Azure Series - Steps to expose an on-premise .NET Core API through Azure API Management

Let's walk through an example of how to expose an on-premise .NET Core API through Azure API Management.

Scenario:
You have a .NET Core API running on-premise, and you want to make it securely accessible through Azure API Management. Azure API Management acts as a gateway, providing features like authentication, authorization, rate limiting, and caching for your API.

Step 1: Set Up On-Premise .NET Core API
Ensure that your .NET Core API is running and accessible on your on-premise server. Make sure it's properly secured and can handle incoming requests.

Step 2: Create an Azure API Management Service
Go to the Azure portal and create a new API Management service. Choose a name, subscription, resource group, location, and pricing tier that best suits your needs.

Step 3: Import API into Azure API Management
In the Azure API Management service, navigate to the "APIs" section and click on "Add a new API." Here, you'll have two options: "Blank API" or "API from OpenAPI file." Choose the appropriate method to import your API.

1. Option 1: If you have an OpenAPI (Swagger) file for your on-premise API, you can directly import it by selecting the "API from OpenAPI file" option and providing the file's URL.

2. Option 2: If you don't have an OpenAPI file, you can choose the "Blank API" option and manually define the endpoints, operations, and other details of your API.

Step 4: Configure Backend to Point to On-Premise .NET Core API
In the API Management service, navigate to your imported API and click on "Settings." Under the "Backend" section, configure the "Web service URL" to point to the endpoint of your on-premise .NET Core API.

Step 5: Secure the API with Policies (Optional)
If your on-premise API requires authentication or additional security measures, you can apply Azure API Management policies to enforce them. For example, you can add JWT validation or client certificate authentication policies.

Step 6: Publish the API
Once you have configured the API Management service with your on-premise API details, click on "Save" and then "Publish" to make it accessible.

Step 7: Test the API
Now that your on-premise .NET Core API is exposed through Azure API Management, you can test it using the provided developer portal or tools like Postman. Verify that your API is accessible and that any security measures you implemented are working as expected.

Conclusion:
By following these steps, you can securely expose your on-premise .NET Core API through Azure API Management. This allows you to leverage the powerful features of API Management while ensuring secure and controlled access to your on-premise API from external clients or applications.