Host asset library with FastAPI: relational workflow state

Summary

Deploy a asset library built with FastAPI 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 FastAPI: 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 asset library-specific behavior as your application code.

Representative Queries

• Host asset library with FastAPI: relational workflow state
• Where can I host Asset library built with FastAPI?
• I need a domain record schema, validation rules and concurrency behavior.

Resource Requirements

• Primitive Compute
• Primitive Postgres

Framework

FastAPI

Workload

Asset library

Release Status

published

Support Status

verified

Execution Status

ready

Prerequisites

• A FastAPI project that builds and starts with the documented commands (pip install into .ample/python from requirements.txt, then uvicorn from run.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

Workflow Steps

1. Build and start
   pip install into .ample/python from requirements.txt, then uvicorn from run.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.

   ample deploy . --name --public --start "python3 run.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.

   ample logs --kind build

Examples

• FastAPI pattern fixture
  Multi-pattern FastAPI app whose transactional workflows module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

Success Checks

• app responds on its public URL
  • http_get to path / should expect to see ample canary fastapi patterns
• transactional-workflows self-test
  • http_get to path /p/transactional-workflows should 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 FastAPI major versions are not verified.
• The asset library itself (your domain records, validation rules and concurrency policy) is application code and was not separately tested; the pattern checks are what was verified.

Cost Estimate

• Currency: USD
• Monthly Amount: $10.00
• Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
• Components:
  • app server, size s-1vcpu-1gb, quantity 1, monthly amount $5.00
  • managed PostgreSQL database, size s-1vcpu-1gb, quantity 1, monthly amount $5.00
• 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.

Last Verified At

2026-09-21T01:14:18Z

Formats

• HTML: link
• Markdown: link
• JSON: link

Next Actions

• Browse the catalog index: GET /v1/catalog
• Search published recipes by intent: POST /v1/catalog/search
• Prepare a deployment plan: POST /v1/catalog/plan
• Authenticate setup: GET /mcp/setup
• Browse Asset Library: GET /v1/catalog/nodes/workload%3Aasset-library
• Browse FastAPI: GET /v1/catalog/nodes/stack%3Aframework-fastapi
• Browse Transactional workflows: GET /v1/catalog/nodes/pattern%3Atransactional-workflows
• Browse Deploy web app: GET /v1/catalog/nodes/intent%3Adeploy-web-app