zongji

A mysql binlog listener running on Node.js

ZongJi

A MySQL binlog listener running on Node.js.

ZongJi (踪迹) is pronounced as zōng jì in Chinese.

This package is a "pure JS" implementation based on node-mysql. Since v0.2.0, The native part (which was written in C++) has been dropped.

This package has been tested with MySQL server 5.5.40 and 5.6.19. All MySQL server versions >= 5.1.15 are supported.

var zongji = new ZongJi({ /* ... MySQL Connection Settings ... */ });
 
// Each change to the replication log results in an event 
zongji.on('binlog', function(evt) {
  evt.dump();
});
 
// Binlog must be started, optionally pass in filters 
zongji.start({
  includeEvents: ['tablemap', 'writerows', 'updaterows', 'deleterows']
});

For a complete implementation see example.js...

  • Requires Node.js v0.10+

    $ npm install zongji
  • Enable MySQL binlog in my.cnf, restart MySQL server after making the changes.

    From MySQL 5.6, binlog checksum is enabled by default. Zongji can work with it, but it doesn't really verify it.

    # binlog config
    server-id        = 1
    log_bin          = /var/log/mysql/mysql-bin.log
    expire_logs_days = 10            # optional
    max_binlog_size  = 100M          # optional
     
    # Very important if you want to receive write, update and delete row events
    binlog_format    = row
  • Create an account with replication privileges, e.g. given privileges to account zongji (or any account that you use to read binary logs)

    GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'zongji'@'localhost'

The ZongJi constructor accepts one argument: an object containg MySQL connection details in the same format as used by node-mysql.

Each instance includes the following methods:

Method Name Arguments Description
start options Start receiving replication events
stop None Disconnect from MySQL server, stop receiving events
set options Change options after start()
on eventName, handler Add a listener to the binlog or error event. Each handler function accepts one argument.

Options available:

Option Name Type Description
serverId integer Unique number (1 - 232) to identify this replication slave instance. Must be specified if running more than one instance of ZongJi. Must be used in start() method for effect.
Default: 1
startAtEnd boolean Pass true to only emit binlog events that occur after ZongJi's instantiation. Must be used in start() method for effect.
Default: false
includeEvents [string] Array of event names to include
Example: ['writerows', 'updaterows', 'deleterows']
excludeEvents [string] Array of event names to exclude
Example: ['rotate', 'tablemap']
includeSchema object Object describing which databases and tables to include (Only for row events). Use database names as the key and pass an array of table names or true (for the entire database).
Example: { 'my_database': ['allow_table', 'another_table'], 'another_db': true }
excludeSchema object Object describing which databases and tables to exclude (Same format as includeSchema)
Example: { 'other_db': ['disallowed_table'], 'ex_db': true }
  • By default, all events and schema are emitted.
  • excludeSchema and excludeEvents take precedence over includeSchema and includeEvents, respectively.

Supported Events:

Event name Description
unknown Catch any other events
query Insert/Update/Delete Query
rotate New Binlog file (not required to be included to rotate to new files)
format Format Description
xid Transaction ID
tablemap Before any row event (must be included for any other row events)
writerows Rows inserted
updaterows Rows changed
deleterows Rows deleted

Event Methods

Neither method requires any arguments.

Name Description
dump Log a description of the event to the console
getEventName Return the name of the event
  • 🌟 All types allowed by node-mysql are supported by this package.
  • 🙊 While 64-bit integers in MySQL (BIGINT type) allow values in the range of 264 (± ½ × 264 for signed values), Javascript's internal storage of numbers limits values to 253, making the allowed range of BIGINT fields only -9007199254740992 to 9007199254740992. Unsigned 64-bit integers must also not exceed 9007199254740992.
  • 👉 TRUNCATE statement does not cause corresponding DeleteRows event. Use unqualified DELETE FROM for same effect.
  • When using fractional seconds with DATETIME and TIMESTAMP data types in MySQL > 5.6.4, only millisecond precision is available due to the limit of Javascript's Date object.
  • Configure MySQL in test/settings/mysql.js
  • Run npm test

I learnt many things from following resources while making ZongJi.

MIT