title | keywords | author | ms.author | ms.date | ms.topic | ms.devlang | ms.service |
---|---|---|---|---|---|---|---|
Azure Cosmos DB client library for JavaScript |
Azure, javascript, SDK, API, @azure/cosmos, cosmosdb |
kushagraThapar |
kuthapar |
03/01/2023 |
reference |
javascript |
cosmosdb |
/TypeScript
Azure Cosmos DB is a globally distributed, multi-model database service that supports document, key-value, wide-column, and graph databases. This package is intended for JavaScript/TypeScript applications to interact with SQL API databases and the JSON documents they contain:
- Create Cosmos DB databases and modify their settings
- Create and modify containers to store collections of JSON documents
- Create, read, update, and delete the items (JSON documents) in your containers
- Query the documents in your database using SQL-like syntax
Key links:
You must have an Azure Subscription, and a Cosmos DB account (SQL API) to use this package.
If you need a Cosmos DB SQL API account, you can use the Azure Cloud Shell to create one with this Azure CLI command:
az cosmosdb create --resource-group <resource-group-name> --name <cosmos-database-account-name>
Or you can create an account in the Azure Portal
This package is distributed via npm which comes preinstalled with NodeJS. You should be using Node v10 or above.
You need to set up Cross-Origin Resource Sharing (CORS) rules for your Cosmos DB account if you need to develop for browsers. Follow the instructions in the linked document to create new CORS rules for your Cosmos DB.
npm install @azure/cosmos
You will need your Cosmos DB Account Endpoint and Key. You can find these in the Azure Portal or use the Azure CLI snippet below. The snippet is formatted for the Bash shell.
az cosmosdb show --resource-group <your-resource-group> --name <your-account-name> --query documentEndpoint --output tsv
az cosmosdb keys list --resource-group <your-resource-group> --name <your-account-name> --query primaryMasterKey --output tsv
Interaction with Cosmos DB starts with an instance of the CosmosClient class
const { CosmosClient } = require("@azure/cosmos");
const endpoint = "https://your-account.documents.azure.com";
const key = "<database account masterkey>";
const client = new CosmosClient({ endpoint, key });
async function main() {
// The rest of the README samples are designed to be pasted into this function body
}
main().catch((error) => {
console.error(error);
});
For simplicity we have included the key
and endpoint
directly in the code but you will likely want to load these from a file not in source control using a project such as dotenv or loading from environment variables
In production environments, secrets like keys should be stored in Azure Key Vault
Once you've initialized a CosmosClient, you can interact with the primary resource types in Cosmos DB:
-
Database: A Cosmos DB account can contain multiple databases. When you create a database, you specify the API you'd like to use when interacting with its documents: SQL, MongoDB, Gremlin, Cassandra, or Azure Table. Use the Database object to manage its containers.
-
Container: A container is a collection of JSON documents. You create (insert), read, update, and delete items in a container by using methods on the Container object.
-
Item: An Item is a JSON document stored in a container. Each Item must include an
id
key with a value that uniquely identifies the item within the container. If you do not provide anid
, the SDK will generate one automatically.
For more information about these resources, see Working with Azure Cosmos databases, containers and items.
The following sections provide several code snippets covering some of the most common Cosmos DB tasks, including:
Important
Management operations like creating a database or a container will not be available if role-based access control (RBAC) is used to authenticate instead of using a key as described above. For more details on using RBAC, see Permissions model.
After authenticating your CosmosClient, you can work with any resource in the account. The code snippet below creates a SQL API database.
const { database } = await client.databases.createIfNotExists({ id: "Test Database" });
console.log(database.id);
This example creates a container with default settings
const { container } = await database.containers.createIfNotExists({ id: "Test Database" });
console.log(container.id);
To insert items into a container, pass an object containing your data to Items.upsert. The Cosmos DB service requires each item has an id
key. If you do not provide one, the SDK will generate an id
automatically.
This example inserts several items into the container
const cities = [
{ id: "1", name: "Olympia", state: "WA", isCapitol: true },
{ id: "2", name: "Redmond", state: "WA", isCapitol: false },
{ id: "3", name: "Chicago", state: "IL", isCapitol: false }
];
for (const city of cities) {
await container.items.create(city);
}
To read a single item from a container, use Item.read. This is a less expensive operation than using SQL to query by id
.
await container.item("1").read();
To delete items from a container, use Item.delete.
// Delete the first item returned by the query above
await container.item("1").delete();
A Cosmos DB SQL API database supports querying the items in a container with Items.query using SQL-like syntax:
const { resources } = await container.items
.query("SELECT * from c WHERE c.isCapitol = true")
.fetchAll();
for (const city of resources) {
console.log(`${city.name}, ${city.state} is a capitol `);
}
Perform parameterized queries by passing an object containing the parameters and their values to Items.query:
const { resources } = await container.items
.query({
query: "SELECT * from c WHERE c.isCapitol = @isCapitol",
parameters: [{ name: "@isCapitol", value: true }]
})
.fetchAll();
for (const city of resources) {
console.log(`${city.name}, ${city.state} is a capitol `);
}
For more information on querying Cosmos DB databases using the SQL API, see Query Azure Cosmos DB data with SQL queries.
The SDK generates various types of errors that can occur during an operation.
ErrorResponse
is thrown if the response of an operation returns an error code of >=400.TimeoutError
is thrown if Abort is called internally due to timeout.AbortError
is thrown if any user passed signal caused the abort.RestError
is thrown in case of failure of underlying system call due to network issues.- Errors generated by any devDependencies. For Eg.
@azure/identity
package could throwCredentialUnavailableError
.
Following is an example for handling errors of type ErrorResponse
, TimeoutError
, AbortError
, and RestError
.
try {
// some code
} catch (err) {
if (err instanceof ErrorResponse) {
// some specific error handling.
} else if (err instanceof RestError) {
// some specific error handling.
}
// handle other type of errors in similar way.
else {
// for any other error.
}
}
It's important to properly handle these errors to ensure that your application can gracefully recover from any failures and continue functioning as expected. More details about some of these errors and their possible solutions can be found here.
When you interact with Cosmos DB errors returned by the service correspond to the same HTTP status codes returned for REST API requests:
HTTP Status Codes for Azure Cosmos DB
For example, if you try to create an item using an id
that's already in use in your Cosmos DB database, a 409
error is returned, indicating the conflict. In the following snippet, the error is handled gracefully by catching the exception and displaying additional information about the error.
try {
await containers.items.create({ id: "existing-item-id" });
} catch (error) {
if (error.code === 409) {
console.log("There was a conflict with an existing item");
}
}
The Azure SDKs are designed to support ES5 JavaScript syntax and LTS versions of Node.js. If you need support for earlier JavaScript runtimes such as Internet Explorer or Node 6, you will need to transpile the SDK code as part of your build process.
While working with Cosmos DB, you might encounter transient failures caused by rate limits enforced by the service, or other transient problems like network outages. For information about handling these types of failures, see Retry pattern in the Cloud Design Patterns guide, and the related Circuit Breaker pattern.
Enabling logging may help uncover useful information about failures. In order to see a log of HTTP requests and responses, set the AZURE_LOG_LEVEL
environment variable to info
. Alternatively, logging can be enabled at runtime by calling setLogLevel
in the @azure/logger
. While using AZURE_LOG_LEVEL
make sure to set it before logging library is initialized.
Ideally pass it through command line, if using libraries like dotenv
make sure such libraries are initialized before logging library.
const { setLogLevel } = require("@azure/logger");
setLogLevel("info");
For more detailed instructions on how to enable logs, you can look at the @azure/logger package docs.
Several samples are available to you in the SDK's GitHub repository. These samples provide example code for additional scenarios commonly encountered while working with Cosmos DB:
- Database Operations
- Container Operations
- Item Operations
- Configuring Indexing
- Reading a container Change Feed
- Stored Procedures
- Changing Database/Container throughput settings
- Multi Region Write Operations
Currently the features below are not supported. For alternatives options, check the Workarounds section below.
- Queries with COUNT from a DISTINCT subquery
- Direct TCP Mode access
- Continuation token for cross partitions queries
- Change Feed: Processor
- Change Feed: Read multiple partitions key values
- Change Feed: Read specific time
- Change Feed: Read from the beginning
- Change Feed: Pull model
- Cross-partition ORDER BY for mixed types
- Get CollectionSizeUsage, DatabaseUsage, and DocumentUsage metrics
- Create Geospatial Index
- Update Autoscale throughput
You can achieve cross partition queries with continuation token support by using Side car pattern. This pattern can also enable applications to be composed of heterogeneous components and technologies.
Typically, you can use Azure Portal, Azure Cosmos DB Resource Provider REST API, Azure CLI or PowerShell for the control plane unsupported limitations.
For more extensive documentation on the Cosmos DB service, see the Azure Cosmos DB documentation on docs.microsoft.com.
- Welcome to Azure Cosmos DB
- Quick start
- Tutorial
- Samples
- Introduction to Resource Model of Azure Cosmos DB Service
- Introduction to SQL API of Azure Cosmos DB Service
- Partitioning
- API Documentation
If you'd like to contribute to this library, please read the contributing guide to learn more about how to build and test the code.