Quickstart: Build a Rust application backed by Azure Cosmos DB's API for MongoDB

The sample presented in this article is a simple command-line based application that uses the Rust driver for MongoDB. Since Azure Cosmos DB's API for MongoDB is compatible with the MongoDB wire protocol, it is possible for any MongoDB client driver to connect to it.

You will learn how to use the MongoDB Rust driver to interact with Azure Cosmos DB's API for MongoDB by exploring CRUD (create, read, update, delete) operations implemented in the sample code. Finally, you can run the application locally to see it in action.

Pre-requisites

• An Azure account with an active subscription. Create one for free. Or try Azure Cosmos DB for free without an Azure subscription. You can also use the Azure Cosmos DB Emulator with the connection string .mongodb://localhost:C2y6yDjf5/R+ob0N8A7Cgv30VRDJIWEHLM+4QDU5DE2nQ9nDuVTqobD4b8mGGyPMbIZnqyMsEcaGQy67XIw/Jw==@localhost:10255/admin?ssl=true.
• Rust (version 1.39 or above)
• Git

Setup Azure Cosmos DB

You need to create a database account for Azure Cosmos DB for Mongo DB API and retrieve the database key that will allow you to connect to the database in subsequent steps.

Run the application

Clone the sample application

Run the following commands to clone the sample repository.

1. Open a command prompt, create a new folder named git-samples, then close the command prompt.

   mkdir "C:\git-samples"

2. Open a git terminal window, such as git bash, and use the cd command to change to the new folder to install the sample app.

   cd "C:\git-samples"

3. Run the following command to clone the sample repository. This command creates a copy of the sample app on your computer.

   git clone https://github.com/Azure-Samples/cosmosdb-rust-mongodb-quickstart

Build the application

To build the binary:

cargo build --release

Configure the application

Export the connection string, MongoDB database, and collection names as environment variables.

export MONGODB_URL="mongodb://<COSMOSDB_ACCOUNT_NAME>:<COSMOSDB_PASSWORD>@<COSMOSDB_ACCOUNT_NAME>.mongo.cosmos.azure.com:10255/?ssl=true&replicaSet=globaldb&maxIdleTimeMS=120000&appName=@<COSMOSDB_ACCOUNT_NAME>@"

The ssl=true option is important because of Cosmos DB requirements. For more information, see Connection string requirements.

For the MONGODB_URL environment variable, replace the placeholders for <COSMOSDB_ACCOUNT_NAME> and <COSMOSDB_PASSWORD>

1. <COSMOSDB_ACCOUNT_NAME>: The name of the Azure Cosmos DB account you created
2. <COSMOSDB_PASSWORD>: The database key extracted in the previous step

export MONGODB_DATABASE=todos_db
export MONGODB_COLLECTION=todos

You can choose your preferred values for MONGODB_DATABASE and MONGODB_COLLECTION or leave them as is.

To run the application, change to the correct folder (where the application binary exists):

cd target/release

To create a todo

./todo create "Create an Azure Cosmos DB database account"

If successful, you should see an output with the MongoDB _id of the newly created document:

inserted todo with id = ObjectId("5ffd1ca3004cc935004a0959")

Create another todo

./todo create "Get the MongoDB connection string using the Azure CLI"

List all the todos

./todo list all

You should see the ones you just added:

todo_id: 5ffd1ca3004cc935004a0959 | description: Create an Azure Cosmos DB database account | status: pending
todo_id: 5ffd1cbe003bcec40022c81c | description: Get the MongoDB connection string using the Azure CLI | status: pending

To update the status of a todo (for example, change it to completed status), use the todo ID as such:

./todo update 5ffd1ca3004cc935004a0959 completed

#output
updating todo_id 5ffd1ca3004cc935004a0959 status to completed
updated status for todo id 5ffd1ca3004cc935004a0959

List only the completed todos

./todo list completed

You should see the one you just updated

listing 'completed' todos

todo_id: 5ffd1ca3004cc935004a0959 | description: Create an Azure Cosmos DB database account | status: completed

Delete a todo using it's ID

./todo delete 5ffd1ca3004cc935004a0959

List the todos to confirm

./todo list all

The todo you just deleted should not be present

View data in Data Explorer

Data stored in Azure Cosmos DB is available to view and query in the Azure portal.

To view, query, and work with the user data created in the previous step, login to the Azure portal in your web browser.

In the top Search box, enter Azure Cosmos DB. When your Cosmos account blade opens, select your Cosmos account. In the left navigation, select Data Explorer. Expand your collection in the Collections pane, and then you can view the documents in the collection, query the data, and even create and run stored procedures, triggers, and UDFs.

Clean up resources

When you're done with your app and Azure Cosmos DB account, you can delete the Azure resources you created so you don't incur more charges. To delete the resources:

Resources

In this quickstart, you learned how to create an Azure Cosmos DB MongoDB API account using the Azure Cloud Shell, and create and run a Rust command-line app to manage todos. You can now import additional data to your Azure Cosmos DB account. You can also explore the following resources:

• Pre-migration steps for data migrations from MongoDB to Azure Cosmos DB's API for MongoDB
• Upgrade the MongoDB wire protocol version of your Azure Cosmos DB's API for MongoDB account
• Quickstart: Connect a Go application to Azure Cosmos DB's API for MongoDB
• Consistency levels for Azure Cosmos DB and the API for MongoDB