctx, round_robin_lb_policy* p) { p->started_picking = true; for (size_t i = 0; i < p->subchannel_list->num_subchannels; i++) { - grpc_lb_subchannel_list_ref_for_connectivity_watch(p->subchannel_list, - "connectivity_watch"); - grpc_lb_subchannel_data_start_connectivity_watch( - exec_ctx, &p->subchannel_list->subchannels[i]); + if (p->subchannel_list->subchannels[i].subchannel != nullptr) { + grpc_lb_subchannel_list_ref_for_connectivity_watch(p->subchannel_list, + "connectivity_watch"); + grpc_lb_subchannel_data_start_connectivity_watch( + exec_ctx, &p->subchannel_list->subchannels[i]); + } } } @@ -346,71 +345,71 @@ static void update_state_counters_locked(grpc_lb_subchannel_data* sd) { } /** Sets the policy's connectivity status based on that of the passed-in \a sd - * (the grpc_lb_subchannel_data associted with the updated subchannel) and the - * subchannel list \a sd belongs to (sd->subchannel_list). \a error will only be - * used upon policy transition to TRANSIENT_FAILURE or SHUTDOWN. Returns the - * connectivity status set. */ -static grpc_connectivity_state update_lb_connectivity_status_locked( - grpc_exec_ctx* exec_ctx, grpc_lb_subchannel_data* sd, grpc_error* error) { + * (the grpc_lb_subchannel_data associated with the updated subchannel) and the + * subchannel list \a sd belongs to (sd->subchannel_list). \a error will be used + * only if the policy transitions to state TRANSIENT_FAILURE. */ +static void update_lb_connectivity_status_locked(grpc_exec_ctx* exec_ctx, + grpc_lb_subchannel_data* sd, + grpc_error* error) { /* In priority order. The first rule to match terminates the search (ie, if we * are on rule n, all previous rules were unfulfilled). * * 1) RULE: ANY subchannel is READY => policy is READY. - * CHECK: At least one subchannel is ready iff p->ready_list is NOT empty. + * CHECK: subchannel_list->num_ready > 0. * * 2) RULE: ANY subchannel is CONNECTING => policy is CONNECTING. * CHECK: sd->curr_connectivity_state == CONNECTING. * - * 3) RULE: ALL subchannels are SHUTDOWN => policy is SHUTDOWN. - * CHECK: p->subchannel_list->num_shutdown == - * p->subchannel_list->num_subchannels. + * 3) RULE: ALL subchannels are SHUTDOWN => policy is IDLE (and requests + * re-resolution). + * CHECK: subchannel_list->num_shutdown == + * subchannel_list->num_subchannels. * * 4) RULE: ALL subchannels are TRANSIENT_FAILURE => policy is - * TRANSIENT_FAILURE. - * CHECK: p->num_transient_failures == p->subchannel_list->num_subchannels. + * TRANSIENT_FAILURE. + * CHECK: subchannel_list->num_transient_failures == + * subchannel_list->num_subchannels. * * 5) RULE: ALL subchannels are IDLE => policy is IDLE. - * CHECK: p->num_idle == p->subchannel_list->num_subchannels. + * CHECK: subchannel_list->num_idle == subchannel_list->num_subchannels. + * (Note that all the subchannels will transition from IDLE to CONNECTING + * in batch when we start trying to connect.) */ - grpc_connectivity_state new_state = sd->curr_connectivity_state; + // TODO(juanlishen): if the subchannel states are mixed by {SHUTDOWN, + // TRANSIENT_FAILURE}, we don't change the state. We may want to improve on + // this. grpc_lb_subchannel_list* subchannel_list = sd->subchannel_list; round_robin_lb_policy* p = (round_robin_lb_policy*)subchannel_list->policy; - if (subchannel_list->num_ready > 0) { /* 1) READY */ + if (subchannel_list->num_ready > 0) { + /* 1) READY */ grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_READY, GRPC_ERROR_NONE, "rr_ready"); - new_state = GRPC_CHANNEL_READY; - } else if (sd->curr_connectivity_state == - GRPC_CHANNEL_CONNECTING) { /* 2) CONNECTING */ + } else if (sd->curr_connectivity_state == GRPC_CHANNEL_CONNECTING) { + /* 2) CONNECTING */ grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE, "rr_connecting"); - new_state = GRPC_CHANNEL_CONNECTING; - } else if (p->subchannel_list->num_shutdown == - p->subchannel_list->num_subchannels) { /* 3) SHUTDOWN */ - grpc_connectivity_state_set(exec_ctx, &p->state_tracker, - GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_REF(error), - "rr_shutdown"); - p->shutdown = true; - new_state = GRPC_CHANNEL_SHUTDOWN; - if (grpc_lb_round_robin_trace.enabled()) { - gpr_log(GPR_INFO, - "[RR %p] Shutting down: all subchannels have gone into shutdown", - (void*)p); - } + } else if (subchannel_list->num_shutdown == + subchannel_list->num_subchannels) { + /* 3) IDLE and re-resolve */ + grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_IDLE, + GRPC_ERROR_NONE, + "rr_exhausted_subchannels+reresolve"); + p->started_picking = false; + grpc_lb_policy_try_reresolve(exec_ctx, &p->base, &grpc_lb_round_robin_trace, + GRPC_ERROR_NONE); } else if (subchannel_list->num_transient_failures == - p->subchannel_list->num_subchannels) { /* 4) TRANSIENT_FAILURE */ + subchannel_list->num_subchannels) { + /* 4) TRANSIENT_FAILURE */ grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE, GRPC_ERROR_REF(error), "rr_transient_failure"); - new_state = GRPC_CHANNEL_TRANSIENT_FAILURE; - } else if (subchannel_list->num_idle == - p->subchannel_list->num_subchannels) { /* 5) IDLE */ + } else if (subchannel_list->num_idle == subchannel_list->num_subchannels) { + /* 5) IDLE */ grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_IDLE, GRPC_ERROR_NONE, "rr_idle"); - new_state = GRPC_CHANNEL_IDLE; } GRPC_ERROR_UNREF(error); - return new_state; } static void rr_connectivity_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, @@ -454,21 +453,16 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, // state (which was set by the connectivity state watcher) to // curr_connectivity_state, which is what we use inside of the combiner. sd->curr_connectivity_state = sd->pending_connectivity_state_unsafe; - // Update state counters and determine new overall state. + // Update state counters and new overall state. update_state_counters_locked(sd); - const grpc_connectivity_state new_policy_connectivity_state = - update_lb_connectivity_status_locked(exec_ctx, sd, GRPC_ERROR_REF(error)); - // If the sd's new state is SHUTDOWN, unref the subchannel, and if the new - // policy's state is SHUTDOWN, clean up. + update_lb_connectivity_status_locked(exec_ctx, sd, GRPC_ERROR_REF(error)); + // If the sd's new state is SHUTDOWN, unref the subchannel. if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) { grpc_lb_subchannel_data_stop_connectivity_watch(exec_ctx, sd); grpc_lb_subchannel_data_unref_subchannel(exec_ctx, sd, "rr_connectivity_shutdown"); grpc_lb_subchannel_list_unref_for_connectivity_watch( exec_ctx, sd->subchannel_list, "rr_connectivity_shutdown"); - if (new_policy_connectivity_state == GRPC_CHANNEL_SHUTDOWN) { - shutdown_locked(exec_ctx, p, GRPC_ERROR_REF(error)); - } } else { // sd not in SHUTDOWN if (sd->curr_connectivity_state == GRPC_CHANNEL_READY) { if (sd->connected_subchannel == nullptr) { @@ -504,7 +498,7 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx* exec_ctx, void* arg, } /* at this point we know there's at least one suitable subchannel. Go * ahead and pick one and notify the pending suitors in - * p->pending_picks. This preemtively replicates rr_pick()'s actions. */ + * p->pending_picks. This preemptively replicates rr_pick()'s actions. */ const size_t next_ready_index = get_next_ready_subchannel_index_locked(p); GPR_ASSERT(next_ready_index < p->subchannel_list->num_subchannels); grpc_lb_subchannel_data* selected = @@ -642,6 +636,15 @@ static void rr_update_locked(grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, } } +static void rr_set_reresolve_closure_locked( + grpc_exec_ctx* exec_ctx, grpc_lb_policy* policy, + grpc_closure* request_reresolution) { + round_robin_lb_policy* p = (round_robin_lb_policy*)policy; + GPR_ASSERT(!p->shutdown); + GPR_ASSERT(policy->request_reresolution == nullptr); + policy->request_reresolution = request_reresolution; +} + static const grpc_lb_policy_vtable round_robin_lb_policy_vtable = { rr_destroy, rr_shutdown_locked, @@ -652,7 +655,8 @@ static const grpc_lb_policy_vtable round_robin_lb_policy_vtable = { rr_exit_idle_locked, rr_check_connectivity_locked, rr_notify_on_state_change_locked, - rr_update_locked}; + rr_update_locked, + rr_set_reresolve_closure_locked}; static void round_robin_factory_ref(grpc_lb_policy_factory* factory) {}