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Refactor MemoryLeakTestSuite

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as we identified two issues where the goroutine count from before differs from after the test.

1) It seemed like a Go runtime specific Goroutine appeared in rare cases before the test. To avoid this, we introduced a short timeout before looking up the Goroutines.
Another solution might be to do the lookup twice and check if the count matches.

2) A Goroutine that periodically monitors some storage unexpectedly got closed in rare cases. As we could not identify the cause for this, we removed the leaking Goroutines by properly cleaning up.
This commit is contained in:
Maximilian Paß
2024-02-27 21:42:18 +01:00
parent 80b8c27924
commit ab938bfc22
6 changed files with 56 additions and 33 deletions
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34
tests/util.go
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@@ -31,31 +31,35 @@ var numGoroutines = regexp.MustCompile(`^goroutine profile: total (\d*)\n`)
// Be aware not to overwrite the SetupTest or TearDownTest function!
type MemoryLeakTestSuite struct {
suite.Suite
ExpectedGoroutingIncrease int
ExpectedGoroutineIncrease int
TestCtx context.Context
testCtxCancel context.CancelFunc
goroutineCountBefore int
goroutinesBefore *bytes.Buffer
}
func (s *MemoryLeakTestSuite) SetupTest() {
// Without this first line we observed some goroutines just closing.
runtime.Gosched()
s.ExpectedGoroutingIncrease = 0
s.goroutinesBefore = &bytes.Buffer{}
err := pprof.Lookup("goroutine").WriteTo(s.goroutinesBefore, 1)
func (s *MemoryLeakTestSuite) lookupGoroutines() (debugOutput *bytes.Buffer, goroutineCount int) {
debugOutput = &bytes.Buffer{}
err := pprof.Lookup("goroutine").WriteTo(debugOutput, 1)
s.Require().NoError(err)
match := numGoroutines.FindSubmatch(s.goroutinesBefore.Bytes())
match := numGoroutines.FindSubmatch(debugOutput.Bytes())
if match == nil {
s.Fail("gouroutines could not be parsed: " + s.goroutinesBefore.String())
s.Fail("gouroutines could not be parsed: " + debugOutput.String())
}
// We do not use runtime.NumGoroutine() to not create inconsistency to the Lookup.
s.goroutineCountBefore, err = strconv.Atoi(string(match[1]))
goroutineCount, err = strconv.Atoi(string(match[1]))
if err != nil {
s.Fail("number of goroutines could not be parsed: " + err.Error())
}
return debugOutput, goroutineCount
}
func (s *MemoryLeakTestSuite) SetupTest() {
runtime.Gosched() // Flush done Goroutines
<-time.After(ShortTimeout) // Just to make sure
s.ExpectedGoroutineIncrease = 0
s.goroutinesBefore, s.goroutineCountBefore = s.lookupGoroutines()
ctx, cancel := context.WithCancel(context.Background())
s.TestCtx = ctx
@@ -66,13 +70,13 @@ func (s *MemoryLeakTestSuite) TearDownTest() {
s.testCtxCancel()
runtime.Gosched() // Flush done Goroutines
<-time.After(ShortTimeout) // Just to make sure
goroutinesAfter := runtime.NumGoroutine()
s.Equal(s.goroutineCountBefore+s.ExpectedGoroutingIncrease, goroutinesAfter)
if s.goroutineCountBefore+s.ExpectedGoroutingIncrease != goroutinesAfter {
goroutinesAfter, goroutineCountAfter := s.lookupGoroutines()
s.Equal(s.goroutineCountBefore+s.ExpectedGoroutineIncrease, goroutineCountAfter)
if s.goroutineCountBefore+s.ExpectedGoroutineIncrease != goroutineCountAfter {
_, err := io.Copy(os.Stderr, s.goroutinesBefore)
s.NoError(err)
err = pprof.Lookup("goroutine").WriteTo(os.Stderr, 1)
_, err = io.Copy(os.Stderr, goroutinesAfter)
s.NoError(err)
}
}