Rabbit MQ setup and MariaDB MaxScale Integration

Introduction

A step by step guide helps installing a RabbitMQ server and testing it before MariaDB MaxScale integration.

New plugin filter and a message consumer application need to be compiled and linked with an external C library, RabbitMQ-c, that provides AMQP protocol integration. Custom configuration, with TCP/IP and Queue parameters, is also detailed here. The software install setup provides RPM and DEB packaging and traditional compilation steps.

Step 1 - Get the RabbitMQ binaries

On Centos 6.5 using fedora / RHEL rpm get the rpm from http://www.rabbitmq.com/

rabbitmq-server-3.3.4-1.noarch.rpm

Please note, before installing RabbitMQ, you must install Erlang.

Example:

yum install erlang Package erlang-R14B-04.3.el6.x86_64 already installed and latest version

Step 2 - Install and Start the Server

Install the packages using your distribution's package manager and start the server:

yum install rabbitmq-server-3.3.4-1.noarch.rpm systemctl start rabbitmq-server.service

To configure your RabbitMQ server, please refer to the RabbitMQ website: http://www.rabbitmq.com/.

rabbitmqctl is a command line tool for managing a RabbitMQ broker. It performs all actions by connecting to one of the broker's nodes.

rabbitmqctl list_queues
rabbitmqctl list_queues | list_exchanges| cluster_status | list_bindings | list_connections | list_consumers | status

Example output:

            [root@maxscale-02 MaxScale]# rabbitmqctl status
            Status of node 'rabbit@maxscale-02' ...
            [{pid,12251},
             {running_applications,[{rabbit,"RabbitMQ","3.3.4"},
                        {os_mon,"CPO  CXC 138 46","2.2.7"},
                        {xmerl,"XML parser","1.2.10"},
                        {mnesia,"MNESIA  CXC 138 12","4.5"},
                        {sasl,"SASL  CXC 138 11","2.1.10"},
                        {stdlib,"ERTS  CXC 138 10","1.17.5"},
                        {kernel,"ERTS  CXC 138 10","2.14.5"}]},
                         {os,{unix,linux}},
                          {erlang_version,"Erlang R14B04 (erts-5.8.5) [source] [64-bit] [smp:2:2] [rq:2] [async-threads:30] [kernel-poll:true]\n"},
                          ...
                           {listeners,[{clustering,25672,"::"},{amqp,5672,"::"}]},
                           ...
                           ...done.


                           [root@maxscale-02 MaxScale]# rabbitmqctl list_bindings
                           Listing bindings ...
                           x1    exchange    q1    queue    k1    []
                           ...done.

Interaction with the server may require stop & reset at some point:

rabbitmqctl stop_app
rabbitmqctl reset
rabbitmqctl start_app

Step 3 - Install and test the client libraries

The selected library for MariaDB MaxScale integration of RabbitMQ is: https://github.com/alanxz/rabbitmq-c

Manual software compilation

To compile the RabbitMQ-C libraries manually:

git clone  https://github.com/alanxz/rabbitmq-c.git
cd rabbitmq-c
cmake -DCMAKE_INSTALL_PREFIX=/usr .
make
make install

Please note, this will install the packages to /usr. If you do not wish to install them to this location, provide a different value for the CMAKE_INSTALL_PREFIX variable.

Setup using the EPEL repository

Check how to configure your distribution for the EPEL repository: https://fedoraproject.org/wiki/EPEL

Configure your repositories and install the software:

yum install librabbitmq.x86_64

you might also like to install:

librabbitmq-tools.x86_64, librabbitmq-devel.x86_64

Please note you may also install the rabbitmq server from the EPEL repository:

yum install rabbitmq-server

Basic tests with library

The required library librabbitmq-c is now installed and we continue with basic operations with amqp_* tools, located in the examples/ folder of the build directory, testing client server interaction.

Please note, those example applications may not be included in the RPM library packages.

Test 1 - create the exchange

[root@maxscale-02 examples]# ./amqp_exchange_declare
Usage: amqp_exchange_declare host port exchange exchangetype

Declare the exchange:

[root@maxscale-02 examples]# ./amqp_exchange_declare 127.0.0.1 5672 foo direct

Test 2 - Listen to exchange with selected binding key

[root@maxscale-02 examples]# ./amqp_listen
Usage: amqp_listen host port exchange bindingkey

Start the listener:

[root@maxscale-02 examples]# ./amqp_listen 127.0.0.1 5672 foo k1 &

Test 3 - Send a message …

[root@maxscale-02 examples]# ./amqp_sendstring
Usage: amqp_sendstring host port exchange routingkey messagebody

[root@maxscale-02 examples]# ./amqp_sendstring 127.0.0.1 5672 foo k1 “This is a new message”

... and watch the listener output

Delivery 1, exchange foo routingkey k1
Content-type: text/plain

Step 4 - Configure new applications

The new filter needs to be configured in maxscale.cnf.

[Test Service]
type=service
router=readconnroute
router_options=slave
servers=server1,server2,server3,server5,server4
user=massi
passwd=massi
filters=MQ

[MQ]
type=filter
module=mqfilter
exchange=x1
key=k1
queue=q1
hostname=127.0.0.1
port=5672
logging_trigger=all

Logging triggers define whether to log all or a subset of the incoming queries using these options:

# log only some elements or all
logging_trigger=[all,source,schema,object]

# Whether to log only SELECT, UPDATE, INSERT and DELETE queries or all possible queries
logging_log_all=true|false

# Log only when any of the trigger parameters match or only if all parameters match
logging_strict=true|false

# specify objects
logging_object=mytable,another_table

# specify logged users
logging_source_user=testuser,testuser

# specify source addresses
logging_source_host=127.0.0.1,192.168.10.14

# specify schemas
logging_schema=employees,orders,catalog

Example:

logging_trigger=object,schema,source
logging_strict=false
logging_log_all=false
logging_object=my1
logging_schema=test
logging_source_user=maxtest

The logging result of the example is:

if user maxtest does something, it's logged
and all queries in test schema are logged
anything targeting my1 table is logged
SELECT NOW(), SELECT MD5(“xyz)” are not logged

Please note that if we want to log only the user ‘maxtest’ accessing the schema ‘test’ with target ‘my1’ the option logging_strict must be set to TRUE and if we want to include those selects without schema name the option logging_log_all must be set to TRUE.

The mqfilter logs into the MariaDB MaxScale TRACE log information about the matched logging triggers and the message delivering:

2014 09/03 06:22:04   Trigger is TRG_SOURCE: user: testuser = testuser
2014 09/03 06:22:04   Trigger is TRG_SCHEMA: test = test
2014 09/03 06:22:04   Trigger is TRG_OBJECT: test.t1 = t1
2014 09/03 06:22:04   Routing message to: 127.0.0.1:5672 / as guest/guest, exchange: x1<direct> key:k1 queue:q1

The consumer application needs to be configured as well:


#The options for the consumer are:
#hostname    RabbitMQ hostname
#port        RabbitMQ port
#vhost        RabbitMQ virtual host
#user        RabbitMQ username
#passwd    RabbitMQ password


#queue        Name of the queue to use
#dbserver    SQL server name
#dbport    SQL server port
#dbname    Name of the database to use
#dbuser    SQL server username
#dbpasswd    SQL server password
#logfile    Message log filename

[consumer]
hostname=127.0.0.1
port=5672
vhost=/
user=guest
passwd=guest
queue=q1
dbserver=127.0.0.1
dbport=3308
dbname=mqpairs
dbuser=xxx
dbpasswd=yyy

We may probably need to modify LD_LIBRARY_PATH before launching ‘consumer’:

# export LD_LIBRARY_PATH=/packages/rabbitmq-c/rabbitmq-c/librabbitmq:/packages/mariadb_client-2.0.0-Linux/lib/mariadb:/usr/lib64

and finally we can launch it:

# ./consumer

If the consumer.cnf file is not in the same directory as the binary file is, you can provide the location of the folder that it is in by passing it the -c flag followed by the path:

# ./consumer -c path/to/file

and start MariaDB MaxScale as well

Step 5 - Test the filter and check collected data

Assuming that MariaDB MaxScale and the message consumer are successfully running let’s connect to the service with an active mqfilter:

[root@maxscale-02 MaxScale]#  mysql -h 127.0.0.1 -P 4506 -uxxx -pyyy
...
MariaDB [(none)]> select RAND(3), RAND(5);
+--------------------+---------------------+
| RAND(3)            | RAND(5)             |
+--------------------+---------------------+
| 0.9057697559760601 | 0.40613597483014313 |
+--------------------+---------------------+
1 row in set (0.01 sec)
…
MariaDB [(none)]> select RAND(3544), RAND(11);

we can check the consumer output in the terminal where it was started:

--------------------------------------------------------------
Received: 1409671452|select @@version_comment limit ?
Received: 1409671452|Columns: 1
...
Received: 1409671477|select RAND(?), RAND(?)
Received: 1409671477|Columns: 2

We query now the database for the content collected so far:

MariaDB [(none)]> use mqpairs;
Database changed



MariaDB [mqpairs]> select * from pairs;

+-------------------------------------+----------------------------------+------------+---------------------+---------------------+---------+
| tag                                 | query                            | reply      | date_in             | date_out            | counter |
+-------------------------------------+----------------------------------+------------+---------------------+---------------------+---------+
| 006c006d006e006f007000710072007374  | select @@version_comment limit ? | Columns: 1 | 2014-09-02 11:14:51 | 2014-09-02 11:26:38 |       3 |
| 00750076007700780079007a007b007c7d  | SELECT DATABASE()                | Columns: 1 | 2014-09-02 11:14:56 | 2014-09-02 11:27:06 |       3 |
| 007e007f00800081008200830084008586  | show databases                   | Columns: 1 | 2014-09-02 11:14:56 | 2014-09-02 11:27:06 |       3 |
| 008700880089008a008b008c008d008e8f  | show tables                      | Columns: 1 | 2014-09-02 11:14:56 | 2014-09-02 11:27:06 |       3 |
| 0090009100920093009400950096009798  | select * from mqpairs.pairs      | Columns: 6 | 2014-09-02 11:15:00 | 2014-09-02 11:27:00 |      12 |
| 00fc00fd00fe00ff0100010101020103104 | select NOW()                     | Columns: 1 | 2014-09-02 11:24:23 | 2014-09-02 11:24:23 |       1 |
| 01050106010701080109010a010b010c10d | select RAND(?), RAND(?)          | Columns: 2 | 2014-09-02 11:24:37 | 2014-09-02 11:24:37 |       1 |
+-------------------------------------+----------------------------------+------------+---------------------+---------------------+---------+
7 rows in set (0.01 sec)

The filter send queries to the RabbitMQ server in the canonical format, i.e select RAND(?), RAND(?). The queries Message Queue Consumer application gets from the server are stored with a counter that quickly shows how many times that normalized query was received:

| 01050106010701080109010a010b010c10d | select RAND(?), RAND(?)           | Columns: 2 | 2014-09-02 11:24:37 | 2014-09-02 11:29:15 |       3 |