What is CanalSharp?
CanalSharp is a .NET Client of alibaba's open source component
Canal,and it provides .NET developer a much easier way to use Canal.
Canal is a incremental Publish&Subscription component based on mysql's
binlog.To learn more a bout Cancal,please visit alibaba/canal/wiki
log based incremental pub&sub model can be applied to many business cases:
- Database Mirroring
- Realtime Database backup
- Multi-level index
- search build
- Busienss cache refresh
- Notification on price change(in e-commerce site) and so on
CanalSharp as a .NET client of canal,it can be used in situations where Canal is being used.We have listed some using scenarios above,here are some more detailed use cases:
As a substitution of polling Database to monitor Database changes,it is much more effective than polling.
Realtime Update data in search engine when data in mysql database changed.For example,in a E-commerce site,when Product information changed,it can be updated to Elasticsearch、solr,etc in a realtime way.
Realtime update data in cache,Also take E-commerce site as an example,when price,inventory and other product information changed,it can be updated to Redis in a realtime way.
To trigger some other business logics on data change,for example,when a customer place an order without payment in a certain period of time and so the order is cancelled automatically,we get the changed status of the order and then we can push a notification to the customer(or take some other actions)
Push changed data to RabbitMq,kafak or other message queues for consuming.
As a .NET client of Canal,it use
Socket for communication,the transfer Protocol is
TCP,and the data exchange Protocol is Google's Protocol Buffer 3.0
Canal connect to Mysql database ,pretented to be a slave of mysql
CanalSharp(as mentioned it is a client of Cancal) connect to Canal
When data in the database changed,it write the changes to binlog
Canal send dump request to mysql database,get binlog and then parse it.
CancalSharp send request to Canal for data.
Canal send parsed data to CanalSharp
CancalSharp get data successfully and then send an acknowledgement to Canal(optional)
Canal record the consumption position
The following picture shows how it works:
1. Install Canal
To Install and configure Canal, please visit
2.Create a .NET Core Console Project
3. Install CanalSharp from Nuget
4. Connect to Canal
//canal' destination config,default to example var destination = "example"; //instantiate a simple CanalClient connector object(it does not support clustering),the parameters are canal's IP Address,port number,destination,username and password var connector = CanalConnectors.NewSingleConnector("127.0.0.1", 11111, destination, "", ""); //connect to Canal connector.Connect(); //Subscription,the parameter is a Filter,if we provided nothing it use Canal's default Filter. a filter is a rule for filtering data,data go throgh the filter will be passed in. connector.Subscribe(".*\\..*"); //Get data with acknowledgement to indicate success connector.Get(batchSize); //Get data without acknowledgement to indicate success connector.GetWithoutAck(batchSize);
for more detailed information please visit Sample
Quick as running sample
1. Run mysql and canal by command
git clone https://github.com/CanalSharp/CanalSharp.git cd CanalSharp cd docker docker-compose up -d
2. Use navicat or orther client to connect to mysql
ip：the ip address of the server where docker running
There is a default database named
test,which contains a table named
3.run the sample project
Execute the following sql:
insert into test values(1000,'111'); update test set name='222' where id=1000; delete from test where id=1000;
we can see that after executing
insrt,update,delete sql,Our CanalSharp get the changed data.
CanalSharp clustering support
One of the easiest ways to contribute is to participate in discussions and discuss issues. You can also contribute by submitting pull requests with code changes.