Cloud Tasks

Google Cloud Tasks is a fully managed service for executing, dispatching, and delivering tasks asynchronously. While Pub/Sub is designed for event-driven messaging between services, Cloud Tasks is designed for task execution — specifically, for situations where you need to control the rate, timing, and retry behaviour of work items sent to a target service.

---

Cloud Tasks vs Pub/Sub

Understanding when to use Cloud Tasks versus Pub/Sub is essential:

Aspect	Cloud Tasks	Pub/Sub
Pattern	Task dispatch (command)	Publish-subscribe (event)
Consumers	One target per task	Many subscribers per topic
Rate control	Yes (configurable rate limits)	No (subscriber controls pace)
Scheduling	Yes (schedule tasks for future execution)	No (immediate delivery)
Deduplication	Yes (task names for deduplication)	Via exactly-once or client-side
Delivery	HTTP (App Engine or generic target)	Pull, push, BigQuery, GCS
Fan-out	No — one task, one handler	Yes — one message, many subscribers
Use case	"Do this later"	"This happened"

When to Use Cloud Tasks

• You need to execute a specific piece of work on a target service
• You want to control the rate at which work is dispatched
• You need to schedule work for future execution
• You want built-in deduplication using task names
• There is exactly one consumer for each task

When to Use Pub/Sub

• Multiple services need to react to the same event
• You need fan-out to multiple subscribers
• You want event-driven architecture
• You need streaming or high-throughput messaging

---

Core Concepts

Queues

A queue is a container for tasks. Each queue has its own configuration for rate limits, retry policies, and routing.

# Create a queue
gcloud tasks queues create order-processing-queue \
  --location=europe-west1

# List queues
gcloud tasks queues list --location=europe-west1

Tasks

A task is a unit of work to be dispatched to a target. Each task contains:

Component	Description
Target	The HTTP endpoint to call
Method	HTTP method (GET, POST, PUT, DELETE)
Body	Request body (for POST/PUT)
Headers	Custom HTTP headers
Schedule time	When the task should be dispatched (optional)
Name	Unique task name for deduplication (optional)

Targets

Cloud Tasks supports two target types:

Target	Description	Authentication
HTTP target	Any publicly reachable HTTPS endpoint	OIDC or OAuth tokens
App Engine target	App Engine service within the same project	Automatic

---

Rate Limiting

One of Cloud Tasks' most valuable features is rate limiting. You can control how fast tasks are dispatched to prevent overwhelming downstream services.

# Configure rate limits on a queue
gcloud tasks queues update order-processing-queue \
  --location=europe-west1 \
  --max-dispatches-per-second=100 \
  --max-concurrent-dispatches=10