gRPC Client-Server Example with RESTful for the Front-end

Example implementation of gRPC bwtween the internal microservices communications. The original request from the front-end is still using a Restful.

Note: This is just an example project, for those who wants to learn about gRPC on NodeJs.

The illustration below is about how this project behave, so you may get the idea about how it's work under the hood.

                                               +----------------------+
                                               |DB|                   |
                         +                     +--+ +--------------+  +------+
                         |                     |    |   Products   |  |      |
                         |                     |    +--------------+  +<---+ |
                         |                     |                      |    | |
                         |                     +----------------------+    | | Queries
                         |                                                 | |
                         |                                                 | |
                    [Restful]                                              | |
+-----------------+ HTTP Req    +----------------+ RPC Calls  +------------+-v+
|                 +------+----->+                +------------>               |
| External Client |      |      | Client Service |            |   Server App  |
|                 <------+------+                <------------+               |
+-----------------+ HTTP Resp   +----------------+            +---------------+
                         |
                         |
                         |
                         |
                         |
                         +

Data Flow

1. HTTP Request coming from the front-end or client via CURL or another RESTful client (e.g. Insomnia, Postman, etc)

2. Client Service requesting data through Rpc to the Server App

3. Server App then doing a DB query and returning the result back

4. Client Service got the result and return back to the original front-end or client.

Project Preparation

1. Clone this project

2. There are 3 subdirectories; server is a server of gRPC; client is a server of client which provide a restful service to the user, and protos holds the .proto file for product.

3. Go to server directory and install dependencies via

$ npm i

4. Do the same step on the client directory

5. Create a new Postgres database called grpc_products (you may configure the username / password of the DB later on server/knexfile.js)

6. Running the migration from the server directory

$ npm run migrate

7. Also the run the seeds

$ npm run seed

Run the gRPC server

Go to server directory and run npm start. If everything Ok you will see a message like

> gRPC server running at http://127.0.0.1:1831

Run the Restful server (Client of gRPC)

go to client directory and run npm start. You should see a message like this

> Server run at 3000

Testing RESTful request via CURL

List Products

$ curl http://127.0.0.1:3000/api/products 

{
  "products": [
    {
      "id": 1,
      "name": "pencil",
      "price": "1.99"
    },
    {
      "id": 2,
      "name": "pen",
      "price": "2.99"
    }
  ]
}

Read Product

$ curl http://127.0.0.1:3000/api/products/1

{
  "id": 1,
  "name": "pencil",
  "price": "1.99"
}

Create new Product

$  -X POST -d '{"name": "lamp", "price": "18.8"}' -H "Content-Type: application/json" http://127.0.0.1:3000/api/products

{"status":"Created"}

Update Product

$ curl -X PUT -d '{"name": "Spoon", "price": "34.53"}' \
-H 'Content-Type: application/json' http://127.0.0.1:3000/api/products/3

{"status":"Updated"}

Delete Product

$ curl -X DELETE http://127.0.0.1:3000/api/products/3

{"status":"Deleted"}

LICENSE

MIT (more)