Many programs rely on the accurate machine time, such as the make command in UNIX. Your machine time may be different and need synchronizing with another time server in your network.

In order to synchronize your machine time with one of the internet time servers, you can write a Python client for that. For this, ntplib will be used. Here, the client/server conversation will be done using Network Time Protocol (NTP). If ntplib is not installed on your machine, you can get it from PyPI with the following command using pip or easy_install:

$ pip install ntplib
  

If pip is not installed on your computer, first install it before executing the preceding command. In Debian-based Linux distributions such as Ubuntu, this can be installed by:

$ sudo apt install python-pip
  

Note that you will need to install pip for Python 3 separately if you are running it along side Python 2, as typically Python 2 is set as the default version:

$ sudo apt-get install python3-pip
  

Similarly, ntplib needs to be installed for python3-pip (also called pip3) separately:

$ pip3 install ntplib  

It is a good idea to upgrade pip to the latest version if you are running an outdated version, by issuing the following command:

$ pip install --upgrade pip  

or:

$ pip3 install --upgrade pip  

If Python 2 and Python 3 are installed alongside in your computer then use pip3.

I am using the pip version 9.0.1, for both Python 2 and Python 3. This is the latest version at the time of writing.

We create an instance of NTPClient and then we call the request() method on it by passing the NTP server address.

Listing 1.11 shows how to print the current time from the internet time server as follows:

    #!/usr/bin/env python
    # Python Network Programming Cookbook, 
      Second Edition -- Chapter - 1
    # This program is optimized for Python 2.7.12 
      and Python 3.5.2.
    # It may run on any other version with/without 
      modifications.
    
    import ntplib
    from time import ctime
    
    
    def print_time():
        ntp_client = ntplib.NTPClient()
        response = ntp_client.request('pool.ntp.org')
        print (ctime(response.tx_time))
    
    
    if __name__ == '__main__':
        print_time()
    
  

In my machine, this recipe shows the following output:

$ python 1_11_print_machine_time.py 
Fri Jun  2 16:01:35 2017
  

Here, an NTP client has been created and an NTP request has been sent to one of the internet NTP servers, pool.ntp.org. The ctime() function is used for printing the response.