fastly-compute-deployment-debugging

# Fastly Compute Deployment Debugging ## Problem After deploying to Fastly Compute, requests return stale content or 404s even though: - `fastly compute publish` reported success - The new version shows as "active" in `fastly service-version list` - The code is correct and works locally ## Context / Trigger Conditions - Version endpoint returns old version string after deployment - New routes/features return 404 - `fastly purge --all` doesn't fix the issue - Requests with cache buster (`?v=random`) work but regular requests don't - `fastly domain list` doesn't show your custom domain - Different POPs return different results ## Solution ### 1. Verify Code is Actually Deployed ```bash # Check the direct edgecompute.app URL (bypasses custom domain config) curl https://your-service.edgecompute.app/version # Compare to custom domain curl https://your-custom-domain.com/version ``` If edgecompute.app works but custom domain doesn't, it's a domain configuration issue. ### 2. Diagnose Cached Error Responses The most common issue: 404s get cached at edge POPs before new code propagates. ```bash # Test with cache buster curl "https://your-domain.com/endpoint?bust=$RANDOM" # Test without curl "https://your-domain.com/endpoint" ``` If cache-busted works but regular doesn't = **cached error response**. **Fix**: Wait 2-5 minutes for full propagation, then purge: ```bash fastly purge --all --service-id YOUR_SERVICE_ID ``` ### 3. Check Domain Configuration (Two APIs!) Fastly has TWO domain management systems: | System | CLI Command | API Endpoint | |--------|-------------|--------------| | Classic Domains | `fastly domain list` | `/service/{id}/version/{ver}/domain` | | Versionless Domains | *(not shown in CLI)* | `/domain-management/v1/domains` | **If `fastly domain list` doesn't show your domain**, check the versionless API: ```bash # Get your API token TOKEN=$(fastly profile token) # Query domain-management API curl -s -H "Fastly-Key: $TOKEN" \ "https://api.fastly.com/domain-management/v1/domains?filter%5Bfqdn%5D=your-domain.com" ``` Look for `"activated": true` and `"verified": true`. ### 4. Force Clean Rebuild If build caching is suspected: ```bash rm -rf pkg target fastly compute publish --comment "clean build" ``` ### 5. Wait for Propagation Fastly Compute deployments can take **2-5 minutes** to propagate to all POPs worldwide. Even after `fastly service-version list` shows the version as active, some POPs may still serve old code. **Timeline**: - Version marked "active": ~30 seconds - Most POPs updated: ~1-2 minutes - All POPs updated: ~3-5 minutes (sometimes longer) ### 6. Check Real-time Logs ```bash fastly log-tail --service-id YOUR_SERVICE_ID ``` Then make a request and see if it appears. If no logs appear, the request isn't reaching your Compute code (likely a domain/routing issue). ## Verification After waiting and purging: ```bash # Multiple requests to hit different POPs for i in 1 2 3 4 5; do curl -s "https://your-domain.com/version" sleep 1 done ``` All should return the new version. ## Example **Scenario**: Deployed thumbnail serving code, but `/hash.jpg` returns 404. **Debug steps**: 1. `curl https://service.edgecompute.app/hash.jpg?v=123` → 200 (code works!) 2. `curl https://custom-domain.com/hash.jpg` → 404 (cached) 3. Wait 3 minutes 4. `fastly purge --all --service-id XXX` 5. `curl https://custom-domain.com/hash.jpg` → 200 (working!) **Root cause**: 404 was cached at edge before new code propagated. ## Notes - **Accounts created before Sept 2025**: May have classic domains, newer accounts use versionless - **Don't panic**: If version check works on edgecompute.app, the code is deployed - just wait - **Purge timing**: Purge AFTER propagation completes, not immediately after deploy - **POP variance**: Different geographic POPs may propagate at different speeds - **Error caching**: Fastly may cache 404/500 responses - this amplifies propagation issues ## References - [Fastly Compute Documentation](https://www.fastly.com/documentation/guides/compute/) - [Working with versionless domains](https://www.fastly.com/documentation/guides/getting-started/domains/working-with-domains/working-with-domains/) - [Working with classic domains](https://www.fastly.com/documentation/guides/getting-started/domains/working-with-domains/working-with-classic-domains/) - [Domain Management API](https://www.fastly.com/documentation/reference/api/domain-management/domains/) - [Classic Domain API](https://www.fastly.com/documentation/reference/api/services/domain/)