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Logging Guide

This document provides guidance for logging in Fabric-X networks.

Log Configuration

Logging is configured in each component's configuration file via the LogSpec field.

Available Log Levels

Level Description
debug Detailed debug information
info General operational information
warning Warning conditions
error Error conditions
fatal Fatal errors (process exits)

Configuration Example

General:
  LogSpec: info

Log Output

By default, logs are written to: - stdout/stderr for all deployments - Log file path if explicitly configured

Viewing Logs

# For systemd deployments (if configured)
journalctl -u arma-router -f

# For direct binary execution
tail -f /var/log/arma/router.log

# For Docker
docker logs -f <container-id>

# For Kubernetes
kubectl logs -f -l app=arma-router
kubectl logs -f -l app=committer-coordinator

Log Format

Logs use the fabric-lib-go flogging format: 

2024-01-15 10:30:45.123 INFO [Router1] Router listening on 127.0.0.1:7050, PartyID: 1
2024-01-15 10:30:46.234 INFO [Batcher1Shard1] Batcher listening on 127.0.0.1:7053
2024-01-15 10:30:47.345 INFO [Consensus1] Consensus listening on 127.0.0.1:7051

Component-Specific Log Prefixes

  • Router: [Router<PartyID>] - ROUTER_METRICS messages
  • Batcher: [Batcher<PartyID>Shard<ShardID>] - BATCHER_METRICS messages
  • Consenter: [Consensus<PartyID>] - CONSENSUS_METRICS messages
  • Assembler: [Assembler<PartyID>] - ASSEMBLER_METRICS messages
  • Committer services: [coordinator], [verifier], [validator-committer], [sidecar], [query]

Troubleshooting with Logs

Common Log Locations

Component Default Location
Arma (all roles) stdout/stderr
Committer (all services) stdout/stderr

Note: Redirect to files via shell redirection or configure your process manager (systemd, Docker, Kubernetes) to capture logs.

Debug Logging

Enable debug logs for troubleshooting:

# Temporary debug logging
General:
  LogSpec: debug

Warning: Debug logging significantly impacts performance. Only enable for troubleshooting.

Note: JSON/structured logging is not supported. The flogging library only supports console text format.

Log Retention

Configuration

No built-in log rotation - use external tools:

# logrotate configuration
/var/log/arma/*.log {
    daily
    rotate 7
    compress
    missingok
    notifempty
}

For Kubernetes Deployments

# View logs
kubectl logs -f -l app=arma-router
kubectl logs -f -l app=committer-coordinator

Audit Logging

Audit logging is not implemented as a separate feature. Security-relevant events are logged at info or warning level:

  • Certificate validation failures
  • Authentication errors
  • Permission denied events

Best Practices

  1. Use info level in production - Balances detail and performance
  2. Enable debug only for troubleshooting - Revert after issue resolution
  3. Centralize logs - Use Fluentd/Fluent Bit to aggregate logs
  4. Monitor error rates - Alert on increasing error log frequency

See Also: Monitoring Guide | Troubleshooting