## Host approval workflow with Phoenix: private attachments

### Summary
Deploy an approval workflow built with Phoenix on Ample using the private document library pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Phoenix: a role-to-document access model with negative tests (401 without identity, 403 for the wrong role) and a private-bucket round-trip for the allowed role (private=ok). Not separately tested: your identity integration and role assignments; treat the approval workflow-specific behavior as your application code.

### Representative Queries
- Host approval workflow with Phoenix: private attachments
- Where can I host Approval workflow built with Phoenix?
- I need attachment metadata, access checks and a tested private object access path.

### Resource Requirements
- compute
- postgres
- s3-compatible-object-storage

### Infrastructure Requirements
1. **Compute**  
   Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.  
   [Details](https://discover/primitive/compute)
2. **Postgres**  
   Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.  
   [Details](https://discover/primitive/postgres)
3. **S3-compatible object storage**  
   Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.  
   [Details](https://discover/primitive/s3-compatible-object-storage)

### Prerequisites
- A Phoenix project that builds and starts with the documented commands (mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs)
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
- A bucket from `ample bucket create` with its credentials passed as encrypted S3_* environment variables
- An Ample account token with servers:write, databases:read, buckets:read

### Workflow Steps
1. **Build and start**  
   `mix deps.get, MIX_ENV=prod mix compile and mix release` in the builder, then the release bin script with `PHX_SERVER=true` on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs. The server must bind 0.0.0.0 on PORT.
2. **Implement the pattern on PostgreSQL**  
   Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Wire object storage**  
   Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
4. **Deploy**  
   Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.
   ```
   ample deploy . --name --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
   ```
5. **Verify**  
   Fetch the live URL and the pattern self-test route(s) (/p/private-document-library) from the example; then run your own checks. On failure read `ample logs --kind build` then `--kind runtime`.
   ```
   ample logs --kind build
   ```

### Cost Estimate
- **Currency**: USD  
- **Monthly Amount**: 10.0  
- **Basis**: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty  
- **Components**:  
  - App server: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0  
  - Managed PostgreSQL database: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0  
- **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

### Limitations
- Verified on the elixir-1.18 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Phoenix major versions are not verified.
- The approval workflow itself (your identity integration and role assignments) is application code and was not separately tested; the pattern checks are what was verified.

### Evidence Summary
1. **Canary Run**: Phoenix pattern fixture deployed on Ample, checks passed for private-document-library and configuration-secrets.
   - **Observed At**: 2026-09-20T23:45:31Z
   - **Implementation Revision**: 4d1511e574302f3904b75088bd4048a0975218b3-dirty (CLI 0.1.21)

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