| # Logging Conventions |
| |
| etcd uses the [zap][zap] library for logging application output categorized into *levels*. A log message's level is determined according to these conventions: |
| |
| * Debug: Everything is still fine, but even common operations may be logged, and less helpful but more quantity of notices. Usually not used in production. |
| * Examples: |
| * Send a normal message to a remote peer |
| * Write a log entry to disk |
| |
| * Info: Normal, working log information, everything is fine, but helpful notices for auditing or common operations. Should rather not be logged more frequently than once per a few seconds in a normal server's operation. |
| * Examples: |
| * Startup configuration |
| * Start to do a snapshot |
| |
| * Warning: (Hopefully) Temporary conditions that may cause errors, but may work fine. A replica disappearing (that may reconnect) is a warning. |
| * Examples: |
| * Failure to send a raft message to a remote peer |
| * Failure to receive heartbeat message within the configured election timeout |
| |
| * Error: Data has been lost, a request has failed for a bad reason, or a required resource has been lost. |
| * Examples: |
| * Failure to allocate disk space for WAL |
| |
| * Panic: Unrecoverable or unexpected error situation that requires stopping execution. |
| * Examples: |
| * Failure to create the database |
| |
| * Fatal: Unrecoverable or unexpected error situation that requires immediate exit. Mostly used in the test. |
| * Examples: |
| * Failure to find the data directory |
| * Failure to run a test function |
| |
| [zap]: https://github.com/uber-go/zap |
