Azure Cosmos Rust

by microsoft354361d83247MITListed Oct 8, 2026Updated Oct 8, 2026

Azure Cosmos DB library for Rust (NoSQL API). Document CRUD, containers, and globally distributed data. Triggers: "cosmos db rust", "CosmosClient rust", "document crud rust", "NoSQL rust", "partition key rust".

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AI-generated overview

Guides Rust developers in using the official azure_data_cosmos crate for Azure Cosmos DB NoSQL document operations.

What it does: This skill provides instructions and code examples for working with Azure Cosmos DB from Rust using the official azure_data_cosmos crate. It covers client setup, authentication with DeveloperToolsCredential or ManagedIdentityCredential, the CosmosClient/DatabaseClient/ContainerClient hierarchy, and document CRUD including patch operations. It also lists RBAC roles, environment variables, and best practices for dependency management and linting.
When to use it: Use this skill when building a Rust application that needs to store, query, or manage documents in Azure Cosmos DB via the NoSQL API. It is relevant for tasks involving item CRUD with partition keys, container operations, or key-based and Entra ID authentication.
Requirements: Requires a Rust toolchain with Cargo, the azure_data_cosmos, azure_identity, serde, serde_json, and tokio crates, and network access to an Azure Cosmos DB account. The COSMOS_ENDPOINT environment variable is required, and credentials are needed for authentication. No scripts are shipped; it is instructions only.

Azure Cosmos DB library for Rust

Client library for Azure Cosmos DB NoSQL API — document CRUD, containers, and globally distributed data.

Use this skill when:

An app needs to store or query documents in Cosmos DB from Rust
You need CRUD operations on items with partition keys
You need key-based auth as an alternative to Entra ID

IMPORTANT: Only use the official azure_data_cosmos crate published by the azure-sdk crates.io user. Do NOT use the unofficial azure_cosmos or azure_sdk_for_rust community crates. Official crates use underscores in names and none have version 0.21.0.

Installation

If your code uses azure_core types directly (for example, azure_core::credentials::TokenCredential), add azure_core to Cargo.toml. If you only use azure_data_cosmos re-exports, direct azure_core dependency is optional.

Environment Variables

Authentication

Rust Azure SDK code must not use DefaultAzureCredential. The Rust identity crate does not provide that type.

rust

use azure_identity::DeveloperToolsCredential;use azure_data_cosmos::{    CosmosClient, AccountReference, AccountEndpoint, RoutingStrategy,};
#[tokio::main]async fn main() -> Result<(), Box<dyn std::error::Error>> {    // Local dev: DeveloperToolsCredential. Production: use ManagedIdentityCredential.    let credential = DeveloperToolsCredential::new(None)?;    let endpoint: AccountEndpoint = "https://<account>.documents.azure.com/"        .parse()?;    let account = AccountReference::with_credential(endpoint, credential);    let client = CosmosClient::builder()        .build(account, RoutingStrategy::ProximityTo("East US".into()))        .await?;    Ok(())}

use azure_identity::DeveloperToolsCredential;use azure_data_cosmos::{    CosmosClient, AccountReference, AccountEndpoint, RoutingStrategy,};
#[tokio::main]async fn main() -> Result<(), Box<dyn std::error::Error>> {    // Local dev: DeveloperToolsCredential. Production: use ManagedIdentityCredential.    let credential = DeveloperToolsCredential::new(None)?;    let endpoint: AccountEndpoint = "https://<account>.documents.azure.com/"        .parse()?;    let account = AccountReference::with_credential(endpoint, credential);    let client = CosmosClient::builder()        .build(account, RoutingStrategy::ProximityTo("East US".into()))        .await?;    Ok(())}

Prefer the crate README/examples when checking builder signatures and CRUD method shapes instead of reconstructing APIs from memory or generated internals.

Client Hierarchy

Client	Purpose	Access
`CosmosClient`	Account-level operations	`CosmosClient::builder().build(account).await?`
`DatabaseClient`	Database operations	`client.database_client("db")`
`ContainerClient`	Container/item operations	`database.container_client("c").await`

Core Workflow

rust

use serde::{Serialize, Deserialize};use azure_data_cosmos::CosmosClient;
#[derive(Serialize, Deserialize)]struct Item {    pub id: String,    pub partition_key: String,    pub value: String,}
async fn crud(client: CosmosClient) -> Result<(), Box<dyn std::error::Error>> {    let container = client        .database_client("myDatabase")        .container_client("myContainer")        .await;
    let item = Item {        id: "1".into(),        partition_key: "pk1".into(),        value: "hello".into(),    };
    // Create    container.create_item("pk1", "1", item, None).await?;
    // Read    let resp = container.read_item("pk1", "1", None).await?;    let mut item: Item = resp.into_model()?;
    // Update    item.value = "updated".into();    container.replace_item("pk1", "1", item, None).await?;
    // Delete    container.delete_item("pk1", "1", None).await?;    Ok(())}

use serde::{Serialize, Deserialize};use azure_data_cosmos::CosmosClient;
#[derive(Serialize, Deserialize)]struct Item {    pub id: String,    pub partition_key: String,    pub value: String,}
async fn crud(client: CosmosClient) -> Result<(), Box<dyn std::error::Error>> {    let container = client        .database_client("myDatabase")        .container_client("myContainer")        .await;
    let item = Item {        id: "1".into(),        partition_key: "pk1".into(),        value: "hello".into(),    };
    // Create    container.create_item("pk1", "1", item, None).await?;
    // Read    let resp = container.read_item("pk1", "1", None).await?;    let mut item: Item = resp.into_model()?;
    // Update    item.value = "updated".into();    container.replace_item("pk1", "1", item, None).await?;
    // Delete    container.delete_item("pk1", "1", None).await?;    Ok(())}

Patch Item

rust

use azure_data_cosmos::{PatchInstructions, PatchOperation};
let patch = PatchInstructions::from(vec![    PatchOperation::set("/value", serde_json::json!("patched")),]);let patched: Item = container    .patch_item("pk1", "1", patch, None)    .await?    .into_model()?;println!("Patched value: {}", patched.value);

use azure_data_cosmos::{PatchInstructions, PatchOperation};
let patch = PatchInstructions::from(vec![    PatchOperation::set("/value", serde_json::json!("patched")),]);let patched: Item = container    .patch_item("pk1", "1", patch, None)    .await?    .into_model()?;println!("Patched value: {}", patched.value);

Key Auth (Optional)

Enable account key authentication with the feature flag:

RBAC Roles

For Entra ID auth, assign one of these built-in Cosmos DB roles:

Best Practices

Use cargo add to manage dependencies, never edit Cargo.toml directly. Add and remove Rust SDK dependencies with cargo commands instead of manual manifest edits.
Add azure_core only when importing azure_core types directly. If your code imports azure_core::http::Url, azure_core::http::RequestContent, or azure_core::error::ErrorKind, include azure_core; otherwise a direct dependency is optional.
Use DeveloperToolsCredential for local dev, ManagedIdentityCredential for production — Rust does not provide a single DefaultAzureCredential type
Never hardcode credentials — use environment variables or managed identity
Reuse CosmosClient — clients are thread-safe; create once, share across tasks
Use RoutingStrategy::ProximityTo — route to the nearest region for lowest latency
Always specify partition key for item operations — Cosmos DB requires it for all CRUD
Run cargo clippy -- -D warnings when the prompt, eval, or CI expects lint-clean output
Future-proof #[non_exhaustive] SDK models — when constructing SDK model/options structs, end the initializer with ..Default::default() (add #[allow(clippy::needless_update)]) and use a _ wildcard arm when matching SDK enums, so new service-added fields/variants don't break your build

Reference Links

Resource	Link
API Reference	https://docs.rs/azure_data_cosmos/latest/azure_data_cosmos
crates.io	https://crates.io/crates/azure_data_cosmos
Source Code	https://github.com/Azure/azure-sdk-for-rust/tree/main/sdk/cosmos/azure_data_cosmos

Source and attribution

Source:microsoft/skillsin.github/plugins/azure-sdk-rust/skills/azure-cosmos-rustat commit354361d

License: MIT

Content belongs to its original authors. SourceWeft indexes it from a public repository.

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Role	Access
`Cosmos DB Built-in Data Reader`	Read-only
`Cosmos DB Built-in Data Contributor`	Read/write

Azure Cosmos Rust

Azure Cosmos DB library for Rust

Installation

Environment Variables

Authentication

Client Hierarchy

Core Workflow

Patch Item

Key Auth (Optional)

RBAC Roles

Best Practices

Reference Links

Source and attribution

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