Examples of integrating moleculer-io with moleculer-web using moleculer-runner instead of ServiceBroker?

Question

I am having fun with using moleculer-runner instead of creating a ServiceBroker instance in a moleculer-web project I am working on. The Runner simplifies setting up services for moleculer-web, and all the services - including the api.service.js file - look and behave the same, using a module.exports = { blah } format.

I can cleanly define the REST endpoints in the api.service.js file, and create the connected functions in the appropriate service files. For example aliases: { 'GET sensors': 'sensors.list' } points to the list() action/function in sensors.service.js . It all works great using some dummy data in an array.

The next step is to get the service(s) to open up a socket and talk to a local program listening on an internal set address/port. The idea is to accept a REST call from the web, talk to a local program over a socket to get some data, then format and return the data back via REST to the client.

BUT When I want to use sockets with moleculer, I'm having trouble finding useful info and examples on integrating moleculer-io with a moleculer-runner-based setup. All the examples I find use the ServiceBroker model. I thought my Google-Fu was pretty good, but I'm at a loss as to where to look to next. Or, can i modify the ServiceBroker examples to work with moleculer-runner? Any insight or input is welcome.

Answer 1

If you want the following chain: localhost:3000/sensor/list -> sensor.list() -> send message to local program:8071 -> get response -> send response as return message to the REST caller.

Then you need to add a socket io client to your sensor service (which has the list() action). Adding a client will allow it to communicate with "outside world" via sockets.

Check the image below. I think it has everything that you need. As a skeleton I've used moleculer-demo project.

What I have:

• API service api.service.js. That handles the HTTP requests and passes them to the sensor.service.js

• The sensor.service.js will be responsible for communicating with remote socket.io server so it needs to have a socket.io client. Now, when the sensor.service.js service has started() I'm establishing a connection with a remote server located at port 8071. After this I can use this connection in my service actions to communicate with socket.io server. This is exactly what I'm doing in sensor.list action.

• I've also created remote-server.service.js to mock your socket.io server. Despite being a moleculer service, the sensor.service.js communicates with it via socket.io protocol.