client: avoid finishing a stream twice when stream creation fails (#9191) In `clientStream.withRetry`, when `newAttemptLocked` fails before an attempt is created, `withRetry` called `cs.finish` and then returned the error. `newClientStream` also runs `endOfClientStream` from its deferred cleanup on an error return, so the stream was finished twice and every `grpc.OnFinish` callback ran twice for a single RPC, breaking its documented "called only once" contract. One of those callbacks is the idleness manager's `OnCallEnd`. The extra `OnCallEnd` pushes the manager's int32 `activeCallsCount` one below its `-math.MaxInt32` idle sentinel and corrupts the counter. After that the channel can get permanently stuck in IDLE, and later RPCs fail with "context deadline exceeded while waiting for connections to become ready" even though the backend is reachable. It happens when RPCs are canceled around the idle-timeout boundary. On this path no attempt is created, so there is nothing to finish: the context is canceled by `newClientStreamWithParams`'s deferred cleanup, and `newClientStream`'s deferred `endOfClientStream` finishes the stream exactly once. Replace the `cs.finish` call with `cs.commitAttemptLocked` so the stream is still committed, releasing resources held for retries such as the config selector's `OnCommitted` callback, without being finished a second time. This mirrors the `retryLocked` give-up path. Add a regression test that fails before this change and passes after it. RELEASE NOTES: * client: Fix a bug where a ClientConn could get permanently stuck in IDLE after an RPC was canceled while the channel was exiting idle mode
The Go implementation of gRPC: A high performance, open source, general RPC framework that puts mobile and HTTP/2 first. For more information see the Go gRPC docs, or jump directly into the quick start.
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import "google.golang.org/grpc"
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The default logger is controlled by environment variables. Turn everything on like this:
$ export GRPC_GO_LOG_VERBOSITY_LEVEL=99 $ export GRPC_GO_LOG_SEVERITY_LEVEL=info
"code = Unavailable desc = transport is closing"This error means the connection the RPC is using was closed, and there are many possible reasons, including:
It can be tricky to debug this because the error happens on the client side but the root cause of the connection being closed is on the server side. Turn on logging on both client and server, and see if there are any transport errors.