(原创)C/C语言， 平台是debian10, grpc版本：grpc-c/1.25.0-dev, 使用的例子是自带的例子GreeterClient
创建 default-executor 和 resolver-executor 线程的主要流程，创建channel时会创建这2个线程
graph TD; 000(grpc::InsecureChannelCredentials #credentials.h:91 调用InsecureChannelCredentials)-->001(grpc_impl::InsecureChannelCredentials #insecure_credentials.cc:59 创建一个共享的InsecureChannelCredentialsImpl对象) 001-->002(grpc_impl::InsecureChannelCredentialsImpl::InsecureChannelCredentialsImpl #insecure_credentials.cc:30 调用父类ChannelCredentials构造函数) 002-->003(grpc_impl::ChannelCredentials::ChannelCredentials #credentials_cc.cc:25 调用父类GrpcLibraryCodegen构造函数) 003-->004(grpc::GrpcLibraryCodegen::GrpcLibraryCodegen #grpc_library.h:45 调用GrpcLibraryInterface的init) 004-->005(grpc::internal::GrpcLibrary::init #grpc_library.h:34 调用grpc_init) 005-->006(grpc_init #init.cc:146 调用grpc_iomgr_init) 006-->007(grpc_iomgr_init #iomgr.cc:60 调用grpc_core::Executor::InitAll) 007-->008(创建 default-executor 和 resolver-executor 线程) 008-->009(grpc_iomgr_start #iomgr.cc:69 调用grpc_timer_manager_init) 009-->010(grpc_timer_manager_init #timer_manager.cc:311 调用start_threads) 010-->011(start_threads #timer_manager.cc:293 调用start_timer_thread_and_unlock) 011-->012(start_timer_thread_and_unlock #timer_manager.cc:91 启动grpc_global_timer线程)
grpc Unary模式下客户端启动到执行grpc_connector_connect的主要流程
graph TD; 000(grpc::internal::BlockingUnaryCall #client_unary_call.h:43)-->001(grpc::internal::BlockingUnaryCallImpl::BlockingUnaryCallImpl #client_unary_call.h:71 创建CompletionQueue, Call, CallOpSet对象, 设置CallOpSet对象参数, 调用PerformOps) 001-->002(grpc::internal::Call::PerformOps #call.h:69 调用PerformOpsOnCall) 002-->003(grpc_impl::Channel::PerformOpsOnCall #channel_cc.cc:164 调用FillOps) 003-->004(grpc::internal::CallOpSet::FillOps #call_op_set.h:874 调用ContinueFillOpsAfterInterception) 004-->005(grpc::internal::CallOpSet::ContinueFillOpsAfterInterception #call_op_set.h:943 调用6个op的AddOp并调用grpc_call_start_batch) 005-->006(grpc::CoreCodegen::grpc_call_start_batch #core_codegen.cc:113 调用grpc_call_start_batch) 006-->007(grpc_call_start_batch #call.cc:1974 调用call_start_batch) 007-->008(call_start_batch #call.cc:1929 根据6个ops的op->op, 设置stream_op, ops, call的参数, 最后调用execute_batch) 008-->009(execute_batch #call.cc:639 调用start_batch_closure的callback函数 execute_batch_in_call_combiner) 009-->010(execute_batch_in_call_combiner #call.cc:628 调用 elem->filter->start_transport_stream_op_batch) 010-->011(grpc_call_next_op #channel_stack.cc:227 调用 next_elem->filter->start_transport_stream_op_batch) 011-->012(grpc_core::CallData::StartTransportStreamOpBatch #client_channel.cc:2140 把batch加入pending:PendingBatchesAdd并调用PickSubchannel) 012-->013(grpc_core::CallData::PickSubchannel #client_channel.cc:3853 调用PickSubchannelLocked返回false) 013-->014(grpc_core::CallData::PickSubchannelLocked #client_channel.cc:3870 picker_是nullptr, 调用CheckConnectivityState, 参数设定为尝试连接) 014-->015(grpc_core::ChannelData::CheckConnectivityState #client_channel.cc:1956 创建closure并调用它的callback函数 TryToConnectLocked) 015-->016(closure_impl::closure_wrapper #closure.h:156 创建closure是callback函数是closure_impl::closure_wrapper, 真正的callback是 TryToConnectLocked) 016-->017(grpc_core::ChannelData::TryToConnectLocked #client_channel.cc:1946 调用CreateResolvingLoadBalancingPolicyLocked) 017-->018(grpc_core::ChannelData::CreateResolvingLoadBalancingPolicyLocked #client_channel.cc:1596 调用ResolvingLoadBalancingPolicy构造函数) 018-->019(grpc_core::ResolvingLoadBalancingPolicy #resolving_lb_policy.cc:199 创建CreateResolver, UpdateState并调用StartLocked开始解析) 019-->020(grpc_core::AresDnsResolver::StartLocked #dns_resolver_ares.cc:177 调用MaybeStartResolvingLocked) 020-->021(grpc_core::AresDnsResolver::MaybeStartResolvingLocked #dns_resolver_ares.cc:409 调用StartResolvingLocked) 021-->022(grpc_core::AresDnsResolver::StartResolvingLocked #dns_resolver_ares.cc:420 调用grpc_dns_lookup_ares_locked) 022-->023(grpc_dns_lookup_ares_locked_impl #grpc_ares_wrapper.cc:625 调用grpc_dns_lookup_ares_continue_after_check_localhost_and_ip_literals_locked) 023-->024(grpc_dns_lookup_ares_continue_after_check_localhost_and_ip_literals_locked #grpc_ares_wrapper.cc:446 使用c-ares通过dns查找ip地址, 最后调用grpc_ares_request_unref_locked) 024-->025(grpc_ares_request_unref_locked #grpc_ares_wrapper.cc:135 如果延迟的查询为0, 调用grpc_ares_ev_driver_on_queries_complete_locked) 025-->026(grpc_ares_ev_driver_on_queries_complete_locked #grpc_ares_ev_driver.cc:191 停止查询,调用grpc_timer_cancel, 参数是query_timeout) 026-->027(grpc_timer_cancel #timer.cc:35 调用grpc_timer_impl->cancel) 027-->028(timer_cancel #timer_generic.cc:474 调用 timer->closure对应的callback函数) 028-->029(on_ares_backup_poll_alarm_locked #grpc_ares_ev_driver.cc:288 调用grpc_ares_ev_driver_unref) 029-->030(grpc_ares_ev_driver_unref #grpc_ares_ev_driver.cc:112 释放资源并调用grpc_ares_complete_request_locked) 030-->031(grpc_ares_complete_request_locked #grpc_ares_wrapper.cc:151 调用on_done对应的callback函数) 031-->032(grpc_core::AresDnsResolver::OnResolvedLocked #dns_resolver_ares.cc:347 解析完成, 调用ReturnResult) 032-->033(grpc_core::ResolvingLoadBalancingPolicy::ResolverResultHandler::ReturnResult #resolving_lb_policy.cc:87 调用OnResolverResultChangedLocked) 033-->034(OnResolverResultChangedLocked #resolving_lb_policy.cc:479 获得lb_policy_name,默认pick_first, 如果lb_policy_name不为空, 则创建或者更新LB policy, 调用的是CreateOrUpdateLbPolicyLocked) 034-->035(CreateOrUpdateLbPolicyLocked #resolving_lb_policy.cc:364 创建或者更新lb_policy, 调用UpdateLocked) 035-->036(PickFirst::UpdateLocked #pick_first.cc:280 调用AttemptToConnectUsingLatestUpdateArgsLocked) 036-->037(PickFirst::AttemptToConnectUsingLatestUpdateArgsLocked #pick_first.cc:236 用latest_update_args_创建 subchannel列表, 如果列表中的subchannel有状态是GRPC_CHANNEL_READY, 则选中此subchannel, 否则选中第0个subchannel) 037-->038(AttemptToConnect #client_channel.cc:921 调用subchannel_->AttemptToConnect) 038-->039(Subchannel::AttemptToConnect #subchannel.cc:823 调用MaybeStartConnectingLocked) 039-->040(Subchannel::MaybeStartConnectingLocked #subchannel.cc:930 调用ContinueConnectingLocked) 040-->041(Subchannel::ContinueConnectingLocked #subchannel.cc:983 设置grpc_connect_in_args参数并调用grpc_connector_connect, 通过connector->vtable->connect最后调用chttp2_connector_connect)