channelz: cleanup channel registration if Dial fails #2733
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menghanl
reviewed
Apr 2, 2019
clientconn.go
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| @@ -153,6 +153,18 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn * | |||
| }) | |||
| } | |||
| cc.csMgr.channelzID = cc.channelzID | |||
| defer func() { | |||
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cc.Close() will also remove channel and add trace channel deleted.
Move RegisterChannel down (right before defer with cc.Close()), then this should be covered by cc.Close().
menghanl
approved these changes
Apr 2, 2019
| @@ -196,18 +208,6 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn * | |||
| defer cancel() | |||
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Does this work if there's a timeout set (cc.dopts.timeout > 0) ? In that case, the deferred actions will happen in the reverse order with this PR, so the auto-cancel() of the replaced ctx (with a timeout) happens before the check whether ctx is Done(), which means a cancellation error will always be returned.
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Right!
I filed #2736 to track. Will have a solution shortly!
Thanks for noting and mentioning this!!
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I've got a fix & testcase on its way.
daviddrysdale
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Apr 3, 2019
Seems like grpc/grpc-go#2733 has resulted in behaviour where any attempt to gRPC dial with a timeout gives a cancelled-context error.
daviddrysdale
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Apr 3, 2019
Seems like grpc/grpc-go#2733 has resulted in behaviour where any attempt to gRPC dial with a timeout gives a cancelled-context error.
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daviddrysdale
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Apr 3, 2019
Seems like grpc/grpc-go#2733 has resulted in behaviour where any attempt to gRPC dial with a timeout gives a cancelled-context error.
daviddrysdale
added a commit
to google/trillian
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Apr 3, 2019
Seems like grpc/grpc-go#2733 has resulted in behaviour where any attempt to gRPC dial with a timeout gives a cancelled-context error.
daviddrysdale
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Apr 3, 2019
Commit 955eb8a ("channelz: cleanup channel registration if Dial fails (grpc#2733)") moved a defer block earlier in DialContext() to ensure that cc.Close() was always called. This defer block also checks whether the ctx.Done() is true, and if so ensures the context error is returned. If the dial options include a timeout, the original context gets replaced with a new context that has the timeout, and this gets a catchall `defer cancel()` to go with it. However, this cancel() now gets called before the cleanup defer block, so when the latter runs the context is always already cancelled. Fix by splitting the larger defer block into two parts: - The part that does cc.Close() stays near the beginning of the method. - The part that checks ctx.Done() returns to below the `defer cancel()` call, and so gets invoked before it.
daviddrysdale
added a commit
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Apr 3, 2019
Commit 955eb8a ("channelz: cleanup channel registration if Dial fails (grpc#2733)") moved a defer block earlier in DialContext() to ensure that cc.Close() was always called. This defer block also checks whether the ctx.Done() is true, and if so ensures the context error is returned. If the dial options include a timeout, the original context gets replaced with a new context that has the timeout, and this gets a catchall `defer cancel()` to go with it. However, this cancel() now gets called before the cleanup defer block, so when the latter runs the context is always already cancelled. Fix by splitting the larger defer block into two parts: - The part that does cc.Close() stays near the beginning of the method. - The part that checks ctx.Done() returns to below the `defer cancel()` call, and so gets invoked before it.
daviddrysdale
added a commit
to daviddrysdale/grpc-go
that referenced
this pull request
Apr 3, 2019
Commit 955eb8a ("channelz: cleanup channel registration if Dial fails (grpc#2733)") moved a defer block earlier in DialContext() to ensure that cc.Close() was always called. This defer block also checks whether the ctx.Done() is true, and if so ensures the context error is returned. If the dial options include a timeout, the original context gets replaced with a new context that has the timeout, and this gets a catchall `defer cancel()` to go with it. However, this cancel() now gets called before the cleanup defer block, so when the latter runs the context is always already cancelled. Fix by splitting the larger defer block into two parts: - The part that does cc.Close() stays near the beginning of the method. - The part that checks ctx.Done() returns to below the `defer cancel()` call, and so gets invoked before it.
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