page:recipes:mobile backend:asp net core:worker state

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

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.

Summary

• Framework: ASP.NET Core
• Workload: Mobile backend
• Release Status: published
• Support Status: verified
• Execution Status: ready
• Docs Only: false

Prerequisites

1. 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 .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)
2. 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
3. An Ample account token with servers:write and databases:write (ample up creates the database)

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

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.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.

Cost Estimate

• Currency: USD
• Monthly Amount: 15.0

Success Checks

1. Web service responds on its public URL

   • Kind: http_get
   • Path: /
   • Expect: ample canary asp net core patterns

2. Worker consumed the enqueued job

   • Kind: http_get
   • Path: /p/worker-queue/status
   • Expect: worker=done attempts=1 result=processed-by-worker

Examples

• Title: ASP.NET Core web + worker fixture
  Description: 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. Source Ref: tests/deploy-canaries/asp-net-core-worker

Evidence Summary

• Kind: canary_run
  Summary: 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 .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).
  Observed At: 2026-09-20T23:09:18Z Implementation Revision: deb0e34-dirty (CLI 0.1.21)