Service Now Integration using pysnow API client for Python

My latest technology initiative, has been doing some first-hand integration to Service Now, using the Service Now API.  The first thing I did, was to load the API calls into PostMan. Once I tested the OAuth 2.0 authentication, and made a couple of test calls, I was ready to proceed with Python.

I searched for a Service Now Python Client, and sure enough, there is one. It is called "pysnow" and it can be installed with the Python pip utility:

>pip install pysnow

Once installed, you can interact with Service Now in a very straightforward manner - although there are some client-specific things one should learn from reading the documentation. Authentication uses OAuth 2.0, and the token re-generation is done as part of the API client, which is convenient. 

Once you have authenticated, you generally bind to a resource first (i.e. a Table), and once you have bound to it, you can then make a call against that resource (i.e. a query).  Data from calls can be accessed using helper functions such as first() or first_or_none().

Here is a snippet (from their documentation) on how the client is used:

import pysnow 

# Create client object
c = pysnow.Client(instance='myinstance', user='myusername', password='mypassword')

# Define a resource, here we'll use the incident table API
incident = c.resource(api_path='/table/incident')

# Query for incidents with state 3
response = incident.get(query={'state': 3})

# Print out the first match, or `None`
print(response.first_or_none())

Service Now, in my mind, is just a huge relational database full of tables. And the API calls are allowing you to retrieve from these tables (GET calls), update these tables (PUT calls), or delete from these tables (DELETE calls). 

You can pass queries as arguments on the GET calls, and the queries are very similar to those you might use with SQL, supporting things such as wildcard with LIKE clauses, etc.

There was one case, where I had to abandon the pysnow client, and use Python Requests. It was a case where one of the API calls required a PATCH call. I had never actually even heard of a PATCH call before encountering this, but it's a valid call - just one that is a bit more rare to encounter and up to now, I had not seen it. The pysnow API did not support a PATCH request, interestingly enough, and after figuring this out, I had to (re) write the API client calls using Python Requests for the PATCH API call.

Aside of this, the only other surprise I had, was the number of fields I was getting back on many of these calls. Some of these records were incredibly large.