Cosmos DB Triggers Tutorials

Explore practical tutorials on leveraging Cosmos DB triggers to automate actions and build reactive applications. Triggers in Cosmos DB can be used to execute custom JavaScript code automatically in response to data modifications within your containers.

Getting Started with Cosmos DB Triggers

Cosmos DB triggers allow you to create event-driven architectures. When an item is created, updated, or deleted in a Cosmos DB container, a pre-trigger or post-trigger function can be executed.

Triggering Azure Functions on Data Changes

Learn how to set up a Cosmos DB trigger for an Azure Function to process incoming data. This is ideal for real-time data validation, aggregation, or sending notifications.

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Implementing Custom Logic with Stored Procedures and Triggers

Dive deeper into writing JavaScript for your Cosmos DB triggers. This tutorial covers common use cases like maintaining data consistency or performing complex calculations.

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Monitoring and Debugging Cosmos DB Triggers

Discover best practices for monitoring the performance of your triggers and debugging potential issues. Understand how to use Azure Monitor and Cosmos DB diagnostic logs.

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Common Use Cases

  • Real-time Data Processing: React instantly to data changes.
  • Data Validation: Enforce business rules before data is committed.
  • Auditing: Log changes made to documents.
  • Notifications: Send alerts or update other services based on data events.
  • Data Synchronization: Keep related data consistent across different parts of your application.

Code Examples

Here's a simple example of a JavaScript trigger that runs after an item is created or updated:


function updateMetadata() {
    var context = getContext();
    var request = context.getRequest();
    var item = getBody();

    if (!item.createdAt) {
        item.createdAt = new Date();
    }
    item.updatedAt = new Date();

    // Validate item content
    if (!item.name || item.name.length === 0) {
        throw new Error("The 'name' property is required.");
    }

    request.execute();
}

This trigger adds or updates createdAt and updatedAt timestamps and performs basic validation on the name property.

Next Steps