diff --git a/README.md b/README.md index 65eec9c..08dd468 100644 --- a/README.md +++ b/README.md @@ -434,15 +434,22 @@ Logrus has a built in facility for asserting the presence of log messages. This * a test logger (`test.NewNullLogger`) that just records log messages (and does not output any): ```go -logger, hook := NewNullLogger() -logger.Error("Hello error") +import ( + "testing" + "github.com/sirupsen/logrus/hooks/null" +) -assert.Equal(1, len(hook.Entries)) -assert.Equal(logrus.ErrorLevel, hook.LastEntry().Level) -assert.Equal("Hello error", hook.LastEntry().Message) +func TestSomething(t *testing.T) { + logger, hook := null.NewNullLogger() + logger.Error("Hello error") -hook.Reset() -assert.Nil(hook.LastEntry()) + assert.Equal(1, len(hook.Entries)) + assert.Equal(logrus.ErrorLevel, hook.LastEntry().Level) + assert.Equal("Hello error", hook.LastEntry().Message) + + hook.Reset() + assert.Nil(hook.LastEntry()) +} ``` #### Fatal handlers diff --git a/hooks/null/null.go b/hooks/null/null.go new file mode 100644 index 0000000..01e9abc --- /dev/null +++ b/hooks/null/null.go @@ -0,0 +1,92 @@ +package null + +import ( + "io/ioutil" + "sync" + + "github.com/sirupsen/logrus" +) + +// Hook is a hook designed for dealing with logs in test scenarios. +type Hook struct { + // Entries is an array of all entries that have been received by this hook. + // For safe access, use the AllEntries() method, rather than reading this + // value directly. + Entries []*logrus.Entry + mu sync.RWMutex +} + +// NewGlobal installs a test hook for the global logger. +func NewGlobal() *Hook { + + hook := new(Hook) + logrus.AddHook(hook) + + return hook + +} + +// NewLocal installs a test hook for a given local logger. +func NewLocal(logger *logrus.Logger) *Hook { + + hook := new(Hook) + logger.Hooks.Add(hook) + + return hook + +} + +// NewNullLogger creates a discarding logger and installs the test hook. +func NewNullLogger() (*logrus.Logger, *Hook) { + + logger := logrus.New() + logger.Out = ioutil.Discard + + return logger, NewLocal(logger) + +} + +func (t *Hook) Fire(e *logrus.Entry) error { + t.mu.Lock() + defer t.mu.Unlock() + t.Entries = append(t.Entries, e) + return nil +} + +func (t *Hook) Levels() []logrus.Level { + return logrus.AllLevels +} + +// LastEntry returns the last entry that was logged or nil. +func (t *Hook) LastEntry() *logrus.Entry { + t.mu.RLock() + defer t.mu.RUnlock() + i := len(t.Entries) - 1 + if i < 0 { + return nil + } + // Make a copy, for safety + e := *t.Entries[i] + return &e +} + +// AllEntries returns all entries that were logged. +func (t *Hook) AllEntries() []*logrus.Entry { + t.mu.RLock() + defer t.mu.RUnlock() + // Make a copy so the returned value won't race with future log requests + entries := make([]*logrus.Entry, len(t.Entries)) + for i, entry := range t.Entries { + // Make a copy, for safety + e := *entry + entries[i] = &e + } + return entries +} + +// Reset removes all Entries from this test hook. +func (t *Hook) Reset() { + t.mu.Lock() + defer t.mu.Unlock() + t.Entries = make([]*logrus.Entry, 0) +}