Azure Cosmos DB SDK for Rust

Client library for Azure Cosmos DB NoSQL API — globally distributed, multi-model database.

Installation

cargo add azure_data_cosmos azure_identity

Environment Variables

COSMOS_ENDPOINT=https://<account>.documents.azure.com:443/ COSMOS_DATABASE=mydb COSMOS_CONTAINER=mycontainer

Authentication

use azure_identity::DeveloperToolsCredential; use azure_data_cosmos::CosmosClient;

let credential = DeveloperToolsCredential::new(None)?; let client = CosmosClient::new( "https://<account>.documents.azure.com:443/", credential.clone(), None, )?;

Client Hierarchy

Client Purpose Get From

CosmosClient

Account-level operations Direct instantiation

DatabaseClient

Database operations client.database_client()

ContainerClient

Container/item operations database.container_client()

Core Workflow

Get Database and Container Clients

let database = client.database_client("myDatabase"); let container = database.container_client("myContainer");

Create Item

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)] struct Item { pub id: String, pub partition_key: String, pub value: String, }

let item = Item { id: "1".into(), partition_key: "partition1".into(), value: "hello".into(), };

container.create_item("partition1", item, None).await?;

Read Item

let response = container.read_item("partition1", "1", None).await?; let item: Item = response.into_model()?;

Replace Item

let mut item: Item = container.read_item("partition1", "1", None).await?.into_model()?; item.value = "updated".into();

container.replace_item("partition1", "1", item, None).await?;

Patch Item

use azure_data_cosmos::models::PatchDocument;

let patch = PatchDocument::default() .with_add("/newField", "newValue")? .with_remove("/oldField")?;

container.patch_item("partition1", "1", patch, None).await?;

Delete Item

container.delete_item("partition1", "1", None).await?;

Key Auth (Optional)

Enable key-based authentication with feature flag:

cargo add azure_data_cosmos --features key_auth

Best Practices

• Always specify partition key — required for point reads and writes

• Use into_model()? — to deserialize responses into your types

• Derive Serialize and Deserialize — for all document types

• Use Entra ID auth — prefer DeveloperToolsCredential over key auth

• Reuse client instances — clients are thread-safe and reusable

Reference Links

Resource Link

API Reference https://docs.rs/azure_data_cosmos

Source Code https://github.com/Azure/azure-sdk-for-rust/tree/main/sdk/cosmos/azure_data_cosmos

crates.io https://crates.io/crates/azure_data_cosmos