amqptap

Sometimes it is difficult to know what goes on in your RabbitMQ exchanges. amqptap is a CLI tool written in node.js that helps you get a better look at the messages that get passed around!

Installation

Install amqptap with npm install -g and you should have the amqptap executable accessible in your PATH.

Usage

For a list of all options run amqptap --help.

amqptap creates an exclusive queue that is bound to the specified exchange, and will receive all messages on that exchange without interfering with other bound queues.

The server URL is specified using the -s or --server flag set to a value that corresponds to the RabbitMQ URI specification.

Almost feature-complete URL for connecting to foo.bar using port 1234, vhost baz, username tester and password password: amqp://tester:[email protected]:1234/baz

Without a specific server set, amqptap attempts to connect to a RabbitMQ server running on localhost using the guest account.

Picking fields from the result

Given a raw message output (see "Automatic deserialization") from amqplib coming on amq.topic with routing key foo.bar that looks like this.

{
  "fields": {
    "consumerTag": "amq.ctag-NFOFYLaMHMzMXD4PwHuLog",
    "deliveryTag": 1,
    "redelivered": false,
    "exchange": "amq.topic",
    "routingKey": "foo.bar"
  },
  "properties": {
    "contentType": "application/json",
    "headers": {
      "test": 2
    },
    "deliveryMode": 1
  },
  "content": {
    "hello": "world!"
  }
}

Picking a single field

Fields are picked using the flag -f or --fields with the notation of the lodash get function.

$ amqptap -f properties.deliveryMode
1

Picking multiple fields using comma as a separator

$ amqptap -f properties.contentType,fields.routingKey
{"properties.contentType": "application/json", "fields.routingKey": "foo.bar"}

Setting the routing key

The routing key can be set with the -r or --route flag.

$ amqptap -r "bar#"

Changing the exchange

The default exchange bound to is always amq.topic. This can be changed with the -e or --exchange flag.

$ amqptap -e "amq.fanout"

Inspector types

amqptap supports some inspectors with the -i or --inspector option that mutates the value before sending it to stdout.

$ amqptap -i eyes
"pretty colored output using npm package eyes"

$ amqptap -i json
"plain JSON output without indentation"

$ amqptap -i string
"output is passed through String()"

Automatic deserialization

By default, raw buffers are returned for the content field.

Messages with a contentType header equal to application/json or text/json will have the content field automatically parsed with JSON.parse.

Messages with a contentType header equal to text/plain will be parsed with Buffer.prototype.toString.

Tests

Running tests require guest access to a RabbitMQ server. The test runner is by default set to attempt a connection to amqp://localhost but this value can be overriden by setting the environment variable AMQP_URL according to the RabbitMQ URI specification.

To run the tests, execute npm test.

Contributions

Most welcome by submitting pull requests to the repository.