You can access on-premises data from your Logic App as well. For this, you can use the on-premises data gateway. The on-premises data gateway can connect on-premises environments to a number of Azure services, such as Azure Analysis Services, Azure Logic Apps, Microsoft Flow, Power Apps, and Power BI. For the on-premises side, there are a number of products that can be connected to the gateway, such as SQL Server, SQL Analysis Services, and SharePoint. 

To use the on-premises data gateway, a client needs to be installed on the on-premises environment. The client consists of a Windows Service that is responsible for setting up the connection with Azure. In Azure, a gateway cloud service needs to be created. The client then communicates with the gateway cloud service using the Azure Service Bus.

When a request for data is created by one of the Azure Services, the cloud gateway service creates a query and encrypts the on-premises credentials. This query and its credentials are then sent to a queue inside the gateway. Afterwards, the gateway sends the query to the Azure Service Bus.

The on-premises client polls the Azure Service Bus regularly. When a message is waiting inside the Service Bus, it decrypts the credentials from the on-premises data source. From there, it will run the query on it to retrieve the data. The following diagram illustrates this:

Now that we have seen how to manage a Logic App, let's look at Azure Event Grid.