Merge pull request #3 from campoy/justforfunc

applying justforfunc changes

Author: thesandlord

logpipe.go

@@ -18,9 +18,9 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"log"
 	"os"
 	"os/signal"
+	"time"
 
 	flags "github.com/jessevdk/go-flags"
 
@@ -33,70 +33,76 @@ func main() {
 		ProjectID string `short:"p" long:"project" description:"Google Cloud Platform Project ID" required:"true"`
 		LogName   string `short:"l" long:"logname" description:"The name of the log to write to" default:"default"`
 	}
-	if _, err := flags.Parse(&opts); err != nil {
+	_, err := flags.Parse(&opts)
+	if err != nil {
 		os.Exit(2)
 	}
 
 	// Check if Standard In is coming from a pipe
 	fi, err := os.Stdin.Stat()
 	if err != nil {
-		log.Fatalf("Could not stat standard input: %v", err)
+		errorf("Could not stat standard input: %v", err)
 	}
 	if fi.Mode()&os.ModeNamedPipe == 0 {
-		fmt.Fprintln(os.Stderr, "Nothing is piped in so there is nothing to log!")
-		os.Exit(2)
+		errorf("Nothing is piped in so there is nothing to log!")
 	}
 
 	// Creates a client.
 	ctx := context.Background()
 	client, err := logging.NewClient(ctx, opts.ProjectID)
 	if err != nil {
-		log.Fatalf("Failed to create client: %v", err)
+		errorf("Failed to create client: %v", err)
 	}
 	errc := make(chan error)
 	client.OnError = func(err error) { errc <- err }
 
+	ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
+	defer cancel()
+	if err := client.Ping(ctx); err != nil {
+		errorf("Failed to ping logging service: %v", err)
+	}
+
 	// Selects the log to write to.
 	logger := client.Logger(opts.LogName)
 
-	// Read from Stdin and log it to Stdout and Stackdriver
 	lines := make(chan string)
 	go func() {
+		defer close(lines)
+		// Read from Stdin and log it to Stdout and Stackdriver
 		s := bufio.NewScanner(io.TeeReader(os.Stdin, os.Stdout))
 		for s.Scan() {
 			lines <- s.Text()
 		}
 		if err := s.Err(); err != nil {
-			errc <- fmt.Errorf("could not read from std in: %v", err)
+			fmt.Fprintf(os.Stderr, "Failed to scan input: %v\n", err)
 		}
-		close(lines)
 	}()
 
 	signals := make(chan os.Signal)
 	signal.Notify(signals, os.Interrupt)
 
-mainLoop:
+loop:
 	for {
 		select {
 		case line, ok := <-lines:
 			if !ok {
-				break mainLoop
+				break loop
 			}
 			logger.Log(logging.Entry{Payload: line})
-		case err := <-errc:
-			log.Printf("error received: %v", err)
-			break mainLoop
-		case <-signals:
-			fmt.Fprintln(os.Stderr, "received interrupt: exiting program")
-			break mainLoop
+		case s := <-signals:
+			fmt.Fprintf(os.Stderr, "Terminating program after receiving signal: %v\n", s)
+			break loop
 		}
 	}
 
 	// Closes the client and flushes the buffer to the Stackdriver Logging
 	// service.
 	if err := client.Close(); err != nil {
-		log.Fatalf("Failed to close client: %v", err)
+		errorf("Failed to close client: %v", err)
 	}
+}
 
-	fmt.Fprintln(os.Stderr, "Finished logging")
+func errorf(format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, format+"\n", args...)
+	os.Exit(2)
 }