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1 Introduction to RabbitMQ
RabbitMQ is an open source implementation of AMQP (Advanced Message Queue) developed by erlang, the official website address: http://www.rabbitmq.com . As a message broker, RabbitMQ is mainly responsible for receiving, storing and forwarding messages. It provides reliable message mechanisms and flexible message routing, and supports message clustering and distributed deployment. It is often used for application decoupling, time-consuming task queues, and traffic reduction. Feng waiting for the scene. This series of articles will systematically introduce RabbitMQ's working mechanism, code driver and cluster configuration. This article mainly introduces some basic concepts in RabbitMQ, commonly used RabbitMQ Control commands, and finally writes a simple chestnut driven by C#. First look at the basic structure of RabbitMQ:
The above picture is a basic structure of RabbitMQ. Producer and Consumer are both clients of RabbitMQ. Producer is responsible for sending messages, and Consumer is responsible for consuming messages.
Next we combine this picture to understand some concepts of RabbitMQ:
Broker (Server) : The process of accepting client connections and realizing AMQP message queue and routing functions. We can call Broker a RabbitMQ server.
Virtual Host : A virtual concept. There can be several Exchanges and Queues in a Virtual Host, which are mainly used for permission control and isolation of applications. If application A uses VhostA and application B uses VhostB, then we only store the exchange, queue, and messages of application A in VhostA. Users of application A can only access VhostA, not the data in VhostB.
Exchange : Accept the message sent by the producer and route the message to the queue in the server according to the Binding rule. ExchangeType determines the behavior of Exchange routing messages. For example, in RabbitMQ, there are four ExchangeTypes: Direct, Fanout, Topic, and Header. Different types of Exchange routing rules are different (these will be described in detail later).
Queue : The message queue is used to store messages that have not been consumed by consumers. The queue is first in, first out. By default, messages stored first are processed first.
Message : It is a message, composed of Header and Body. Header is a collection of various attributes added by the producer, including whether the Message is persisted, which Message Queue accepts, and what is the priority. Body is the data that is actually transmitted. The content format is byte[].
Connection : Connection, for RabbitMQ, is actually a TCP connection between the client and the Broker.
Channel : Channel. After only the connection between the client and the Broker is created, the client cannot send messages. A Channel needs to be created on the basis of the Connection. The AMQP protocol stipulates that AMQP commands can only be executed through the Channel. A Connection can contain multiple Channels. Channel is needed because the establishment and release of TCP connections are very expensive.
2 RabbitMQ installation
Because RabbitMQ is developed in erlang language, we must install erlang support before installing RabbitMQ.
1 Windows platform installation
1 Install erlang
First download erlang and download the latest version directly. The current download is OTP 21.3 Windows 64-bit Binary File. After the download is complete, you can install it in the next step.
2 Install RabbitMQ
Download RabbtMQ on the Windows platform . The current download is rabbitmq-server-3.7.14.exe. After the download is complete, you can install it in the next step.
3 Install the web management plugin
Open RabbitMQ Command Prompt and execute the command rabbitmq-plugins enable rabbitmq_management to complete the installation of the web monitoring plug-in. 
After the installation is complete, open the browser and enter http://127.0.0.1:15672/ and use the default account [name:guest / password:guest] to log in. The interface is as follows. Using this UI plugin, we can easily view the exchange in RabbitMQ (exchange ), queue and other content, you can also add, modify, and delete exchange, queue, and users.
At this point, the Windows platform installation of RabbitMQ is complete. Open the service manager, RabbitMQ is already running normally, as follows:
2 Centos install RabbitMQ
1 Install RabbitMQ
The virtual machine system here is Centos7, and the installation method adopted is yum installation. For simplicity, we directly use the official erlang and RabbitMQ-server automatic installation scripts ( official installation documents ), and execute the following code line by line to install erlang. And RabbitMQ.
#Install socat yum install socat #Install erlang curl -s https://packagecloud.io/install/repositories/rabbitmq/erlang/script.rpm.sh | sudo bash yum -y install erlang #Install rabbitmq-server curl -s https ://packagecloud.io/install/repositories/rabbitmq/rabbitmq-server/script.rpm.sh | sudo bash yum -y install rabbitmq-server #Start rabbitmq service systemctl start rabbitmq-server #Add web management plug-in rabbitmq-plugins enable rabbitmq_management
Supplement: If the RabbitMQ execution command is particularly slow after the installation is complete, or an error occurs [ rabbitmq unable to perform an operation on node xxx@xxx ], the solution:
Edit hosts, execute the command vim /etc/hosts, add the local IP (or virtual machine IP)
After the command is executed, use a browser to visit http://127.0.0.1:15672/ and the web management interface will also appear. RabbitMQ installed through the installation steps above will generate Unit files, so we can use Systemd to manage RabbitMQ services. Here are a few commonly used commands:
#Start the RabbitMQ service systemctl start rabbitmq-server #Stop the RabbitMQ service systemctl stop rabbitmq-server #View the running status of RabbitMQ systemctl status rabbitmq-server #Restart the RabbitMQ service systemctl restart rabbitmq-server
2 RabbitMQ Control tool
Most of the common functions of RabbitMQ can be realized by using the Web management interface, but some functions cannot be achieved by the WebUI, such as opening/closing the RabbitMQ application and cluster management. RabbitMQ Control is a command line management tool of RabbitMQ, which can call all the built-in functions of RabbitMQ. The main command is rabbitmqctl. Below is a command to query the user list. Note that you need to switch to the sbin directory to execute:
In order to use the RabbitMQ Control tool conveniently, we'd better add an environment variable. When Windows is installed by default, add one to the PATH: C:\Program Files\RabbitMQ Server\rabbitmq_server-3.7.14\sbin, if it is not installed by default, find the corresponding Add PATH to the installation directory. According to the installation method above, Centos can directly use RabbitMQ Control tool without extra configuration. If you want to learn more about the RabbitMQ Control tool, you can refer to the official documentation of RabbitMQ Control .
Here is a summary of some of the most commonly used RabbitMQ Controll commands. Interested friends can try to run these commands. For example, use the command rabbitmqctl add_user <username> <password> in the command line tool to add a new user.
1 Basic control commands
Basic control commands are mainly used to start and stop applications, runtime, etc.
#Stop rabbitmq and runtime rabbitmqctl shutdown #Stop erlang node rabbitmqctl stop #Enable rabbitmq rabbitmqctl start_app #Stop rabbitmq rabbitmqctl stop_app #View status rabbitmqctl reset status #View environment rabbitmqctl environment #rabbitmqctl environment #rabbitmqctlrabbit and the internal exchanges are cleared .
2 Service status management
These commands are mainly used to view exchange, channel, binding, queue, consumers:
#Return to queue information list_queues [-p <vhostpath>] [<queueinfoitem> ...] #Return to exchange information list_exchanges [-p <vhostpath>] [<exchangeinfoitem> ...] #Return to binding information list_bindings [- p <vhostpath>] [<bindinginfoitem> ...] #Return link information list_connections [<connectioninfoitem> ...] #Return all current channels list_channels [<channelinfoitem> ...] #Return consumers list_consumers [-p <vhostpath >]
3 User management commands
These commands are mainly used to add, modify, delete users and manage user permissions
#Add user in rabbitmq's internal database add_user <username> <password> #Delete a user delete_user <username> #Change user password change_password <username> <newpassword> #Clear user password and prohibit user login clear_password <username> #Set user tags , Is to set the user role set_user_tags <username> <tag> # View user list list_users #Create a vhost add_vhost <vhostpath> #Delete a vhosts delete_vhost <vhostpath> #List vhosts list_vhosts [<vhostinfoitem> ...] #For a vhosts Give users relevant permissions set_permissions [-p <vhostpath>] <user> <conf> <write> <read> #Clear a user's permissions on vhost clear_permissions [-p <vhostpath>] <username> all users' permissions on a vhost list_permissions [-p <vhostpath>] #List the access permissions of a user list_user_permissions <username>
4 cluster management commands
#clusternode indicates the name of the node, --ram indicates that the node joins the cluster as a ram node. By default, a node joins the cluster as a disc node. Before a node joins the cluster, the rabbitmq application of the node must be stopped, that is, stop_app must be executed first. join_cluster <clusternode> [--ram] #Display all nodes in the cluster cluster_status #Set the cluster name set_cluster_name <clustername> #Modify the cluster name rename_cluster_node <oldname> <newname> #Change the mode of a node in a cluster, the node is before conversion It must be stopped first, and the only disk node in a cluster cannot be converted to ram node change_cluster_node_type <disc | ram> #Remotely delete a node, the node must be stopped before deleting rabbitmqctl forget_cluster_node rabbit@rabbit1 #Synchronization mirror queue sync_queue <queuename> #Cancel synchronization queue cancel_sync_queue <queuename> #Empty all messages in the queue purge_queue [-p vhost] <queuename>
Many of the commands listed here are not used at this stage, such as cluster control related commands. The usage of these commands will be gradually understood in the following chapters.