## Enforce private-file authorization for Axum

### Summary
Private file access for an Axum app on Ample. Verified on Axum: a role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=ok). Build and start: `cargo build --release` in the rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL.

### Representative Queries
- Enforce private-file authorization for Axum
- Where can I host Enforce private-file authorization built with Axum?
- 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**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes. (Status: verified)
- **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. (Status: verified)
- **S3-compatible object storage**: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified. (Status: verified)

### Prerequisites
- An Axum project (`cargo build --release` in the rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL)
- 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**: `cargo build --release` in the rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL; 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`

### Success Checks
- App responds on its public URL (expect: `ample canary axum patterns`)
- Private-document-library check from the example (expect: see the pattern fixture checks).

### Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-2gb; other sizes and Axum major versions are not verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.
- PutObject and GetObject with path-style addressing are verified; other S3 operations are not.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: $10.00
- **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: $5.00
- **Managed PostgreSQL database**: size: `s-1vcpu-1gb`, quantity: 1.0, monthly amount: $5.00

**Note**: Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

### Evidence Summary
- **Kind**: canary_run
- **Summary**: Axum pattern fixture deployed on Ample (`cargo build --release` in the rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL); for this guide: a role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=ok).
- **Observed At**: 2026-09-21T02:46:37Z
- **Expiration**: 2027-03-20T02:46:37Z

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