ImageService

An gRPC based parallel image processing and storage microservice. Image Service takes an original image and a set of 'operations' to process and streams the results as they're complete back to the client. Optional no operations can be requested and the original is stored using the storage provided for later use with external services (imgix.com etc).

Processing is done by a set of 'workers' to limit concurrency and overloading.

By default 5 workers are run, meaning only 5 image resizing or uploading operations happen concurrently. New operations are queued and streamed back to the client when completed.

A "sync" method is there for convenience, it's worth nothing that this method still uploads and processes concurrently but returns all the images at once when they're all complete.

Image processing uses bimg which is backed by libvips.

service ImageService {
  rpc Store(ImageStoreRequest) returns (stream Image) {}
  rpc StoreSync(ImageStoreRequest) returns (ImageSyncResponse) {}
  rpc Delete(DeleteRequest) returns (DeleteResponse) {}
}

Docker

A pre build Docker container is available at:

docker pull lileio/image_service

Setup

Configuration of storage is done via ENV variables

Worker Pool Size

To increase or decrease the number of parallel workers, set the WORKER_POOL_SIZE var.

WORKER_POOL_SIZE=10

Cloud Storage

To point to a cloud storage service instance.

CLOUD_STORAGE_ADDR=10.0.0.1:8000

File Storage

File system storage is also available, note that you will be responsible for hosting/serving behind something like nginx or a CDN.

FILE_LOCATION=/path/to/webserver

Example

// Setup a client connection
client = image_service.NewImageServiceClient(conn)

// Create a request object
b, err := ioutil.ReadFile("pic.jpg")
if err != nil {
  panic(err) 
}

ctx := context.Background()
req := &image_service.ImageStoreRequest{
  Filename: "pic.jpg",
  Data:     b,
  Ops: []*image_service.ImageOperation{
    &image_service.ImageOperation{
      Crop:        true,
      Width:       200,
      Height:      200,
      VersionName: "small",
    },
    &image_service.ImageOperation{
      Crop:        true,
      Width:       600,
      Height:      600,
      VersionName: "medium",
    },
    &image_service.ImageOperation{
      Crop:        true,
      Width:       1000,
      Height:      1000,
      VersionName: "large",
    },
  },
}


stream, err := client.Store(ctx, req)

for {
  img, err := stream.Recv()
  if err == io.EOF {
    break
  }

  if err != nil {
    fmt.Printf("err = %+v\n", err)
  }

  fmt.Printf("img = %+v\n", img.URL)
}