page:guides:echo:private file access

Enforce private-file authorization for Echo

Summary

Private file access for a Echo app on Ample. Verified on Echo: 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 Echo
• Where can I host Enforce private-file authorization built with Echo?
• 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.
• 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.
• S3-compatible object storage: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

Prerequisites

• A Echo project (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build))
• 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: 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Authorize before touching storage: Return 401 for unauthenticated requests and 403 for the wrong role; keep the bucket unpublished and stream objects through the app.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

• Echo pattern fixture: Verified private file access on Echo. Source: tests/deploy-canaries/echo-patterns

Success Checks

• App responds on its public URL (HTTP GET /)
• Private-document-library check from the example (HTTP GET /p/private-document-library)

Limitations

• Verified on the ubuntu-24.04 template at s-1vcpu-1gb; other sizes and Echo 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:
  • 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.

Evidence Summary

• Canary Run: Echo pattern fixture deployed on Ample (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build)); role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=ok).

Last Verified At

2026-09-21T02:34:39Z

Next Actions

• Browse the catalog index: Operation ID: catalog_index, Method: GET, Relative Path: /v1/catalog
• Search published recipes by intent, stack and constraints: Operation ID: search_recipes, Method: POST, Relative Path: /v1/catalog/search, Parameters: { "body": { "limit": 5, "query": "Enforce private-file authorization for Echo" }}
• Prepare a deployment plan for an authorized project: Operation ID: plan_deployment, Method: POST, Relative Path: /v1/catalog/plan, Parameters: { "body": { "inputs": {}, "projectId": "", "recipeId": "page:guides:echo:private-file-access", "recipeRevision": "r1" }}
• Read the existing agent authentication setup: Operation ID: existing_auth_setup, Method: GET, Relative Path: /mcp/setup
• Browse Echo: Operation ID: browse_node, Method: GET, Relative Path: /v1/catalog/nodes/stack%3Aframework-echo
• Browse Connect app to storage: Operation ID: browse_node, Method: GET, Relative Path: /v1/catalog/nodes/intent%3Aconnect-app-to-storage
• Browse Private document library: Operation ID: browse_node, Method: GET, Relative Path: /v1/catalog/nodes/pattern%3Aprivate-document-library