# Host approval workflow with Flask: relational workspace data

Deploy a approval workflow 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. 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 approval workflow-specific behavior as your application code.

## Representative Queries
- Host approval workflow with Flask: relational workspace data
- Where can I host Approval workflow built with Flask?
- I need a workspace-specific schema, state transitions and access rules.

## 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)
- An Ample account token with servers:write, databases:read

## Tested Configuration
- Template: python-3.12
- Runtime: python
- Size: s-1vcpu-1gb
- Install: python3 -m pip install --target .ample/python -r requirements.txt
- Start: PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 app.py

## Input Schema
- **name**: App name
  - *Max length*: 63
  - *Min length*: 1
  - *Pattern*: ^[a-z0-9-]+$
- **path**: Project directory or ample.toml service
  - *Max length*: 512
  - *Min length*: 1
- **start**: Start command (Python apps pass one explicitly)
  - *Max length*: 512

## 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. **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"
4. **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

## 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 approval workflow 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; apps and their databases are placed together.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: Size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
- **Components**:
  - App server (size: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0)
  - Managed PostgreSQL database (size: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0)