Made the transcoder run as a periodic task, with the interval defined in the config TOML file

src/main/java/tech/bitgoblin/transcoder/Transcoder.java

@@ -0,0 +1,124 @@
+package tech.bitgoblin.transcoder;
+
+import java.io.File;
+import java.io.IOException;
+import java.lang.InterruptedException;
+import java.lang.Process;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.Timer;
+
+import tech.bitgoblin.config.Config;
+import tech.bitgoblin.io.IOUtils;
+
+public class Transcoder {
+
+  private String repo_dir;
+  private Config config;
+  private String ffmpeg_path = "/usr/bin/ffmpeg";
+
+  // only define the working directory; use default FFMPEG path
+  public Transcoder(Config config) {
+    this.config = config;
+    this.repo_dir = IOUtils.resolveTilda(this.config.getString("transcoder.repo_path"));
+    if (this.config.contains("transcoder.ffmpeg_path")) {
+      this.ffmpeg_path = this.config.getString("transcoder.ffmpeg_path");
+    }
+    this.initDirectory();
+  }
+
+  // create a periodic timer task and start it
+  public void start() {
+    Timer timer = new Timer();
+    timer.scheduleAtFixedRate(new RunTranscoderTask(this), 10000, this.config.getInt("transcoder.interval") * 60 * 1000);
+  }
+
+  // transcode files in the working directory
+  public void transcode() {
+    // search for files
+    System.out.println("Searching for files to transcode in " + this.repo_dir);
+    File repo = new File(Paths.get(this.repo_dir, "ingest").toString());
+    File[] sourceFiles = repo.listFiles();
+
+    if (sourceFiles.length == 0) {
+      System.out.println("There is nothing to transcode in " + this.repo_dir + "/ingest.");
+      return;
+    }
+
+    // transcode
+    System.out.println("Transcoding files in " + this.repo_dir + "/ingest...");
+    for (File f : sourceFiles) {
+      String filePath = f.toString().substring(0, f.toString().lastIndexOf("."));
+      String filename = Paths.get(filePath).getFileName().toString();
+      String outputPath = Paths.get(this.repo_dir, "output", String.format("%s.mov", filename)).toString();
+
+      String cmd = String.format("%s -i %s -y -f %s -c:v %s -vf %s -profile:v %s -c:a %s %s",
+        this.ffmpeg_path, // FFMPEG binary path
+        f.toString(), // input file
+        this.config.getString("transcoder.video_format"), // video container format
+        this.config.getString("transcoder.video_codec"), // video codec
+        this.config.getString("transcoder.video_parameters"), // video format
+        this.config.getString("transcoder.video_profile"), // video profile
+        this.config.getString("transcoder.audio_codec"), // audio codec
+        outputPath // output file path
+      );
+
+      ProcessBuilder pb = new ProcessBuilder(cmd.split("\\s+"));
+      pb.inheritIO(); // use the java processes' input and output streams
+      try {
+        Process process = pb.start();
+        int ret = process.waitFor();
+        System.out.printf("Program exited with code: %d\n", ret);
+        System.out.println(String.join(" ", pb.command()));
+        System.out.println();
+      } catch (IOException | InterruptedException e) {
+        throw new RuntimeException(e);
+      }
+    }
+
+    // end output
+    System.out.println("------------ End of transcoding ------------");
+    System.out.println();
+  }
+
+  // copies sources files to the archive directory
+  public void archive() {
+    File repo = new File(Paths.get(this.repo_dir, "ingest").toString());
+    File[] sourceFiles = repo.listFiles();
+
+    for (File f : sourceFiles) {
+      Path filePath = Path.of(f.toString());
+      String filename = filePath.getFileName().toString();
+      String archivePath = Paths.get(this.repo_dir, "archive", filename).toString();
+
+      try {
+        Files.copy(filePath, Paths.get(archivePath), StandardCopyOption.COPY_ATTRIBUTES, StandardCopyOption.REPLACE_EXISTING);
+      } catch (IOException e) {
+        throw new RuntimeException(e);
+      }
+    }
+  }
+
+  // clean up the ingest directory once we're done
+  public void cleanup() {
+    File repo = new File(Paths.get(this.repo_dir, "ingest").toString());
+    File[] sourceFiles = repo.listFiles();
+
+    for (File f : sourceFiles) {
+      f.delete();
+    }
+  }
+
+  // ensures the transcoder's working directory is available
+  private void initDirectory() {
+    // create transcoder directory
+    IOUtils.createDirectory(this.repo_dir);
+    // create the sub-directories
+    IOUtils.createDirectory(Paths.get(this.repo_dir, "ingest").toString());
+    IOUtils.createDirectory(Paths.get(this.repo_dir, "archive").toString());
+    IOUtils.createDirectory(Paths.get(this.repo_dir, "output").toString());
+  }
+
+}