v0.0.75

cmdext/cmdrunner.go

@@ -1,8 +1,8 @@
 package cmdext
 
 import (
-	"bufio"
+	"gogs.mikescher.com/BlackForestBytes/goext/mathext"
-	"io"
+	"gogs.mikescher.com/BlackForestBytes/goext/syncext"
 	"os/exec"
 	"time"
 )
@@ -30,119 +30,41 @@ func run(opt CommandRunner) (CommandResult, error) {
 		return CommandResult{}, err
 	}
 
+	preader := pipeReader{
+		stdout: stdoutPipe,
+		stderr: stderrPipe,
+	}
+
 	err = cmd.Start()
 	if err != nil {
 		return CommandResult{}, err
 	}
 
-	errch := make(chan error, 3)
+	type resultObj struct {
-	go func() { errch <- cmd.Wait() }()
+		stdout      string
+		stderr      string
+		stdcombined string
+		err         error
+	}
 
-	// [1] read raw stdout
+	outputChan := make(chan resultObj)
-
-	stdoutBufferReader, stdoutBufferWriter := io.Pipe()
-	stdout := ""
 	go func() {
-		buf := make([]byte, 128)
+		// we need to first fully read the pipes and then call Wait
-		for true {
+		// see https://pkg.go.dev/os/exec#Cmd.StdoutPipe
-			n, out := stdoutPipe.Read(buf)
 
-			if n > 0 {
+		stdout, stderr, stdcombined, err := preader.Read(opt.listener)
-				txt := string(buf[:n])
+		if err != nil {
-				stdout += txt
+			outputChan <- resultObj{stdout, stderr, stdcombined, err}
-				_, _ = stdoutBufferWriter.Write(buf[:n])
-				for _, lstr := range opt.listener {
-					lstr.ReadRawStdout(buf[:n])
-				}
-			}
-			if out == io.EOF {
-				break
-			}
-			if out != nil {
-				errch <- out
-				_ = cmd.Process.Kill()
-				break
-			}
 		}
-		_ = stdoutBufferWriter.Close()
-	}()
 
-	// [2] read raw stderr
+		err = cmd.Wait()
-
+		if err != nil {
-	stderrBufferReader, stderrBufferWriter := io.Pipe()
+			outputChan <- resultObj{stdout, stderr, stdcombined, err}
-	stderr := ""
-	go func() {
-		buf := make([]byte, 128)
-		for true {
-			n, err := stderrPipe.Read(buf)
-
-			if n > 0 {
-				txt := string(buf[:n])
-				stderr += txt
-				_, _ = stderrBufferWriter.Write(buf[:n])
-				for _, lstr := range opt.listener {
-					lstr.ReadRawStderr(buf[:n])
-				}
-			}
-			if err == io.EOF {
-				break
-			}
-			if err != nil {
-				errch <- err
-				_ = cmd.Process.Kill()
-				break
-			}
 		}
-		_ = stderrBufferWriter.Close()
+
+		outputChan <- resultObj{stdout, stderr, stdcombined, nil}
 	}()
 
-	combch := make(chan string, 32)
-	stopCombch := make(chan bool)
-
-	// [3] collect stdout line-by-line
-
-	go func() {
-		scanner := bufio.NewScanner(stdoutBufferReader)
-		for scanner.Scan() {
-			txt := scanner.Text()
-			for _, lstr := range opt.listener {
-				lstr.ReadStdoutLine(txt)
-			}
-			combch <- txt
-		}
-	}()
-
-	// [4] collect stderr line-by-line
-
-	go func() {
-		scanner := bufio.NewScanner(stderrBufferReader)
-		for scanner.Scan() {
-			txt := scanner.Text()
-			for _, lstr := range opt.listener {
-				lstr.ReadStderrLine(txt)
-			}
-			combch <- txt
-		}
-	}()
-
-	defer func() { stopCombch <- true }()
-
-	// [5] combine stdcombined
-
-	stdcombined := ""
-	go func() {
-		for {
-			select {
-			case txt := <-combch:
-				stdcombined += txt + "\n" // this comes from bufio.Scanner and has no newlines...
-			case <-stopCombch:
-				return
-			}
-		}
-	}()
-
-	// [6] run
-
 	var timeoutChan <-chan time.Time = make(chan time.Time, 1)
 	if opt.timeout != nil {
 		timeoutChan = time.After(*opt.timeout)
@@ -155,24 +77,37 @@ func run(opt CommandRunner) (CommandResult, error) {
 		for _, lstr := range opt.listener {
 			lstr.Timeout()
 		}
-		return CommandResult{
-			StdOut:          stdout,
-			StdErr:          stderr,
-			StdCombined:     stdcombined,
-			ExitCode:        -1,
-			CommandTimedOut: true,
-		}, nil
 
-	case err := <-errch:
+		if fallback, ok := syncext.ReadChannelWithTimeout(outputChan, mathext.Min(32*time.Millisecond, *opt.timeout)); ok {
-		if exiterr, ok := err.(*exec.ExitError); ok {
+			// most of the time the cmd.Process.Kill() should also ahve finished the pipereader
+			// and we can at least return the already collected stdout, stderr, etc
+			return CommandResult{
+				StdOut:          fallback.stdout,
+				StdErr:          fallback.stderr,
+				StdCombined:     fallback.stdcombined,
+				ExitCode:        -1,
+				CommandTimedOut: true,
+			}, nil
+		} else {
+			return CommandResult{
+				StdOut:          "",
+				StdErr:          "",
+				StdCombined:     "",
+				ExitCode:        -1,
+				CommandTimedOut: true,
+			}, nil
+		}
+
+	case outobj := <-outputChan:
+		if exiterr, ok := outobj.err.(*exec.ExitError); ok {
 			excode := exiterr.ExitCode()
 			for _, lstr := range opt.listener {
 				lstr.Finished(excode)
 			}
 			return CommandResult{
-				StdOut:          stdout,
+				StdOut:          outobj.stdout,
-				StdErr:          stderr,
+				StdErr:          outobj.stderr,
-				StdCombined:     stdcombined,
+				StdCombined:     outobj.stdcombined,
 				ExitCode:        excode,
 				CommandTimedOut: false,
 			}, nil
@@ -183,9 +118,9 @@ func run(opt CommandRunner) (CommandResult, error) {
 				lstr.Finished(0)
 			}
 			return CommandResult{
-				StdOut:          stdout,
+				StdOut:          outobj.stdout,
-				StdErr:          stderr,
+				StdErr:          outobj.stderr,
-				StdCombined:     stdcombined,
+				StdCombined:     outobj.stdcombined,
 				ExitCode:        0,
 				CommandTimedOut: false,
 			}, nil

cmdext/cmdrunner_test.go

@@ -1,6 +1,9 @@
 package cmdext
 
-import "testing"
+import (
+	"testing"
+	"time"
+)
 
 func TestStdout(t *testing.T) {
 
@@ -57,3 +60,27 @@ func TestStdcombined(t *testing.T) {
 	}
 
 }
+
+func TestPartialRead(t *testing.T) {
+	res1, err := Runner("python").
+		Arg("-c").
+		Arg("import sys; import time; print(\"first message\", flush=True); time.sleep(5); print(\"cant see me\", flush=True);").
+		Timeout(100 * time.Millisecond).
+		Run()
+	if err != nil {
+		t.Errorf("%v", err)
+	}
+	if !res1.CommandTimedOut {
+		t.Errorf("!CommandTimedOut")
+	}
+	if res1.StdErr != "" {
+		t.Errorf("res1.StdErr == '%v'", res1.StdErr)
+	}
+	if res1.StdOut != "first message\n" {
+		t.Errorf("res1.StdOut == '%v'", res1.StdOut)
+	}
+	if res1.StdCombined != "first message\n" {
+		t.Errorf("res1.StdCombined == '%v'", res1.StdCombined)
+	}
+
+}

cmdext/pipereader.go

@@ -0,0 +1,146 @@
+package cmdext
+
+import (
+	"bufio"
+	"gogs.mikescher.com/BlackForestBytes/goext/syncext"
+	"io"
+	"sync"
+)
+
+type pipeReader struct {
+	stdout io.ReadCloser
+	stderr io.ReadCloser
+}
+
+// Read ready stdout and stdin until finished
+// also splits both pipes into lines and calld the listener
+func (pr *pipeReader) Read(listener []CommandListener) (string, string, string, error) {
+	type combevt struct {
+		line string
+		stop bool
+	}
+
+	errch := make(chan error, 8)
+
+	wg := sync.WaitGroup{}
+
+	// [1] read raw stdout
+
+	wg.Add(1)
+	stdoutBufferReader, stdoutBufferWriter := io.Pipe()
+	stdout := ""
+	go func() {
+		buf := make([]byte, 128)
+		for true {
+			n, out := pr.stdout.Read(buf)
+
+			if n > 0 {
+				txt := string(buf[:n])
+				stdout += txt
+				_, _ = stdoutBufferWriter.Write(buf[:n])
+				for _, lstr := range listener {
+					lstr.ReadRawStdout(buf[:n])
+				}
+			}
+			if out == io.EOF {
+				break
+			}
+			if out != nil {
+				errch <- out
+				break
+			}
+		}
+		_ = stdoutBufferWriter.Close()
+		wg.Done()
+	}()
+
+	// [2] read raw stderr
+
+	wg.Add(1)
+	stderrBufferReader, stderrBufferWriter := io.Pipe()
+	stderr := ""
+	go func() {
+		buf := make([]byte, 128)
+		for true {
+			n, err := pr.stderr.Read(buf)
+
+			if n > 0 {
+				txt := string(buf[:n])
+				stderr += txt
+				_, _ = stderrBufferWriter.Write(buf[:n])
+				for _, lstr := range listener {
+					lstr.ReadRawStderr(buf[:n])
+				}
+			}
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				errch <- err
+				break
+			}
+		}
+		_ = stderrBufferWriter.Close()
+		wg.Done()
+	}()
+
+	combch := make(chan combevt, 32)
+
+	// [3] collect stdout line-by-line
+
+	wg.Add(1)
+	go func() {
+		scanner := bufio.NewScanner(stdoutBufferReader)
+		for scanner.Scan() {
+			txt := scanner.Text()
+			for _, lstr := range listener {
+				lstr.ReadStdoutLine(txt)
+			}
+			combch <- combevt{txt, false}
+		}
+		combch <- combevt{"", true}
+		wg.Done()
+	}()
+
+	// [4] collect stderr line-by-line
+
+	wg.Add(1)
+	go func() {
+		scanner := bufio.NewScanner(stderrBufferReader)
+		for scanner.Scan() {
+			txt := scanner.Text()
+			for _, lstr := range listener {
+				lstr.ReadStderrLine(txt)
+			}
+			combch <- combevt{txt, false}
+		}
+		combch <- combevt{"", true}
+		wg.Done()
+	}()
+
+	// [5] combine stdcombined
+
+	wg.Add(1)
+	stdcombined := ""
+	go func() {
+		stopctr := 0
+		for stopctr < 2 {
+			vvv := <-combch
+			if vvv.stop {
+				stopctr++
+			} else {
+				stdcombined += vvv.line + "\n" // this comes from bufio.Scanner and has no newlines...
+			}
+		}
+		wg.Done()
+	}()
+
+	// wait for all (5) goroutines to finish
+	wg.Wait()
+
+	if err, ok := syncext.ReadNonBlocking(errch); ok {
+		return "", "", "", err
+	}
+
+	return stdout, stderr, stdcombined, nil
+}