This little command line tool is used to retrieve the latitude and longitude
for a given IP address. It uses the IPStack API to do so, and requires a free
API key to do the work.

To install:
Load all required Python libraries :
pip install -r requirements.txt
Note that since the project requirements said no third party libraries, I've used some old
code to implement the request get. This code came from the Internet at some point.


This presumes that you have Python 3 (or better) installed on your system.

Notes:
When you have an API key, you must set it in an environment variable called
IPSTACK_KEY in either your startup code or the terminal that you want to run the thing
in. This is to avoid having any secret keys in the code.

Usage:
fetch_ip <ip-address>
where ip-address is the address you want to fetch.
The return from the program is one of the following
Exit Code 0: The program will output the latitude and longitude as a single
comma separated line like:
34.0655517578125,-118.24053955078125

Exit Code 1: The output will be an error message indicating that no parameter was given
Exit Code 2: The output will be an error message indicating that no API Key was found
Exit Code 3: The output will be an error message indicating that the API returned an error (most likely a bad IP address).

Since a caller (or script) can query the exit code, there is no need to output anything but the actual
data needed, as a Unix pipeline app would do.

Other notes:
1. The key is stored in an environment variable so that it is secure. In a CI/CD environment, this would
be placed in a secrets vault on the CI machine.
2. No checking is done for the validity of the IP address, since the IPStack api already does this. Might
make a nice feature