fix: refactor error reporting code sample (#3291)

Align code sample for error reporting with code in other languages.
Use an explicit error with the "fixed" message.
Use "official" env variable name.

errorreporting/errorreporting_quickstart/main.go

@@ -21,41 +21,47 @@ package main
 
 import (
 	"context"
+	"errors"
 	"log"
-	"net/http"
+	"os"
 
 	"cloud.google.com/go/errorreporting"
 )
 
 var errorClient *errorreporting.Client
 
 func main() {
-	ctx := context.Background()
-
-	// Sets your Google Cloud Platform project ID.
-	projectID := "YOUR_PROJECT_ID"
+	// Set your Google Cloud Platform project ID via environment or explicitly
+	projectID := os.Getenv("GOOGLE_CLOUD_PROJECT")
+	args := os.Args[1:]
+	if len(args) > 0 && args[0] != "" {
+		projectID = args[0]
+	}
 
+	ctx := context.Background()
 	var err error
 	errorClient, err = errorreporting.NewClient(ctx, projectID, errorreporting.Config{
-		ServiceName: "myservice",
+		ServiceName:    "errorreporting_quickstart",
+		ServiceVersion: "0.0.0",
 		OnError: func(err error) {
-			log.Printf("Could not log error: %v", err)
+			log.Printf("Could not report the error: %v", err)
 		},
 	})
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer errorClient.Close()
 
-	resp, err := http.Get("not-a-valid-url")
+	err = errors.New("something went wrong")
 	if err != nil {
 		logAndPrintError(err)
 		return
 	}
-	log.Print(resp.Status)
 }
 
 func logAndPrintError(err error) {
+	/// Client autopopulates the error context of the error. For more details about the context see:
+	/// https://cloud.google.com/error-reporting/reference/rest/v1beta1/ErrorContext
 	errorClient.Report(errorreporting.Entry{
 		Error: err,
 	})