Scheduler

daggle serve starts a long-running daemon that monitors DAG files and executes triggers automatically.

Starting and stopping

# Start the scheduler
daggle serve

# Start with REST API enabled
daggle serve --port 8787

# Stop the scheduler
daggle stop

daggle stop sends SIGTERM for graceful shutdown. The scheduler stops accepting new runs and waits up to 5 minutes for in-flight runs to finish.

What the scheduler does

• Scans all DAG sources (global directory, registered projects, cwd) for files with trigger: blocks
• Manages all trigger types: cron, file watcher, webhook, DAG completion, condition polling, git
• Hot-reloads DAG files every 30 seconds (detects changes via SHA-256 hashing)
• Immediate reload on kill -HUP <pid> (SIGHUP)
• Enforces overlap policy per DAG (skip or cancel)
• Limits to 4 concurrent DAG runs
• Writes a PID file at ~/.local/share/daggle/proc/scheduler.pid
• Serves a read-only status dashboard when --port is specified — open the port URL in a browser
• Optionally serves the REST API when --port is specified

Without the scheduler

daggle run works without daggle serve – the scheduler is only needed for automated triggers. You can use daggle purely as a manual DAG runner.

Multi-project scheduling

The scheduler watches DAGs from multiple sources:

1. Global directory (~/.config/daggle/dags/)
2. All registered projects (from ~/.config/daggle/projects.yaml)
3. .daggle/ in the current working directory

Register projects so the scheduler picks up their triggers:

cd my-project
daggle register

daggle register and daggle unregister send SIGHUP to the running scheduler for immediate reload. DAG names must be unique across all sources.

Running as a system service

The scheduler doesn’t auto-start on host restart. Use your OS service manager for persistent operation.

macOS (launchd)

Create ~/Library/LaunchAgents/com.cynkra.daggle.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.cynkra.daggle</string>
  <key>ProgramArguments</key>
  <array>
    <string>/usr/local/bin/daggle</string>
    <string>serve</string>
    <string>--port</string>
    <string>8787</string>
  </array>
  <key>RunAtLoad</key>
  <true/>
  <key>KeepAlive</key>
  <true/>
  <key>StandardOutPath</key>
  <string>/tmp/daggle.stdout.log</string>
  <key>StandardErrorPath</key>
  <string>/tmp/daggle.stderr.log</string>
</dict>
</plist>

# Load (starts immediately and on login)
launchctl load ~/Library/LaunchAgents/com.cynkra.daggle.plist

# Unload
launchctl unload ~/Library/LaunchAgents/com.cynkra.daggle.plist

# Check status
launchctl list | grep daggle

Linux (systemd, user-level)

Create ~/.config/systemd/user/daggle.service:

[Unit]
Description=daggle scheduler
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/bin/daggle serve --port 8787
ExecStop=/usr/local/bin/daggle stop
Restart=on-failure
RestartSec=5s

[Install]
WantedBy=default.target

# Enable and start
systemctl --user daemon-reload
systemctl --user enable daggle
systemctl --user start daggle

# Check status
systemctl --user status daggle

# View logs
journalctl --user -u daggle -f

For system-level (all users), place the unit file in /etc/systemd/system/daggle.service, add a User= directive, and use systemctl without --user.