page:guides:axum:private file access

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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