Logging

The edge controller provides configurable logging to help you monitor its operation and troubleshoot issues.

Log output configuration

The FOXGLOVE_LOG_OUTPUT environment variable controls where the edge controller writes its logs. Three output modes are available:

Mode	Output destination	Best for
journald	System journal (systemd)	Production deployments with systemd
json	JSON-formatted logs to stderr	Log aggregation and automated parsing
text	Human-readable logs to stderr	Development and manual troubleshooting

Without FOXGLOVE_LOG_OUTPUT, the edge controller writes JSON logs to stderr. The installation guide's environment templates configure journald for the Debian package, and text for the standalone executable and Docker. The Kubernetes chart uses the default.

Viewing logs

How you access edge controller logs depends on your installation method and log output configuration.

Debian package

The edge controller writes structured log entries to the system journal. View logs with journalctl:

# View recent logs
journalctl -u foxglove-edge-controller

# Follow logs in real-time
journalctl -u foxglove-edge-controller -f

To export the binary journal (for example, to provide to Foxglove support):

journalctl -u foxglove-edge-controller --since "1 hour ago" -o export > foxglove-edge-controller.journal

Statically linked Linux executable

If you run the edge controller under systemd with FOXGLOVE_LOG_OUTPUT=journald, view logs with journalctl, replacing <unit-name> with your service's unit name:

# View recent logs
journalctl -u <unit-name>

# Follow logs in real-time
journalctl -u <unit-name> -f

To export the binary journal (for example, to provide to Foxglove support):

journalctl -u <unit-name> --since "1 hour ago" -o export > foxglove-edge-controller.journal

Otherwise, logs are written to stderr based on your FOXGLOVE_LOG_OUTPUT setting.

Docker image

Logs are written to stderr. Use docker logs to view them:

# View recent logs
docker logs foxglove-edge-controller

# Follow logs in real-time
docker logs -f foxglove-edge-controller

Kubernetes

Logs are written to stderr. Use kubectl logs to view them:

# View recent logs
kubectl logs -n foxglove statefulset/site-controller

# Follow logs in real-time
kubectl logs -n foxglove statefulset/site-controller -f

Log levels

The edge controller uses the following log levels, from least to most verbose:

• error: Critical errors that require attention
• warn: Warnings about potential issues or degraded operation
• info: General informational messages about edge controller activity (default)
• debug: Detailed diagnostic information for troubleshooting

Enabling debug logging

Set the FOXGLOVE_LOG environment variable to enable debug logging:

FOXGLOVE_LOG=info,edge_controller=debug,recording_store=debug

This configuration sets the log level to debug for the edge controller and its recording catalog, but retains a default log level of info for its other library dependencies.

Debug logging may be useful for:

• Investigating recording discovery and cataloging issues
• Troubleshooting upload problems
• Providing detailed logs when reporting issues to Foxglove support

warning

Don't leave debug logging enabled continuously in production environments, as it can:

• Generate large log volumes
• Make it harder to identify important messages
• Impact performance in high-throughput scenarios

Enable debug logging temporarily when investigating specific issues, then return to the default log level.