# Host appointment booking with Phoenix: relational workflow state

## Summary
Deploy a appointment booking built with Phoenix 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 Phoenix: 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 appointment booking-specific behavior as your application code.

## Representative Queries
- Host appointment booking with Phoenix: relational workflow state
- Where can I host Appointment booking built with Phoenix?
- I need a domain record schema, validation rules and concurrency behavior.

## 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.

## Infrastructure Requirements
- **Compute**: Verified 
- **Postgres**: Verified

## Workflow Steps
1. **Build and start**  
mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs. 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

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
- **Phoenix pattern fixture** - Multi-pattern Phoenix app whose transactional workflows module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

## Success Checks
- **App responds on its public URL**  
**Kind**: http_get  
**Path**: /  
**Expect**: ample canary phoenix patterns  
- **Transactional-workflows self-test**  
**Kind**: http_get  
**Path**: /p/transactional-workflows  
**Expect**: tx=ok history=2 conflict=rejected

## Limitations
- Verified on the elixir-1.18 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Phoenix major versions are not verified.
- The appointment booking 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
1. **Canary run**  
**Summary**: Phoenix pattern fixture deployed on Ample (mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs); checks passed for transactional-workflows and configuration-secrets.  
**Observed At**: 2026-09-20T23:45:31Z
2. **Canary run**  
**Summary**: The same Phoenix app deployed with a --release-command migration; the marker it created was readable after activation.

## Next Actions
- **Browse the catalog index** (GET /v1/catalog)
- **Search published recipes** by intent, stack, and constraints (POST /v1/catalog/search)
- **Prepare a side-effect-free deployment plan** for an authorized project (POST /v1/catalog/plan) 
- **Read the existing agent authentication setup** (GET /mcp/setup)
- **Browse Appointment booking** (GET /v1/catalog/nodes/workload%3Aappointment-booking) 
- **Browse Phoenix** (GET /v1/catalog/nodes/stack%3Aframework-phoenix) 
- **Browse Transactional workflows** (GET /v1/catalog/nodes/pattern%3Atransactional-workflows) 
- **Browse Deploy web app** (GET /v1/catalog/nodes/intent%3Adeploy-web-app)