Raft Homework

Here we have an incomplete implementation of a distributed calculator. This program has some HTTP POST APIs to receive addition, subtraction, and multiplication commands, as well as an HTTP GET API to return the current replicated result. It also has a web-based dashboard to facilitate issuing these commands and seeing the result on each node.

The requirement is syncing these commands with the other nodes in an asynchronous and fault-resilient way, with the Raft consensus algorithm.

Demo & Development

You can run the nodes manually and use the web-based dashboards to test your implementation.

python3 node.py -i 50 -m 10101 -o 10103 10102 -p 9010
python3 node.py -i 50 -m 10102 -o 10103 10101 -p 9020
python3 node.py -i 50 -m 10103 -o 10102 10101 -p 9030

What you need to do

This homework has three sections:

1. You should use the raft protocol and complete the consensus.py file to pass all test cases. There is no need to change other files.
   • There are some test cases provided in the test.py file. You can run them with python3 test.py.
2. Explain in the Raft terminology, how nodes interact with each other in the test_failure_and_recovery test case.
3. Explain in the Raft terminology, why test_weird passes.

Note that:

• Usage of the third-party packages is permitted.
• If you want to solve this homework with another programming language, you can write your own node program and still use python3 test.py to test it. In this case, you should change RUN_PREFIX in the test.py file to address the executable of your node program.
• You should not change the test.py file unless you need to change the PYTHON_ADDR or RUN_PREFIX constants.
• You should not store/retrieve anything on/from the persistent storage. All communication between the nodes should be network-based.
• You should not use time.sleep in the consensus.py file if you use the third-party packages.