Redroc

• Scalabale image service that allow users download, search, and upload images.
• Support for Encryption when uploading image, Decryption when downloading image.
• pub/sub when uploading image

The Stack

• Golang/Chi mux, gRPC for the backend.
• NextJS for the frontend
• GCP (Google Cloud Platform) (Cloud Run, Firestore, Cloud Storage, Pub/Sub) for deploying the backend services.
• Vercel for deploying the frontend.
• Explore Bazel with this project.

To Use .env

Rename .env.example to .env and fill the correct values.

TODO

• DONE: make encryption/decryption key read from env variable
• DONE: Pub/Sub when uploading image

Services

We have two type of services gRPC, and RESTful services.

RESTful service

This service is authenticated to call other gRPC services on Google Cloud (Cloud Run), and this is the only services exposed to the world.

Used Technologies: Golang, and Chi mux for handling routs.

---

API

• Welcome page: this the root path return Simple html Welcoming the user

    /

• Health check

    GET /health

• Download image

    GET /download/{image_name}

    image_name: required

• Search for image

    GET /search?q={search_keyword}

    search_keyword: optional: if not provided we return latest images uploaded

• Upload Image

This trigger pub/sub service.

    POST /upload

    multipart/form-data:
        username: required: username who is upload the image
        file:     required: image supported type (png, jpeg, gif)
        hashtags: optional: metadata in format ["hashtag1", "hashtags2", ...]

---

gRPC services

We cannot call those services directly, those services required authentication from the caller in Google Cloud (Cloud Run).

1. Download

   Download service that allow user to get download the image by image name.

   the service proto is

       message DownloadPhotoRequest {
           string img_name = 1;
       }
   
       message DownloadPhotoResponse {
           bytes img_blob = 1;
       }
   
       service DownloadPhoto {
           /*
           * RPC for download a photo
           */
           rpc Download(DownloadPhotoRequest) returns (DownloadPhotoResponse);
       }

2. Upload

   Upload service that allow user upload image with it's metadata to search for image later.

   Require username, and file.

   Optional hashtags.

   the service proto is

       message UploadImageRequest {
           string obj_name = 1;
           bytes image = 2;
       }
   
       message UploadImageResponse {}
   
       message CreateMetadataRequest {
           string obj_name = 1;
           string user = 2;
           repeated string hashtags = 3;
       }
       message CreateMetadataResponse {}
   
       service UploadPhoto {
           /*
           * RPC for upload a photo to the image database
           */
           rpc Upload(UploadImageRequest) returns (UploadImageResponse);
   
           /*
           * RPC for create hashtag-image mapping in the metadata database
           */
           rpc CreateMetadata(CreateMetadataRequest) returns (CreateMetadataResponse);
       }
   

3. Search

   Search service that allow user to search for images with hashtags attached with the image.

   if search keyword is empty it will return latest image uploaded.

   the service proto is

       message GetThumbnailImagesRequest {
           // if keyword=="latest", return recent photo
           // in the service, we will update metadata such as download_times accordingly
           string search_keyword = 1;
       }
   
       message GetThumbnailImagesResponse {
           // get the storage image-serving address and return
           repeated string storage_url = 1;
       }
   
       service GetThumbnail {
       /*
           RPC for getting the UIDs of images relevant to the keyword
       */
       rpc GetThumbnail(GetThumbnailImagesRequest)
           returns (GetThumbnailImagesResponse);
       }

Resources

• Google Image Server