## Host REST API with Echo: Worker Execution and Job State

### Summary
Deploy a REST API built with Echo as a public web service plus a dedicated worker process on Ample. `ample plan --write` discovers both services and their shared database and writes ample.toml; `ample up` reconciles the topology: a managed PostgreSQL 16 database, a public web microVM, and a private worker microVM (kind worker, no public URL), both reading DATABASE_URL. Verified on Echo: a separately deployed worker service (kind worker, no public URL) sharing a declared managed PostgreSQL database with the web service, consuming a jobs table with row locks and marking jobs done once (worker=done attempts=1). Not separately tested: your job payloads, retry policy, and scheduling; treat the REST API-specific behavior as your application code.

### Representative Queries
- Host REST API with Echo: worker execution and job state
- Where can I host a REST API built with Echo?
- I need a separately runnable worker, durable job records, and idempotent retries; not a managed queue.

### Resource Requirements
- Primitive: Compute
- Primitive: Postgres

### 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.

### Workflow Steps
1. **Plan the topology**  
   - Body: Run the planner once. It discovers the web and worker services, infers kind = "worker" for the process without a port, declares the database each service needs, and writes ample.toml. Exit 2 means it left questions in the manifest; answer them with --answer or by editing the file.  
   - Command: `ample plan --write .`

2. **Share one database**  
   - Body: Keep a single [databases.main] with engine = "postgres", drop any per-service database the planner added, and set DATABASE_URL = { database = "main" } under both [services.web.env] and [services.worker.env].  
   - Command: `ample plan --offline .`

3. **Apply**  
   - Body: Reconcile the whole manifest in dependency order: the database first, then both services. It is idempotent and never destructive; exit 0 means everything applied, 2 needs input, 1 a failed resource (independent siblings still proceed and re-running resumes).  
   - Command: `ample up .`

4. **Verify**  
   - Body: Fetch the web service URL and its worker status route (/p/worker-queue/status in the example) and confirm the worker processed the enqueued job; on failure read the worker service's runtime logs.  
   - Command: `ample logs --kind runtime`

### Prerequisites
- A repository with the web app and the worker as separate service directories (the fixture uses apps/web and apps/worker), each building and starting with the documented commands (`CGO_ENABLED=0 go build -o app ./...` then `./app` on the ubuntu-24.04 template). The worker starts with `./worker` and binds no port.
- Both services read DATABASE_URL at runtime and share one jobs table; the worker claims rows with `SELECT ... FOR UPDATE SKIP LOCKED` and marks them done once.
- An Ample account token with servers:write and databases:write (ample up creates the database).

### Tested Configuration
- **Template**: ubuntu-24.04
- **Runtime**: go
- **Size**: s-1vcpu-1gb
- **Build**: `CGO_ENABLED=0 go build -o app ./...`
- **Start**: `./app`

### Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-1gb for both services with the example fixture; other sizes, templates, and Echo major versions are not verified.
- The REST API itself (your job payloads, retry policy, and scheduling) is application code and was not separately tested; the worker-queue check is what was verified.
- The worker is a single long-running process supervised in its own microVM; there is no scheduler, cron, or horizontal worker scaling in this recipe.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 15.0
- **Note**: Always-on monthly price of the tested sizes for the web service, the worker service, and the database; apps auto-pause when idle.

### Next Actions
- **Browse the catalog index**  
   - ActionId: browse-catalog  
   - Method: GET  
   - RelativePath: /v1/catalog  
   
- **Search published recipes by intent, stack, and constraints**  
   - ActionId: search-recipes  
   - Method: POST  
   - RelativePath: /v1/catalog/search  
   - Parameters: {"body":{"limit":5,"query":"Host REST API with Echo: worker execution and job state"}}
   
- **Prepare a side-effect-free deployment plan for an authorized project**  
   - ActionId: plan:page:recipes:rest-api:echo:worker-state  
   - Method: POST  
   - RelativePath: /v1/catalog/plan  
   - Parameters: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:rest-api:echo:worker-state","recipeRevision":"r1"}}