Message Broker Service

• This Rest API was created using Golang. It features functions like registering publisher or subscriber, publishing messages or extracting updates.
• This utilises RSA encryption and the key can be passed to the functions for encryption/decryption, following a required format.
• This api has used clean code principle
• This api is completely unit tested and all the errors have been handled

Formatting the RSA key

• RSA key can be supplied by the user
• The RSA public key follows a specific format that can be obtained by the pkg function

import "github.com/vatsal278/msgbroker/pkg/crypt"
.
.
pubKey := crypt.KeyAsPEMStr(RSA public key)
//pubKey is the string formating of the RSA public key that will be used for subscriber registration

Starting the message broker service

• Running locally :

go run cmd/main.go

• Running via docker :

docker build -t msgbrokersvc .
docker run -p 9090:9090 msgbrokersvc

API Spec

You can test the api using post man, just import the collection into your postman app.

Register a Publisher

• Method: POST
• Path: /register/publisher
• Request Body:

{
    "channel": "channel",
}

• Response Header: HTTP 201
• Response Body:

{
    "status": 201,
    "message": "Successfully Registered as publisher to the channel",
    "data": {
      "id": "Uuid"
    }
}

Register a subscriber

• Method: POST
• Path: /register/subscriber
• Request Body:

{
    "callback":{
          "httpmethod":"POST",
          "callbackUrl":"URL",
          "key":"RSA public  key (in pem string format)"
    },
    "channel": "channel"
}

• Response Header: HTTP 201
• Response Body:

{
    "status": 201,
    "message": "Successfully Registered as subscriber to the channel",
    "data": null
}

Push Messages

• Method: POST
• Path: /publish
• Request Body:

{
    "publisher": {
        "id": "Uuid",
        "channel": "channel"
    },
    "update": "message"
}

• Response Header: HTTP 200
• Response Body:

{
    "status": 200,
    "message": "Notified All Subscriber",
    "data": null
}

In order to use the SDK functions:

• go get the package

go get github.com/vatsal278/msgbroker

• import the sdk package in the source code

import "github.com/vatsal278/msgbroker/pkg/sdk"

• Get an instance to the SDK Wrapper, Passing in the url to a running message broker service.

s := sdk.NewMsgBrokerSvc("Message broker service url")

• Register a publisher to push messages to a channel. A Uuid of the publisher will be returned that needs to be used to push message to the channel.

uuid, _ := s.RegisterPub("channel")

• Register a subscriber to receive messages on a channel. Send in the HTTP method, URL to the subscriber endpoint, optional RSA public key (this will be used by the message broker to encrypt the message before notifying the subscriber) and the channel

_ = s.RegisterSub("HTTP method", "URL", "RSA public key", "channel")

• Push message to all the subscribers registered on the channel using the registered publishers Uuid.

_ = s.PushMsg(`message`, Uuid, "channel")

• Extract message pushed to the subscriber registered on the channel, additionally decrypting with RSA private key, if opted for receiving encrypted messages during subscriber registration. source is of type io.ReadClosure which can be requests body.

MsgExtractor := s.ExtractMsg(RSA private key)
msg, _ := MsgExtractor(source)

• Examples of the sdk usage can be found here

Additional read

• Docs
• To check the code coverage

cd docs
go tool cover -html=coverage