# Host GraphQL API with Gin: Worker Execution and Job State

## Summary
Deploy a GraphQL API built with Gin 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 Gin: 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 GraphQL API-specific behavior as your application code.

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

## Resource Requirements
- Compute
- Postgres

## 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.

## 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 (go.sum committed for a reproducible build); 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

## Workflow Steps
1. **Plan the topology**: 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**: 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**: 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**: 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`

## Examples
### Gin Web + Worker Fixture
- **Description**: A Gin web app (apps/web) and a worker process (apps/worker) sharing one managed PostgreSQL database; the queue module is under tests/deploy-canaries/_pattern-modules.
- **Source Ref**: tests/deploy-canaries/gin-worker

## Success Checks
1. Web service responds on its public URL
   - **Type**: http_get
   - **Path**: /
   - **Expect**: ample canary gin patterns  
2. Worker consumed the enqueued job
   - **Type**: http_get
   - **Path**: /p/worker-queue/status
   - **Expect**: worker=done attempts=1 result=processed-by-worker

## Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-1gb for both services with the example fixture; other sizes, templates, and Gin major versions are not verified.
- The GraphQL 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, and the check ran immediately after deploy so idle behavior of the worker VM is not verified.
- The worker service is private: it has no public URL and is reached only through the shared database; both services are placed with their database.
- Managed PostgreSQL 16 only; extensions, connection limits, and backup or restore procedures are not verified; apps and their databases are placed together.
- Region, compliance attestations, and request-duration limits are unknown and not claimed.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 15.0
- **Basis**: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
- **Components**:
   1. Web server: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0
   2. Worker server: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0
   3. Managed PostgreSQL database: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0
- **Note**: Always-on monthly price of the tested sizes for the web service, the worker service, and the database; apps auto-pause when idle.