## Host knowledge base with Rails: Postgres-backed content

### Summary
Deploy a knowledge base built with Rails 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 Rails: 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 knowledge base-specific behavior as your application code.

### Representative Queries
- Host knowledge base with Rails: Postgres-backed content
- Where can I host Knowledge base built with Rails?
- 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.

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.

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.

### 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**  
   Body: 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**  
   Body: 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 (transitions=true isolation=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. **Wire object storage**  
   Body: 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. Publish only the bucket that serves public assets and reference its CDN URL.

4. **Deploy**  
   Body: 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=... --env CDN_PUBLIC_URL=...

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

### 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 knowledge base itself (your record schema, states and access rules) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not.
- The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified (the fixture sets Cache-Control on upload and versions keys).

### Cost Estimate
- **Monthly Amount**: $10.00  
  - Components:  
   1. App server: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: $5.0  
   2. Managed PostgreSQL database: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: $5.0  
- 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.

### Success Checks
1. **App responds on its public URL**  
   Kind: http_get, Path: /, Expect: ample canary rails patterns

2. **Relational-records self-test**  
   Kind: http_get, Path: /p/relational-records, Expect: records=ok transitions=true isolation=true

### Evidence Summary
- **Canary Run**: Rails pattern fixture deployed on Ample; checks passed for relational-records and configuration-secrets.
- **Camera Run**: The same Rails app deployed with a --release-command migration; the marker it created was readable after activation.

### Last Verified At
2026-09-20T21:55:28Z

### Next Actions
1. **Browse the catalog index**  
   Operation: catalog_index  
   Method: GET  
   Relative Path: /v1/catalog

2. **Search published recipes by intent, stack and constraints**  
   Operation: search_recipes  
   Method: POST  
   Relative Path: /v1/catalog/search
   Parameters: {"body":{"limit":5,"query":"Host knowledge base with Rails: Postgres-backed content"}}

3. **Prepare a side-effect-free deployment plan for an authorized project**  
   Operation: plan_deployment  
   Method: POST  
   Relative Path: /v1/catalog/plan
   Parameters: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:knowledge-base:rails:relational-content","recipeRevision":"r1"}}

4. **Read the existing agent authentication setup**  
   Operation: existing_auth_setup  
   Method: GET  
   Relative Path: /mcp/setup

5. **Browse Knowledge base**  
   Operation: browse_node  
   Method: GET  
   Relative Path: /v1/catalog/nodes/workload%3Aknowledge-base

6. **Browse Rails**  
   Operation: browse_node  
   Method: GET  
   Relative Path: /v1/catalog/nodes/stack%3Aframework-rails

7. **Browse Relational records**  
   Operation: browse_node  
   Method: GET  
   Relative Path: /v1/catalog/nodes/pattern%3Arelational-records

8. **Browse Deploy web app**  
   Operation: browse_node  
   Method: GET  
   Relative Path: /v1/catalog/nodes/intent%3Adeploy-web-app