# Host rest api with Echo: stored input and output artifacts

Deploy a rest api built with Echo on Ample using the generated downloads pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Echo: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the rest api-specific behavior as your application code.

## Representative Queries
- Host rest api with Echo: stored input and output artifacts
- Where can I host REST API built with Echo?
- I need an input/output artifact contract, object metadata and access boundaries.

## Resource Requirements
- Compute
- PostgreSQL
- S3-compatible object storage

## Infrastructure Requirements
1. **Compute**  
   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**  
   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**  
   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. **Implement the pattern on PostgreSQL**  
   The fixture's module implements generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Wire object storage**  
   Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
4. **Deploy**  
   Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.  
   `ample deploy . --name  --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...`
5. **Verify**  
   Fetch the live URL and the pattern self-test route(s) (/p/generated-downloads) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.
   `ample logs  --kind build`

## Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Echo major versions are not verified.
- The rest api itself (your export formats, retention policy and entitlement model) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules 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 (s-1vcpu-1gb):** $5.00  
  - **Managed PostgreSQL database (s-1vcpu-1gb):** $5.00  
- **Note:** Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

## Success Checks
- **App responds on its public URL**  
  Expected: `ample canary echo patterns`  
  Path: `/`
- **Generated-downloads self-test**  
  Expected: `export=ok rows=3 (with ?token=...; 401 without)`  
  Path: `/p/generated-downloads`

## Example
### Echo pattern fixture
**Description:** Multi-pattern Echo app whose generated downloads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.  
**Source Ref:** tests/deploy-canaries/echo-patterns

## Next Actions
1. **Browse Catalog**  
   [Browse the catalog index](https://api.ample.computer/v1/catalog)
2. **Search Recipes**  
   [Search published recipes by intent, stack and constraints](https://api.ample.computer/v1/catalog/search)
3. **Prepare Deployment Plan**  
   [Prepare a side-effect-free deployment plan for an authorized project](https://api.ample.computer/v1/catalog/plan)
4. **Read Existing Agent Authentication Setup**  
   [Read the existing agent authentication setup](https://api.ample.computer/mcp/setup)
5. **Browse REST API**  
   [Browse REST API](https://api.ample.computer/v1/catalog/nodes/workload%3Arest-api)
6. **Browse Echo**  
   [Browse Echo](https://api.ample.computer/v1/catalog/nodes/stack%3Aframework-echo)
7. **Browse Generated Downloads**  
   [Browse Generated downloads](https://api.ample.computer/v1/catalog/nodes/pattern%3Agenerated-downloads)
8. **Browse Deploy API**  
   [Browse Deploy API](https://api.ample.computer/v1/catalog/nodes/intent%3Adeploy-api)