gopaper/main.go

145 lines
3.3 KiB
Go

package main
import (
"errors"
"flag"
"io/fs"
"log"
"os"
"os/exec"
"strconv"
"sync"
"github.com/natefinch/lumberjack"
)
var config Config
const sockfile = "/tmp/gopaper.sock"
const pidfilePath = "/tmp/gopaper.pid"
var clog = log.New(os.Stdout, "## ", 0)
var elog = log.New(os.Stdout, "ERROR: ", 3)
func main() {
//SETUP FLAGS
var debugFlag = flag.Bool("debug", false, "debug mode sends logs to $HOME/.gopaper/logfile")
var dirFlag = flag.String("dir", "", "the directory from which to randomly select images")
flag.Parse()
clog.Println("Welcome to GoPaper!")
//INIT CONFIG
err := config.load()
if err != nil {
elog.Println("unable to initialize config", err)
}
handleProcesses()
setupLogging(*debugFlag)
var waitGroup sync.WaitGroup
waitGroup.Add(1)
slideshowDir := make(chan string)
func() {
defer func() {
if r := recover(); r != nil {
log.Println("Panic recovered at top level", r)
cleanExit(1)
}
}()
go server(slideshowDir)
go slideshow(slideshowDir)
}()
slideshowDir <- *dirFlag
waitGroup.Wait()
}
func cleanExit(code int) {
if code == 1 {
log.Println("shutting down gracefully after errors")
} else {
log.Println("shutting down gracefully")
}
err := os.Remove(sockfile)
if err != nil && !os.IsNotExist(err) {
elog.Printf("unable to remove sockfile at %v. Error: %v\n", sockfile, err)
} else if !os.IsNotExist(err) {
log.Println("sockfile removed")
} else {
log.Println("no need to remove sockfile -- it doesn't exist")
}
err = os.Remove(pidfilePath)
if err != nil && !os.IsNotExist(err) {
elog.Printf("unable to remove pidfile at %v. Error: %v\n", pidfilePath, err)
} else if !os.IsNotExist(err) {
log.Println("pidfile removed")
} else {
log.Println("no need to remove pidfile -- it doesn't exist")
}
os.Exit(code)
}
func killPrevProc() error {
//check if pidfile already exists
if _, err := os.Stat(pidfilePath); errors.Is(err, fs.ErrNotExist) {
return nil
}
//if it does, kill the process and delete the pidfile
prexPid, err := os.ReadFile(pidfilePath)
if err != nil {
elog.Println("unable to read pre-existing pidfile", err)
return err
}
//kill process
err = exec.Command("kill", string(prexPid)).Run()
if err != nil {
elog.Printf("Error attempting to kill process %v: %v\n", string(prexPid), err)
}
//remove pidfile
err = os.Remove(pidfilePath)
if err != nil && !os.IsNotExist(err) {
elog.Printf("unable to remove pidfile at %v. Error: %v\n", pidfilePath, err)
}
return nil
}
func handleProcesses() {
err := killPrevProc()
if err != nil {
elog.Println("error attempting to kill pre-existing process: ", err)
os.Exit(1)
}
//create new pidfile
pid := strconv.FormatInt(int64(os.Getpid()), 10)
pidfile, err := os.Create(pidfilePath)
if err != nil {
elog.Println("error trying to create pidfile:", err)
os.Exit(1)
}
pidfile.WriteString(pid)
}
func setupLogging(debug bool) {
//SETUP LOGGERS
if debug {
logfile := config.Cache + "logfile"
clog.Printf("DEBUG MODE. Logging to %v", logfile)
output := &lumberjack.Logger{
Filename: logfile,
MaxSize: 1, // megabytes after which new file is created
MaxBackups: 3, // number of backups
MaxAge: 28, //days
}
log.SetOutput(output)
clog.SetOutput(output)
elog.SetOutput(output)
}
elog.SetFlags(log.LstdFlags | log.Lshortfile)
log.SetFlags(log.LstdFlags)
}