How do I use context with HTTP requests in Go?

How do I use context with HTTP requests in Go?

In Go, you can use the context package to manage request deadlines, cancellation signals, and other request-scoped values. You typically create a context using context.Background() or context.TODO() and pass it to your HTTP request.

Can you show me a code example?

Sure! Here's a simple example:

package main

import (
    "context"
    "fmt"
    "net/http"
    "time"
)

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

    req, err := http.NewRequestWithContext(ctx, "GET", "https://example.com", nil)
    if err != nil {
        fmt.Println(err)
        return
    }

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        fmt.Println(err)
        return
    }
    defer resp.Body.Close()

    fmt.Println("Response status:", resp.Status)
}

This code sets a timeout of 2 seconds for the HTTP request.

What happens if the request takes longer than the timeout?

If the request takes longer than the specified timeout, the context will be canceled, and the HTTP request will return an error indicating that the context was canceled.

Is it possible to use context for cancellation in a long-running process?

Yes, you can use context for cancellation in long-running processes by creating a context with a cancel function. When you call the cancel function, it will signal all operations using that context to stop.