github moleculerjs/moleculer v0.14.0-beta1
on GitHub

latest releases: v0.14.34, v0.15.0-beta1, v0.14.33...
pre-release5 years ago

Migration guide from 0.13 to 0.14

Breaking changes

Communication protocol has been changed

The Moleculer communication protocol has been changed. The new protocol version is 4.
It means the new Moleculer 0.14 nodes can't communicate with old <= 0.13 nodes.

Validation settings changed

The validation: true broker options was removed to follow other module configuration. Use validator option, instead.

Enable validation with built-in validator (default option) 

const broker = new ServiceBroker({
    validator: true
});

Disable validation/validator 

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

Use custom validation 

const broker = new ServiceBroker({
    validator: new MyCustomValidator()
});

The broker.use removed

The broker.use has been deprecated in version 0.13 and now it is removed. Use middleware: [] broker options to define middlewares.

loading middleware after the broker has started is no longer available.

The $node.health response changed

The $node.health action's response has been changed. The transit property is removed. To get transit metrics, use the new $node.metrics internal action.

Middleware shorthand definition is dropped

In previous versions you could define middleware which wraps the localAction hook with a simple Function.
In version 0.14 this legacy shorthand is dropped. When you define a middleware as a Function, the middleware handler will call it as an initialization and pass the ServiceBroker instance as a parameter.

Old shorthand middleware definition as a Function 

const MyMiddleware = function(next, action) {
    return ctx => next(ctx);
};

const broker = new ServiceBroker({
    middlewares: [MyMiddleware]
});

New middleware definition as a Function 

const MyMiddleware = function(broker) {
    // Create a custom named logger
    const myLogger = broker.getLogger("MY-LOGGER");

    return {
        localAction: function(next, action) {
            return ctx => {
                myLogger.info(`${action.name} has been called`);
                return next(ctx);
            }
        }
    }
};

const broker = new ServiceBroker({
    middlewares: [MyMiddleware]
});

The localEvent middleware hook signature changed

Old signature 

// my-middleware.js
module.exports = {
    // Wrap local event handlers
    localEvent(next, event) {
        return (payload, sender, event) => {
            return next(payload, sender, event);
        };
    },
};

New context-based signature 

// my-middleware.js
module.exports = {
    // Wrap local event handlers
    localEvent(next, event) {
        return (ctx) => {
            return next(ctx);
        };
    },
};

New

Context-based events

The new 0.14 version comes context-based event handler. It is very useful when you are using event-driven architecture and you would like to tracing the event. The Event Context is same as Action Context. They are the same properties except a few new properties related to the event.
It doesn't mean you should rewrite all existing event handlers. Moleculer detects the signature if your event handler. If it finds that the signature is "user.created(ctx) { ... }, it will call it with Event Context. If not, it will call with old arguments & the 4th argument will be the Event Context, like "user.created"(payload, sender, eventName, ctx) {...}

Use Context-based event handler & emit a nested event 

module.exports = {
    name: "accounts",
    events: {
        "user.created"(ctx) {
            console.log("Payload:", ctx.params);
            console.log("Sender:", ctx.nodeID);
            console.log("We have also metadata:", ctx.meta);
            console.log("The called event name:", ctx.eventName);

            ctx.emit("accounts.created", { user: ctx.params.user });
        }
    }
};

New built-in metrics

Moleculer v0.14 comes with a brand-new and entirely rewritten metrics module. It is now a built-in module. It collects a lot of internal Moleculer & process metric values. You can easily define your custom metrics. There are several built-in metrics reporters like Console, Prometheus, Datadog, ...etc.
Multiple reporters can be defined.

Enable metrics & define console reporter 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            "Console"
        ]
    }
});

Define custom metrics 

// posts.service.js
module.exports = {
    name: "posts",

    actions: {
        get(ctx) {
            // Update metrics
            this.broker.metrics.increment("posts.get.total");
            return posts;
        }
    },

    created() {
        // Register new custom metrics
        this.broker.metrics.register({ type: "counter", name: "posts.get.total" });
    }
};

Enable metrics & define Prometheus reporter with filtering 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "Prometheus",
                options: {
                    port: 3030,
                    includes: ["moleculer.**"],
                    excludes: ["moleculer.transit.**"]
                }
            }
        ]
    }
});

Supported metric types

  • counter - A counter is a cumulative metric that represents a single monotonically increasing counter whose value can only increase or be reset to zero. For example, you can use a counter to represent the number of requests served, tasks completed, or errors.

  • gauge - A gauge is a metric that represents a single numerical value that can arbitrarily go up and down. Gauges are typically used for measured values like current memory usage, but also "counts" that can go up and down, like the number of concurrent requests.

  • histogram - A histogram samples observations (usually things like request durations or response sizes) and counts them in configurable buckets. It also provides a sum of all observed values and calculates configurable quantiles over a sliding time window.

  • info - An info is a single string or number value like process arguments, hostname or version numbers.

Internal metrics

Process metrics

  • process.arguments (info)
  • process.pid (info)
  • process.ppid (info)
  • process.eventloop.lag.min (gauge)
  • process.eventloop.lag.avg (gauge)
  • process.eventloop.lag.max (gauge)
  • process.eventloop.lag.count (gauge)
  • process.memory.heap.size.total (gauge)
  • process.memory.heap.size.used (gauge)
  • process.memory.rss (gauge)
  • process.memory.external (gauge)
  • process.memory.heap.space.size.total (gauge)
  • process.memory.heap.space.size.used (gauge)
  • process.memory.heap.space.size.available (gauge)
  • process.memory.heap.space.size.physical (gauge)
  • process.memory.heap.stat.heap.size.total (gauge)
  • process.memory.heap.stat.executable.size.total (gauge)
  • process.memory.heap.stat.physical.size.total (gauge)
  • process.memory.heap.stat.available.size.total (gauge)
  • process.memory.heap.stat.used.heap.size (gauge)
  • process.memory.heap.stat.heap.size.limit (gauge)
  • process.memory.heap.stat.mallocated.memory (gauge)
  • process.memory.heap.stat.peak.mallocated.memory (gauge)
  • process.memory.heap.stat.zap.garbage (gauge)
  • process.uptime (gauge)
  • process.internal.active.handles (gauge)
  • process.internal.active.requests (gauge)
  • process.versions.node (info)
  • process.gc.time (gauge)
  • process.gc.total.time (gauge)
  • process.gc.executed.total (gauge)

OS metrics

  • os.memory.free (gauge)
  • os.memory.total (gauge)
  • os.uptime (gauge)
  • os.type (info)
  • os.release (info)
  • os.hostname (info)
  • os.arch (info)
  • os.platform (info)
  • os.user.uid (info)
  • os.user.gid (info)
  • os.user.username (info)
  • os.user.homedir (info)
  • os.network.address (info)
  • os.network.mac (info)
  • os.datetime.unix (gauge)
  • os.datetime.iso (info)
  • os.datetime.utc (info)
  • os.datetime.tz.offset (gauge)
  • os.cpu.load.1 (gauge)
  • os.cpu.load.5 (gauge)
  • os.cpu.load.15 (gauge)
  • os.cpu.utilization (gauge)
  • os.cpu.user (gauge)
  • os.cpu.system (gauge)
  • os.cpu.total (gauge)
  • os.cpu.info.model (info)
  • os.cpu.info.speed (gauge)
  • os.cpu.info.times.user (gauge)
  • os.cpu.info.times.sys (gauge)

Moleculer metrics

  • moleculer.node.type (info)
  • moleculer.node.versions.moleculer (info)
  • moleculer.node.versions.protocol (info)
  • moleculer.broker.namespace (info)
  • moleculer.broker.started (gauge)
  • moleculer.broker.local.services.total (gauge)
  • moleculer.broker.middlewares.total (gauge)
  • moleculer.registry.nodes.total (gauge)
  • moleculer.registry.nodes.online.total (gauge)
  • moleculer.registry.services.total (gauge)
  • moleculer.registry.service.endpoints.total (gauge)
  • moleculer.registry.actions.total (gauge)
  • moleculer.registry.action.endpoints.total (gauge)
  • moleculer.registry.events.total (gauge)
  • moleculer.registry.event.endpoints.total (gauge)
  • moleculer.request.bulkhead.inflight (gauge)
  • moleculer.request.timeout.total (counter)
  • moleculer.request.retry.attempts.total (counter)
  • moleculer.request.fallback.total (counter)
  • moleculer.request.total (counter)
  • moleculer.request.active (gauge)
  • moleculer.request.error.total (counter)
  • moleculer.request.time (histogram)
  • moleculer.request.levels (counter)
  • moleculer.event.emit.total (counter)
  • moleculer.event.broadcast.total (counter)
  • moleculer.event.broadcast-local.total (counter)
  • moleculer.event.received.total (counter)
  • moleculer.transit.publish.total (counter)
  • moleculer.transit.receive.total (counter)
  • moleculer.transit.requests.active (gauge)
  • moleculer.transit.streams.send.active (gauge)
  • moleculer.transporter.packets.sent.total (counter)
  • moleculer.transporter.packets.sent.bytes (counter)
  • moleculer.transporter.packets.received.total (counter)
  • moleculer.transporter.packets.received.bytes (counter)

Built-in reporters

All reporters have the following options: 

{
    includes: null,
    excludes: null,

    metricNamePrefix: null,
    metricNameSuffix: null,

    metricNameFormatter: null,
    labelNameFormatter: null
}

Console reporter

This is a debugging reporter which prints metrics to the console periodically. 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "Console",
                options: {
                    interval: 5 * 1000,
                    logger: null,
                    colors: true,
                    onlyChanges: true
                }
            }
        ]
    }
});

CSV reporter

CSV reporter saves changed to CSV file. 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "CSV",
                options: {
                    folder: "./reports/metrics",
                    delimiter: ",",
                    rowDelimiter: "\n",

                    mode: MODE_METRIC, // MODE_METRIC, MODE_LABEL

                    types: null,

                    interval: 5 * 1000,

                    filenameFormatter: null,
                    rowFormatter: null,
                }
            }
        ]
    }
});

Datadog reporter

Datadog reporter sends metrics to the Datadog server. 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "Datadog",
                options: {
                    host: "my-host",
                    apiVersion: "v1",
                    path: "/series",
                    apiKey: process.env.DATADOG_API_KEY,
                    defaultLabels: (registry) => ({
                        namespace: registry.broker.namespace,
                        nodeID: registry.broker.nodeID
                    }),
                    interval: 10 * 1000
                }
            }
        ]
    }
});

Event reporter

Event reporter sends Moleculer events with metric values. 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "Event",
                options: {
                    eventName: "$metrics.snapshot",

                    broadcast: false,
                    groups: null,

                    onlyChanges: false,

                    interval: 5 * 1000,
                }
            }
        ]
    }
});

Prometheus reporter

Prometheus reporter publishes metrics in Prometheus format. The Prometheus server can collect them. Default port is 3030. 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "Prometheus",
                options: {
                    port: 3030,
                    path: "/metrics",
                    defaultLabels: registry => ({
                        namespace: registry.broker.namespace,
                        nodeID: registry.broker.nodeID
                    })
                }
            }
        ]
    }
});

StatsD reporter

The StatsD reporter sends metric values to StatsD server via UDP. 

const broker = new ServiceBroker({
    metrics: {
        enabled: true,
        reporter: [
            {
                type: "StatsD",
                options: {
                    protocol: "udp",
                    host: "localhost",
                    port: 8125,

                    maxPayloadSize: 1300,
                }
            }
        ]
    }
});

New tracing feature

An enhanced tracing middleware has been implemented in version 0.14. It support several exporters, custom tracing spans and integration with instrumentation libraries (like dd-trace).

Enable tracing 

const broker = new ServiceBroker({
    tracing: true
});

Tracing with console exporter 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Console",
                options: {
                    width: 80,
                    colors: true,
                }
            }
        ]        
    }
});

Tracing with Zipkin exporter 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Zipkin",
                options: {
                    baseURL: "http://zipkin-server:9411",
                }
            }
        ]        
    }
});

Add context values to span tags

In action defintion you can define which Context params or meta values want to add to the span tags.

Example 

// posts.service.js
module.exports = {
    name: "posts",
    actions: {
        get: {
            tracing: {
                // Add `ctx.params.id` and `ctx.meta.loggedIn.username` values
                // to tracing span tags.
                tags: {
                    params: ["id"],
                    meta: ["loggedIn.username"],
                    response: ["id", "title"] // add data to tags from the action response.
            },
            async handler(ctx) {
                // ...
            }
        }
    }
});

Example with all properties of params without meta (actually it is the default) 

// posts.service.js
module.exports = {
    name: "posts",
    actions: {
        get: {
            tracing: {
                // Add all params without meta
                tags: {
                    params: true,
                    meta: false,
            },
            async handler(ctx) {
                // ...
            }
        }
    }
});

Example with custom function
Please note, the tags function will be called two times in case of success execution. First with ctx, and second times with ctx & response as the response of action call. 

// posts.service.js
module.exports = {
    name: "posts",
    actions: {
        get: {
            tracing: {
                tags(ctx, response) {
                    return {
                        params: ctx.params,
                        meta: ctx.meta,
                        custom: {
                            a: 5
                        },
                        response
                    };
                }
            },
            async handler(ctx) {
                // ...
            }
        }
    }
});

Example with all properties of params in event definition 

// posts.service.js
module.exports = {
    name: "posts",
    events: {
        "user.created": {
            tracing: {
                // Add all params without meta
                tags: {
                    params: true,
                    meta: false,
            },
            async handler(ctx) {
                // ...
            }
        }
    }
});

Built-in exporters

Console exporter

This is a debugging exporter which prints the full local trace to the console.

Please note that it can't follow remote calls, only locals. 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Console",
                options: {
                    logger: null,
                    colors: true,
                    width: 100,
                    gaugeWidth: 40
                }
            }
        ]
    }
});

Datadog exporter

Datadog exporter sends tracing data to Datadog server via dd-trace. It is able to merge tracing spans between instrumented Node.js modules and Moleculer modules.

TODO screenshot 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Datadog",
                options: {
                    agentUrl: process.env.DD_AGENT_URL || "http://localhost:8126",
                    env: process.env.DD_ENVIRONMENT || null,
                    samplingPriority: "AUTO_KEEP",
                    defaultTags: null,
                    tracerOptions: null,
                }
            }
        ]
    }
});

To use this exporter, install the dd-trace module with npm install dd-trace --save command.

Event exporter

Event exporter sends Moleculer events ($tracing.spans) with tracing data. 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Event",
                options: {
                    eventName: "$tracing.spans",

                    sendStartSpan: false,
                    sendFinishSpan: true,

                    broadcast: false,

                    groups: null,

                    /** @type {Number} Batch send time interval. */
                    interval: 5,

                    spanConverter: null,

                    /** @type {Object?} Default span tags */
                    defaultTags: null

                }
            }
        ]
    }
});

Event (legacy) exporter

This is another event exporter which sends legacy moleculer events (metrics.trace.span.start & metrics.trace.span.finish). It is compatible with <= 0.13 Moleculer metrics trace events. 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            "EventLegacy"
        ]
    }
});

Jaeger exporter

Jaeger exporter sends tracing spans information to a Jaeger server. 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Jaeger",
                options: {
                    /** @type {String?} HTTP Reporter endpoint. If set, HTTP Reporter will be used. */
                    endpoint: null,                    
                    /** @type {String} UDP Sender host option. */
                    host: "127.0.0.1",
                    /** @type {Number?} UDP Sender port option. */
                    port: 6832,

                    /** @type {Object?} Sampler configuration. */
                    sampler: {
                        /** @type {String?} Sampler type */
                        type: "Const",

                        /** @type: {Object?} Sampler specific options. */
                        options: {}
                    },

                    /** @type {Object?} Additional options for `Jaeger.Tracer` */
                    tracerOptions: {},

                    /** @type {Object?} Default span tags */
                    defaultTags: null
                }
            }
        ]
    }
});

To use this exporter, install the jaeger-client module with npm install jaeger-client --save command.

Zipkin exporter

Zipkin exporter sends tracing spans information to a Zipkin server. 

const broker = new ServiceBroker({
    tracing: {
        enabled: true,
        exporter: [
            {
                type: "Zipkin",
                options: {
                    /** @type {String} Base URL for Zipkin server. */
                    baseURL: process.env.ZIPKIN_URL || "http://localhost:9411",

                    /** @type {Number} Batch send time interval. */
                    interval: 5,

                    /** @type {Object} Additional payload options. */
                    payloadOptions: {

                        /** @type {Boolean} Set `debug` property in v2 payload. */
                        debug: false,

                        /** @type {Boolean} Set `shared` property in v2 payload. */
                        shared: false
                    },

                    /** @type {Object?} Default span tags */
                    defaultTags: null
                }
            }
        ]
    }
});

Custom tracing spans

// posts.service.js
module.exports = {
    name: "posts",
    actions: {
        async find(ctx) {
            const span1 = ctx.startSpan("get data from DB", {
                tags: {
                    ...ctx.params
                }
            }); 
            const data = await this.getDataFromDB(ctx.params);
            span1.finish();

            const span2 = ctx.startSpan("populating");
            const res = await this.populate(data);
            span2.finish();

            return res;
        }
    }
};

Caller action

There is a new caller property in Context. It contains the action name of the caller when you use ctx.call in action handlers. 

broker2.createService({
    name: "greeter",
    actions: {
        hello(ctx) {
            this.logger.info(`This action is called from '${ctx.caller}' on '${ctx.nodeID}'`);
        }
    }
});

NodeID conflict handling

Having remote nodes with same nodeID in the same namespace can cause communication problems. In v0.14 ServiceBroker checks the nodeIDs of remote nodes. If some node has the same nodeID, the broker will throw a fatal error and stop the process.

Sharding built-in strategy

There is a new built-in shard invocation strategy. It uses a key value from context params or meta to route the request a specific node. It means the same key value will be route to the same node.

Example with shard key as name param in context 

const broker = new ServiceBroker({
    registry: {
        strategy: "Shard",
        strategyOptions: {
            shardKey: "name"
        }
    }
});

Example with shard key as user.id meta value in context 

const broker = new ServiceBroker({
    registry: {
        strategy: "Shard",
        strategyOptions: {
            shardKey: "#user.id"
        }
    }
});

All available options of Shard strategy 

const broker = new ServiceBroker({
    registry: {
        strategy: "Shard",
        strategyOptions: {
            shardKey: "#user.id",
            vnodes: 10,
            ringSize: 1000,
            cacheSize: 1000
        }
    }
});

Extending internal services

Now the internal services can be extended. You can define mixin schema for every internal service under internalServices broker option. 

// moleculer.config.js
module.exports = {
    nodeID: "node-1",
    logger: true,
    internalServices: {
        $node: {
            actions: {
                // Call as `$node.hello`
                hello(ctx) {
                    return `Hello Moleculer!`;
                }
            }
        }
    }
};

Action hook inside action definition

Sometimes it's better to define action hooks inside action definition instead of service hooks property. 

broker.createService({
    name: "greeter",
    hooks: {
        before: {
            "*"(ctx) {
                broker.logger.info(chalk.cyan("Before all hook"));
            },
            hello(ctx) {
                broker.logger.info(chalk.magenta("  Before hook"));
            }
        },
        after: {
            "*"(ctx, res) {
                broker.logger.info(chalk.cyan("After all hook"));
                return res;
            },
            hello(ctx, res) {
                broker.logger.info(chalk.magenta("  After hook"));
                return res;
            }
        },
    },

    actions: {
        hello: {
            hooks: {
                before(ctx) {
                    broker.logger.info(chalk.yellow.bold("    Before action hook"));
                },
                after(ctx, res) {
                    broker.logger.info(chalk.yellow.bold("    After action hook"));
                    return res;
                }
            },

            handler(ctx) {
                broker.logger.info(chalk.green.bold("      Action handler"));
                return `Hello ${ctx.params.name}`;
            }
        }
    }
});

Output 

INFO  - Before all hook
INFO  -   Before hook
INFO  -     Before action hook
INFO  -       Action handler
INFO  -     After action hook
INFO  -   After hook
INFO  - After all hook

Metadata in broker options

There is a new metadata property in broker options to store custom values. You can use the metadata property in your custom middlewares or strategies. 

const broker2 = new ServiceBroker({
    nodeID: "broker-2",
    transporter: "NATS",
    metadata: {
        region: "eu-west1"
    }
});

This information is available in response of $node.list action.

Enhanced hot-reload feature

In v0.14 the built-in hot-reload feature was entirely rewritten. Now, it can detect dependency-graph between service files and other loaded (with require) files. This means that the hot-reload mechanism now watches the service files and their dependencies. Every time a file change is detected the hot-reload mechanism will track the affected services and will restart them.

New middleware hooks

There are some new middleware hooks.

registerLocalService

It's called before registering a local service instance.

Signature 

// my-middleware.js
module.exports = {
    registerLocalService(next) {
        return (svc) => {
            return next(svc);
        };
    }
}

serviceCreating

It's called before a local service instance creating. At this point the service mixins are resolved, so the service schema is merged completely.

Signature 

// my-middleware.js
module.exports = {
    serviceCreating(service, schema) {
        // Modify schema
        schema.myProp = "John";
    }
}

transitPublish

It's called before communication packet publishing.

Signature 

// my-middleware.js
module.exports = {
    transitPublish(next) {
        return (packet) => {
            return next(packet);
        };
    },
}

transitMessageHandler

It's called before transit receives & parses an incoming message

Signature 

// my-middleware.js
module.exports = {
    transitMessageHandler(next) {
        return (cmd, packet) => {
            return next(cmd, packet);
        };
    }
}

transporterSend

It's called before transporter send a communication packet (after serialization). Use it to encrypt or compress the packet buffer.

Signature 

// my-middleware.js
module.exports = {
    transporterSend(next) {
        return (topic, data, meta) => {
            // Do something with data
            return next(topic, data, meta);
        };
    }
}

transporterReceive

It's called after transporter received a communication packet (before serialization). Use it to decrypt or decompress the packet buffer.

Signature 

// my-middleware.js
module.exports = {
    transporterReceive(next) {
        return (cmd, data, s) => {
            // Do something with data
            return next(cmd, data, s);
        };
    }
}

New built-in middlewares

Encryption

AES encryption middleware protects all inter-services communications that use the transporter module.
This middleware uses built-in Node crypto library. 

const { Middlewares } = require("moleculer");

// Create broker
const broker = new ServiceBroker({
    middlewares: [
        Middlewares.Transmit.Encryption("secret-password", "aes-256-cbc", initVector) // "aes-256-cbc" is the default
    ]
});

Compression

Compression middleware reduces the size of messages that go through the transporter module.
This middleware uses built-in Node zlib library. 

const { Middlewares } = require("moleculer");

// Create broker
const broker = new ServiceBroker({
    middlewares: [
        Middlewares.Transmit.Compression("deflate") // or "deflateRaw" or "gzip"
    ]
});

Transit Logger

Transit logger middleware allows to easily track the messages that are exchanged between services. 

const { Middlewares } = require("moleculer");

// Create broker
const broker = new ServiceBroker({
    middlewares: [
        Middlewares.Debugging.TransitLogger({
            logPacketData: false,
            folder: null,
            colors: {
                send: "magenta",
                receive: "blue"
            },
            packetFilter: ["HEARTBEAT"]
        })
    ]
});

Action Logger

Action Logger middleware tracks "how" service actions were executed. 

const { Middlewares } = require("moleculer");

// Create broker
const broker = new ServiceBroker({
    middlewares: [
        Middlewares.Debugging.ActionLogger({
            logParams: true,
            logResponse: true,
            folder: null,
            colors: {
                send: "magenta",
                receive: "blue"
            },
            whitelist: ["**"]
        })
    ]
});

Load middlewares by names

To load built-in middlewares, use its names in middleware broker option. 

const { Middlewares } = require("moleculer");

// Extend with custom middlewares
Middlewares.MyCustom = {
    created(broker) {
        broker.logger.info("My custom middleware is created!");
    }
};


const broker1 = new ServiceBroker({
    logger: true,
    middlewares: [
        // Load by middleware name
        "MyCustom"
    ]
});

Global error handler

There is a new global error handler in ServiceBroker. It can be defined in broker options as errorHandler(err, info).
It catches unhandled errors in action & event handlers.

Catch, handle & log the error 

const broker = new ServiceBroker({
    errorHandler(err, info) {

        this.logger.warn("Error handled:", err);
    }
});

Catch & throw further the error 

const broker = new ServiceBroker({
    errorHandler(err, info) {
        this.logger.warn("Error handled:", err);
        throw err; // Throw further
    }
});

The info object contains the broker and the service instances, the current context and the action or the event definition.

Async storage for current context

ServiceBroker has a continuous local storage in order to store the current context. It means you don't need to always pass the ctx from actions to service methods. You can get it with this.currentContext. 

// greeter.service.js
module.exports = {
    name: "greeter",
    actions: {
        hello(ctx) {
            return this.Promise.resolve()
                .then(() => this.doSomething());

        }
    },
    methods: {
        doSomething() {
            const ctx = this.currentContext;
            return ctx.call("other.service");
        }
    }
});

Buffer supporting improved in serializers

In earlier version, if request, response or event data was a Buffer, the schema-based serializers convert it to JSON string which was not very efficient. In this version all schema-based serializers (ProtoBuf, Avro, Thrift) can detect the type of data & convert it based on the best option and send always as binary data.

Other notable changes

  • Kafka transporter upgrade to support kafka-node@4.
  • rename ctx.metrics to ctx.tracing.
  • broker.hotReloadService method has been removed.
  • new hasEventListener & getEventListeners broker method.
  • new uidGenerator broker options to overwrite the default UUID generator code.
Check out latest releases or
releases around moleculerjs/moleculer v0.14.0-beta1

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