Non-negative one/two-word description for person who regularly enforces rules verbatim without any consideration for circumstances?

I frequently come across people who go no further than the text defining rules and who try to enforce said rules without taking into consideration the circumstances behind rule offenses or the potential reasons why the rule was put into effect to begin with. I can imagine that not being a precise enough definition, so here is an example:

Management in an imaginary software development company with a limited number of office computers puts a rule into effect prohibiting employees from coming to work when they're not scheduled to in an attempt to ensure there are always open computers available. PersonA (who is not scheduled to work) needs to give PersonB (currently working) a flashdrive, and plans to leave the office immediately after giving it to PersonB. PersonA arrives at the office, but PersonC refuses to let him/her into the building, even after PersonA explains that he/she just needs to drop something off. PersonC states that "rules are rules" and "they cannot be broken under any circumstance" without any consideration for why the rule exists and the circumstances regarding PersonA "breaking" the rule.

Regardless of whether or not that viewpoint of rules is right/wrong and what PersonA could have done differently (e.g. give the flashdrive to PersonC to give to PersonB), is there a term respectful enough to be used in a workplace discussion that describes that way of thinking regarding rules that's more manageable than "person who regularly enforces rules verbatim without any consideration for circumstances"?

Consider stickler

one who insists on exactness or completeness in the observance of something: a stickler for the rules

Merriam-Webster

The term is used for rigid adherents for things beyond formal recorded requirements, such as manners, customs, etc.

Similarly pedant

A person who is excessively concerned with minor details and rules or with displaying academic learning.

Oxford Dictionaries Online

Disciplinarian is the word you should use in scenarios where you want to point to a Martinet but with respect. Refer to this definition of Disciplinarian on vocabulary.com

Such a person would probably not be offended by being referred to as “a strict constructionist {of the rules}”
(example usage from ‘[The Senate] Committee on Civil Service and Retrenchment’ via ‘Google Books’)

strict constructionist
one who favors giving a narrow conservative construction of a given document or instrument [including the/a text defining rules?]; …

(from ‘Merriam-Webster’)

In British English, we would say he is a jobsworth.

noun (informal) a person in a position  of minor authority who invokes the letter of the law in order to avoid any action requiring  initiative, cooperation, etc.

Word Origin C20: from it's more than my job's worth to …

— Collins English Dictionary - Complete & Unabridged 2012 

It's informal disapproving according to CAL's definition.