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How Worker Pools Work

The "Restaurant Kitchen" Mental Model

1. The Mental Model

Think of your Go Application as a busy restaurant. The goal is to handle many customers (HTTP Requests) efficiently without overwhelming the kitchen.

The Owner. Unlocks the doors and turns on the lights. Starts the system.

The Customers. They walk in and place orders (tasks) like "Resize this image".

The Order Window. A buffer where waiters place tickets. It has a limit (buffer size).

The Kitchen Staff. A fixed number of chefs (Goroutines) waiting for tickets.

Watch how the system behaves. Customers arrive, place orders, and leave. Chefs pick up orders from the window and cook them.

Dining Area (Requests)

Channel (Buffer)

Kitchen (Worker Pool)

Customers Waiting

Orders in Channel

0/5

Chefs Busy

Total Served

Decoupling: The waiter (HTTP Handler) doesn't cook. They just take the order. This keeps the front-of-house fast.
Concurrency vs Parallelism: Multiple chefs can cook at the same time (Parallelism) if you have multiple CPU cores.
Backpressure: If the Order Window is full, the waiter has to wait before taking new orders (Channel Blocking).
Lifecycle: The chefs are hired once (at startup) and stay forever. They don't quit after one steak.