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Daemon

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What it does

The netglance daemon manages a background monitoring service that runs scheduled network checks on a cron-like schedule. It automatically discovers devices, monitors DNS integrity, verifies TLS certificates, captures network baselines, and generates periodic health reports. Results are stored in SQLite for later analysis and alerting.

On macOS, the daemon integrates with launchd for automatic start-on-login and persistent operation.

Quick start

Start the daemon in the foreground (for testing or manual use):

netglance daemon start

Install as a macOS launchd service (runs automatically on login):

netglance daemon install
netglance daemon status

Check daemon and schedule status:

netglance daemon status

Commands

netglance daemon start

Start the scheduler in the foreground. Useful for testing or initial setup.

Flags:

  • --config PATH, -c PATH — Path to a YAML config file (optional). If not provided, uses system defaults.

Example:

netglance daemon start --config ~/.config/netglance/config.yaml

The daemon will display a table of scheduled tasks and run them according to their cron expressions. Press Ctrl+C to stop.

netglance daemon install

Generate and install the launchd plist file at ~/Library/LaunchAgents/com.netglance.daemon.plist. This enables auto-start on login.

Flags:

  • --netglance-path PATH — Override the path to the netglance executable. Auto-detected if not specified.
  • --config PATH, -c PATH — Path to a YAML config file for the daemon (optional).

Example:

netglance daemon install --config ~/.config/netglance/config.yaml

After installation, the plist is loaded automatically. You can manually load or unload it with:

launchctl load ~/Library/LaunchAgents/com.netglance.daemon.plist
launchctl unload ~/Library/LaunchAgents/com.netglance.daemon.plist

netglance daemon uninstall

Remove the launchd plist file. The daemon will no longer start automatically.

Example:

netglance daemon uninstall

netglance daemon status

Display the current daemon installation and configuration status, including all scheduled tasks and their cron expressions.

Example:

netglance daemon status

Understanding the output

Scheduled tasks table

When you start the daemon, you'll see a table showing all active scheduled tasks:

netglance daemon starting

┏━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ Task          ┃ Schedule        ┃
┡━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ discover      │ */15 * * * *    │
│ dns_check     │ 0 * * * *      │
│ tls_verify    │ 0 */6 * * *    │
│ baseline_diff │ 0 2 * * *      │
│ report        │ 0 7 * * *      │
└───────────────┴─────────────────┘

Each task runs according to its cron expression:

  • discover — Device discovery every 15 minutes
  • dns_check — DNS consistency check hourly
  • tls_verify — TLS certificate verification every 6 hours
  • baseline_diff — Network baseline capture daily at 2 AM
  • report — Health report generation daily at 7 AM

Cron expression format

Daemon schedules use standard 5-field cron syntax: minute hour day-of-month month day-of-week

Common patterns:

  • */15 * * * * — Every 15 minutes
  • 0 * * * * — Every hour at minute 0
  • 0 2 * * * — Daily at 2 AM
  • 0 */6 * * * — Every 6 hours

Daemon logs

On macOS, daemon output is written to:

~/.config/netglance/daemon.log

Check the log if tasks are failing silently:

tail -f ~/.config/netglance/daemon.log

Results storage

All check results are stored in SQLite:

~/.config/netglance/netglance.db

Each task saves its result under a key: discover, dns_check, tls_verify, baseline_diff, report.

  • Baseline — Capture and compare network snapshots to detect changes
  • Alert — Evaluate rules against daemon results and trigger notifications
  • Metrics — Query and analyze stored results over time

Troubleshooting

Daemon fails to start

Check for permission issues:

ls -la ~/Library/LaunchAgents/

The plist file should be readable. If permissions are wrong:

chmod 644 ~/Library/LaunchAgents/com.netglance.daemon.plist

Check if the netglance binary is found:

which netglance
netglance --version

If not found, reinstall with:

netglance daemon install --netglance-path /absolute/path/to/netglance

launchd plist not loading

Verify the plist is valid:

plutil ~/Library/LaunchAgents/com.netglance.daemon.plist

If invalid, reinstall:

netglance daemon uninstall
netglance daemon install

Load it manually:

launchctl load ~/Library/LaunchAgents/com.netglance.daemon.plist

High CPU or memory usage

The scheduler checks tasks once per minute. If a single task is taking too long (e.g., scanning a large subnet), reduce the frequency in your config:

daemon:
  schedules:
    discover: "0 */4 * * *"  # Every 4 hours instead of every 15 minutes

Checks failing silently

Check daemon logs:

tail -50 ~/.config/netglance/daemon.log

Common issues:

  • Network interface not specified or invalid
  • Subnet unreachable from current network
  • Insufficient permissions for ARP or raw socket operations

Database locked errors

If you run netglance CLI commands while the daemon is running, you may see "database locked" warnings. This is normal and usually brief. To avoid contention:

  1. Stop the daemon before running intensive CLI operations
  2. Increase metric retention or prune frequency if the database grows large
  3. Run CLI commands during off-peak times (not during daemon check windows)
Alert Wol