resh/daemon/resh-daemon.go

package main

import (
    "encoding/json"
    //"flag"
    "log"
    "io/ioutil"
    "path/filepath"
    "os"
    "os/exec"
    "os/user"
    "strconv"
    "strings"
    //"syscall"
    "net/http"
    common "github.com/curusarn/resh/common"
    "github.com/BurntSushi/toml"
)



func main() {
    usr, _ := user.Current()
    dir := usr.HomeDir
    pidfilePath := filepath.Join(dir, ".resh/resh.pid")
    configPath := filepath.Join(dir, "/.config/resh.toml")

    var config common.Config
	if _, err := toml.DecodeFile(configPath, &config); err != nil {
		log.Println("Error reading config", err)
		return
	}
    res, err := isDaemonRunning(config.Port)
    if err != nil {
	    log.Println("Error while checking if the daemon is runnnig", err)
    }
    if res {
        log.Println("Daemon is already runnnig - exiting!")
        return
    }
    _, err = os.Stat(pidfilePath)
    if err == nil {
		log.Println("Pidfile exists")
        // kill daemon
        err = killDaemon(pidfilePath)
        if err != nil {
            log.Println("Error while killing daemon", err)
        }
    }
    err = ioutil.WriteFile(pidfilePath, []byte(strconv.Itoa(os.Getpid())), 0644)
    if err != nil {
		log.Fatal("Could not create pidfile", err)
    }
    server(config.Port)
    err = os.Remove(pidfilePath)
    if err != nil {
		log.Println("Could not delete pidfile", err)
    }
}

func statusHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("OK\n"))
    log.Printf("Status OK\n")
}

func recordHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("OK\n"))
    record := common.Record{}

    jsn, err := ioutil.ReadAll(r.Body)
	if err != nil {
		log.Println("Error reading the body", err)
        return
	}

    err = json.Unmarshal(jsn, &record)
	if err != nil {
		log.Println("Decoding error: ", err)
		log.Println("Payload: ", jsn)
        return
	}

    log.Printf("Received: %v\n", record)
    // fmt.Println("cmd:", r.CmdLine)
    // fmt.Println("pwd:", r.Pwd)
    // fmt.Println("git:", r.GitWorkTree)
    // fmt.Println("exit_code:", r.ExitCode)
}

func server(port int) {
	http.HandleFunc("/status", statusHandler)
	http.HandleFunc("/record", recordHandler)
	http.ListenAndServe(":" + strconv.Itoa(port) , nil)
}

func killDaemon(pidfile string) error {
    dat, err := ioutil.ReadFile(pidfile)
    if err != nil {
        log.Println("Reading pid file failed", err)
    }
    log.Print(string(dat))
    pid, err := strconv.Atoi(strings.TrimSuffix(string(dat), "\n"))
    if err != nil {
        log.Fatal("Pidfile contents are malformed", err)
    }
    cmd := exec.Command("kill", strconv.Itoa(pid))
	err = cmd.Run()
    if err != nil {
        log.Printf("Command finished with error: %v", err)
        return err
    }
    return nil
}

func isDaemonRunning(port int) (bool, error) {
    url := "http://localhost:" + strconv.Itoa(port) + "/status"
    resp, err := http.Get(url)
    if err != nil {
        log.Println("Error while checking daemon status - " +
                    "it's probably not runnig!", err)
        return false, err
    }
    defer resp.Body.Close()
    return true, nil
    //body, err := ioutil.ReadAll(resp.Body)


//    dat, err := ioutil.ReadFile(pidfile)
//    if err != nil {
//        log.Println("Reading pid file failed", err)
//        return false, err
//    }
//    log.Print(string(dat))
//    pid, err := strconv.ParseInt(string(dat), 10, 64)
//    if err != nil {
//        log.Fatal(err)
//    }
//    process, err := os.FindProcess(int(pid))
//    if err != nil {
//        log.Printf("Failed to find process: %s\n", err)
//        return false, err
//    } else {
//        err := process.Signal(syscall.Signal(0))
//        log.Printf("process.Signal on pid %d returned: %v\n", pid, err)
//    }
//    return true, nil
}