Serialize transcode jobs

workers.go

@@ -0,0 +1,192 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+	"gorm.io/gorm"
+)
+
+func ensureDirFor(path string) error {
+	dir := filepath.Dir(path)
+	fmt.Println("Create", dir)
+	return os.MkdirAll(dir, 0700)
+}
+
+func videoToVideo(transID uint, height uint, srcFilepath string) {
+
+	// determine destination path
+	dstFilename := uuid.Must(uuid.NewV7()).String()
+	dstFilename = fmt.Sprintf("%s.mp4", dstFilename)
+	dstFilepath := filepath.Join(getDataDir(), dstFilename)
+
+	err := ensureDirFor(dstFilepath)
+	if err != nil {
+		fmt.Println("Error: couldn't create dir for ", dstFilepath, err)
+		db.Model(&Transcode{}).Where("id = ?", transID).Update("status", "failed")
+		return
+	}
+
+	// FIXME: ignoring any requested audio bitrate
+
+	// determine audio bitrate
+	var audioBitrate uint = 160
+	if height <= 144 {
+		audioBitrate = 64
+	} else if height <= 240 {
+		audioBitrate = 96
+	} else if height < 720 {
+		audioBitrate = 128
+	}
+
+	// start ffmpeg
+	ffmpeg := "ffmpeg"
+	ffmpegArgs := []string{"-i", srcFilepath,
+		"-vf", fmt.Sprintf("scale=-2:%d", height), "-c:v", "libx264",
+		"-crf", "23", "-preset", "veryfast", "-c:a", "aac", "-b:a", fmt.Sprintf("%dk", audioBitrate),
+		dstFilepath}
+	fmt.Println(ffmpeg, strings.Join(ffmpegArgs, " "))
+	cmd := exec.Command(ffmpeg, ffmpegArgs...)
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	cmd.Stdout, cmd.Stderr = &stdout, &stderr
+	db.Model(&Transcode{}).Where("id = ?", transID).Update("status", "running")
+	err = cmd.Run()
+	if err != nil {
+		fmt.Println("Error: convert to video file", srcFilepath, "->", dstFilepath, stdout.String(), stderr.String())
+		return
+	}
+
+	// look up original
+	var trans Transcode
+	db.First(&trans, transID)
+	var orig Original
+	db.First(&orig, "id = ?", trans.OriginalID)
+
+	// create video record
+	video := Video{OriginalID: orig.ID, Source: "transcode", Filename: dstFilename}
+
+	fileSize, err := getSize(dstFilepath)
+	if err == nil {
+		video.Size = humanSize(fileSize)
+	}
+
+	meta, err := getVideoMeta(dstFilepath)
+	fmt.Println("meta for", dstFilepath, meta)
+	if err == nil {
+		video.Width = meta.width
+		video.Height = meta.height
+		video.FPS = meta.fps
+	}
+
+	db.Create(&video)
+
+	// complete transcode
+	db.Delete(&trans)
+}
+
+func videoToAudio(transID uint, bitrate uint, videoFilepath string) {
+
+	// determine destination path
+	audioFilename := uuid.Must(uuid.NewV7()).String()
+	audioFilename = fmt.Sprintf("%s.mp3", audioFilename)
+	audioFilepath := filepath.Join(getDataDir(), audioFilename)
+
+	// ensure destination directory
+	err := ensureDirFor(audioFilepath)
+	if err != nil {
+		fmt.Println("Error: couldn't create dir for ", audioFilepath, err)
+		db.Model(&Transcode{}).Where("id = ?", transID).Update("status", "failed")
+		return
+	}
+
+	ffmpeg := "ffmpeg"
+	ffmpegArgs := []string{"-i", videoFilepath, "-vn", "-acodec",
+		"mp3", "-b:a",
+		fmt.Sprintf("%dk", bitrate),
+		audioFilepath}
+	fmt.Println(ffmpeg, strings.Join(ffmpegArgs, " "))
+	cmd := exec.Command(ffmpeg, ffmpegArgs...)
+	db.Model(&Transcode{}).Where("id = ?", transID).Update("status", "running")
+	err = cmd.Run()
+	if err != nil {
+		fmt.Println("Error: convert to audio file", videoFilepath, "->", audioFilepath)
+		db.Model(&Transcode{}).Where("id = ?", transID).Update("status", "failed")
+		return
+	}
+
+	// look up original
+	var trans Transcode
+	db.First(&trans, "id = ?", transID)
+	var orig Original
+	db.First(&orig, "id = ?", trans.OriginalID)
+
+	// create audio record
+	audio := Audio{OriginalID: orig.ID, Filename: audioFilename}
+
+	fileSize, err := getSize(audioFilepath)
+	if err == nil {
+		audio.Size = humanSize(fileSize)
+	}
+
+	db.Create(&audio)
+
+	// complete transcode
+	db.Delete(&trans)
+}
+
+func transcodePending() {
+	fmt.Println("transcodePending...")
+
+	// any running jobs here got stuck or dead in the midde, so reset them
+	db.Model(&Transcode{}).Where("status = ?", "running").Update("status", "pending")
+
+	// loop until no more pending jobs
+	for {
+		var trans Transcode
+		err := db.First(&trans, "status = ?", "pending").Error
+		if err == gorm.ErrRecordNotFound {
+			fmt.Println("no pending transcode jobs")
+			break // no more pending jobs
+		}
+
+		if trans.SrcKind == "video" {
+
+			var srcVideo Video
+			err = db.First(&srcVideo, "id = ?", trans.SrcID).Error
+			if err != nil {
+				fmt.Println("no such source video for video Transcode", trans)
+				db.Delete(&trans)
+				continue
+			}
+			srcFilepath := filepath.Join(getDataDir(), srcVideo.Filename)
+
+			if trans.DstKind == "video" {
+				videoToVideo(trans.ID, trans.Height, srcFilepath)
+			} else if trans.DstKind == "audio" {
+				videoToAudio(trans.ID, trans.Rate, srcFilepath)
+			} else {
+				fmt.Println("unexpected src/dst kinds for Transcode", trans)
+				db.Delete(&trans)
+			}
+		} else {
+			fmt.Println("unexpected src kind for Transcode", trans)
+			db.Delete(&trans)
+		}
+	}
+
+}
+
+func transcodeWorker() {
+	transcodePending()
+	ticker := time.NewTicker(10 * time.Second)
+	for range ticker.C {
+		transcodePending()
+	}
+}