## Host event registration with Django: relational workflow state

### Summary
Deploy an event registration 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 event registration-specific behavior as your application code.

### Representative Queries
- Host event registration with Django: relational workflow state
- Where can I host Event registration built with Django?
- I need a domain record schema, validation rules and concurrency behavior.

### 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.

### 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

### 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**  
   - `ample deploy . --name  --public --start "python3 run.py"`
 
4. **Verify**  
   - `ample logs  --kind build`

### 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`

### 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

### 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 event registration 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  
- **Note:** Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.
- **Components:**  
   1. App Server  
      - Size: s-1vcpu-1gb  
      - Quantity: 1.0  
      - Monthly Amount: 5.0  
   2. Managed PostgreSQL Database  
      - Size: s-1vcpu-1gb  
      - Quantity: 1.0  
      - Monthly Amount: 5.0

### Last Verified At
- 2026-09-20T03:31:44Z

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