Extending MariaDB Shell

Add your own reports, global objects, plugins, and SQL statements to MariaDB Shell with Python.

MariaDB Shell runs an embedded Python interpreter, and the same Python APIs that the built-in features use are open to you. With a few lines of Python you can add a report that \show and \watch display, a global object with documented functions, or a handler that answers an SQL statement the server doesn't know.

The extension mechanisms build on each other:

• A report is a Python function registered with shell.register_report(). It returns rows or a structured document, and the shell formats the output.
• A plugin is a directory with an init.py file that the shell loads at startup. Plugins add global objects with documented functions, which appear next to shell and util and are documented by \?, and they register reports and SQL handlers. The plugin decorators generate the help text from your docstrings.
• An SQL handler intercepts SQL statements that start with a given prefix and returns a result that the shell displays like a server result.

To load your code automatically, put it in a plugin directory, in the init.d directory of the user configuration directory, or in the startup script.

Reports

The built-in query, thread, and threads reports, the \show and \watch commands, and how to write your own reports.

Plugins

The plugin directory layout, the plugin decorators, the built-in plugins, the plugins global object, and the extension object API that the decorators build on.

SQL Handlers

How to intercept SQL statements by prefix and return custom results built with shell.create_result().