## Host public directory with Phoenix: Postgres-backed content

### Summary
Deploy a public directory built with Phoenix on Ample using the relational records 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, and a published bucket serves public assets from the CDN host. Verified on Phoenix: a workspace-scoped table, an explicit state machine (draft to review to published) that rejects invalid transitions, and a cross-workspace read that returns nothing (transitions=true isolation=true). Not separately tested: your record schema, states and access rules; treat the public directory-specific behavior as your application code.

### Representative Queries
- Host public directory with Phoenix: Postgres-backed content
- Where can I host Public directory built with Phoenix?
- I need a content schema, publishing workflow and cache behavior after content updates.

### Resource Requirements
- primitive:compute
- primitive:postgres
- primitive:cdn

### Infrastructure Requirements
1. **Compute**  
   * **Status:** verified  
   * **Summary:** Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
   * [More info](/content/discover/primitive/compute/index.html)

2. **Postgres**  
   * **Status:** verified  
   * **Summary:** Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
   * [More info](/content/discover/primitive/postgres/index.html)

3. **CDN**  
   * **Status:** verified  
   * **Summary:** The CDN host serves objects from published buckets. It does not front app compute and is not a cache or key-value store.
   * [More info](/content/discover/primitive/cdn/index.html)

### 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**  
   Run: `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. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
   The fixture's module implements relational records: a workspace-scoped table, an explicit state machine (draft to review to published) that rejects invalid transitions, and a cross-workspace read that returns nothing. Run migrations 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.
   Command: `ample deploy . --name --public --env S3_ENDPOINT=... - -env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=... --env CDN_PUBLIC_URL=...`

5. **Verify**  
   Fetch the live URL and check the pattern self-test routes, then run your own checks. Command: `ample logs  --kind build`

### Cost Estimate
- **Monthly Amount:** $10.0  
- **Currency:** USD  
- **Components:**  
   - App server (s-1vcpu-1gb): $5.0  
   - Managed PostgreSQL database (s-1vcpu-1gb): $5.0

### 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 public directory (your record schema, states and access rules) is application code and was not separately tested.

### Success Checks
1. App responds on its public URL.
2. Relational-records self-test.

### Examples
- **Phoenix pattern fixture**  
  A multi-pattern Phoenix app whose relational records module was checked live. The module is under tests/deploy-canaries/_pattern-modules.

### Evidence Summary
- **Kind:** canary_run  
  Summary: Phoenix pattern fixture deployed on Ample. Checks passed for relational-records and configuration-secrets.
- **Last Verified At**: 2026-09-20T23:45:31Z