Breaking changes

Protocol changed #86

The Moleculer transportation protocol has been changed. It means, the new (>= v0.11) versions can't communicate with the old (<= v0.10.x) ones.
You can find more information about changes in #86 issue.

Balanced events

The whole event handling has been rewritten. By now Moleculer supports event driven architecture. It means that event emits are balanced like action calls are.

For example, you have 2 main services: users & payments. Both subscribe to the user.created event. You start 3 instances from users service and 2 instances from payments service. If you emit the event with broker.emit('user.created'), broker groups & balances the event, so only one users and one payments service receive the event.
You can also send broadcast events with the broker.broadcast('user.created) command. This way every service instance on every node receives the event.
The broker.broadcastLocal('user.created') command sends events only to the local services.

Renamed & new internal events

Every internal event name starts with '$'. These events are not transferred to remote nodes.

Renamed events:

node.connected -> $node.connected
node.updated -> $node.updated
node.disconnected -> $node.disconnected
services.changed -> $services.changed. It is called if local or remote service list is changed.
circuit-breaker.closed -> $circuit-breaker.closed
circuit-breaker.opened -> $circuit-breaker.opened
circuit-breaker.half-opened -> $circuit-breaker.half-opened

New events:

global circuit breaker events for metrics: metrics.circuit-breaker.closed, metrics.circuit-breaker.opened, metrics.circuit-breaker.half-opened

Switchable built-in load balancer

The built-in Moleculer load balancer is switchable. You can turn it off, if the transporter has internal balancer (currently AMQP has it).

const broker = new ServiceBroker({
    disableBalancer: false
});

Please note! If built-in balancer is disabled, every call & emit (including local ones too) are transferred via transporter.

Removed broker methods

Some internal broker methods have been removed or renamed.

broker.bus has been removed.
broker.on has been removed. Use events in service schema instead.
broker.once has been removed.
broker.off has been removed.
broker.getService has been renamed to broker.getLocalService
broker.hasService has been removed.
broker.hasAction has been removed.
broker.getAction has been deprecated.
broker.isActionAvailable has been removed.

Changed local service responses

Internal action ($node.list, $node.services, $node.actions, $node.health) responses are changed. New internal action ($node.events) to list event subscriptiion is added.

Broker option changes

heartbeatInterval default value is changed from 10 to 5.
heartbeatTimeout default value is changed from 30 to 15.
circuitBreaker.maxFailures default value is changed from 5 to 3.
logFormatter accepts string. The simple value is a new formatter to show only log level & log messages.

New

Ping command

New PING & PONG feature has been implemented. Ping remite nodes to measure the network latency and system time differences.

broker.createService({
    name: "test",
    events: {
        "$node.pong"({ nodeID, elapsedTime, timeDiff }) {
            this.logger.info(`Pong received from '${nodeID}' - Time: ${elapsedTime}ms, System time difference: ${timeDiff}ms`);
        }
    }
});

broker.start().then(() => broker.transit.sendPing(/*nodeID*/));

Pluggable validator

The Validator in ServiceBroker is plugable. So you can change the built-in fastest-validator to a slower one :) Example Joi validator

Waiting for other services feature

If your services depend on other ones, use the waitForService method to make services wait until dependencies start.

let svc = broker.createService({
    name: "seed",
    started() {
        return this.waitForServices(["posts", "users"]).then(() => {
            // Do work...
        });
    }
});

Signature:

this.waitForServices(serviceNames: String|Array<String>, timeout: Number/*milliseconds*/, interval: Number/*milliseconds*/): Promise

New error types

We added some new Moleculer error classes.

MoleculerRetryableError - Common Retryable error. Caller retries the request if retryCount > 0.
MoleculerServerError - Common server error (5xx).
MoleculerClientError - Common client/request error (4xx).
ServiceNotAvailable - Raises if the service is registered but isn't available (no live nodes or CB disabled them).
ProtocolVersionMismatchError - Raises if connect a node with an older client (<= v0.10.0)).

Other changes

The cachers don't listen "cache.clean" event.

moleculerjs/moleculer v0.11.0 on GitHub