Pull vs push subscriptions in GCP - When to Use Which

The Big Idea

Discover how choosing pull or push can save you time and avoid missed messages!

The Scenario

Imagine you have a busy mailbox and you want to get your letters. You can either go check the mailbox yourself whenever you want, or have the mailman deliver letters directly to your door.

The Problem

Checking the mailbox yourself means you might waste time looking when there is no mail, or miss important letters if you check too late. Waiting for the mailman to deliver can cause delays or lost letters if the delivery fails.

The Solution

Pull and push subscriptions let you choose how messages arrive: either you pull messages when ready, or they are pushed automatically. This way, you control timing and reliability without manual guesswork.

Before vs After

✗ Before

while True:
  check_mailbox()
  sleep(10)

✓ After

subscribe(push_endpoint)
# or
messages = pull_messages()

What It Enables

You can build systems that get messages exactly when you want, improving efficiency and reliability.

Real Life Example

A news app can use push subscriptions to get breaking news instantly, or pull subscriptions to check for updates only when the user opens the app.

Key Takeaways

Pull lets you fetch messages when ready.

Push sends messages automatically to you.

Choosing the right method improves message handling.