Implement and query Azure Cosmos DB logs

Azure Cosmos DB is a distributed database service offered by Microsoft Azure, suitable for building native applications with global reach. It provides comprehensive support for querying and analyzing logs, enabling developers to gain valuable insights into their application’s performance and behavior. In this article, we will explore the implementation and querying of Azure Cosmos DB logs, leveraging the capabilities provided by the service.

Enabling Diagnostic Logs for Azure Cosmos DB:

Before we can start querying Azure Cosmos DB logs, we need to enable diagnostic logs for our Cosmos DB account. Enabling diagnostic logs allows the service to capture logs related to various activities performed on the database, such as operations, executions, and metrics.

To enable diagnostic logs for Azure Cosmos DB, follow these steps:

1. Open the Azure portal and navigate to your Cosmos DB account.
2. In the left-hand menu, click on “Diagnostic settings” under the Monitoring section.
3. Click on “Add diagnostic setting” to create a new diagnostic setting.
4. Provide a name for the diagnostic setting and select the desired target resource (Cosmos DB account).
5. Under the “Logs” section, select the log types that you want to enable. For Azure Cosmos DB, you can choose from three log types: Operations, Executions, and Metrics.
6. Choose the desired retention period for the logs.
7. Click on “Save” to enable the diagnostic setting.

Once the diagnostic logs are enabled, Azure Cosmos DB will start capturing the relevant logs for your account.

Querying Azure Cosmos DB Logs:

Now that we have enabled diagnostic logs for Azure Cosmos DB, let’s explore how we can query these logs to gain insights into the performance and behavior of our application.

Azure Cosmos DB provides a REST-based API to query the logs. You can use tools like PowerShell, Azure CLI, or even send HTTP requests programmatically to query the logs.

Here is an example using PowerShell to query the Azure Cosmos DB logs:

# Set the variables for the Cosmos DB account
$resourceGroupName = ""
$accountName = ""
$subscriptionId = ""

# Set the start and end time for the log query
$startTime = "2022-01-01T00:00:00Z"
$endTime = "2022-01-02T23:59:59Z"

# Set the query string
$query = "AzureDiagnostics | where ResourceProvider == 'MICROSOFT.DOCUMENTDB' | where Category == 'DataPlaneRequests'"

# Use the Azure CLI to query the logs
az monitor log-analytics query --workspace "" --subscription "$subscriptionId" `
--query "AzureDiagnostics | where ResourceProvider == 'MICROSOFT.DOCUMENTDB' | where Category == 'DataPlaneRequests' | where TimeGenerated >= '$startTime' and TimeGenerated <= '$endTime'"

In the example above, we are querying the logs for data plane requests made to Azure Cosmos DB. We filter the logs based on the ResourceProvider and Category fields and use the TimeGenerated field to specify the desired time range.

You can modify the query to include additional filters or fields based on your requirements. Refer to the Azure Monitor documentation for detailed information on querying Azure Cosmos DB logs.

Conclusion:

Querying Azure Cosmos DB logs provides valuable insights into the performance and behavior of your application. By enabling diagnostic logs and leveraging the querying capabilities of Azure Cosmos DB, you can easily monitor and analyze various metrics related to your database operations. This helps in identifying and resolving issues, optimizing performance, and ensuring the smooth functioning of your native applications built on Azure Cosmos DB.