page:guides:gin:private file access

Enforce Private-File Authorization for Gin

Summary

Private file access for a Gin app on Ample. Verified on Gin: a role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=ok). Build and start: CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build).

Representative Queries

• Enforce private-file authorization for Gin
• Where can I host Enforce private-file authorization built with Gin?
• 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

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.

3. S3-compatible object storage

   • Status: verified
   • Summary: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

Workflow Steps

1. Build and start
   CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build); 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   Return 401 for unauthenticated requests and 403 for the wrong role; keep the bucket unpublished and stream objects through the app.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

• Gin pattern fixture
  Verified private file access on Gin.

Success Checks

1. app responds on its public URL

   • Kind: http_get
   • Path: /
   • Expect: ample canary gin patterns

2. 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 ubuntu-24.04 template at s-1vcpu-1gb; other sizes and Gin 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: 10.0
• Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty

Components

1. App server

   • Size: s-1vcpu-1gb
   • Quantity: 1.0
   • Monthly Amount: 5.0

2. 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.

Next Actions

1. Browse the catalog index
   Action ID: browse-catalog
   Method: GET
   Relative Path: /v1/catalog

2. Search published recipes by intent, stack and constraints
   Action ID: search-recipes
   Method: POST
   Relative Path: /v1/catalog/search

3. Prepare a side-effect-free deployment plan for an authorized project
   Action ID: plan:page:guides:gin:private-file-access
   Method: POST
   Relative Path: /v1/catalog/plan

4. Read existing agent authentication setup
   Action ID: auth-setup
   Method: GET
   Relative Path: /mcp/setup

5. Browse Gin
   Action ID: browse:stack:framework-gin
   Method: GET
   Relative Path: /v1/catalog/nodes/stack%3Aframework-gin

6. Browse Connect app to storage
   Action ID: browse:intent:connect-app-to-storage
   Method: GET
   Relative Path: /v1/catalog/nodes/intent%3Aconnect-app-to-storage

7. Browse Private document library
   Action ID: browse:pattern:private-document-library
   Method: GET
   Relative Path: /v1/catalog/nodes/pattern%3Aprivate-document-library