Operational Logging

File-based logging creates multiple log files in the configured directory, one per level. The naming scheme is cbl_, the log level, the creation timestamp, .cbllog.

Log files are rotated (a new file created) when they reach the maxSize or when the server restarts. There will be up to rotateCount + 1 files of each log level; older files are deleted.

Keeping a separate file for each log level makes log rotation more effective: Logs of the important but less common levels warning and error will be kept around longer, since their log files grow more slowly.

The binary format is recommended because it is significantly faster to write, and more compact.

Log files can be read with the cbl-log tool. It decodes the binary format and merges all the log levels together sorted by timestamp.

Couchbase Lite groups log messages into named domains based on their subject. Common log domains are "Default", "REST", "Listener", "DB", "Query", "Sync".

The "REST" domain is used by the HTTP server to log client connections and requests. Its default level is "info", since a server typically logs these.

Other domains default to "warning", i.e. they log only warnings and errors, but for troubleshooting purposes the --verbose CLI flag overrides this and sets every domain to "info".

You can customize the level of each domain by adding a domains object to the logging configuration. Each key is a domain name and its value is the minimum level of messages to log.