hato-logging

A plugin for logging messages passing through hato

About

This is a plugin for hato, an amqp framework.

This plugin facilitates logging of messages that are published and consumed by hato.

The plugin accepts a logging function to which messages will be passed as they are published and consumed. The passed logging function should accept one argument which will be passed in the following format:

{
    command, // Either 'publish' or 'consume'
    exchange,
    routingKey,
    content
}

Getting Started

Import the package

const Logging = require('hato-logging');

Instantiate the logging plugin with a logging function of your choice, if left empty the default is console.log

const MyPlugin = new Logging({
    log: (level, data, msg) => logger[level](data, msg), // example: bunyan
    body: {
        enabled: true,
        maxBytes: 10000
    }
});

Construct a new client including the logging plugin

const client = new Client(BROKER_URL, {
    plugins: [
        ...,
        MyPlugin
    ],
});

Options

All options are optional, and by default every message is logged at info with all details, as in earlier versions.

| Option | Default | Description | | --- | --- | --- | | log | logger[level](struct, msg) | The logging function, (level, struct, msg) | | logger | the client's logger | Logger used when log is not given | | body | { enabled: false, maxBytes: 1000 } | Log the message content, if it is at most maxBytes | | level | 'info' | Level messages are logged at: one level, or { publish, consume } | | include | everything | Leave parts out of the logged struct, see below | | filter | none | Called with each message; return false to skip logging it |

Every message logged carries the connection (protocol, addresses and broker product), the options it was published or consumed with, the delivery fields (consumed messages) and the message properties. Logging is billed by volume in many setups, so each can be left out with include:

new Logging({
    log,
    level: { publish: 'info', consume: 'debug' },
    include: {
        connection: false, // protocol, addresses and broker product of the connection
        options: false,
        fields: false,
        properties: ['correlationId', 'replyTo'] // or false, or true (default) for all of them
    },
    // for example, leave the replies of RPC calls out: the request is logged and
    // its correlation id is enough to follow it
    filter: ({ queue, routingKey }) => !String(queue || routingKey).startsWith('amq.gen-')
});

filter only decides whether to log. If it throws, the message is logged anyway, with a warning. Individual calls can also be left out with the silent option of hato.

Running Tests

Make sure you have a message broker running. The tests expect RabbitMQ.

$ docker run -it --name rabbitmq -p 5672:5672 rabbitmq:3.6-alpine

Then run

$ make test
$ make lint

License

MIT