feat(output): print stderr/stdout live

closes #3

Author: mstruebing

.circleci/config.yml

@@ -8,7 +8,7 @@ jobs:
 
       - restore_cache:
           keys:
-            - go-mod-v4-{{ checksum "go.mod" }}
+            - go-mod-v4-{{ checksum "go.sum" }}
       - run:
           name: Run unit tests
           command: |
@@ -19,7 +19,7 @@ jobs:
       - run: make run
 
       - save_cache:
-          key: go-mod-v4-{{ checksum "go.mod" }}
+          key: go-mod-v4-{{ checksum "go.sum" }}
           paths:
             - "/go/pkg/mod"
 

cmd/duration/duration.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
 	"os"
 	"os/exec"
 	"strings"
 	"time"
+
+	tm "github.com/buger/goterm"
 )
 
 // Pads an integer with zeroes to the left
@@ -29,21 +32,43 @@ func getHours(time time.Duration) string {
 	return padTimePart(hours)
 }
 
-// Prints the duration how long a command is already running
-func printDuration() {
-	fmt.Printf("command running since: %s:%s:%s", getHours(0), getMinutes(0), getSeconds(0))
-	start := time.Now()
+func clearTime() {
+	tm.MoveCursor(tm.Width()-30, tm.Height())
+	tm.Printf("                               ")
+}
 
-	ticker := time.NewTicker(time.Second)
+func printDuration(start time.Time) {
+	currentTime := time.Since(start)
 
-	for range ticker.C {
-		currentTime := time.Since(start)
-		fmt.Printf("\rcommand running since: %s:%s:%s", getHours(currentTime), getMinutes(currentTime), getSeconds(currentTime))
-	}
+	tm.MoveCursor(tm.Width()-30, tm.Height())
+	tm.Printf("command running since: %s:%s:%s", getHours(currentTime), getMinutes(currentTime), getSeconds(currentTime))
+	tm.Flush()
 }
 
-func printCmdOutput(output string) {
-	fmt.Printf("\n\nOutput:\n%s", output)
+func printDurationAndOutput(output *bytes.Buffer) {
+	ticker := time.NewTicker(time.Nanosecond)
+
+	outputAccumulator := ""
+	outputPrint := ""
+
+	start := time.Now()
+	printDuration(start)
+
+	for range ticker.C {
+		currentOutput := output.String()
+
+		if strings.Compare(currentOutput, outputAccumulator) == 1 {
+			outputPrint = strings.Replace(currentOutput, outputAccumulator, "", 1)
+			outputAccumulator = currentOutput
+
+			clearTime()
+			tm.MoveCursor(0, tm.Height())
+			tm.Printf("%s", string(outputPrint))
+			tm.Flush()
+		}
+
+		printDuration(start)
+	}
 }
 
 func main() {
@@ -55,17 +80,19 @@ func main() {
 	program := strings.Join(os.Args[1:2], "")
 	args := strings.Join(os.Args[2:], " ")
 
-	go printDuration()
 	cmd := exec.Command(program, args)
 
-	// Currently the output is printed at the end of the program
-	// We can not differntiate between stdout and stderr anymore
-	// I couldn't find a good solution to print realtime while also
-	// printing the current duration readable until now.
-	output, err := cmd.CombinedOutput()
+	var output bytes.Buffer
+
+	cmd.Stdout = &output
+	cmd.Stderr = &output
+
+	go printDurationAndOutput(&output)
+
+	err := cmd.Run()
 	if err != nil {
 		panic(err)
 	}
 
-	printCmdOutput(string(output))
+	time.Sleep(time.Second)
 }

go.mod

@@ -1,3 +1,8 @@
 module github.com/mstruebing/duration
 
 go 1.12
+
+require (
+	github.com/buger/goterm v0.0.0-20181115115552-c206103e1f37
+	golang.org/x/sys v0.0.0-20190610081024-1e42afee0f76 // indirect
+)

go.sum

@@ -0,0 +1,4 @@
+github.com/buger/goterm v0.0.0-20181115115552-c206103e1f37 h1:uxxtrnACqI9zK4ENDMf0WpXfUsHP5V8liuq5QdgDISU=
+github.com/buger/goterm v0.0.0-20181115115552-c206103e1f37/go.mod h1:u9UyCz2eTrSGy6fbupqJ54eY5c4IC8gREQ1053dK12U=
+golang.org/x/sys v0.0.0-20190610081024-1e42afee0f76 h1:QSmW7Q3mFdAGjtAd0byXmFJ55inUydyZ4WQmiuItAIQ=
+golang.org/x/sys v0.0.0-20190610081024-1e42afee0f76/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

test-script/script.sh

@@ -2,6 +2,8 @@
 
 sleep 1
 echo hello 
+sleep 1
+echo error 1>&2
 sleep 2
 echo world
 sleep 3