# Host form collection with Rails: file attachments

## Summary
Deploy a form collection built with Rails on Ample using the browser file uploads 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: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Not separately tested: your upload UI, allowed types, size limits and virus scanning; treat the form collection-specific behavior as your application code.

## Representative Queries
- Host form collection with Rails: file attachments  
- Where can I host Form collection built with Rails?  
- I need a restricted upload flow, file validation and record-to-object linkage.

## 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

## Tested Configuration
- **Template**: ruby-3.4  
- **Runtime**: ruby  
- **Size**: s-1vcpu-1gb  
- **Install Command**: bundle config set --local path vendor/bundle && bundle config set --local without 'development test' && bundle install  
- **Start Command**: bundle exec rails server -b 0.0.0.0 -p $PORT

## 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 browser file uploads: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). 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/browser-file-uploads) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.  
   Command: ample logs  --kind build

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

## Success Checks
- App responds on its public URL. 
- Browser-file-uploads 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 form collection itself (your upload UI, allowed types, size limits and virus scanning) is application code and was not separately tested; the pattern checks are what was verified.  
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.

## Cost Estimate
- **Monthly Amount**: $10 (USD)  
- **Components**:  
  - App server: s-1vcpu-1gb (1.0) - $5.00  
  - Managed PostgreSQL database: s-1vcpu-1gb (1.0) - $5.00  
  - Note: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

## Evidence Summary
- Rails pattern fixture deployed on Ample (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); checks passed for browser-file-uploads and configuration-secrets.  
- The same Rails app deployed with a --release-command migration; the marker it created was readable after activation.