Salt File Server

Salt comes with a simple file server suitable for distributing files to the salt minions. The file server is a stateless ZeroMQ server that is built into the salt master.

The main intent of the Salt File server is the present files for use in the Salt state system. With this said, the Salt file server can be used for any general file transfer from the master to the minions.

The cp Module

The cp module is the home of minion side file server operations. The cp module is used by the Salt state system, salt-cp and can be used to distribute files presented by the Salt file server.

Environments

Since the file server is made to work with the Salt state system, it supports environments. The environments are defined in the master config file and when referencing an environment the file specified will be based on the root directory of the environment.

get_file

The cp.get_file function can be used on the minion to download a file from the master, the syntax looks like this:

# salt '*' cp.get_file salt://vimrc /etc/vimrc

This will instruct all salt minions to download the vimrc file and copy it to /etc/vimrc

File Server Client API

A client API is available which allows for modules and applications to be written which make use of the Salt file server.

The file server uses the same authentication and encryption used by the rest of the Salt system for network communication.

FileClient Class

The FileClient class is used to set up the communication from the minion to the master. When creating a FileClient object the minion configuration needs to be passed in. When using the FileClient from within a minion module the built in __opts__ data can be passed:

import salt.minion

def get_file(path, dest, env='base'):
    '''
    Used to get a single file from the salt master

    CLI Example:
    salt '*' cp.get_file salt://vimrc /etc/vimrc
    '''
    # Create the FileClient object
    client = salt.minion.FileClient(__opts__)
    # Call get_file
    return client.get_file(path, dest, False, env)

Using the FileClient class outside of a minion module where the __opts__ data is not available, it needs to be generated:

import salt.minion
import salt.config

def get_file(path, dest, env='base'):
    '''
    Used to get a single file from the salt master
    '''
    # Get the configuration data
    opts = salt.config.minion_config('/etc/salt/minion')
    # Create the FileClient object
    client = salt.minion.FileClient(opts)
    # Call get_file
    return client.get_file(path, dest, False, env)

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