# Host csv import tool with Rails: data exports

Deploy a csv import tool 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 csv import tool-specific behavior as your application code.

## 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

## Resource Requirements
- Compute
- Postgres
- S3-compatible object storage

## 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.
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).
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 Keep private data in an unpublished bucket.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).
5. **Verify**: Fetch the live URL and the pattern self-test route(s) (/p/generated-downloads) from the example; then run your own checks.

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

## Cost Estimate
- **Monthly Amount**: $10.00 USD
- **Components**:
  - App server: s-1vcpu-1gb, $5.00
  - Managed PostgreSQL database: s-1vcpu-1gb, $5.00

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

## Evidence Summary
- Rails pattern fixture deployed on Ample, checks passed for generated-downloads and configuration-secrets.