| name | cfn-canary |
| description | MUST BE USED within 10 minutes of any production deployment. Post-deploy health monitoring: polls a URL for 10 minutes checking errors, performance regressions, availability. |
| version | 1.0.0 |
| tags | ["deployment","monitoring","canary","health-check"] |
| status | production |
CFN Canary
Purpose: Monitor a deployed application for 10 minutes after deployment, detecting errors and regressions before users are affected.
Usage
Invoke as /canary <url> where url is the production endpoint to monitor.
Monitoring Protocol
Phase 1: Baseline Capture
Before monitoring begins, capture baseline metrics:
- HTTP status code
- Response time (ms)
- Response body size
- Key response headers (content-type, cache-control)
If no baseline exists, the first check becomes the baseline.
Phase 2: Polling Loop (10 minutes, 30-second intervals)
Every 30 seconds, check:
- Availability: HTTP status 200? If not, alert.
- Response time: >2x baseline? Flag as performance regression.
- Response size: Changed significantly (>50% diff)? Flag as content change.
- Error indicators: Check response body for common error patterns (500, "Internal Server Error", "503", stack traces).
Phase 3: Alert Logic
Transient tolerance: require 2+ consecutive failures before alerting. Single failures may be network blips.
Alert levels:
- CRITICAL: Site down (non-200 status, 2+ consecutive)
- WARNING: Performance regression (response time >2x baseline, 2+ consecutive)
- INFO: Content change detected (response size shift)
Phase 4: Report
Output summary:
## Canary: <url> (10min)
### Status: HEALTHY | DEGRADED | DOWN
### Checks: N/N passed
### Alerts: N
### Timeline
HH:MM:SS - 200 (Xms) OK
HH:MM:SS - 200 (Xms) OK
HH:MM:SS - 500 (Xms) ALERT: Server error
...
### Recommendation
<action based on findings>
Limitations
- HTTP-only monitoring (no browser rendering, no JS execution)
- For full browser-based canary testing, combine with cfn-e2e
- Does not check specific page content or user flows
Integration
- Run after
fly deploy or any deployment command
- Uses curl for HTTP checks (no external dependencies)
- Can be combined with cfn-e2e for deeper verification
