## Host approval workflow with Rails: downloadable reports

Deploy a approval workflow built with Rails 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 Rails: 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 approval workflow-specific behavior as your application code.

### Representative Queries
- Host approval workflow with Rails: downloadable reports
- Where can I host Approval workflow built with Rails?
- I need an export query, generated artifact retention and authorized download flow.

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

### 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.

### Prerequisites
- A Rails project that builds and starts with the documented commands (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via `rails server` reading PORT on the ruby-3.4 template with RAILS_ENV=production)
- 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**  
   `bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via rails server reading PORT on the ruby-3.4 template with RAILS_ENV=production. The server must bind 0.0.0.0 on PORT.`
2. **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.
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.  
   Command: `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/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
- App responds on its public URL
- Generated-downloads self-test

### Limitations
- Verified on the ruby-3.4 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Rails major versions are not verified.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: $10.00
- **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

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

### Evidence Summary
- **Canary Run**: Rails pattern fixture deployed on Ample.

### Formats
- **HTML**: [Link](/content/recipes/approval-workflow/rails/report-exports/index.html)
- **Markdown**: [Link](/content/recipes/approval-workflow/rails/report-exports.md)
- **JSON**: [Link](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Aapproval-workflow%3Arails%3Areport-exports)