## Diagnose Deployment Failures for NestJS

### Summary
Deployment diagnostics for a NestJS app on Ample. Verified on NestJS: the same app deployed with a deliberate boot failure (CANARY_FAIL=boot): `ample deploy` exited 1 with a coded failure (health_check_failed when the process dies at boot, public_ingress_failed when the framework boots but every request answers 500) and the app's own error line was readable with `ample logs --kind runtime`, so the cause is read from the framework's output rather than guessed. Build and start: npm install, nest build (TypeScript) then node dist/main.js on the node-22 template.

### Prerequisites
- A NestJS project (npm install, nest build (TypeScript) then node dist/main.js on the node-22 template)
- An Ample account token with servers:write

### Resource Requirements
- primitive:compute

### Infrastructure Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.

### Workflow Steps
1. **Read the failure code**  
   Deploy is synchronous. Exit 1 with build_failed means the isolated build failed; health_check_failed means the app built but never answered on PORT (it crashed at boot or bound the wrong port); public_ingress_failed means it answered on PORT but the public URL returned an error status (a request handler or bootstrap failed); exit 2 means a required preflight action is blocking.

2. **Read the build log**  
   The last lines name the failing command and its output.  
   Command: `ample logs --kind build`

3. **Read the runtime log**  
   For health_check_failed the runtime log carries the NestJS process output: in the verified run the deliberate boot failure's own error line was there, followed by the platform's health-check verdict and the start command it ran.  
   Command: `ample logs --kind runtime`

4. **Fix and redeploy once**  
   Change the source, the environment or the command override, then run ample deploy again. Do not loop deploys to poll status; an unchanged redeploy is a no-op.

5. **Verify**  
   Fetch the live URL on the example; on failure read the build and runtime logs.  
   Command: `ample logs --kind build`

### Success Checks
- Failed deploy reports health_check_failed synchronously  
  Expect: `ample deploy` exits 1 with error.code health_check_failed
- Runtime log carries the app's own error line  
  Expect: `ample logs --kind runtime` shows the framework's error output before the health-check verdict

### Limitations
- Verified on the node-22 template at s-1vcpu-1gb; other sizes and NestJS major versions are not verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 5.0
- **Basis**: Size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
- **Components**:  
  - App server (size: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0)

_Note: Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included._

### Next Actions
- **Browse the catalog index**  
- **Search published recipes by intent, stack and constraints**  
- **Prepare a side-effect-free deployment plan for an authorized project**  
- **Read the existing agent authentication setup**  
- **Browse NestJS**  
- **Browse Troubleshoot deployment**  
- **Browse Public web service**

### Examples
- **NestJS pattern fixture**: Verified deployment diagnostics on NestJS.
  - Source Reference: tests/deploy-canaries/nestjs-patterns

### Evidence Summary
- **Canary Run**: NestJS pattern fixture deployed on Ample with CANARY_FAIL=boot; the same app deployed with a deliberate boot failure: `ample deploy` exited 1 with a coded failure (health_check_failed...) 
  - Observed At: 2026-09-21T02:23:07Z 
  - Expires At: 2027-03-20T02:23:07Z