How do I use the context package in Go?

How do I use the context package in Go?

The context package in Go is used to manage deadlines, cancellation signals, and request-scoped values across API boundaries. You can create a context using context.Background() or context.TODO(), and then use functions like context.WithCancel, context.WithDeadline, or context.WithValue to derive new contexts.

Can you give me an example of using context with a goroutine?

Sure! Here's a simple example:

package main

import (
    "context"
    "fmt"
    "time"
)

func main() {
    ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
    defer cancel()

    go func() {
        // Simulate work
        time.Sleep(1 * time.Second)
        fmt.Println("Goroutine finished work")
    }()

    <-ctx.Done() // Wait for the context to be done
    fmt.Println("Main function finished")
}

What happens if the context is canceled?

If the context is canceled, any goroutines that are listening to that context will receive a signal that they should stop their work. This is typically done by checking ctx.Done() in the goroutine and exiting if it's closed.

Are there any best practices for using the context package?

Yes, some best practices include:

1. Use context only for request-scoped data, not for passing optional parameters.
2. Avoid storing context in global variables.
3. Always cancel contexts when they are no longer needed to avoid resource leaks.