rabtap - RabbitMQ wire tap

Swiss army knife for RabbitMQ. Tap/Pub/Sub messages, create/delete/bind queues and exchanges, inspect broker.

Contents

• Features
• Screenshots
• Installation
• Usage
  • Basic commands
  • Broker URI specification
  • Environment variables
    • Default RabbitMQ broker
    • Default RabbitMQ management API endpoint
    • Disable color output
  • Examples
    • Broker info
    • Wire-tapping messages
      • Connect to multiple brokers
      • Message recorder
    • Publish messages
    • Messages consumer (subscribe)
    • Poor mans shovel
    • Close connection
    • Queue commands
• JSON message format
• Filtering output of info command
  • Filtering expressions
    • Evaluation context
    • Examples
  • Type reference
    • Exchange type
    • Queue type
    • Binding type
• Build from source
  • Download and build using go get
  • Build using Makefile
• Test data generator
• Contributing
• Author
• Copyright and license

Features

• tap to messages being sent to exchanges using RabbitMQ exchange-to-exchange bindings without affecting actual message delivery (aka tapping)
• display broker related information using the RabbitMQ REST management API
• save messages and meta data for later analysis and replay
• publish messages to exchanges
• consume messages from a queue (subscribe)
• supports TLS
• no runtime dependencies (statically linked golang single file binary)
• simple to use command line tool
• runs on Linux, Windows, Mac and wherever you can compile go

Screenshots

Output of rabtap info command:

Output of rabtap info --stats command, showing additional statistics:

Output of rabtap running in tap mode, showing message meta data with unset attributes filtered out and the message body:

Installation

Pre-compiled binaries can be downloaded for multiple platforms from the releases page.

See below if you prefer to compile from source.

Usage

rabtap - RabbitMQ wire tap.                    github.com/jandelgado/rabtap

Usage:
  rabtap -h|--help
  rabtap tap EXCHANGES [--uri URI] [--saveto=DIR] [-jknv]
  rabtap (tap --uri URI EXCHANGES)... [--saveto=DIR] [-jknv]
  rabtap info [--api APIURI] [--consumers] [--stats] 
              [--filter EXPR] 
              [--omit-empty] [--show-default] [--by-connection] [-knv]
  rabtap pub [--uri URI] EXCHANGE [FILE] [--routingkey=KEY] [-jkv]
  rabtap sub QUEUE [--uri URI] [--saveto=DIR] [--no-auto-ack] [-jkvn]
  rabtap exchange create EXCHANGE [--uri URI] [--type TYPE] [-adkv]
  rabtap exchange rm EXCHANGE [--uri URI] [-kv]
  rabtap queue create QUEUE [--uri URI] [-adkv]
  rabtap queue bind QUEUE to EXCHANGE --bindingkey=KEY [--uri URI] [-kv]
  rabtap queue unbind QUEUE from EXCHANGE --bindingkey=KEY [--uri URI] [-kv]
  rabtap queue rm QUEUE [--uri URI] [-kv]
  rabtap queue purge QUEUE [--uri URI] [-kv]
  rabtap conn close CONNECTION [--reason=REASON] [--api APIURI] [-kv]
  rabtap --version

Options:
 EXCHANGES            comma-separated list of exchanges and binding keys,
                      e.g. amq.topic:# or exchange1:key1,exchange2:key2.
 EXCHANGE             name of an exchange, e.g. amq.direct.
 FILE                 file to publish in pub mode. If omitted, stdin will
                      be read.
 QUEUE                name of a queue.
 CONNECTION           name of a connection.
 -a, --autodelete     create auto delete exchange/queue.
 --api APIURI         connect to given API server. If APIURI is omitted,
                      the environment variable RABTAP_APIURI will be used.
 -b, --bindingkey KEY binding key to use in bind queue command.
 --by-connection      output of info command starts with connections.
 --consumers          include consumers and connections in output of info command.
 -d, --durable        create durable exchange/queue.
 --filter EXPR        Predicate for info command to filter queues [default: true]
                      (see README.md for details)
 -h, --help           print this help.
 -j, --json           print/save/publish message metadata and body to a
                      single JSON file. JSON body is base64 encoded. Otherwise
                      metadata and body (as-is) are saved separately.
 -k, --insecure       allow insecure TLS connections (no certificate check).
 -n, --no-color       don't colorize output (also environment variable NO_COLOR)
 --no-auto-ack        disable auto-ack in subscribe mode. This will lead to 
                      unacked messages on the broker which will be requeued 
                      when the channel is closed.
 -o, --omit-empty     don't show echanges without bindings in info command.
 --reason=REASON      reason why the connection was closed 
                      [default: closed by rabtap].
 -r, --routingkey KEY routing key to use in publish mode.
 --saveto DIR         also save messages and metadata to DIR.
 --show-default       include default exchange in output info command.
 --stats              include statistics in output of info command.
 -t, --type TYPE      exchange type [default: fanout].
 --uri URI            connect to given AQMP broker. If omitted, the
                      environment variable RABTAP_AMQPURI will be used.
 -v, --verbose        enable verbose mode.
 --version            show version information and exit.

Examples:
  rabtap tap --uri amqp://guest:guest@localhost/ amq.fanout:
  rabtap tap --uri amqp://guest:guest@localhost/ amq.topic:#,amq.fanout:
  rabtap pub --uri amqp://guest:guest@localhost/ amq.topic message.json -j
  rabtap info --api http://guest:guest@localhost:15672/api

  # use RABTAP_AMQPURI environment variable to specify broker instead of --uri
  export RABTAP_AMQPURI=amqp://guest:guest@localhost:5672/
  echo "Hello" | rabtap pub amq.topic -r "some.key"
  rabtap sub JDQ
  rabtap queue create JDQ
  rabtap queue bind JDQ to amq.direct --bindingkey=key
  rabtap queue rm JDQ

  # use RABTAP_APIURI environment variable to specify mgmt api uri instead of --api
  export RABTAP_APIURI=http://guest:guest@localhost:15672/api
  rabtap info
  rabtap info --filter "binding.Source == 'amq.topic'" -o
  rabtap conn close "172.17.0.1:40874 -> 172.17.0.2:5672" 

Basic commands

Rabtap understands the following commands:

• tap - taps to an exchange and transparently receives messages sent to the exchange, without affecting actual message delivery (using exchange-to-exchange binding). Simulatanous
• sub - subscribes to a queue and consumes messages sent to the queue (acts like a RabbitMQ consumer)
• pub - send messages to an exchange.
• info - show broker related info (exchanges, queues, bindings, stats). The features of an exchange are displayed in square brackets with D (durable), AD (auto delete) and I (internal). The features of a queue are displayed in square brackets with D (durable), AD (auto delete) and EX (exclusive). If --statistics option is enabled, basic statistics are included in the output. The --filter option allows to filter output. See filtering section for details. Use the --by-connection to sort output by connection (implies --consumers)
• queue - create/bind/unbind/remove/purge queue
• exchange - create/remove exchange
• connection - close connections

See the examples section for further information.

Broker URI specification

The specification of the RabbitMQ broker URI follows the AMQP URI specification as implemented by the go RabbitMQ client library.

Examples:

• amqp://guest:guest@localhost:5672/
• amqps://guest:guest@my-broker.dev:5671/
• amqps://guest:guest@my-broker.dev:5671/vhost

Environment variables

Use environment variables to specify standard values for broker and api endpoint.

Default RabbitMQ broker

In cases where the URI argument is optional, e.g. rabtap tap [-uri URI] exchange ..., the URI of the RabbitMQ broker can be set with the environment variable RABTAP_AMQPURI. Example:

$ export RABTAP_AMQPURI=amqp://guest:guest@localhost:5672/
$ rabtap tap amq.fanout:
...

Default RabbitMQ management API endpoint

The default RabbitMQ management API URI can be set using the RABTAP_APIURI environment variable. Example:

$ export RABTAP_APIURI=http://guest:guest@localhost:15672/api
$ rabtap info
...

Disable color output

Set environment variable NO_COLOR to disable color output.

Examples

The following examples assume a RabbitMQ broker running on localhost:5672 and the management API available on port 15672. Easiest way to start such an instance is by running docker run -ti --rm -p 5672:5672 -p 15672:15672 rabbitmq:3-management or similar command to start a RabbitMQ container.

Broker info

The info command uses the REST API of RabbitMQ to gather and display topolgy related information from the broker. Example:

• $ rabtap info --api http://guest:guest@localhost:15672/api --consumers - shows virtual hosts exchanges, queues and consumers of given broker in an tree view (see screenshot). Note that if RABTAP_APIURI environment variable is set, the command reduces to $ rabtap info --consumers
• $ rabtap info --by-connection - shows virtual hosts, connections, consumers and queues of given broker in an tree view.

Wire-tapping messages

The tap command allows to tap exchanges and transparently receives messages sent to the exchanges. Rabtap automatically reconnects on connections failures. The syntax of the tap command is rabtap tap [--uri URI] EXCHANGES where the EXCHANGES argument specifies the exchanges and binding keys to use. The EXCHANGES argument is of the form EXCHANGE:[KEY][,EXCHANGE:[KEY]]*. If the exchange name contains a colon, use \\: to escape it, e.g. myexchange\\:with\\:colons:KEY.

The acutal format of the binding key depends on the exchange type (e.g. direct, topic, headers) and is described in the RabbitMQ documentation.

Examples for binding keys used in tap command:

• # on an exchange of type topic will make the tap receive all messages on the exchange.
• a valid queue name for an exchange of type direct binds exactly to messages destined for this queue
• an empty binding key for exchanges of type fanout or type headers will receive all messages published to these exchanges

Note: on exchanges of type headers the binding key is currently ignored and all messages are received by the tap.

The following examples assume that the RABTAP_AMQPURI environment variable is set, otherwise you have to pass the additional --uri URI parameter to the commands below.

• $ rabtap tap my-topic-exchange:#
• $ rabtap tap my-fanout-exchange:
• $ rabtap tap my-headers-exchange:
• $ rabtap tap my-direct-exchange:binding-key

The following example connects to multiple exchanges:

• $ rabtap tap my-fanout-exchange:,my-topic-exchange:#,my-other-exchange:binding-key

Connect to multiple brokers

Rabtap allows you also to connect simultaneously to multiple brokers and exchanges:

• $ rabtap tap --uri amqp://broker1 amq.topic:# tap --uri amqp://broker2 amq.fanout:

The example connects to broker1 and taps to the amq.topic exchange and to the amq.fanout exchange on broker2.

Message recorder

All tapped messages can be also be saved for later analysis or replay. Rabtap supports saving of messages in two formats: raw body and metadata in separate files or JSON message format with embedded metadata and message the body base64 encoded (--json option). Examples:

• $ rabtap tap amq.topic:# --saveto /tmp - saves messages as pair of files consisting of raw message body and JSON meta data file to /tmp directory.
• $ rabtap tap amq.topic:# --saveto /tmp --json - saves messages as JSON files to /tmp directory.

Files are created with file name rabtap-+<Unix-Nano-Timestamp>+ . + <extension>.

Publish messages

The pub command allows to send messages to an exchange, specifying a routing key.

• $ rabtap pub amq.direct -r routingKey message.json --json - publish message(s) in JSON format to exchange amq.direct with routing key routingKey.
• $ rabtap pub amqp.direct -r routingKey --json < message.json - same as above, but read message(s) from stdin.

Messages consumer (subscribe)

The sub command reads messages from a queue. Note that unlike tap, sub will consume messages that are in effect removed from the specified queue. Example:

• $ rabtap sub somequeue -j

Will consume messages from queue somequeue and print out messages in JSON format (-j). Example assumes that RABTAP_AMQPURI environment variable is set.

Poor mans shovel

Rabtap instances can be connected through a pipe and messages will be read on one side and published to the other. Note that for publish to work in streaming mode, the JSON mode (--json) must be used on both sides, so that messages are encapsulated in JSON messages.

The example taps messages on broker1 and publishes the messages to the amq.direct exchange on broker2

$ rabtap tap --uri amqp://broker1 my-topic-exchange:# --json | \
  rabtap pub --uri amqp://broker2 amq.direct -r routingKey --json

Close connection

The conn command allows to close a connection. The name of the connection to be closed is expected as parameter. Use the info command with the --consumers option to find the connection associated with a queue. Example:

$ rabtap info --consumers
http://localhost:15672/api (broker ver='3.6.9', mgmt ver='3.6.9', cluster='rabbit@ae1ad1477419')
└── Vhost /
    ├── amq.direct (exchange, type 'direct', [D])
    :
    └── test-topic (exchange, type 'topic', [AD])
        ├── test-q-test-topic-0 (queue, key='test-q-test-topic-0', running, [])
        │   └── __rabtap-consumer-4823a3c0 (consumer user='guest', chan='172.17.0.1:59228 -> 172.17.0.2:5672 (1)')
        │       └── '172.17.0.1:59228 -> 172.17.0.2:5672' (connection client='https://github.com/streadway/amqp', host='172.17.0.2:5672', peer='172.17.0.1:59228')
        ├── test-q-test-topic-1 (queue, key='test-q-test-topic-1', running, [])
        :
$ rabtap conn close '172.17.0.1:59228 -> 172.17.0.2:5672' 

Queue commands

The queue command can be used to easily create, remove, bind or unbind queues:

$ rabtap queue create myqueue 
$ rabtap info --show-default
http://localhost:15672/api (broker ver='3.7.8', mgmt ver='3.7.8', cluster='rabbit@b2fe3b3b6826')
└── Vhost /
    ├── (default) (exchange, type 'direct', [D])
    │   └── myqueue (queue, key='myqueue', idle since 2018-12-07 20:46:15, [])
    :
    └── amq.topic (exchange, type 'topic', [D])
$ rabtap queue bind myqueue to amq.topic --bindingkey hello
$ rabtap info --show-default
http://localhost:15672/api (broker ver='3.7.8', mgmt ver='3.7.8', cluster='rabbit@b2fe3b3b6826')
└── Vhost /
    ├── (default) (exchange, type 'direct', [D])
    │   └── myqueue (queue, key='myqueue', idle since 2018-12-07 20:46:15, [])
    :
    └── amq.topic (exchange, type 'topic', [D])
        └── myqueue (queue, key='hello', idle since 2018-12-07 20:46:15, [])
$ rabtap queue unbind myqueue from amq.topic --bindingkey hello
$ rabtap info --show-default
http://localhost:15672/api (broker ver='3.7.8', mgmt ver='3.7.8', cluster='rabbit@b2fe3b3b6826')
└── Vhost /
    ├── (default) (exchange, type 'direct', [D])
    │   └── myqueue (queue, key='myqueue', idle since 2018-12-07 20:46:15, [])
    :
    └── amq.topic (exchange, type 'topic', [D])
$ rabtap queue rm myqueue
$ raptap info
http://localhost:15672/api (broker ver='3.7.8', mgmt ver='3.7.8', cluster='rabbit@b2fe3b3b6826')
└── Vhost /
    :
    └── amq.topic (exchange, type 'topic', [D])

Additionally use the purge command to remove all elements from a queue, e.g.

$ rabtap queue purge myqueue

JSON message format

When using the --json option, messages are print/read as a stream of JSON messages in the following format:

...
{
  "ContentType": "text/plain",
  "ContentEncoding": "",
  "DeliveryMode": 0,
  "Priority": 0,
  "CorrelationID": "",
  "ReplyTo": "",
  "Expiration": "",
  "MessageID": "",
  "Timestamp": "2017-11-10T00:13:38+01:00",
  "Type": "",
  "UserID": "",
  "AppID": "rabtap.testgen",
  "DeliveryTag": 27,
  "Redelivered": false,
  "Exchange": "amq.topic",
  "RoutingKey": "test-q-amq.topic-0",
  "XRabtapReceivedTimestamp": "2019-06-13T19:33:51.920711583+02:00",
  "Body": "dGhpcyB0ZXN0IG1lc3NhZ2U .... IGFuZCBoZWFkZXJzIGFtcXAuVGFibGV7fQ=="
}
...

Note that in JSON mode, the Body is base64 encoded.

Filtering output of info command

When your brokers topology is complex, the output of the info command can become very bloated. The --filter helps you to narrow output to the desired information.

Filtering expressions

A filtering expression is a function that evaluates to true or false (i.e. a predicate). Rabtap allows the specification of predicates to be applied when printing queues using the info command. The output will only proceed if the predicate evaluates to true.

Rabtap uses the govalute to evaluate the predicate. This allows or complex expressions.

See official govaluate documentation for further information.

Note: currently the filter is ignored when used in conjunction with --by-connection.

Evaluation context

During evaluation the context (i.e. the current exchange, queue and binding) is available in the expression as variables:

• the current exchange is bound to the variable exchange
• the current queue is bound to the variable queue
• the curren binding is bound to the variable binding

Examples

The examples assume that RABTAP_APIURI environment variable points to the broker to be used, e.g. http://guest:guest@localhost:15672/api).

• rabtap info --filter "exchange.Name == 'amq.direct'" --omit-empty: print only queues bound to exchange amq.direct and skip all empty exchanges.
• rabtap info --filter "queue.Name =~ '.*test.*'" --omit-empty: print all queues with test in their name.
• rabtap info --filter "queue.Name =~ '.*test.*' && exchange.Type == 'topic'" --omit-empty: like before, but consider only exchanges of type topic.
• rabtap info --filter "queue.Consumers > 0" --omit --stats --consumers: print all queues with at one consumer

Type reference

The types reflect more or less the JSON API objects of the REST API of RabbitMQ transformed to golang types.

Exchange type

type Exchange struct {
	Name       string
	Vhost      string
	Type       string
	Durable    bool
	AutoDelete bool
	Internal   bool
	MessageStats struct {
		PublishOut
		PublishOutDetails struct {
			Rate float64
		}
		PublishIn        int
		PublishInDetails struct {
			Rate float64
		}
	}
}

Queue type

type Queue struct {
	MessagesDetails struct {
		Rate float64 
	} 
	Messages 
	MessagesUnacknowledgedDetails struct {
		Rate float64 
	} 
	MessagesUnacknowledged int 
	MessagesReadyDetails   struct {
		Rate float64 
	} 
	MessagesReady     int 
	ReductionsDetails struct {
		Rate float64 
	} 
	Reductions int    
	Node       string 
	Exclusive            bool   
	AutoDelete           bool   
	Durable              bool   
	Vhost                string 
	Name                 string 
	MessageBytesPagedOut int    
	MessagesPagedOut     int    
	BackingQueueStatus   struct {
		Mode string 
		Q1   int    
		Q2   int    
		Q3  int 
		Q4  int 
		Len int 
		NextSeqID         int     
		AvgIngressRate    float64 
		AvgEgressRate     float64 
		AvgAckIngressRate float64 
		AvgAckEgressRate  float64 
	} 
	MessageBytesPersistent     int 
	MessageBytesRAM            int 
	MessageBytesUnacknowledged int 
	MessageBytesReady          int 
	MessageBytes               int 
	MessagesPersistent         int 
	MessagesUnacknowledgedRAM  int 
	MessagesReadyRAM           int 
	MessagesRAM                int 
	GarbageCollection          struct {
		MinorGcs        int 
		FullsweepAfter  int 
		MinHeapSize     int 
		MinBinVheapSize int 
		MaxHeapSize     int 
	} 
	State string 
	Consumers int 
	IdleSince string 
	Memory    int    
}

Binding type

type Binding struct {
	Source          string
	Vhost           string
	Destination     string
	DestinationType string
	RoutingKey      string
	PropertiesKey string
}

Build from source

Download and build using go get

$ GO111MODULE=on go get github.com/jandelgado/rabtap/cmd/rabtap

Build using Makefile

To build rabtap from source, you need go (version >= 12) and the following tools installed:

• ineffassign
• misspell
• golint
• gocyclo

$ export GO111MODULE=on
$ git clone https://github.com/jandelgado/rabtap && cd rabtap
$ make test
$ make

Test data generator

A simple test data generator tool for manual tests is included in the cmd/testgen directory.

Contributing

• fork this repository
• create your feature branch
• add code
• add tests and make sure test coverage does not fall
• make sure pre-commit hook does not fail
• add documentation
• commit changes
• submit a PR

Author

Jan Delgado (jdelgado at gmx dot net)

Copyright and license

Copyright (c) 2017-2019 Jan Delgado. rabtap is licensed under the GPLv3 license.