mkapnick / go-mirror-hw

Running locally

• dep ensure
• cd server
• GOOS=linux go build -o main
• docker run -p 9000:9000 go-mirror

Deployment

• Deployed on Kubernetes/GCP
• Can be found here: http://35.232.131.106

DockerHub

• Can be found on docker hub here: https://hub.docker.com/r/mdotm/go-mirror
• docker pull mdotm/go-mirror
• docker run -p 9000:9000 mdotm/go-mirror

Context

• Every user has a userId and a channelId
• The user's channelId is a public channel. Anyone can subscribe to that channel and write to it. Upon login, I automatically subscribe the logged in user to their channelId so they can see any messages coming in on that channel from other users
• The user's userId is used to DM a user.

The flow of how DM's work

• User logs in and a websocket connection is established with the server
• Once the websocket connection is established, the server sends an acknowledgment (ACK) to the client which basically says: hey, you are now registered correctly on the server, here is your websocketId.
• A user initiates a DM request to another user.
• The client sends a message to the server over the websocket connection that includes the channelId (the channelId is formed on the client to contain both userIds), the client's userId, and the client's websocketId, and the message code
• A DM channel is 2 user id's concatanted together by a .. So a DM channel looks like userId1.userId2. The 2nd userId (userId2) is the receiving user. The first userId (userId1) is the sending user.
• The server receives this message and recognizes that it's a DM request from the message code.
• The server loops through all the websocket clients, and checks to see if the client userId matches userId2. If it matches then the server knows to relay this message to that client over that particular websocket connection. The server then relays the message over the ws connection with a specific message code subscribe.direct.
• The client listens for incoming messages on the ws, sees the incoming message code of type subscribe.direct, and displays the message to that user.

Pubnub

• Pubnub is used to subscribe users to channels, to send messages into channels, and to receive messages from channels. My code wraps around Pubnub to handle which users should subscribe to what channel and what messages they should send and receive from a channel.