Add src

go.mod

@@ -0,0 +1,3 @@
+module git.sdf.org/rudi/headless9
+
+go 1.18

main.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"time"
+)
+
+var (
+	controlFile = "/adm/services"
+	services    = make(map[string]string)
+)
+
+func main() {
+	log.Println("Starting headless9")
+	for {
+		log.Printf("Refreshing controlFile %+v", controlFile)
+		startup, err := readLines(controlFile)
+		if err != nil {
+			log.Fatalln(err)
+		}
+		for _, svc := range startup {
+			running := false
+			for runningProc := range services {
+				if svc == runningProc {
+					running = true
+					log.Printf("%+v exists as PID %+v", svc, services[svc])
+				}
+			}
+			if !running {
+				log.Printf("Svc not detected, starting: %+v", svc)
+				go execCommand(svc)
+			}
+		}
+		err = watchFile(controlFile)
+		if err != nil {
+			log.Println(err)
+		}
+	}
+}
+
+func execCommand(cmd string, arg ...string) {
+	proc := exec.Command(cmd, arg...)
+	// open the out file for writing
+	outfile, err := os.Create(fmt.Sprintf("/adm/log/%+v.log", cmd))
+	if err != nil {
+		panic(err)
+	}
+	infile, err := os.Create(fmt.Sprintf("/adm/log/%+v.ctl", cmd))
+	if err != nil {
+		panic(err)
+	}
+	defer outfile.Close()
+	defer infile.Close()
+	proc.Stderr = outfile
+	proc.Stdout = outfile
+	proc.Stdin = infile
+	err = proc.Start()
+	if err != nil {
+		panic(err)
+	}
+	services[cmd] = fmt.Sprint(proc.Process.Pid)
+	proc.Wait()
+}
+
+// readLines reads a whole file into memory
+// and returns a slice of its lines.
+func readLines(path string) ([]string, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var lines []string
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+	return lines, scanner.Err()
+}
+
+func watchFile(filePath string) error {
+	initialStat, err := os.Stat(filePath)
+	if err != nil {
+		return err
+	}
+
+	for {
+		stat, err := os.Stat(filePath)
+		if err != nil {
+			return err
+		}
+
+		if stat.Size() != initialStat.Size() || stat.ModTime() != initialStat.ModTime() {
+			break
+		}
+
+		time.Sleep(250 * time.Millisecond)
+	}
+
+	return nil
+}