App Platform Troubleshooting Skill
Transform debugging from guessing to rapid diagnosis and fix.
Philosophy
Traditional: See error → Guess → Change → Push → Wait 5-7 min → Repeat
With skill: See error → Diagnose → Fix → Verify → Commit proper fix
Quick Decision
Is the app deployed with running containers?
├── YES → Can we access the shell?
│ ├── YES → LIVE MODE (SDK shell access)
│ └── NO → LOGS-ONLY MODE (fetch logs)
└── NO (build/deploy failed) → LOGS-ONLY MODE
Mode 1: Live Troubleshooting (Quick Start)
from do_app_sandbox import Sandbox
app = Sandbox.get_from_id(app_id="<app-id>", component="web")
# Diagnostics
app.exec("env | grep DATABASE")
app.exec("curl -v localhost:8080/health")
app.exec("ps aux | head -10")
Full guide: See live-troubleshooting.md
Mode 2: Logs-Only (Quick Start)
# Runtime logs
doctl apps logs <app_id> <component> --type run
# Build logs
doctl apps logs <app_id> <component> --type build
# Crash logs
doctl apps logs <app_id> --type=run_restarted
Full guide: See logs-analysis.md
Debug Container (Infrastructure Issues)
Deploy in ~30-45 seconds to isolate infrastructure from application:
services:
- name: debug
image:
registry_type: GHCR
registry: ghcr.io
repository: bikramkgupta/debug-python
tag: latest
http_port: 8080
envs:
- key: DATABASE_URL
value: ${db.DATABASE_URL}
# Run validation suite
validate-infra all
validate-infra database
validate-infra kafka
Full guide: See debug-container.md
Quick Reference: Exit Codes
| Code | Signal | Meaning |
|---|---|---|
| 0 | - | Clean exit (shouldn't exit) |
| 1 | - | General error |
| 127 | - | Command not found |
| 137 | SIGKILL | OOM killed |
| 143 | SIGTERM | Graceful shutdown |
Quick Reference: Common Fixes
| Problem | Quick Fix |
|---|---|
| App exits immediately | Check if listening on $PORT |
| 502 errors | Check health endpoint, verify running |
| Database connection fails | Use Debug Container, verify trusted sources |
| Build fails | Check dependencies, review build logs |
| OOM kills | Upgrade instance size |
| Health checks fail | Bind to 0.0.0.0, not localhost |
| Slow startup | Increase initial_delay_seconds |
Reference Files
- live-troubleshooting.md — SDK shell access, diagnostics, hot fixes
- logs-analysis.md — Log patterns, error codes, health check config
- debug-container.md — Infrastructure validation, validation suite
- networking-issues.md — DNS, CORS, VPC, routing
- app-maintenance.md — Archive/unarchive workflow
- diagnostic-scripts.md — Scripts, testing strategy, performance
When to Escalate
Contact DigitalOcean Support when:
- Internal error persists after redeploy
- Resource limit increases needed
- Multiple apps affected (platform issue)
- VPC/networking issues can't be diagnosed
Before escalating, gather:
doctl apps get <app_id> -o json > app_info.json
doctl apps logs <app_id> <component> --type run > runtime.log
doctl apps spec get <app_id> > app_spec.yaml
Integration with Other Skills
- → deployment: After fixing, deploy proper changes
- → devcontainers: Reproduce issues locally
- → postgres: Database-specific configuration
- → networking: Comprehensive networking docs