# Host form collection with Flask: relational workflow state

## Summary
Deploy a form collection built with Flask on Ample using the transactional workflows 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: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Not separately tested: your domain records, validation rules and concurrency policy; treat the form collection-specific behavior as your application code.

## Representative Queries
- Host form collection with Flask: relational workflow state
- Where can I host Form collection built with Flask?
- I need a domain record schema, validation rules and concurrency behavior.

## Resource Requirements
- primitive:compute
- primitive:postgres

## Infrastructure Requirements
### Compute
- **Summary**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **Status**: verified

### Postgres
- **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.
- **Status**: verified

## Framework
Flask

## Workload
Form collection

## Release Status
published

## Support Status
verified

## Execution Status
ready

## Prerequisites
1. 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)
2. A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
3. 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
{"additionalProperties":false,"properties":{"env":{"description":"Encrypted environment variables (bucket credentials, secrets)","items":{"pattern":"^[A-Z][A-Z0-9_]*=.*$","type":"string"},"maxItems":50,"type":"array"},"name":{"description":"App name","maxLength":63,"minLength":1,"pattern":"^[a-z0-9-]+$","type":"string"},"path":{"description":"Project directory or ample.toml service","maxLength":512,"minLength":1,"type":"string"},"release_command":{"description":"Migration command run before activation","maxLength":512,"type":"string"},"start":{"description":"Start command (Python apps pass one explicitly)","maxLength":512,"type":"string"}},"required":["name","path","start"],"type":"object"}

## 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 transactional workflows: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). 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/transactional-workflows) 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
1. **App responds on its public URL**  
- **Kind**: http_get  
- **Path**: /  
- **Expect**: ample canary flask patterns
2. **Transactional-workflows self-test**  
- **Kind**: http_get  
- **Path**: /p/transactional-workflows  
- **Expect**: tx=ok history=2 conflict=rejected

## 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 form collection itself (your domain records, validation rules and concurrency policy) 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.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Authoritative**: true
- **Basis**: size prices from pricing.toml at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty.
- **Components**:  
  - **Name**: app server  
    **Size**: s-1vcpu-1gb  
    **Quantity**: 1.0  
    **Monthly Amount**: 5.0  
  - **Name**: managed PostgreSQL database  
    **Size**: 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.

## Evidence Summary
1. **Kind**: canary_run  
   **Summary**: Flask pattern fixture deployed on Ample; checks passed for transactional-workflows and configuration-secrets. 
   **Observed At**: 2026-09-21T01:14:18Z  
   **Implementation Revision**: 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21)  
   **Expires At**: 2027-03-20T01:14:18Z
2. **Kind**: canary_run  
   **Summary**: The same Flask app deployed with a --release-command migration; the marker it created was readable after activation.  
   **Observed At**: 2026-09-20T01:54:51Z  
   **Implementation Revision**: 199ff1dfd52683832ae75d3f98b53a7a4bff7f96-dirty (CLI e3181f5)  
   **Expires At**: 2027-03-19T01:54:51Z

## Last Verified At
2026-09-21T01:14:18Z

## Next Actions
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   **Method**: POST  
   **Relative Path**: /v1/catalog/search  
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   **Operation ID**: plan_deployment  
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4. **Label**: Read the existing agent authentication setup  
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