Do I have access to GraphicsMagicks or ImageMagicks in a Google Cloud Function?

Question

I want to make a Google Cloud Function that will correctly set the content type of uploaded files. I know how to do this with GraphicsMagick or ImageMagick, but I'm not sure if Google Cloud Function has those native libraries. How do I find out if they have them or failing that how do I get them installed?

Answer 1

Google Cloud Functions run in a container that has ImageMagick installed. Somehow the Firebase documentation seems to have best documentation for it. From there:

Cloud Functions provides an image-processing program called ImageMagick that can perform manipulations on graphical image files. The following is an example of how to create a thumbnail image for an uploaded image file:

    // Download file from bucket.
    const bucket = gcs.bucket(fileBucket);
    const tempFilePath = `/tmp/${fileName}`;
    return bucket.file(filePath).download({
      destination: tempFilePath
    }).then(() => {
      console.log('Image downloaded locally to', tempFilePath);
      // Generate a thumbnail using ImageMagick.
      return exec(`convert "${tempFilePath}" -thumbnail '200x200>' "${tempFilePath}"`).then(() => {
        console.log('Thumbnail created at', tempFilePath);
        // We add a 'thumb_' prefix to thumbnails file name. That's where we'll upload the thumbnail.
        const thumbFilePath = filePath.replace(/(\/)?([^\/]*)$/, `$1thumb_$2`);
        // Uploading the thumbnail.
        return bucket.upload(tempFilePath, {
          destination: thumbFilePath
        });
      });
    });

This code executes the ImageMagick command line program convert to create a 200x200 thumbnail for the image saved in a temporary directory, then uploads it back to Cloud Storage.

Also see the Firebase functions-sample repo for an example of how to use it: https://github.com/firebase/functions-samples/tree/master/generate-thumbnail