# Host order tracking with Django: relational catalog data

Deploy a order tracking 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 order tracking-specific behavior as your application code.

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

## Resource Requirements
- Compute  
- 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.

## Prerequisites
- 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)
- 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

## 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.
   - Command: 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`.  
   - Command: ample logs  --kind build

## Examples
- **Django pattern fixture**  
   - Description: Multi-pattern Django app whose transactional workflows module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
   - Source Reference: tests/deploy-canaries/django-patterns

## Success Checks
1. **App responds on its public URL**  
   - Kind: http_get  
   - Path: /  
   - Expect: ample canary django patterns

2. **Transactional-workflows self-test**  
   - Kind: http_get  
   - Path: /p/transactional-workflows  
   - 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 Django major versions are not verified.
- The order tracking 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, monthlyAmount: 5.0)  
  - Managed PostgreSQL database (size: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 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**: Django pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then waitress serving project.wsgi from run.py reading PORT on the python-3.12 template); checks passed for transactional-workflows and configuration-secrets. Pattern proof: 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

## Next Actions
1. **Browse the catalog index**  
   - Operation Id: catalog_index  
   - Method: GET  
   - Relative Path: /v1/catalog
2. **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 order tracking with Django: relational catalog data"}}
3. **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:order-tracking:django:relational-catalog","recipeRevision":"r1"}}
4. **Read the existing agent authentication setup**  
   - Operation Id: existing_auth_setup  
   - Method: GET  
   - Relative Path: /mcp/setup
5. **Browse Order tracking**  
   - Operation Id: browse_node  
   - Method: GET  
   - Relative Path: /v1/catalog/nodes/workload%3Aorder-tracking
6. **Browse Django**  
   - Operation Id: browse_node  
   - Method: GET  
   - Relative Path: /v1/catalog/nodes/stack%3Aframework-django
7. **Browse Transactional workflows**  
   - Operation Id: browse_node  
   - Method: GET  
   - Relative Path: /v1/catalog/nodes/pattern%3Atransactional-workflows
8. **Browse Deploy web app**  
   - Operation Id: browse_node  
   - Method: GET  
   - Relative Path: /v1/catalog/nodes/intent%3Adeploy-web-app