code cleanup and minor refactorings

3 files changed, 8 insertions, 154 deletions

diff --git a/internal/io/line/line.go b/internal/io/line/line.go
index 9db93c0..715be34 100644
--- a/internal/io/line/line.go
+++ b/internal/io/line/line.go
@@ -15,7 +15,11 @@ type Line struct {
 	// lines if that happens but it will signal to the client how
 	// many log lines in % could be transmitted to the client.
 	TransmittedPerc int
-	SourceID        string
+	// Contains the unique identifier of the source log file.
+	// It could be the name of the log or it could be one of the parent
+	// directories in case multiple log files with the same basename are
+	// followed.
+	SourceID string
 }
 
 // Return a human readable representation of the followed line.
diff --git a/internal/io/prompt/prompt.go b/internal/io/prompt/prompt.go
index a438d33..36ebdb5 100644
--- a/internal/io/prompt/prompt.go
+++ b/internal/io/prompt/prompt.go
@@ -3,9 +3,10 @@ package prompt
 import (
 	"bufio"
 	"fmt"
-	"github.com/mimecast/dtail/internal/io/logger"
 	"os"
 	"strings"
+
+	"github.com/mimecast/dtail/internal/io/logger"
 )
 
 // Answer is a user input of a prompt question.
@@ -18,8 +19,7 @@ type Answer struct {
 	Callback func()
 	// Runs after Callback and after logging resumes
 	EndCallback func()
-
-	AskAgain bool
+	AskAgain    bool
 }
 
 // Prompt used for interactive user input.
diff --git a/internal/io/run/run.go b/internal/io/run/run.go
deleted file mode 100644
index 2bb3756..0000000
--- a/internal/io/run/run.go
+++ /dev/null
@@ -1,150 +0,0 @@
-package run
-
-import (
-	"bufio"
-	"context"
-	"io"
-	"os/exec"
-	"sync"
-	"syscall"
-	"time"
-
-	"github.com/mimecast/dtail/internal/io/line"
-	"github.com/mimecast/dtail/internal/io/logger"
-)
-
-// Run is for execute a command.
-type Run struct {
-	command      string
-	args         []string
-	cmd          *exec.Cmd
-	pgroupKilled chan struct{}
-}
-
-// New returns a new command runner.
-func New(command string, args []string) Run {
-	return Run{
-		command:      command,
-		args:         args,
-		pgroupKilled: make(chan struct{}),
-	}
-}
-
-// StartBackground starts running the command in background.
-func (r Run) StartBackground(ctx context.Context, wg *sync.WaitGroup, ec chan<- int, lines chan<- line.Line) (pid int, err error) {
-	pid = -1
-
-	if len(r.args) > 0 {
-		logger.Debug(r.command, r.args, " ")
-		r.cmd = exec.CommandContext(ctx, r.command, r.args...)
-	} else {
-		logger.Debug(r.command)
-		r.cmd = exec.CommandContext(ctx, r.command)
-	}
-
-	// Create a new process group, so that kill() will only kill this command + pgroup.
-	r.cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
-
-	stdoutPipe, myErr := r.cmd.StdoutPipe()
-	if err != nil {
-		wg.Done()
-		err = myErr
-		return
-	}
-
-	stderrPipe, myErr := r.cmd.StderrPipe()
-	if myErr != nil {
-		wg.Done()
-		err = myErr
-		return
-	}
-
-	if myErr := r.cmd.Start(); err != nil {
-		wg.Done()
-		err = myErr
-		return
-	}
-
-	if r.cmd.Process != nil {
-		pid = r.cmd.Process.Pid
-	}
-
-	commandExited := make(chan struct{})
-
-	var pipeWg sync.WaitGroup
-	pipeWg.Add(2)
-
-	go r.killPgroup(ctx, commandExited, pid)
-	go r.pipeToLines(commandExited, &pipeWg, pid, stdoutPipe, "STDOUT", lines)
-	go r.pipeToLines(commandExited, &pipeWg, pid, stderrPipe, "STDERR", lines)
-
-	go func() {
-		exitCode := 255
-		if waitErr := r.cmd.Wait(); waitErr != nil {
-			if exitError, ok := waitErr.(*exec.ExitError); ok {
-				exitCode = exitError.ExitCode()
-			}
-		}
-		ec <- exitCode
-
-		// Tell pipes we are done
-		close(commandExited)
-		// Wait for process group to be killed
-		<-r.pgroupKilled
-		// Wait for the pipes to flush the contents
-		pipeWg.Wait()
-		// Now the job is truly done
-		wg.Done()
-	}()
-
-	return
-}
-
-func (r Run) pipeToLines(commandExited chan struct{}, wg *sync.WaitGroup, pid int, reader io.Reader, what string, lines chan<- line.Line) {
-	defer wg.Done()
-	bufReader := bufio.NewReader(reader)
-
-	for {
-		time.Sleep(time.Millisecond * 10)
-		lineStr, err := bufReader.ReadString('\n')
-
-		if err != nil {
-			select {
-			case <-commandExited:
-				return
-			default:
-			}
-			continue
-		}
-
-		newLine := line.Line{
-			Content:         []byte(lineStr),
-			Count:           uint64(pid),
-			TransmittedPerc: 100,
-			SourceID:        what,
-		}
-
-		select {
-		case lines <- newLine:
-		case <-commandExited:
-			return
-		}
-	}
-}
-
-func (r Run) killPgroup(ctx context.Context, commandExited chan struct{}, pid int) {
-	if pid == -1 {
-		close(r.pgroupKilled)
-		return
-	}
-
-	if pgid, err := syscall.Getpgid(pid); err == nil {
-		// Kill process group when done
-		select {
-		case <-ctx.Done():
-		case <-commandExited:
-		}
-		syscall.Kill(-pgid, syscall.SIGKILL)
-		close(r.pgroupKilled)
-	}
-}