Enforce private-file authorization for Phoenix

Summary

Private file access for a Phoenix app on Ample. Verified on Phoenix: a role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=ok). 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.

Representative Queries

• Enforce private-file authorization for Phoenix
• Where can I host Enforce private-file authorization built with Phoenix?
• I need application identity integration, per-file access rules and negative authorization tests.

Resource Requirements

• primitive:compute
• primitive:postgres
• primitive:s3-compatible-object-storage

Infrastructure Requirements

• Compute: Verified. Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
• Postgres: Verified. Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
• S3-compatible object storage: Verified. Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

Prerequisites

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

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. The server must bind 0.0.0.0 on PORT.

2. Create the bucket and pass its credentials

   Create it once with ample bucket create, then pass endpoint, region, bucket and keys with --env; use path-style addressing. Command: ample deploy . --name --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...

3. Authorize before touching storage

   Return 401 for unauthenticated requests and 403 for the wrong role; keep the bucket unpublished and stream objects through the app.

4. Verify

   Fetch the live URL and /p/private-document-library on the example; on failure read the build and runtime logs. Command: ample logs --kind build

Examples

• Phoenix pattern fixture: Verified private file access on Phoenix. Source Reference: tests/deploy-canaries/phoenix-patterns.

Success Checks

• Check: app responds on its public URL
  Kind: http_get
  Path: /
  Expect: ample canary phoenix patterns
• Check: private-document-library check from the example
  Kind: http_get
  Path: /p/private-document-library
  Expect: see the pattern fixture checks.

Limitations

• Verified on the elixir-1.18 template at s-1vcpu-1gb; other sizes and Phoenix major versions are not verified.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• Managed PostgreSQL 16 only; extensions and connection limits are not verified.

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 auto-pause when idle. Buckets are allocation-priced per quota and not included.