Introduction to Concurrency in Go

Concurrency is one of Go's most powerful features, but it's often misunderstood. Let's start by clarifying what concurrency actually means.

Concurrency vs Parallelism#

Concurrency is not parallelism

Some quotes to support this statement:

"Concurrency is a property of the code; parallelism is a property of the running program"

"Concurrency is about dealing with lots of things at once. Parallelism is about doing lots of things at once."

Concurrency refers to the design pattern where multiple tasks can make progress independently, even if they're not executing simultaneously. Parallelism, on the other hand, is about executing multiple tasks simultaneously.

In Go, concurrency is built into the language design with three main components:

• Concurrency execution (goroutines) - Lightweight threads managed by the Go runtime
• Synchronization and messaging (channels) - Safe communication between concurrent code
• Multi-way concurrent control (select) - Coordination of multiple concurrent operations

Why Go's Approach to Concurrency is Different#

Go provides first-class support for concurrent code in a program, and channels solve the problem of communicating safely between concurrently running code.

Go also supports more traditional tools for writing concurrent code. Mutexes, pools, and locks are implemented in the sync package, but channels are often preferred for their simplicity and readability.

Key Concurrency Features in Go#

1. Goroutines: Lightweight threads that allow functions to run concurrently
2. Channels: Communication pipes that allow goroutines to share data safely
3. Select Statement: A control structure for handling multiple channel operations
4. WaitGroups: A synchronization mechanism from the sync package
5. Mutex: A way to protect shared data from concurrent access
6. Context Package: Tools for cancellation, deadlines, and request-scoped values

In the following labs, we'll explore each of these features in depth and learn how to use them to write efficient concurrent programs.

Summary#

• Concurrency is about structure, parallelism is about execution
• Go has built-in language features for concurrency
• Go's approach favors communication over shared memory
• Understanding concurrency patterns is essential for writing efficient Go programs

In the next lab, we'll dive deeper into channels, the fundamental communication mechanism in Go's concurrency model.