Propagating errors with errgroup

This recipe will show how to easily use the errgroup extension package to detect the error within the group of goroutines that run subtasks, within a common task.

How to do it...

1. Open the console and create the folder chapter10/recipe07.
2. Navigate to the directory.
3. Create the file lines.go with the following content:

        package main

        import (
          "bufio"
          "context"
          "fmt"
          "log"
          "strings"

          "golang.org/x/sync/errgroup"
        )

        const data = `line one
        line two with more words
        error: This is erroneous line`

        func main() {
          log.Printf("Application %s starting.", "Error Detection")
          scanner := bufio.NewScanner(strings.NewReader(data))
          scanner.Split(bufio.ScanLines)

          // For each line fire a goroutine
          g, _ := errgroup.WithContext(context.Background())
          for scanner.Scan() {
            row := scanner.Text()
      ...