Auth-Microservice

This application represents a small ZeroMQ-based authentication microservice. This tiny auth server will listen on a port-bound socket for incoming packets containing simple JSON objects, in the format {"username": [username], "password": [password]}. The serialized JSON object received by the server will be validated against a JSON schema definition of that format.

Assuming the provided object produces no validation error, the given case-sensitive username will be checked against the record of the service's connected DB. If a username match is found, the case-sensitive password will be checked against the same username record. If the match of both keys is successful, a simple string message response of valid will be sent by the server. Should either of those matches fail, or the aforementioned data validation fail, a message response of invalid will be sent by the server. Please see the test_client.py file in the repo for an example of the data validation in action.

The microservice supports querying against a live mySQL database or a static JSON database---- the latter provided as a single file containing an array of JSON objects describing users. See the static_db.json file in this repo for an example of the expected format. User objects in either type of database may contain any number of attributes/keys, but they must contain username and password attributes/keys.

By default, the microservice python file does not require any CLI arguments and will try to connect to an SQL database. However, it will expect a .env file to be located in the same directory as the auth_server.py file. The .env file should contain the following variables, one to a line: MYSQL_HOST=, MYSQL_USER=, MYSQL_PASSWORD=, MYSQL_DATABASE=. DB details can be entered directly after the equal sign, without quotes or wrapped in quotes. Spaces are permitted before and after the equal sign. The .env_example file contains an example of the required variables.

Alternatively, to utilize a static JSON db, a JSON file can be provided via CLI flags -j or --json.

Dependencies

To get started, ensure that the pyzmq, mysql, mysql-connector-python, python-dotenv, and jsonschema packages are installed to your environment or system: pip install pyzmq, mysql, mysql-connector-python, python-dotenv, jsonschema

Configuration

If you would like the microservice to listen on a specific port, please edit the PORT constant in the auth_server.py file. The service currently defaults to port 8080.

Calling the service

The authentication microservice is intended to be started via the CLI. To start the service: python auth_server.py

For an elaboration of currently available command line arguments: python auth_server.py -h

To utilize the service with a static JSON DB file: python auth_server.py --json db_filename.json

Sending and Receiving Data

The contents of data requests sent to the service must be sent strictly in the following format (with values in brackets replaced with strings wrapped in double-quotes): {"username": [username], "password": [password]} For example, a real packet might contain: {"username": "julioJones", "password": "falcons"}

In the client, standard the dependencies named above should be imported, and then a ZeroMQ socket readied to make calls to the server. For example:

import zmq
import json

context = zmq.Context()
socket = context.socket(zmq.REQ)
socket.connect("tcp://localhost:8080")

data = '{"username": "julioJones", "password": "falcons"}'

# Send data to server
socket.send_string(data)
# Receive server reply
reply = socket.recv_string()
print(reply)

Notably, it is not mandatory to utilize ZeroMQ's send_string() and recv_string(), but it does simplify encoding and serialization within the code. Please see the ZMQ Socket Class documentation for more details (i.e. see recv* and send_ class methods). For example, to avoid serialization of JSON objects (i.e. stringifying), an approach like the following could be used:

import zmq
import json

context = zmq.Context()
socket = context.socket(zmq.REQ)
socket.connect("tcp://localhost:8080")

data = {"username": "julioJones", "password": "falcons"}

# Send data to server; python dictionary -> JSON object
socket.send_json(data)
# Receive server reply as byte object; requires decode to convert to string
reply = socket.recv()
print(reply.decode())