# Host graphql api with FastAPI: Postgres-backed state

Deploy a graphql api built with FastAPI on Ample using the durable job state 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: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Not separately tested: your job types, payload schema and retry policy; treat the graphql api-specific behavior as your application code.

## Representative Queries
- Host graphql api with FastAPI: Postgres-backed state
- Where can I host GraphQL API built with FastAPI?
- I need a durable state schema and retry/recovery semantics implemented by application code.

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

## Infrastructure Requirements
1. **Compute**: 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)
2. **Postgres**: 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)

## 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

## 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 run.py

## Input Schema
- **Required**:
  - **name**: App name (maxLength: 63, minLength: 1, pattern: ^[a-z0-9-]+$)
  - **path**: Project directory or ample.toml service (maxLength: 512, minLength: 1)
  - **start**: Start command (maxLength: 512)
- **Optional**:
  - **env**: Encrypted environment variables (bucket credentials, secrets)
  - **release_command**: Migration command run before activation

## 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 durable job state: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=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 run.py"

4. **Verify**  
   Fetch the live URL and the pattern self-test route(s) (/p/durable-job-state) 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 (Path: /, Expect: ample canary fastapi patterns)
- Durable-job-state self-test (Path: /p/durable-job-state, Expect: job=done attempts=1 idempotent=true)

## 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 graphql api itself (your job types, payload schema and retry 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
- **Monthly Amount**: $10.00 (Currency: USD)
- 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.

## Next Actions
1. **Browse the catalog index**  
   (Action ID: browse-catalog)
2. **Search published recipes by intent, stack, and constraints**  
   (Action ID: search-recipes)
3. **Prepare a side-effect-free deployment plan for an authorized project**  
   (Action ID: plan:page:recipes:graphql-api:fastapi:persistent-state)
4. **Read the existing agent authentication setup**  
   (Action ID: auth-setup)
5. **Browse GraphQL API**  
   (Action ID: browse:workload:graphql-api)
6. **Browse FastAPI**  
   (Action ID: browse:stack:framework-fastapi)
7. **Browse Durable job state**  
   (Action ID: browse:pattern:durable-job-state)
8. **Browse Deploy API**  
   (Action ID: browse:intent:deploy-api)