| 253 | } |
| 254 | |
| 255 | func (w *TriggerLevelWriter) WriteLevel(l Level, p []byte) (n int, err error) { |
| 256 | w.mu.Lock() |
| 257 | defer w.mu.Unlock() |
| 258 | |
| 259 | // At first trigger level or above log line, we flush the buffer and change the |
| 260 | // trigger state to triggered. |
| 261 | if !w.triggered && l >= w.TriggerLevel { |
| 262 | err := w.trigger() |
| 263 | if err != nil { |
| 264 | return 0, err |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | // Unless triggered, we buffer everything at and below ConditionalLevel. |
| 269 | if !w.triggered && l <= w.ConditionalLevel { |
| 270 | if w.buf == nil { |
| 271 | w.buf = triggerWriterPool.Get().(*bytes.Buffer) |
| 272 | } |
| 273 | |
| 274 | // We prefix each log line with a byte with the level. |
| 275 | // Hopefully we will never have a level value which equals a newline |
| 276 | // (which could interfere with reconstruction of log lines in the trigger method). |
| 277 | w.buf.WriteByte(byte(l)) |
| 278 | w.buf.Write(p) |
| 279 | return len(p), nil |
| 280 | } |
| 281 | |
| 282 | // Anything above ConditionalLevel is always passed through. |
| 283 | // Once triggered, everything is passed through. |
| 284 | if lw, ok := w.Writer.(LevelWriter); ok { |
| 285 | return lw.WriteLevel(l, p) |
| 286 | } |
| 287 | return w.Write(p) |
| 288 | } |
| 289 | |
| 290 | // trigger expects lock to be held. |
| 291 | func (w *TriggerLevelWriter) trigger() error { |