Logging

Logs are, by default, sent to the console and will be visible as output to the docker logs. If you want to access the full set of logs, you can run docker logs {container name or id}.

Set the log level with the LOG_LEVEL environment variable. The options, from highest to lowest, are fatal, error, warn, info, debug, trace, and silent. Each level also logs everything above it, so fatal logs the least and trace the most. silent disables logging.

The default is info, which logs startup messages, messages the browser sends, warnings, and errors. For more detail, set it to debug to also log each successful request, cancelled queries, and retries. With Docker, pass --env LOG_LEVEL=debug to docker run. When running from source, add LOG_LEVEL=debug to .env.local in your configuration folder, which is packages/graph-explorer unless you set CONFIGURATION_FOLDER_PATH.

At debug and trace, when Enable database query logging on proxy server is turned on in Settings > General, the query text sent to the database is written to the logs. The setting is off by default. Queries can contain sensitive data, so use those levels for troubleshooting and restrict access to wherever the logs are stored. On SageMaker, the logs go to a CloudWatch log group shared with the notebook. See Logging and privacy.

The proxy server logging is split across a few key modules:

1. logging.ts - Contains the logger instance (using pino) that is responsible for actually recording the logs.
2. error-handler.ts - Contains errorHandlingMiddleware which catches errors thrown within Express routes, logs allowlisted request headers, and sends appropriate error responses. It also contains a handleError function used for global error handling.
3. The /logger endpoint in app.ts - This is how the browser logs to the server. It takes a POST with a JSON body of level (error, warn, info, debug, or trace) and message. The server logs the message at that level with source: "client" and responds with a 400 if the body is invalid.