piframe-go/ui/slideshow.go

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package ui
import (
"context"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"syscall"
"time"
"github.com/eiannone/keyboard"
"github.com/knadh/koanf"
"git.kemonine.info/PiFrame/config"
)
const (
PATH_TEMP_FOR_SLIDESHOW = "/run/piframe/fim"
)
// fim placeholders so we can reset them as needed
var fim *exec.Cmd = nil
var stdin io.WriteCloser = nil
func setupFim(PATH_TEMP_FOR_SLIDESHOW string) {
// Prep slideshow command and arguments
// NOTE: The random flag is seeded with time() ; this is bad as we will be restarting the slideshow at about the same time per the configurd schedule
// We use the non-seeded form to ensure that it's a little more random (or at least hope it's a little more random)
CMD_FIM := "/usr/bin/fim"
ARGS_FIM := []string{"--no-commandline", "--no-history", "--etc-fimrc", "/usr/local/etc/fimrc",
"--device", "/dev/fb0", "--vt", "1",
"--execute-commands-early", "\"clear\"", "--final-commands", "\"clear\"",
"--autozoom", "--random", "--recursive", "--cd-and-readdir",
PATH_TEMP_FOR_SLIDESHOW}
// fim command that'll be executed
fim = exec.Command(CMD_FIM, ARGS_FIM...)
// Put fim into a process group so ALL processes that may be executed are exited when main process exits
fim.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
// Setup stdin for fim to control slideshow
stdinLocal, err := fim.StdinPipe()
if err != nil {
log.Fatalf("Error getting fim stdin : %s", err)
}
stdin = stdinLocal
}
func Slideshow(pfconfig *koanf.Koanf) {
// Prep folder setup needed for fim
// fim does NOT allow multiple folders passed on the CLI (as far as KemoNine can tell)
// We build a temp folder stup in /run/piframe/fim that has symlinks to selected albums
// After we build up this directory setup we'll kick off fim against the temp dir with recursive
// /run is a tmpfs so this won't wear on the sd card storage
// Create temp folder
_, err := os.Stat(PATH_TEMP_FOR_SLIDESHOW)
if os.IsNotExist(err) {
errDir := os.MkdirAll(PATH_TEMP_FOR_SLIDESHOW, 0755)
if errDir != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
}
// Cleanup temp folder if it already existed
dirRead, err := os.Open(PATH_TEMP_FOR_SLIDESHOW)
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
dirFiles, err := dirRead.Readdir(0)
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
// Loop over the directory's files.
for index := range dirFiles {
fileHere := dirFiles[index]
// Get name of file and its full path.
nameHere := fileHere.Name()
fullPath := PATH_TEMP_FOR_SLIDESHOW + "/" + nameHere
// Remove the file.
err = os.Remove(fullPath)
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
}
// Setup symlinks to selected albums to be used with slideshow
// Add albums full paths to command line args for fim
albumRootPath := pfconfig.String(config.CONFIG_KEY_ALBUMS_ROOT)
for _, album := range pfconfig.Strings(config.CONFIG_KEY_ALBUMS_SELECTED) {
source := albumRootPath + album
destination := PATH_TEMP_FOR_SLIDESHOW + album
if album == "/" {
files, err := ioutil.ReadDir(albumRootPath)
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
for _, file := range files {
filePath := albumRootPath + "/" + file.Name()
fileStat, err := os.Stat(filePath)
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
mode := fileStat.Mode()
if mode.IsRegular() {
err = os.Symlink(filePath, PATH_TEMP_FOR_SLIDESHOW+"/"+file.Name())
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
}
}
continue
}
err = os.Symlink(source, destination)
if err != nil {
log.Fatalf("Error setting up slideshow : %s", err)
}
}
// Setup fim for run
// Commands can't be re-used so we move this to a function to support the restart interval cleanly
setupFim(PATH_TEMP_FOR_SLIDESHOW)
// Advance slideshow every interval as defined in const()
slideshowAdvanceDurationString := pfconfig.String(config.CONFIG_KEY_SLIDESHOW_INTERVAL)
slideshowAdvanceDuration, err := time.ParseDuration(slideshowAdvanceDurationString)
if err != nil {
log.Fatalf("Error parsing slide duration : %s", err)
}
ticker := time.NewTicker(slideshowAdvanceDuration)
stop_ticker := make(chan struct{})
go func() {
for {
select {
case <-ticker.C:
_, err = io.WriteString(stdin, "n")
if err != nil {
log.Fatalf("Error advancing slides : %s", err)
}
case <-stop_ticker:
ticker.Stop()
stdin.Close()
return
}
}
}()
// Start watching for key strokes and echo them back to stdout
keysEvents, err := keyboard.GetKeys(10)
if err != nil {
log.Fatalf("Error setting up keyboard listener : %s", err)
}
// NOT deferring keyboard.close as we do that by hand further down when fim exits ahead of showing the config UI
// Keep running fim until we're signaled by the user to do otherwise
// Common reasons that we MUST do this kind of goofy (bugs / behavior)
// - fim doesn't quite see the /run changes where the albums are linked and bails out
// - OOM kicks in and kills fim (it's kinda RAM heavy sometimes)
// - Corrupt or invalid image causes fim to crash
// - The timeout for re-randomizing kicked free and fim needs to restart
// - fim thinks the slideshow has 'ended' for whatever reason and we really want to always show no matter what
STOP_SLIDESHOW := false
// Goroutine for tracking which keys are pressed and controlling fim if appropriate
keyboardCtx, keyboardCancel := context.WithCancel(context.Background())
go func(keyboardCtx context.Context) {
for {
select {
case <-keyboardCtx.Done():
return
case event := <-keysEvents:
if event.Err != nil {
log.Fatalf("Error listening to key events : %s", err)
}
// Keys for fim event management (previous/next in particular)
fimKey := ""
if event.Key == keyboard.KeyArrowLeft || event.Key == keyboard.KeyArrowDown {
fimKey = "p"
}
if event.Key == keyboard.KeyArrowRight || event.Key == keyboard.KeyArrowUp {
fimKey = "n"
}
// Exit fim and move to the config UI
if event.Key == keyboard.KeyEsc || event.Key == keyboard.KeyEnter || event.Key == keyboard.KeySpace {
// We are being told to stop the slideshow, oblidge the user
STOP_SLIDESHOW = true
if fim != nil { // Just in case someone lays on exit key or similar during startup
pgid, err := syscall.Getpgid(fim.Process.Pid)
if err == nil {
if err := syscall.Kill(-pgid, 9); err != nil {
log.Fatalf("failed to kill fim : %s", err)
}
}
}
break
}
// Control fim if we received a valid key for next/previous slide
if fimKey != "" {
_, err = io.WriteString(stdin, fimKey)
if err != nil {
log.Fatalf("Error controlling fim : %s", err)
}
ticker.Reset(pfconfig.Duration(config.CONFIG_KEY_SLIDESHOW_INTERVAL))
}
}
}
}(keyboardCtx)
// Restart fim after configured timeout ; This is setup as a ticker due to KemoNine not getting CommandWithContext stuff to work properly (lots of pointer related crashes and the like)
fimRestartDurationString := pfconfig.String(config.CONFIG_KEY_SLIDESHOW_RESTART_INTERVAL)
fimRestartDuration, err := time.ParseDuration(fimRestartDurationString)
if err != nil {
log.Fatalf("Error parsing restart duration : %S", err)
}
fimTicker := time.NewTicker(fimRestartDuration)
stop_fim_ticker := make(chan struct{})
go func() {
for {
select {
case <-fimTicker.C:
if fim != nil { // Just in case someone lays on exit key or similar during startup
pgid, err := syscall.Getpgid(fim.Process.Pid)
if err == nil {
if err := syscall.Kill(-pgid, 9); err != nil {
log.Fatalf("failed to kill fim : %s", err)
}
}
}
case <-stop_fim_ticker:
fimTicker.Stop()
return
}
}
}()
// Run fim
for !STOP_SLIDESHOW {
if err := fim.Run(); err != nil {
// Unwrap the error a bit so we can find out if a signal killed fim or something else
// An exit code of -1 means the program didn't exit in time or was terminated by a signal (per the docs)
if exitError, ok := err.(*exec.ExitError); ok && exitError.ExitCode() != -1 {
// We are NOT going to fatal here as there are many 'valid' reasons fim would exit for no good reason ;)
log.Printf("Error running fim : %s", err)
}
}
setupFim(PATH_TEMP_FOR_SLIDESHOW)
}
// Stop fim slideshow advancing go routine
close(stop_ticker)
// Stop restart go routine
close(stop_fim_ticker)
// Stop listening to keyboard events
keyboard.Close()
keyboardCancel()
}