[common] Introduce testlogger as a workaround of poor lifecycle #1398
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| // Copyright (c) 2017-2021 Uber Technologies Inc. | ||
| // | ||
| // Permission is hereby granted, free of charge, to any person obtaining a copy | ||
| // of this software and associated documentation files (the "Software"), to deal | ||
| // in the Software without restriction, including without limitation the rights | ||
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | ||
| // copies of the Software, and to permit persons to whom the Software is | ||
| // furnished to do so, subject to the following conditions: | ||
| // | ||
| // The above copyright notice and this permission notice shall be included in | ||
| // all copies or substantial portions of the Software. | ||
| // | ||
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | ||
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | ||
| // THE SOFTWARE. | ||
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| package testlogger | ||
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| import ( | ||
| "fmt" | ||
| "slices" | ||
| "strings" | ||
| "sync" | ||
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| "github.com/stretchr/testify/require" | ||
| "go.uber.org/atomic" | ||
| "go.uber.org/zap" | ||
| "go.uber.org/zap/zapcore" | ||
| "go.uber.org/zap/zaptest" | ||
| "go.uber.org/zap/zaptest/observer" | ||
| ) | ||
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| type TestingT interface { | ||
| zaptest.TestingT | ||
| Cleanup(func()) // not currently part of zaptest.TestingT | ||
| } | ||
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| // NewZap makes a new test-oriented logger that prevents bad-lifecycle logs from failing tests. | ||
| func NewZap(t TestingT) *zap.Logger { | ||
| /* | ||
| HORRIBLE HACK due to async shutdown, both in our code and in libraries: | ||
| normally, logs produced after a test finishes will *intentionally* fail the test and/or | ||
| cause data to race on the test's internal `t.done` field. | ||
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| that's a good thing, it reveals possibly-dangerously-flawed lifecycle management. | ||
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| unfortunately some of our code and some libraries do not have good lifecycle management, | ||
| and this cannot easily be patched from the outside. | ||
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| so this logger cheats: after a test completes, it logs to stderr rather than TestingT. | ||
| EVERY ONE of these logs is bad and we should not produce them, but it's causing many | ||
| otherwise-useful tests to be flaky, and that's a larger interruption than is useful. | ||
| */ | ||
| logAfterComplete, err := zap.NewDevelopment() | ||
| require.NoError(t, err, "could not build a fallback zap logger") | ||
| replaced := &fallbackTestCore{ | ||
| t: t, | ||
| fallback: logAfterComplete.Core(), | ||
| testing: zaptest.NewLogger(t).Core(), | ||
| completed: &atomic.Bool{}, | ||
| } | ||
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| t.Cleanup(replaced.UseFallback) // switch to fallback before ending the test | ||
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| return zap.New(replaced) | ||
| } | ||
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| // NewObserved makes a new test logger that both logs to `t` and collects logged | ||
| // events for asserting in tests. | ||
| func NewObserved(t TestingT) (*zap.Logger, *observer.ObservedLogs) { | ||
| obsCore, obs := observer.New(zapcore.DebugLevel) | ||
| z := NewZap(t) | ||
| z = z.WithOptions(zap.WrapCore(func(core zapcore.Core) zapcore.Core { | ||
| return zapcore.NewTee(core, obsCore) | ||
| })) | ||
| return z, obs | ||
| } | ||
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| type fallbackTestCore struct { | ||
| sync.Mutex | ||
| t TestingT | ||
| fallback zapcore.Core | ||
| testing zapcore.Core | ||
| completed *atomic.Bool | ||
| } | ||
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| var _ zapcore.Core = (*fallbackTestCore)(nil) | ||
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| func (f *fallbackTestCore) UseFallback() { | ||
| f.completed.Store(true) | ||
| } | ||
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| func (f *fallbackTestCore) Enabled(level zapcore.Level) bool { | ||
| if f.completed.Load() { | ||
| return f.fallback.Enabled(level) | ||
| } | ||
| return f.testing.Enabled(level) | ||
| } | ||
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| func (f *fallbackTestCore) With(fields []zapcore.Field) zapcore.Core { | ||
| // need to copy and defer, else the returned core will be used at an | ||
| // arbitrarily later point in time, possibly after the test has completed. | ||
| return &fallbackTestCore{ | ||
| t: f.t, | ||
| fallback: f.fallback.With(fields), | ||
| testing: f.testing.With(fields), | ||
| completed: f.completed, | ||
| } | ||
| } | ||
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| func (f *fallbackTestCore) Check(entry zapcore.Entry, checked *zapcore.CheckedEntry) *zapcore.CheckedEntry { | ||
| // see other Check impls, all look similar. | ||
| // this defers the "where to log" decision to Write, as `f` is the core that will write. | ||
| if f.fallback.Enabled(entry.Level) { | ||
| return checked.AddCore(entry, f) | ||
| } | ||
| return checked // do not add any cores | ||
| } | ||
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| func (f *fallbackTestCore) Write(entry zapcore.Entry, fields []zapcore.Field) error { | ||
| if f.completed.Load() { | ||
| entry.Message = fmt.Sprintf("COULD FAIL TEST %q, logged too late: %v", f.t.Name(), entry.Message) | ||
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| hasStack := slices.ContainsFunc(fields, func(field zapcore.Field) bool { | ||
| // no specific stack-trace type, so just look for probable fields. | ||
| return strings.Contains(strings.ToLower(field.Key), "stack") | ||
| }) | ||
| if !hasStack { | ||
| fields = append(fields, zap.Stack("log_stack")) | ||
| } | ||
| return f.fallback.Write(entry, fields) | ||
| } | ||
| // Ensure no concurrent writes to the test logger. | ||
| f.Lock() | ||
| defer f.Unlock() | ||
| return f.testing.Write(entry, fields) | ||
| } | ||
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| func (f *fallbackTestCore) Sync() error { | ||
| if f.completed.Load() { | ||
| return f.fallback.Sync() | ||
| } | ||
| return f.testing.Sync() | ||
| } | ||
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