add timestamp function for stdout logging

Author: leontappe

examples/bootjob.d/job.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+sleep 10
+exit 0

examples/bootjob.d/job2.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+sleep 5
+exit 0

examples/bootjob.d/one_shot.hcl

@@ -0,0 +1,25 @@
+boot "oneshotzero" {
+  command = "/bin/bash"
+  args = [
+    "examples/bootjob.d/job2.sh"
+  ]
+}
+
+boot "oneshot" {
+  command = "/bin/bash"
+  args = [
+    "examples/bootjob.d/job.sh"
+  ]
+}
+
+job "memes" {
+  command = "/bin/bash"
+  args = [
+    "-c",
+    "while true ; do echo 'memes'; sleep 10; done"
+  ]
+
+  stdout = "memes.log"
+  stdout = "memes_error.log"
+  enableTimestamps = true
+}

internal/config/types.go

@@ -96,6 +96,7 @@ type BaseJobConfig struct {
 	WorkingDirectory string   `hcl:"workingDirectory" json:"workingDirectory,omitempty"`
 	Stdout           string   `hcl:"stdout" json:"stdout,omitempty"`
 	Stderr           string   `hcl:"stderr" json:"stderr,omitempty"`
+	EnableTimestamps bool     `hcl:"enableTimestamps" json:"enableTimestamps"`
 }
 
 type Laziness struct {

pkg/proc/basejob.go

@@ -114,8 +114,26 @@ func (job *baseJob) startOnce(ctx context.Context, process chan<- *os.Process) e
 	cmd := exec.Command(job.Config.Command, job.Config.Args...)
 	cmd.Env = os.Environ()
 	cmd.Dir = job.Config.WorkingDirectory
-	cmd.Stdout = job.stdout
-	cmd.Stderr = job.stderr
+
+	// pipe stdout and stderr through timestamp function if they are enabled
+	if job.Config.EnableTimestamps {
+		stdoutPipe, err := cmd.StdoutPipe()
+		if err != nil {
+			return fmt.Errorf("failed to create stdout pipe for process: %s", err.Error())
+		}
+
+		stderrPipe, _ := cmd.StderrPipe()
+		if err != nil {
+			return fmt.Errorf("failed to create stderr pipe for process: %s", err.Error())
+		}
+
+		go job.logWithTimestamp(stdoutPipe, job.stdout)
+		go job.logWithTimestamp(stderrPipe, job.stderr)
+	} else {
+		cmd.Stdout = job.stdout
+		cmd.Stderr = job.stderr
+	}
+
 	cmd.SysProcAttr = &syscall.SysProcAttr{
 		Setpgid: true,
 	}
@@ -201,6 +219,20 @@ func (job *baseJob) closeStdFiles() {
 	}
 }
 
+func (job *baseJob) logWithTimestamp(r io.Reader, w io.Writer) {
+	l := log.WithField("job.name", job.Config.Name)
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		timestamp := time.Now().Format(time.RFC3339)
+		line := fmt.Sprintf("[%s] %s\n", timestamp, scanner.Text())
+		w.Write([]byte(line))
+	}
+	if err := scanner.Err(); err != nil {
+		l.Info(os.Stderr, "error reading from process: %v\n", err)
+	}
+}
+
 func (job *baseJob) readStdFile(ctx context.Context, wg *sync.WaitGroup, filePath string, outChan chan []byte, errChan chan error, follow bool, tailLen int) {
 	stdFile, err := os.OpenFile(filePath, os.O_RDONLY, 0o666)
 	if err != nil {