# Host documentation site with Flask: Postgres-backed content

## Summary
Deploy a documentation site built with Flask 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 Flask: 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 documentation site-specific behavior as your application code.

## Representative Queries
- Host documentation site with Flask: Postgres-backed content
- Where can I host Documentation site built with Flask?
- I need a content schema, publishing workflow and cache behavior after content updates.

## Resource Requirements
- Compute
- Postgres
- 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 Flask project that builds and starts with the documented commands (pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template).
- 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**  
   - pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
   - 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**  
   - 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**  
   - 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 --start "python3 app.py" --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**  
   - 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`

## Examples
- **Title**: Flask pattern fixture  
  **Description**: Multi-pattern Flask app whose relational records module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
  **Source Ref**: tests/deploy-canaries/flask-patterns

## Success Checks
- **App responds on its public URL**  
  - Kind: http_get  
  - Path: /  
  - Expect: ample canary flask patterns

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

## Limitations
- Verified on the python-3.12 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Flask major versions are not verified.
- The documentation site itself (your record schema, states and access rules) is application code and was not separately tested; the pattern checks are what was verified.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.

## Cost Estimate
- Currency: USD  
- Monthly Amount: 10.0  
- Authoritative: true  
- Basis: size prices from pricing.toml at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty  
- Components:  
  - App server: quantity 1.0, size: s-1vcpu-1gb, monthlyAmount: 5.0  
  - Managed PostgreSQL database: quantity 1.0, size: s-1vcpu-1gb, monthlyAmount: 5.0
- Note: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

## Next Actions
- Browse the catalog index  
  **Action ID**: browse-catalog  
- Search published recipes by intent, stack and constraints  
  **Action ID**: search-recipes  
- Browse Documentation site  
  **Action ID**: browse:workload:documentation-site  
- Browse Flask  
  **Action ID**: browse:stack:framework-flask  
- Browse Relational records  
  **Action ID**: browse:pattern:relational-records  
- Browse Deploy web app  
  **Action ID**: browse:intent:deploy-web-app