Go Context: Timeout & Cancellation Expertise-Go Context Expertise

Example

ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

Scenario

Used to create a context that automatically cancels itself after a specified timeout. This is useful in scenarios where an operation should not exceed a certain duration, such as an HTTP request to an external service.

Example

select { case <-ctx.Done(): fmt.Println("Operation cancelled") case result := <-doSomething(): fmt.Println("Operation completed", result) }

Scenario

This function is critical in propagating cancellation signals across different parts of an application, particularly in concurrent operations. For instance, in a microservice architecture, when a service needs to aggregate data from multiple sources, it can cancel all outgoing requests if one fails, to quickly free up resources.

Example

if ctx.Err() == context.DeadlineExceeded { fmt.Println("Operation exceeded its time limit") }

Scenario

Managing operations that must be completed within a certain timeframe. For example, a database query that must return within 2 seconds to ensure a web application maintains a responsive user experience.

Example

userID := ctx.Value("userID").(string)

Scenario

Passing request-scoped values such as user IDs or transaction IDs through the layers of an application without changing the signatures of functions. This is particularly useful in logging or authentication, where such values are critical for monitoring and security.