page:recipes:form collection:flask:relational workflow

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

Resource Requirements

Infrastructure Requirements

Compute

Postgres

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

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
  1. Transactional-workflows self-test

Limitations

Cost Estimate

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

  1. Label: Browse the catalog index
    Operation ID: catalog_index
    Method: GET
    Relative Path: /v1/catalog
  2. Label: Search published recipes by intent, stack and constraints
    Operation ID: search_recipes
    Method: POST
    Relative Path: /v1/catalog/search
    Parameters: {"body":{"limit":5,"query":"Host form collection with Flask: relational workflow state"}}
  3. Label: Prepare a side-effect-free deployment plan for an authorized project
    Operation ID: plan_deployment
    Method: POST
    Relative Path: /v1/catalog/plan
    Parameters: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:form-collection:flask:relational-workflow","recipeRevision":"r1"}}
  4. Label: Read the existing agent authentication setup
    Operation ID: existing_auth_setup
    Method: GET
    Relative Path: /mcp/setup
  5. Label: Browse Form collection
    Operation ID: browse_node
    Method: GET
    Relative Path: /v1/catalog/nodes/workload%3Aform-collection
  6. Label: Browse Flask
    Operation ID: browse_node Method: GET
    Relative Path: /v1/catalog/nodes/stack%3Aframework-flask
  7. Label: Browse Transactional workflows
    Operation ID: browse_node
    Method: GET
    Relative Path: /v1/catalog/nodes/pattern%3Atransactional-workflows
  8. Label: Browse Deploy web app
    Operation ID: browse_node
    Method: GET
    Relative Path: /v1/catalog/nodes/intent%3Adeploy-web-app