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Linux Cron with curl or CLI

Monitor traditional Linux cron jobs with minimal changes using curl commands or the Saturn CLI.

Prerequisites​

  • A Saturn account with a monitor created
  • Your monitor's unique ID (from dashboard)
  • curl (pre-installed on most Linux systems) or Saturn CLI
Creating a Monitor

Go to your dashboard → Add Monitor → Set schedule → Copy the monitor ID from the URL or settings.

Basic Success Ping​

Add a curl command after your existing cron job:

crontab
0 3 * * * /path/to/backup.sh && curl -X POST https://api.saturnmonitor.com/api/ping/YOUR_MONITOR_ID/success

This sends a success ping after the script completes successfully (due to &&).

With Failure Handling​

Send different pings based on exit status:

crontab
0 3 * * * /path/to/backup.sh && curl -X POST https://api.saturnmonitor.com/api/ping/YOUR_MONITOR_ID/success || curl -X POST https://api.saturnmonitor.com/api/ping/YOUR_MONITOR_ID/fail

With Duration Tracking​

Measure job duration and include in ping:

crontab
0 3 * * * start=$(date +%s) && /path/to/backup.sh && end=$(date +%s) && duration=$((end - start)) && curl -X POST https://api.saturnmonitor.com/api/ping/YOUR_MONITOR_ID/success -H "Content-Type: application/json" -d "{\"durationMs\": $((duration * 1000))}"

The CLI automatically handles start/success/fail pings and captures output.

Install CLI​

# Linux/macOS
curl -fsSL https://get.saturnmonitor.com | sh

# Or with npm
npm install -g @saturn/cli

# Verify installation
pulse --version

Authenticate​

# Device flow (browser-based)
saturn login

# Or with token directly
saturn login --token YOUR_TOKEN

Configuration is stored in ~/.pulse/config.json.

Wrap Your Command​

Instead of running the job directly, wrap it with saturn run:

crontab
0 3 * * * saturn run --monitor YOUR_MONITOR_ID -- /path/to/backup.sh

The CLI will:

  1. Send a start ping
  2. Run your command
  3. Capture stdout/stderr (optional)
  4. Send success or fail ping with exit code and duration

With Output Capture​

0 3 * * * saturn run --monitor YOUR_MONITOR_ID --capture-output -- /path/to/backup.sh

Output is sent with the ping and visible in the Saturn dashboard.

Multiple Commands​

0 3 * * * saturn run --monitor YOUR_MONITOR_ID -- bash -c "cd /app && ./backup.sh && ./verify.sh"

Method 3: Bash Wrapper Script​

For more control, create a wrapper script:

/usr/local/bin/saturn-wrapper.sh
#!/bin/bash

MONITOR_ID="$1"
shift  # Remove first arg, rest is the command

API_URL="https://api.saturnmonitor.com/api/ping/${MONITOR_ID}"

# Start ping
curl -X POST "${API_URL}/start" -s > /dev/null

# Run command and capture exit code
START=$(date +%s)
"$@"
EXIT_CODE=$?
END=$(date +%s)
DURATION=$(( (END - START) * 1000 ))

# Success or fail ping
if [ $EXIT_CODE -eq 0 ]; then
  curl -X POST "${API_URL}/success" \
    -H "Content-Type: application/json" \
    -d "{\"durationMs\": ${DURATION}}" \
    -s > /dev/null
else
  curl -X POST "${API_URL}/fail" \
    -H "Content-Type: application/json" \
    -d "{\"exitCode\": ${EXIT_CODE}, \"durationMs\": ${DURATION}}" \
    -s > /dev/null
fi

exit $EXIT_CODE

Make it executable:

chmod +x /usr/local/bin/saturn-wrapper.sh

Use in cron:

crontab
0 3 * * * /usr/local/bin/saturn-wrapper.sh YOUR_MONITOR_ID /path/to/backup.sh

Examples​

Database Backup​

crontab
# Daily at 3 AM
0 3 * * * saturn run --monitor mon_abc123 -- pg_dump mydb > /backups/$(date +\%Y\%m\%d).sql

Cleanup Script​

crontab
# Hourly cleanup
0 * * * * saturn run --monitor mon_xyz789 -- find /tmp -type f -mtime +7 -delete

Log Rotation​

crontab
# Daily at midnight
0 0 * * * saturn run --monitor mon_log001 -- logrotate /etc/logrotate.conf

Authentication with Tokens​

For servers without browser access, use monitor-specific tokens:

# Using token in URL (less secure, but simple)
curl -X POST https://api.saturnmonitor.com/api/ping/YOUR_MONITOR_ID/success?token=YOUR_TOKEN

# Using Authorization header (recommended)
curl -X POST https://api.saturnmonitor.com/api/ping/YOUR_MONITOR_ID/success \
  -H "Authorization: Bearer YOUR_TOKEN"

Get tokens from Dashboard → Monitor Settings → API Tokens.

Validation​

After your first run, verify in the dashboard:

  1. Monitor shows last ping time
  2. Duration is recorded
  3. Status is "OK"
Testing cron jobs

Don't wait for the schedule! Run manually first:

# Run the cron command directly
/path/to/backup.sh

# Or test with CLI
saturn run --monitor YOUR_MONITOR_ID -- /path/to/backup.sh

Troubleshooting​

Ping Not Received​

Check network connectivity:

curl -v https://api.saturnmonitor.com/api/health

Check cron logs:

# Most systems log to syslog
grep CRON /var/log/syslog

# Or check mail for cron errors
mail

Wrong Timezone​

Cron uses system timezone. Verify:

timedatectl
# or
cat /etc/timezone

In Saturn dashboard, ensure monitor timezone matches.

Permissions Issues​

Ensure the cron user has execute permissions:

chmod +x /path/to/backup.sh

And check ownership:

ls -l /path/to/backup.sh

Next Steps​

You should now see your first healthy monitor within 10 minutes.

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