Mongodog

Mongodog is a final project for Brown University's CS2390: Privacy-Conscious Computer Systems developed by Naafiyan Ahmed, Swetabh Changkakoti and Lucas Gelfond. We aim to improve developer experience and ensure correct deletion of data in a MongoDB database. It consists a Rust crate called mongowner as well as example implementations of this crate on applications.

You can read our report here!

Mongowner

We provide a Rust crate called mongowner that allows for easy-to-implement data ownership modelling and safe cascade deletion for MongoDB. The mongowner crate is still under development and will be published once it is stable and feature-ready.

Building the crate:

cd mongowner
cargo build

Example of struct annotations for 2 schemas - User and Post to model the ownership relationship, i.e. Post is owned by User

#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Schema)]
#[collection(users)]
#[data_subject]
pub struct User {
    #[index]
    pub user_id: u32,
    pub username: String,
    pub first_name: String,
    pub last_name: String,
    pub age: u8,
    pub email: String,
}

#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Schema)]
#[collection(posts)]
pub struct Post {
    #[index]
    pub post_id: u32,
    // uncomment this to test out cycle detection
    // #[owned_by(comments, text)]
    pub text: String,
    #[owned_by(users, user_id)]
    pub posted_by: u32,
    pub date: String,
}

Examples

We provide 2 examples of using the mongowner library in the application code.

social-rs

social-rs is a simple social media application that demonstrates the ease of use of our mongowner library. We provide a Makefile for easy building and running of the backend server. To run the backend for social-rs:

1. Ensure that you have an instance of mongod running - by default we assume that it is running on port 27017 but you can configure this by setting the MONGO_URI environment variable in the .env files located at examples/social-rs/
2. Once the database is running, you can run the following make command from the root of mongodog:

make run_server

To run the frontend for social-rs:

1. Ensure you have bun installed
2. Run the following command to install all the dependencies:

make social_bun_deps

3. Lastly run the following to build and run the frontend client in developer mode:

make social_client

websubmit-rs

This is a proof-of-concept application that highlights our library's ability to translate and model SQL ownership relations from K9Db to a NoSQL paradigm. We currently have a file named mongo_schemas.rs that contain an example of what the annotated schemas may look like Example of translating the Answer schema from K9Db's MySQL syntax to mongowner annotations:

Original K9Db (MySQL) Schema:

CREATE TABLE answers (
    id varchar(255),
    email varchar(255),
    question_id int,
    answer text,
    submitted_at datetime,
    PRIMARY KEY (id),
    FOREIGN KEY (email) OWNED_BY users(email),
    FOREIGN KEY (question_id) REFERENCES questions(id)
);

mongowner schema:

#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Schema)]
#[collection(answers)]
pub struct Answer {
    #[index]
    id: u32,
    #[owned_by(users, email)]
    email: String, // FK but NOT owned_by
    question_id: u32,
    answer: String,
    submitted_at: String,
}