Fix datarace while update a channel.lastEventID #30
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The usage pattern: Imagine we have a client which subsribed to multiple topics
inside one connection. It track changes of specific items state by their ID
as example.
The test is passing in general case. But run it with race detection option and
it fails due data race condition detected.
==================
WARNING: DATA RACE
Write at 0x00c0000120d8 by goroutine 39:
github.com/alexandrevicenzi/go-sse.(*Channel).SendMessage()
/Users/iscander/projects/go-sse/channel.go:26 +0x8c
github.com/alexandrevicenzi/go-sse.(*Server).SendMessage()
/Users/iscander/projects/go-sse/sse.go:116 +0x21b
github.com/alexandrevicenzi/go-sse.TestMultipleTopics.func2()
/Users/iscander/projects/go-sse/sse_test.go:135 +0xce
Previous write at 0x00c0000120d8 by goroutine 38:
github.com/alexandrevicenzi/go-sse.(*Channel).SendMessage()
/Users/iscander/projects/go-sse/channel.go:26 +0x8c
github.com/alexandrevicenzi/go-sse.(*Server).SendMessage()
/Users/iscander/projects/go-sse/sse.go:116 +0x21b
github.com/alexandrevicenzi/go-sse.TestMultipleTopics.func2()
/Users/iscander/projects/go-sse/sse_test.go:135 +0xce
Goroutine 39 (running) created at:
github.com/alexandrevicenzi/go-sse.TestMultipleTopics()
/Users/iscander/projects/go-sse/sse_test.go:132 +0x735
testing.tRunner()
/usr/local/Cellar/go/1.16.3/libexec/src/testing/testing.go:1193 +0x202
Goroutine 38 (running) created at:
github.com/alexandrevicenzi/go-sse.TestMultipleTopics()
/Users/iscander/projects/go-sse/sse_test.go:132 +0x735
testing.tRunner()
/usr/local/Cellar/go/1.16.3/libexec/src/testing/testing.go:1193 +0x202
Protect the option by wrappring into a mutex. The datarace is gone. It closes alexandrevicenzi#18
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Protect the option by wrapping into a mutex. The data race is gone.
It closes #18
Provide fix and a unit test. The test was failing if run with race detection on.
go test -timeout 30s -v -race -run ^TestMultipleTopics$
....
WARNING: DATA RACE
Write at 0x00c0000120d8 by goroutine 39:
github.com/alexandrevicenzi/go-sse.(*Channel).SendMessage()
/Users/iscander/projects/go-sse/channel.go:26 +0x8c
github.com/alexandrevicenzi/go-sse.(*Server).SendMessage()
/Users/iscander/projects/go-sse/sse.go:116 +0x21b
github.com/alexandrevicenzi/go-sse.TestMultipleTopics.func2()
/Users/iscander/projects/go-sse/sse_test.go:135 +0xce
Previous write at 0x00c0000120d8 by goroutine 38:
github.com/alexandrevicenzi/go-sse.(*Channel).SendMessage()
/Users/iscander/projects/go-sse/channel.go:26 +0x8c
github.com/alexandrevicenzi/go-sse.(*Server).SendMessage()
/Users/iscander/projects/go-sse/sse.go:116 +0x21b
github.com/alexandrevicenzi/go-sse.TestMultipleTopics.func2()
/Users/iscander/projects/go-sse/sse_test.go:135 +0xce
Goroutine 39 (running) created at:
github.com/alexandrevicenzi/go-sse.TestMultipleTopics()
/Users/iscander/projects/go-sse/sse_test.go:132 +0x735
testing.tRunner()
/usr/local/Cellar/go/1.16.3/libexec/src/testing/testing.go:1193 +0x202
Goroutine 38 (running) created at:
github.com/alexandrevicenzi/go-sse.TestMultipleTopics()
/Users/iscander/projects/go-sse/sse_test.go:132 +0x735
testing.tRunner()
/usr/local/Cellar/go/1.16.3/libexec/src/testing/testing.go:1193 +0x202
...