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Choosing a runtime

Every Alchemy app on GCP needs somewhere for its code to run. Each runtime takes the same Effect program: you bundle it with main, bind resources to it, and Alchemy grants the IAM.

  • Cloud Run service (GCP.Function) — an HTTP server that scales to zero. Use this by default.
  • Cloud Run job (GCP.Run.Job) — a batch task that runs to completion and exits.
  • Cloud Run worker pool (GCP.Run.WorkerPool) — always-on containers with no URL, for queue consumers.
  • Cloud Function (GCP.CloudFunctions.Function) — an HTTP function built in the cloud, with no local Docker.
  • GKE (Kubernetes.Deployment on GCP.Container.Cluster) — Kubernetes workloads on a cluster you own.

At a glance

Section titled “At a glance”
Service Job Worker pool Cloud Function GKE
Entry fetch run run or a pull event source fetch fetch or run
Triggered by HTTP, push event sources RunJob, Cloud Scheduler Nothing: always running HTTP, push event sources HTTP via a load balancer, Jobs on apply
Cost shape Per request; zero idle Per execution; zero idle Per running instance Per request; zero idle Cluster plus pods
Packaging Image built locally Image built locally Image built locally Source built by Google Image built locally
Deploy time About a minute About a minute About a minute A few minutes Cluster: ~10 min. Pods: seconds

Cloud Run service — the default

Section titled “Cloud Run service — the default”

An HTTP container that scales with traffic and down to zero. It serves many requests per instance, streams responses, and runs your fetch handler as-is. Pub/Sub, Cloud Storage, Cloud Scheduler, and Eventarc can all push to it.

→ Cloud Run

Cloud Run job — batch work

Section titled “Cloud Run job — batch work”

A container with a run entry. It starts, does the work, and exits. Nothing is billed between executions. Start it from a service with the RunJob binding, or on a timer with Cloud Scheduler.

→ Cloud Run jobs

Cloud Run worker pool — background consumers

Section titled “Cloud Run worker pool — background consumers”

A pool of containers with no URL. It suits a worker that pulls from Pub/Sub around the clock and should keep running whether or not anyone sends HTTP traffic.

→ Worker pools

Cloud Functions — no Docker needed

Section titled “Cloud Functions — no Docker needed”

A 2nd-gen Cloud Function runs on Cloud Run underneath. The difference is the build: Alchemy uploads your bundled program and Google builds it, so you can deploy from a machine without Docker.

→ Cloud Functions

GKE — Kubernetes

Section titled “GKE — Kubernetes”

Reach for GKE when you need Kubernetes itself: Helm charts, long-lived pods, custom networking, or workloads you already run elsewhere. Bindings work the same way. They grant roles to the pod’s identity through Workload Identity.

→ GKE

Where next

Section titled “Where next”