gRPC源碼/服務發現

代碼

GitHub - messixukejia/grpc-wrapper: wrapper of grpc

關鍵資料結構

流程處理

關鍵流程圖

1、用戶端開工階段從etcd擷取所有服務端地址，並watch服務端變更。
2、服務端變化，推送給watch的用戶端。
3、服務端開工階段，將自己的地址資訊put到etcd。

服務端

1、向ETCD建立用戶端串連：etcd.New。
2、建立ETCD註冊器：NewEtcdRegisty，用於與ETCD的互動，例如註冊服務地址等。
3、建立grpc server，並註冊相應的服務。
4、啟動server，並將自己服務資訊通過etcdRegistry.Register
向ETCD註冊，在監聽用戶端串連強求，處理相應業務。

用戶端

1、向ETCD建立用戶端串連：etcd.New。
2、建立ETCD resolver：NewEtcdResolver，用於與ETCD的互動。
3、建立負載平衡策略，並向服務端Dial。
3.1、newCCResolverWrapper->Builder
.Build(Builder creates a resolver that will be used to watch name resolution updates。預設使用defaultScheme = ”passthrough“。)->passthroughResolver.start->NewAddress->轉到3.2
3.2、resolverWrapper.start->ccResolverWrapper.watcher監控地址變化->handleResolvedAddrs/handleServiceConfig

3.3、首次newCCBalancerWrapper->balancerWrapperBuilder.Build->根據制定的負載平衡策略Start->Resolve（建立watcher）->起goroutine監控地址變化watchAddrUpdates（Next中watch etcd資料變化）-> update地址寫入addrCh
3.4、lbWatcher監控addrCh->生效到用戶端NewSubConn/RemoveSubConn

4、向服務端發起資料請求。

日誌

用戶端日誌：ETCD相關：{"level":"info","ts":1528723680.321994,"caller":"client/client.go:64","msg":"begin to create etcd"}{"level":"info","ts":1528723680.32224,"caller":"grpc/clientconn.go:494","msg":"parsed scheme: \"\""}{"level":"info","ts":1528723680.322293,"caller":"grpc/clientconn.go:500","msg":"scheme \"\" not registered, fallback to default scheme"}{"level":"info","ts":1528723680.3223171,"caller":"passthrough/passthrough.go:51","msg":"passthrough newaddress add 127.0.0.1:2379\n"}{"level":"info","ts":1528723680.322419,"caller":"client/client.go:70","msg":"end etcd"}{"level":"info","ts":1528723680.322929,"caller":"grpc/resolver_conn_wrapper.go:116","msg":"ccResolverWrapper: sending new addresses to cc: [{127.0.0.1:2379 0  <nil>}]"}{"level":"warn","ts":1528723680.323195,"caller":"grpc/balancer_v1_wrapper.go:269","msg":"Handle [{127.0.0.1:2379 0  <nil>}]. Err: <nil>"}{"level":"info","ts":1528723680.32329,"caller":"grpc/balancer_v1_wrapper.go:125","msg":"balancerWrapper: got update addr from Notify: [{127.0.0.1:2379 <nil>}]\n"}服務側相關：2018/06/11 21:28:00 Initializing logging reporter{"level":"info","ts":1528723680.324028,"caller":"client/client.go:85","msg":"begin to dial"}{"level":"info","ts":1528723680.324024,"caller":"grpc/balancer_v1_wrapper.go:125","msg":"balancerWrapper: got update addr from Notify: [{127.0.0.1:2379 <nil>}]\n"}{"level":"info","ts":1528723680.324088,"caller":"grpc/clientconn.go:494","msg":"parsed scheme: \"\""}{"level":"info","ts":1528723680.324113,"caller":"grpc/clientconn.go:500","msg":"scheme \"\" not registered, fallback to default scheme"}{"level":"info","ts":1528723680.324137,"caller":"passthrough/passthrough.go:51","msg":"passthrough newaddress add HelloServer\n"}{"level":"info","ts":1528723680.324235,"caller":"grpc/resolver_conn_wrapper.go:116","msg":"ccResolverWrapper: sending new addresses to cc: [{HelloServer 0  <nil>}]"}{"level":"warn","ts":1528723680.324367,"caller":"grpc/balancer_v1_wrapper.go:269","msg":"Handle [{HelloServer 0  <nil>}]. Err: <nil>"}{"level":"info","ts":1528723680.3257082,"caller":"plugins/etcd.go:136","msg":"etcd get upt is {0 127.0.0.1:1234 ...}\n"}{"level":"info","ts":1528723680.327142,"caller":"grpc/balancer_v1_wrapper.go:125","msg":"balancerWrapper: got update addr from Notify: [{127.0.0.1:1234 ...}]\n"}2018/06/11 21:28:00 Reporting span 72551c84db313989:72551c84db313989:0:1{"level":"info","ts":1528723680.431375,"caller":"client/client.go:106","msg":"Greeting: Hello defaultName"}