Firebase Functions) Can I exclude certain files when importing them from the Storage bucket?

Question

I'm going to delete old images using the schedule function. Before deleting these images, I have created thumbnail images, and I want to delete only the original images except for these thumbnail images.

The following is part of my code

scedule function

exports.scheduledDeleteFile = functions
  .region("asia-northeast3")
  .pubsub.schedule("every 5 minutes")
  .onRun(async (context) => {
    try {
      const bucket = firebase.storage().bucket();

      // get storage file
      const [filesArray] = await bucket.getFiles({
        prefix: "chat/files",
      });

      totalCount = filesArray.length;

      // variables with our settings to be reused below
      const now = Date.now();
      const time_ago = Date.now() - 180000; // 3min test
      const TIMESTAMP_AGO = new Date(time_ago); // change datetime
      const DELETE_OPTIONS = { ignoreNotFound: true }; // ??

      functions.logger.log(
        `Found ${totalCount} files that need to be checked.`
      );

      const deleteOldFileResults = await Promise.all(
        filesArray.map(async (file) => {
          let metadata;

          try {
            // 파일에 대한 메타데이터를 가져옴
            [metadata] = await file.getMetadata();

            // metadata of file
            const { temporaryHold, eventBasedHold, timeCreated } = metadata;

            const TIME_CREATED = new Date(timeCreated);

            const dispose = TIME_CREATED < TIMESTAMP_AGO;

            // delete
            if (dispose) {
              await file.delete(DELETE_OPTIONS);
              functions.logger.log("delete");
              disposedCount++;

              // ===================
              // firestore file chat 업데이트
              // 트리거 함수를 따로 만들어서 사용
            }

            return { file, metadata, disposed: dispose, skipped: activeHold };
          } catch (error) {}
        })
      );
    } catch (error) {}
  });

My thumbnail image is in the same path as the original file. Is there an option to exclude certain files when importing them? (For example, except for a file whose name precedes "thumb_")

await bucket.getFiles({
        prefix: "chat/files",
      });

The following is a create thumbnail function. I referred to the example provided by firebase. https://github.com/firebase/functions-samples/tree/main/2nd-gen/thumbnails

// thumb image name size
const THUMB_MAX_HEIGHT = 200;
const THUMB_MAX_WIDTH = 200;
// thumb image name
const THUMB_PREFIX = "thumb_";

exports.generateThumbnail = functions
  .region("asia-northeast3")
  .storage.object()
  .onFinalize(async (object) => {
    // custom metadata
    const userKey = object.metadata["userKey"];
    const chatroomKey = object.metadata["chatroomKey"];
    const type = object.metadata["type"];

    // File and directory paths.
    const filePath = object.name;
    const contentType = object.contentType; // This is the image MIME type
    const fileDir = path.dirname(filePath);
    const fileName = path.basename(filePath);
    const thumbFilePath = path.normalize(
      // ! if change path, error!
      path.join(fileDir, `${THUMB_PREFIX}${fileName}`)
    );

    const tempLocalFile = path.join(os.tmpdir(), filePath);
    const tempLocalDir = path.dirname(tempLocalFile);
    const tempLocalThumbFile = path.join(os.tmpdir(), thumbFilePath);

    if (!contentType.startsWith("image/")) {
      return functions.logger.log("This is not an image.");
    }

    if (fileName.startsWith(THUMB_PREFIX)) {
      return functions.logger.log("Already a Thumbnail.");
    }

    // Cloud Storage files.
    const bucket = admin.storage().bucket(object.bucket);
    const file = bucket.file(filePath);
    const thumbFile = bucket.file(thumbFilePath);
    const metadata = {
      contentType: contentType,
    };

    await mkdirp(tempLocalDir);
    // Download file from bucket.
    await file.download({ destination: tempLocalFile });
    functions.logger.log("The file has been downloaded to", tempLocalFile);

    // Generate a thumbnail using ImageMagick.
    await spawn(
      "convert",
      [
        tempLocalFile,
        "-thumbnail",
        `${THUMB_MAX_WIDTH}x${THUMB_MAX_HEIGHT}>`, 
        tempLocalThumbFile,
      ],
      { capture: ["stdout", "stderr"] }
    );

    functions.logger.log("Thumbnail created at", tempLocalThumbFile);

    // Uploading the Thumbnail.
    await bucket.upload(tempLocalThumbFile, {
      destination: thumbFilePath,
      metadata: metadata,
    });

    functions.logger.log("Thumbnail uploaded to Storage at", thumbFilePath);

    fs.unlinkSync(tempLocalFile);
    fs.unlinkSync(tempLocalThumbFile);

    const results = await Promise.all([
      thumbFile.getSignedUrl({
        action: "read",
        expires: "03-01-2500",
      }),
      file.getSignedUrl({
        action: "read",
        expires: "03-01-2500",
      }),
    ]);
    functions.logger.log("Got Signed URLs.");

    const thumbResult = results[0];
    const originalResult = results[1];
    const thumbFileUrl = thumbResult[0];
    const fileUrl = originalResult[0];

    await file.delete().then((value) => {
      functions.logger.log("원본 삭제 완료");
    });

    // Add the URLs to the Database
    await admin
      .database()
      .ref("images")
      .push({ path: fileUrl, thumbnail: thumbFileUrl });

    return functions.logger.log("Thumbnail URLs saved to database.");
  });

Answer 1

Is there an option to exclude certain files when importing them? (For example, except for a file whose name precedes "thumb_")

No. You can filter out the objects you don't want in the code that iterates the results.