# Host asset library with Phoenix: data exports

## Summary
Deploy a asset library built with Phoenix on Ample using the generated downloads 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: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the asset library-specific behavior as your application code.

## 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.
- **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.
- **S3-compatible object storage**: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

## Resource Requirements
- `primitive:compute`
- `primitive:postgres`
- `primitive:s3-compatible-object-storage`

## Prerequisites
1. 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).
2. A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env).
3. A bucket from `ample bucket create` with its credentials passed as encrypted S3_* environment variables.
4. An Ample account token with servers:write, databases:read, buckets:read.

## Workflow Steps
### 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.

### Implement the pattern on PostgreSQL
The fixture's module implements generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

### 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.

### 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.
**Command**: ample deploy . --name  --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...

### Verify
Fetch the live URL and the pattern self-test route(s) (/p/generated-downloads) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.
**Command**: ample logs  --kind build

## Success Checks
- The app responds on its public URL (expected: `ample canary phoenix patterns`).
- The generated-downloads self-test (expected: `export=ok rows=3 (with ?token=...; 401 without)`).

## 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 asset library itself (your export formats, retention policy and entitlement model) is application code and was not separately tested; the pattern checks are what was verified.

## Examples
### Phoenix pattern fixture
Multi-pattern Phoenix app whose generated downloads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.