## Host GraphQL API with Flask: Postgres-backed state

Deploy a GraphQL API built with Flask 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 Flask: 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 Flask: Postgres-backed state  
- Where can I host GraphQL API built with Flask?  
- I need a durable state schema and retry/recovery semantics implemented by application code.

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

### Framework
**Flask**  
**Workload**: GraphQL API  
**Release Status**: published  
**Support Status**: verified  
**Execution Status**: ready

### 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

### 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 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.  
   `ample deploy . --name  --public --start "python3 app.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`.  
   `ample logs  --kind build`

### 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 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**: 10.0 USD  
**Components**:
- App server: s-1vcpu-1gb (quantity: 1.0, amount: 5.0)  
- Managed PostgreSQL database: s-1vcpu-1gb (quantity: 1.0, amount: 5.0)  
**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.

### Evidence Summary
- **Canary Run**: Flask pattern fixture deployed on Ample; checks passed for durable-job-state and configuration-secrets.  
- **Observed At**: 2026-09-21T01:14:18Z

### Next Actions
- **Browse the catalog index**  
- **Search published recipes by intent, stack and constraints**  
- **Prepare a side-effect-free deployment plan for an authorized project**  
- **Read the existing agent authentication setup**  
- **Browse GraphQL API**  
- **Browse Flask**  
- **Browse Durable job state**  
- **Browse Deploy API**

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For more detailed documentation and insights, visit [the official documentation](/content/recipes/graphql-api/flask/persistent-state/index.html).