Introduction

For this assignment, your starting point will be your completed code from the end of lesson 2:

• main.py
• menu.py
• user_status.py
• users.py

You are also given a version of accounts.csv and status_updates.csv with 1,000 and 100,000 records, respectively.

The goal is easier to state than to implement: Once again, you need to migrate from using CSV files to storing your data into a database, this time, into MongoDB (non-relational).

If you want to try generating your own source data, you can use the following Github repository as a reference: https://github.com/ldconejo/social_network_generator

What you need to do

1. Implement a MongoDB database that will contain both user account and well as user status data:

   • Create one collection called UserAccounts.
   • Create another collection called StatusUpdates.

2. Your code should make sure that some basic rules are followed:

   • No duplicated UserID or StatusID.
   • Every status update should be associated to a particular user that exists.
   • If a user is deleted, all associated status updates should be deleted as well.

3. Modify UserStatusCollection to work with MongoDB. This means that every operation (add, modify, delete, search) needs to interact with the database.

4. Update the feature to load the CSV files for users and user status to populate your MongoDB database. Remove the features to save to CSV files, as the data will be stored in your database.

Submission

At least the following files need to be submitted:

• main.py
• menu.py
• user_status.py
• users.py
• test_main.py

Any other files required by your implementation of this assignment (including data and test files!).

How will your code be evaluated?

• The instructor will run menu.py and load the sample CSV files into your database.
• The instructor will interact with your database using the user interface in menu.py and try to add, modify, search and delete data.
• The instructor would also try common error conditions: Adding a duplicated user_id, deleting a non-existing user, etc. Your code should not crash due to these errors and please, no bare exceptions.
• The instructor will look at your code and verify that all operations are being performed directly on the database.

As usual, your code will need to be linted and score 10/10 on Pylint.

notes on testing / CI

In order for your tests to run, you need to have mongodb running.

The CI (gitHub Actions) is set up to use this command to start mongo:

mongod -f mongo_config_dev.yml

That will configure mongo to use the configuration in the mongo_config_dev.yml.

Take a look at the .yml file, it's pretty self explanatory, but the key bits are:

The files Mongo creates will go in the mongo_files dir.

The server will be listening on localhost, and port number 27017 (which is the default for mongo)

To be consistent, you should use the same config (same command), and this command to start the pymongo client:

client = MongoClient(host='localhost', port=27017)

MongoDB allows more than one database at a time -- so you can use one a different one for testing than for operational use. That way your tests won't mess up your real data.

If you have any other requirements than loguru and pymongo, they should be added to the requirements.txt file.

Tips

• To get MongoDB to use user_id and status_id as primary keys for your users and user status collections, use those values as the _id field for the entries into your collections.

• pymongo has several exceptions that could be useful for your error handling. One example is pymongo.errors.DuplicateKeyError. You should probably import that into both users.py and user_status.py.

• The update_one and delete_one methods return True even if the associated record does not exist. You will need to verify first and return the corresponding error message if an update or deletion is attempted on a non-existing record.

• Enable all operations (add, modify, search and delete) for users first, the process to do the same for the status collections will be very similar.

• Before adding a new status ID, remember to check that the corresponding user ID exists.

• It is always a good idea to write tests for your code. Try to use TDD, and attempt to reach 100% coverage.