# Host mobile backend with ASP.NET Core: worker execution and job state

## Summary

Deploy a mobile backend built with ASP.NET Core 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 ASP.NET Core: 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 mobile backend-specific behavior as your application code.

## Infrastructure requirements

- **Compute**: verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- **Postgres**: verified (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 (dotnet publish -c Release -o out in the builder, then dotnet <entry>.dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT; the worker starts with dotnet of its own console project (plain Npgsql) 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)

## Exact tested configuration

- **template**: `dotnet-10`
- **runtime**: `dotnet`
- **size**: `s-1vcpu-1gb`
- **build**: `dotnet publish -c Release -o out`
- **start**: `ASPNETCORE_URLS=http://0.0.0.0:$PORT dotnet out/$(basename $(ls out/*.runtimeconfig.json | head -n 1) .runtimeconfig.json).dll`

## 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.
   
   ```
   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].
   
   ```
   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).
   
   ```
   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.
   
   ```
   ample logs <deployment_id> --kind runtime
   ```

## Tested examples

- **ASP.NET Core web + worker fixture** (tests/deploy-canaries/asp-net-core-worker): A ASP.NET Core 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.

## Success checks

- web service responds on its public URL (`/` on the live URL, expect ample canary asp net core patterns)
- worker consumed the enqueued job (`/p/worker-queue/status` on the live URL, expect worker=done attempts=1 result=processed-by-worker)

## Limitations

- Verified on the dotnet-10 template at s-1vcpu-1gb for both services with the example fixture; other sizes, templates and ASP.NET Core major versions are not verified.
- The mobile backend 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

Estimated 15.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- web server x1 `s-1vcpu-1gb`: 5.00 USD
- worker server x1 `s-1vcpu-1gb`: 5.00 USD
- managed PostgreSQL database x1 `s-1vcpu-1gb`: 5.00 USD

Always-on monthly price of the tested sizes for the web service, the worker service and the database; apps auto-pause when idle.

## Verification evidence

- canary_run on 2026-09-20T23:09:18Z at revision `deb0e34-dirty (CLI 0.1.21)`: ASP.NET Core web service plus a separate ASP.NET Core worker process deployed on Ample with `ample plan --write` then `ample up` (dotnet publish -c Release -o out in the builder, then dotnet <entry>.dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT); the web service enqueued a job that the private worker service consumed from the shared managed PostgreSQL database. Pattern proof: 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). (expires 2027-03-19T23:09:18Z)

Last verified: 2026-09-20T23:09:18Z

## Execution binding

MCP tool `ample_up` (registry `mcp:ample_up`), schema hash `db7ca0facfe2cd28` observed 2026-09-21T03:19:59.525781+00:00 at revision `49962bcade4f`, binding state `current`, required scopes: servers:write, databases:write.