historyposter/historyposter/historyposter.go

package historyposter

import (
	"context"
	"io"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"syscall"
	"time"

	"git.eeqj.de/sneak/goutil"
	"git.eeqj.de/sneak/historyposter/store"
	"github.com/mattn/go-isatty"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"github.com/spf13/viper"
)

// HistoryPoster is the main app framework object
type HistoryPoster struct {
	version      string
	buildarch    string
	startup      time.Time
	appCtx       context.Context
	shutdownFunc context.CancelFunc
	exitCode     int
	store        *store.Store
	logfh        *os.File
}

// CLIEntry is the main entrypoint
func CLIEntry(version, buildarch string) int {
	hp := new(HistoryPoster)
	hp.version = version
	hp.buildarch = buildarch
	hp.startup = time.Now()
	hp.exitCode = 0

	c := make(chan os.Signal)
	signal.Ignore(syscall.SIGPIPE)
	signal.Notify(c, os.Interrupt, syscall.SIGTERM)

	hp.configure()
	hp.setupLogging()

	s, err := store.NewStore()
	if err != nil {
		hp.shutdown("cannot create state file: "+err.Error(), -1)
		return hp.exitCode
	}
	hp.store = s

	hp.appCtx, hp.shutdownFunc = context.WithCancel(context.Background())
	go func() {
		// this sits and waits for an interrupt to be received
		sig := <-c
		log.Info().Msgf("signal received: %+v", sig)
		hp.shutdownFunc()
	}()
	return hp.runForever(hp.appCtx)
}

func (hp *HistoryPoster) configure() {
	viper.SetConfigName("historyposter")
	viper.SetConfigType("yaml")
	viper.AddConfigPath("/etc/historyposter")          // path to look for the config file in
	viper.AddConfigPath("$HOME/.config/historyposter") // call multiple times to add many search paths
	viper.SetEnvPrefix("HISTORYPOSTER")
	viper.AutomaticEnv()

	viper.SetDefault("Debug", false)
	viper.SetDefault("Logfile", os.Getenv("HOME")+"/Library/Logs/historyposter/historyposter.log")

	if err := viper.ReadInConfig(); err != nil {
		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
			// Config file not found; ignore error if desired
		} else {
			// Config file was found but another error was produced
			log.Panic().
				Err(err).
				Msg("config file malformed")
		}
	}

	// if viper.GetBool("debug") {
	//	pp.Print(viper.AllSettings())
	// }
}

func (hp *HistoryPoster) runForever(ctx context.Context) int {
	log.Info().Msg("entering main loop")

	interval := 60 * time.Second
	timeout := 10 * time.Second

	ticker := time.NewTicker(interval)
	go func() {
		// do it once right now, without an insta-tick
		go func() { hp.postURLs(context.WithTimeout(ctx, timeout)) }()

		// then go do it repeatedly:
		for {
			select {
			case <-ticker.C:
				go func() { hp.postURLs(context.WithTimeout(ctx, timeout)) }()
			case <-ctx.Done():
				ticker.Stop()
				return
			}
		}
	}()

	<-ctx.Done()
	hp.cleanup()
	log.Info().Msgf("exiting")
	hp.logfh.Close()
	return hp.exitCode
}

func (hp *HistoryPoster) cleanup() {
	log.Info().Msgf("begin cleanup")
	hp.store.Close()
}
func (hp *HistoryPoster) setupLogging() {
	// always log in UTC
	zerolog.TimestampFunc = func() time.Time {
		return time.Now().UTC()
	}
	log.Logger = log.With().Caller().Logger()
	zerolog.SetGlobalLevel(zerolog.InfoLevel)

	tty := isatty.IsTerminal(os.Stdin.Fd()) || isatty.IsCygwinTerminal(os.Stdin.Fd())

	consoleWriter := zerolog.NewConsoleWriter(
		func(w *zerolog.ConsoleWriter) {
			// Customize time format
			w.TimeFormat = time.RFC3339
		},
	)

	var writers []io.Writer
	if tty {
		writers = append(writers, consoleWriter)
	}

	logfile := viper.GetString("Logfile")
	logfileDir := filepath.Dir(logfile)
	err := goutil.Mkdirp(logfileDir)
	if err != nil {
		log.Error().Err(err).Msg("unable to create log dir")
	}

	hp.logfh, err = os.OpenFile(logfile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
	if err != nil {
		panic("unable to open logfile: " + err.Error())
	}

	writers = append(writers, hp.logfh)

	multi := zerolog.MultiLevelWriter(writers...)
	logger := zerolog.New(multi).With().Timestamp().Logger().With().Caller().Logger()

	log.Logger = logger
	// FIXME get caller back in there zerolog.New(multi).Caller().Logger()

	if viper.GetBool("debug") {
		zerolog.SetGlobalLevel(zerolog.DebugLevel)
	}

	hp.identify()
}

func (hp *HistoryPoster) identify() {
	log.Info().
		Str("version", hp.version).
		Str("buildarch", hp.buildarch).
		Str("os", runtime.GOOS).
		Msg("starting")
}

func (hp *HistoryPoster) shutdown(reason string, exitcode int) {
	log.Info().Msgf("shutting down: %s", reason)
	hp.exitCode = exitcode
	hp.shutdownFunc()
}