rpcfetch/fetch/main.go

package main

import (
	"encoding/gob"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"os"
	"os/signal"
	"sync/atomic"
	"syscall"
	"time"

	"git.ophivana.moe/cat/rpcfetch"
)

var (
	d *rpcfetch.Client

	active     = new(atomic.Bool)
	confPath   string
	headless   bool
	dumpConfig bool
)

func init() {
	flag.StringVar(&confPath, "conf", "rpcfetch.conf", "path to rpcfetch configuration file")
	flag.BoolVar(&headless, "headless", false, "run without graphical interface")
	flag.BoolVar(&dumpConfig, "dump", false, "dump configuration as JSON then exit")
}

func main() {
	flag.Parse()

	if cf, err := os.Open(confPath); err != nil {
		if !os.IsNotExist(err) {
			log.Fatalf("error opening configuration file: %s", err)
		}

		// use defaults
		log.Print("configuration file does not exist, using defaults")
		conf = &defaultConfig
	} else {
		// decode from existing file
		if err = gob.NewDecoder(cf).Decode(&conf); err != nil {
			log.Fatalf("error reading configuration: %s", err)
		}
		if err = cf.Close(); err != nil {
			log.Fatalf("error closing configuration file: %s", err)
		}
	}
	profLast.Store(profLastCache{})

	if dumpConfig {
		b, _ := json.Marshal(conf)
		fmt.Println(string(b))
		os.Exit(0)
	}

	// update periodically
	active.Store(true)
	go func() {
		for {
			if active.Load() {
				apply()
			}
			time.Sleep(5 * time.Second)
		}
	}()

	// set up clean exit signal handling
	sig := make(chan os.Signal, 1)
	signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
	go func() {
		log.Printf("received signal %s, exiting", (<-sig).String())
		exit()
	}()

	if headless {
		select {}
	} else {
		// run the UI
		if err := ui(); err != nil {
			log.Fatalf("error in user interface: %s", err)
		}
		log.Print("window closed, exiting")
		exit()
	}
}

func exit() {
	active.Store(false)
	if err := d.Close(); err != nil {
		log.Printf("error closing client: %s", err)
	}
	log.Print("rpc client closed")
	os.Exit(0)
}