page:recipes:rest api:echo:worker state

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"}}