page:recipes:public directory:phoenix:relational content

Host public directory with Phoenix: Postgres-backed content

Summary

Deploy a public directory built with Phoenix on Ample using the relational records 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, and a published bucket serves public assets from the CDN host. Verified on Phoenix: a workspace-scoped table, an explicit state machine (draft to review to published) that rejects invalid transitions, and a cross-workspace read that returns nothing (transitions=true isolation=true). Not separately tested: your record schema, states and access rules; treat the public directory-specific behavior as your application code.

Representative Queries

• Host public directory with Phoenix: Postgres-backed content
• Where can I host Public directory built with Phoenix?
• I need a content schema, publishing workflow and cache behavior after content updates.

Resource Requirements

• primitive:compute
• primitive:postgres
• primitive:cdn

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.
   • More info

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.
   • More info

3. CDN

   • Status: verified
   • Summary: The CDN host serves objects from published buckets. It does not front app compute and is not a cache or key-value store.
   • More info

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)
• A bucket from ample bucket create with its credentials passed as encrypted S3_* environment variables
• An Ample account token with servers:write, databases:read, buckets:read

Workflow Steps

1. Build and start
   Run: 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. The server must bind 0.0.0.0 on PORT.

2. Implement the pattern on PostgreSQL
   The fixture's module implements relational records: a workspace-scoped table, an explicit state machine (draft to review to published) that rejects invalid transitions, and a cross-workspace read that returns nothing. Run migrations with --release-command.

3. Wire object storage
   Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.

4. Deploy
   Run the synchronous deploy once and read the result. Command: ample deploy . --name --public --env S3_ENDPOINT=... - -env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=... --env CDN_PUBLIC_URL=...

5. Verify
   Fetch the live URL and check the pattern self-test routes, then run your own checks. Command: ample logs --kind build

Cost Estimate

• Monthly Amount: $10.0
• Currency: USD
• Components:
  • App server (s-1vcpu-1gb): $5.0
  • Managed PostgreSQL database (s-1vcpu-1gb): $5.0

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 public directory (your record schema, states and access rules) is application code and was not separately tested.

Success Checks

1. App responds on its public URL.
2. Relational-records self-test.

Examples

• Phoenix pattern fixture
  A multi-pattern Phoenix app whose relational records module was checked live. The module is under tests/deploy-canaries/_pattern-modules.

Evidence Summary

• Kind: canary_run
  Summary: Phoenix pattern fixture deployed on Ample. Checks passed for relational-records and configuration-secrets.
• Last Verified At: 2026-09-20T23:45:31Z