PHP AMQP bindings

Object-oriented PHP bindings for the AMQP C library (https://github.com/alanxz/rabbitmq-c)

Requirements:

• PHP >= 5.6 (PHP 7 included) with either ZTS or non-ZTS version.
• RabbitMQ C library, commonly known as librabbitmq (since php-amqp>=1.9.4 librabbitmq >= 0.7.1, see release notes).
• to run tests RabbitMQ server >= 3.4.0 required.

Installation

Linux

Some systems has php-amqp extension in their repo or available via external repositories, so it is MAY be the preferable way to install.

RPM packages are available in Fedora and EPEL (for RHEL and CentOS) official repositories, see php-pecl-amqp

Fresh php-pecl-amqp and librabbitmq RPMs available via remi repo.

If you want to stay on the bleeding edge and have the latest version, install php-amqp extension from PECL or compile from sources (follow PHP official docs instruction).

Windows

• Before download, check if your PHP installation is thread safe or non-thread safe by entering php -i|findstr "Thread" in your terminal
• Download thread safe or non-thread safe version of the extension for your PHP version from https://pecl.php.net/package/amqp. Look for the "DLL" link next to each release in the list of available releases
• After download, copy the rabbitmq.4.dll and rabbitmq.4.pdb files to the PHP root folder and copy php_amqp.dll and php_amqp.pdb files to PHP\ext folder
• Add extension=amqp to the php.ini file
• Check if the module is properly installed with php -m

Documentation

View RabbitMQ official tutorials and php-amqp specific examples.

There are also available stub files with accurate PHPDoc which may be also used in your IDE for code completion, navigation and documentation in-place.

Finally, check out the tests to see typical usage and edge cases.

Notes

• Max channels per connection means how many concurrent channels per connection may be opened at the same time (this limit may be increased later to max AMQP protocol number - 65532 without any problem).

• Nested header arrays may contain only string values.

• You can't share none of AMQP API objects (none of AMQPConnection, AMQPChannel, AMQPQueue, AMQPExchange) between threads. You have to use separate connection and so on per thread.

Related libraries

• enqueue/amqp-ext is a amqp interop compatible wrapper.

Persistent connection

Limitations:

• there may be only one persistent connection per unique credentials (login+password+host+port+vhost). If there will be an attempt to create another persistent connection with the same credentials, an exception will be thrown.
• channels on persistent connections are not persistent: they are destroyed between requests.
• heartbeats are limited to blocking calls only, so if there are no any operations on a connection or no active consumer set, connection may be closed by the broker as dead.

Developers note: alternatively for built-in persistent connection support raphf pecl extension may be used.

How to report a problem

1. First, search through the closed issues and stackoverflow.com.
2. Submit an issue with short and definitive title that describe your problem
3. Provide platform info, PHP interpreter version, SAPI mode (cli, fpm, cgi, etc) extension is used in, php-amqp extension version, librabbitmq version, make tools version.
4. Description should provide information on how to reproduce a problem (gist is the most preferable way to include large sources) in a definitive way. Use Vagrant to replicate unusual environments.
5. If stack trace is generated, include it in full via gist or the important part (if you definitely know what you are doing) directly in the description.

Things to check before reporting a problem

Some of them, the list is not complete.

1. You are running on correct machine in correct environment and your platform meets your application requirement.
2. librabbimq is installed and discoverable in your environment so php-amqp extension can load it.
3. php-amqp extension present in system (find amqp.so or amqp.dll if you are on windows), it is loaded (php --ri amqp produced some info), and there are no underlying abstraction that MAY emulate php-amqp work.
4. You hav correct RabbitMQ credentials.
5. You are using the latest php-amqp, librabbitmq, RabbitMQ and sometimes PHP version itself. Sometimes your problem is already solved.
6. Other extensions disabled (especially useful when PHP interpreter crashes and you get stack trace and segmentation fault).

Development

There is a Vagrant environment with pre-installed software and libraries necessary to build, test and run the php-amqp extension.

To start it, just type vagrant up and then vagrant ssh in php-amqp directory.

Services available out of the box are:

• Apache2 - on 192.168.33.10:8080
• nginx - on 192.168.33.10:80
• RabbitMQ on 192.168.33.10:15672 with guest access (login: guest, password: guest)

Additional tools are pre-installed to make development process as simple as possible:

valgrind

Valgrind is ready to help find memory-related problems if you export TEST_PHP_ARGS=-m before running tests.

phpbrew

phpbrew waits to help you to test extension on various PHP versions. phpbrew install 5.6 +debug+default+fpm is a nice start. To switch to some version just use phpbrew switch <version>.

To start php-fpm just run phpbrew fpm start (don't forget to run sudo service stop php5-fpm befor).

This development environment out of the box ready for php-fpm and cli extension usage, if need to test it when php used as apache module, refer to Apache2 support on phpbrew wiki. Keep in mind that +apxs2 conficts with +fpm and it is a bit tricky to specify which libphp .so will be loaded.

tshark

tshark - Dump and analyze network traffic

... TShark is able to detect, read and write the same capture files that are supported by Wireshark.

To use it you probably have to set network privileges for dumpcap first(see Platform-Specific information about capture privileges Wireshark docs page and running wireshark “Lua: Error during loading” SO question):

sudo setcap 'CAP_NET_RAW+eip CAP_NET_ADMIN+eip' /usr/bin/dumpcap

To start capturing, run tshark -i lo to see output in terminal or tshark -i lo -w capture.log to save capture and analyze it later (even with AMQP protocol Wireshark plugin). You may filter AMQP packages using -Y amqp attribute, just give a try - tshark -i lo -Y amqp.

NOTE: -w provides raw packet data, not text. If you want text output you need to redirect stdout (e.g. using '>'), don't use the -w option for this.

Configuring a RabbitMQ server

If you need to tweek RabbitMQ server params use default config rabbitmq.config.example (raw) from official RabbitmMQ repo, so it may looks like sudo curl https://raw.githubusercontent.com/rabbitmq/rabbitmq-server/master/docs/rabbitmq.config.example /etc/rabbitmq/rabbitmq.config

To reset RabbitMQ application run in CLI (as privileged user) rabbitmqctl stop_app && rabbitmqctl reset && rabbitmqctl start_app.

Keeping track of the workers

It is a good practice to keep php processes (i.e workers/consumers) under control. Usually, system administrators write their own scripts which ask services about current status or performs some desired actions. Usually request is sent via UNIX signals.
Because amqp consume method is blocking, pcntl extension seems to be useless.

php-signal-handler extension uses signal syscall, so it will work even if blocking method was executed. Some use cases are presented on extension's github page and examples are available here.

Rolling a release

Say we want to release "1.1000.0" next. We first run php tools/make-release.php 1.1000.0. This will update the version numbers and pre-populate the changelog with the latest git commits between the previous version and now. It will prompt you to edit the changelog in between. Once the release is done it tells you what to do next. Run php tools/make-dev.php 1.1000.1 to bring master back into development mode afterwards.