Dispatch

Messages come in, messages go out

The dispatch program is designed to front all externally driven changes to the Sparks platform.

What is an externally driven change? A user who wants to do something. They (or more precisely our website) issues a command that arrives at the dispatcher. The dispatcher then:

• Validates the message using a schema from sparks-schemas
• Authorizes that the user is allowed to make this change
• Puts the message onto a message bus for services to take actions
• Returns a response that says yea or ney

At the return stage the user (well software) only knows that we accepted the message. Any actual changes happen further down.

Moving parts:

• index.ts: In / validate / auth / dispatch / respond
• queue.ts: In, currently reads firebase queue for messages
• validate.ts: Validates the command in the message using sparks-schemas
• auth.ts: Auth, checks a whole bunch of shit
• dispatch.ts: Out, adds the message to kinesis

Environment:

The following variables are required:

FIREBASE_DATABASE_URL: the database url
KINESIS_STREAM: name of kinesis stream

Running

To run it you need a firebase and a firebase credentials.json file:

npm install
npm start