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SSH CLI commands
================

Preparing commands and templates
--------------------------------

CLI commands are implemented in the Connector() class by using the Netmiko library.
This provides standard SSH access into a device.

Predefined CLI commands are run by calling *Connector().run_command()*,
whereas form template input commands are calling *Connector().run_command_string()*.
See *switches/connect/connector.py*, around line 1210

These functions expand the commands and templates to regular strings to send over SSH.


Executing commands
------------------

Both functions then call *Connector()._execute_command()* to execute the SSH command.
See *switches/connect/connector.py*, around line 1160

This function calls *self.netmiko_connect()* to create a vendor-specific *netmiko.ConnectHandler*.
The ConnectHandler() is Netmiko's SSH object. It then uses that handle to send and receive data over SSH
via calls to *netmiko.send_command_timing()* or *netmiko.send_command()*


Implementing CLI functionality
------------------------------

Drivers can override the *self.execute_command()* functionality to implement their own
mechanism to execute CLI commands on a device.

An example if this is the Arista eAPI driver, in switches/connect/arista_eapi/connector.py,
the *_execute_command()* function. This uses the eAPI in "text" mode to run a command.
Note: for this device type, this is significanly faster then the normal SSH implementation via Netmiko.

Additionally, the Aruba AOS-S driver implements *_execute_command()* to implement using their REST API, instead of SSH.

**Note:** it is possible to implement a complete SSH interface to manage devices.
The Napalm library attempts to do this, but lacks support for 802.1q, PoE, and more.
This exercise is left to the reader...