# Host marketplace with Django: relational catalog data

Deploy a marketplace built with Django 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 Django: 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 marketplace-specific behavior as your application code.

## Representative Queries
- Host marketplace with Django: relational catalog data
- Where can I host Marketplace built with Django?
- I need catalog tables, transactional update logic and application-level access boundaries.

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

## Infrastructure Requirements

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

## Framework
- Django

## Workload
- Marketplace

## Prerequisites
1. A Django project that builds and starts with the documented commands (pip install into .ample/python from requirements.txt, then waitress serving project.wsgi from run.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 run.py

## Workflow Steps
1. **Build and start**  
   pip install into .ample/python from requirements.txt, then waitress serving project.wsgi 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
   ```

## Limitations
- Verified on the python-3.12 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Django major versions are not verified.
- The marketplace 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  
- **Basis**: Size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty  
- **Components**:  
  - app server  
    - Size: s-1vcpu-1gb  
    - Quantity: 1.0  
    - Monthly Amount: 5.0  
  - 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. Buckets are allocation-priced per quota and not included.

## Evidence Summary
- **Canary Run Statistics**  
   - **Django Pattern Fixture**: Deployed on Ample; checks passed for transactional-workflows and configuration-secrets.  
   - **Summary**: 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).  
   - **Observed At**: 2026-09-20T03:31:44Z  
   - **Implementation Revision**: 03b6402b1b3e19178985f08ea4033804521d85d4-dirty (CLI b75e104)  
   - **Expires At**: 2027-03-19T03:31:44Z

## Next Actions
1. **Browse the catalog index**  
   - **Operation ID**: catalog_index  
   - **Method**: GET  
   - **Path**: /v1/catalog

2. **Prepare a side-effect-free deployment plan for an authorized project**  
   - **Operation ID**: plan_deployment  
   - **Method**: POST  
   - **Path**: /v1/catalog/plan

3. **Browse Marketplace**  
   - **Operation ID**: browse_node  
   - **Method**: GET  
   - **Path**: /v1/catalog/nodes/workload%3Amarketplace

4. **Browse Django**  
   - **Operation ID**: browse_node  
   - **Method**: GET  
   - **Path**: /v1/catalog/nodes/stack%3Aframework-django

5. **Browse Transactional workflows**  
   - **Operation ID**: browse_node  
   - **Method**: GET  
   - **Path**: /v1/catalog/nodes/pattern%3Atransactional-workflows

6. **Browse Deploy web app**  
   - **Operation ID**: browse_node  
   - **Method**: GET  
   - **Path**: /v1/catalog/nodes/intent%3Adeploy-web-app.