Inter-namespace middleware

README.md

Inter-namespace middleware

This middleware can connect to other namespaces.

Usage

Connect to other namespaces with the same broker options

moleculer.config.js

const InterNamespaceMiddleware = require("./inter-namespace.js");

module.exports {
    namespace: "local",
    nodeID: "node-1",
    transporter: "NATS",
    middlewares: [
        InterNamespaceMiddleware(["ns-mars", "ns-venus"])
    ]
}

or with different broker options

moleculer.config.js

const InterNamespaceMiddleware = require("./inter-namespace.js");

module.exports {
    namespace: "local",
    nodeID: "node-1",
    transporter: "NATS",
    middlewares: [
        InterNamespaceMiddleware([
            { 
                namespace: "ns-mars",
                transporter: "NATS"
            }, 
            {
                namespace: "ns-venus",
                transporter: "Redis",
            }
        ])
    ]
}

Calling services

// Call service in the local namespace
broker.call("greeter.hello");

// Call service in the local namespace with the namespace
broker.call("greeter.hello@local");

// Call service in the "ns-venus" namespace
broker.call("greeter.hello@ns-venus");

// Call service in the "ns-mars" namespace
broker.call("greeter.hello@ns-mars");

inter-namespace.js

const { ServiceBroker } = require("moleculer");
const _ = require("lodash");

module.exports = function InterNamespaceMiddleware(opts) {
    if (!Array.isArray(opts))
        throw new Error("Must be an Array");

    let thisBroker;
    const brokers = {};

    return {
        created(broker) {
            thisBroker = broker;
            opts.forEach(nsOpts => {
                if (_.isString(nsOpts)) {
                    nsOpts = {
                        namespace: nsOpts
                    };
                }
                const ns = nsOpts.namespace;

                this.logger.info(`Create internamespace broker for '${ns} namespace...'`);
                const brokerOpts = _.defaultsDeep({}, nsOpts, { nodeID: null, middlewares: null }, broker.options);
                brokers[ns] = new ServiceBroker(brokerOpts);
            });
        },

        started() {
            return Promise.all(Object.values(brokers).map(b => b.start()));
        },

        stopped() {
            return Promise.all(Object.values(brokers).map(b => b.stop()));
        },

        call(next) {
            return function(actionName, params, opts = {}) {
                if (_.isString(actionName) && actionName.includes("@")) {
                    const [action, namespace] = actionName.split("@");

                    if (brokers[namespace]) {
                        return brokers[namespace].call(action, params, opts);
                    } else if (namespace === thisBroker.namespace) {
                        return next(action, params, opts);
                    } else {
                        throw new Error("Unknow namespace: " + namespace);
                    }
                }

                return next(actionName, params, opts);
            };
        },
    };
};

@jellydn nice addition. I think you should add middlewares: null to brokerOpts else I think you will get an infinite broker creation loop.