page:recipes:order tracking:phoenix:relational catalog

Host Order Tracking with Phoenix: Relational Catalog Data

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

Representative Queries

• Host order tracking with Phoenix: relational catalog data
• Where can I host Order tracking built with Phoenix?
• 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.

Prerequisites

• A Phoenix project that builds and starts with the documented commands (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).
• 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
   • mix deps.get, MIX_ENV=prod mix compile and mix release in the builder.
   • Run the release bin script with PHX_SERVER=true on the elixir-1.18 template.
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).
3. Deploy
   • Command: ample deploy . --name <YourAppName> --public
4. Verify
   • Command: ample logs --kind build

Cost Estimate

• Monthly Amount: $10.00
• Components:
  • App server (s-1vcpu-1gb): $5.00
  • Managed PostgreSQL database (s-1vcpu-1gb): $5.00
• Note: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

Limitations

• Verified only 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 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.