This section describes how to edit the DSN configuration and then authenticate and connect to Azure Data Lake Storage APIs.

DSN Configuration

You can use the Microsoft ODBC Data Source Administrator to edit the DSN configuration. Note that the installation process creates a both a user DSN and a system DSN, as described in Installing the Connector.

Note: The connector stores connection information in the Windows registry. To ensure that the connector can write to the registry, either run Power BI as an administrator or use a User DSN for your connection instead of a System DSN.

User DSN

Complete the following steps to edit the DSN configuration:

1. Select Start > Search, and enter ODBC Data Sources in the Search box.
2. Choose the version of the ODBC Administrator that corresponds to the bitness of your Power BI Desktop installation (32-bit or 64-bit).
3. Select the system data source and click Configure.
4. Edit the information on the Connection tab and click OK.

System DSN

Configure the system DSN the same way as the user DSN, except you will need to switch to the System DSN tab before performing Step 3.

If you're using Power BI's On-Premises Data Gateway with Standard mode, you must use the system DSN.

You must also specify a valid location for OAuthSettingsLocation (a path where OAuth credentials are locally stored to avoid repeated OAuth prompts).

This is because the Standard mode runs on service mode and can only access permitted locations, such as C:\Windows\ServiceProfiles\PBIEgwService\AppData\Local\Microsoft\On-premises data gateway.

Connecting to CData Power BI Connector for Azure Data Lake Storage Gen 2

To connect to a Gen 2 DataLakeStorage account, set the following properties:

• Account: The name of the storage account.
• FileSystem: The file system name used for this account. For example, the name of an Azure Blob Container.
• Directory (Optional): The path to the location where the replicated file should be stored. If no path is specified, the file is stored in the root directory.

Authenticating to CData Power BI Connector for Azure Data Lake Storage Gen 2

CData Power BI Connector for Azure Data Lake Storage supports four different ways to authenticate: using an AccessKey, using a Shared Access Signature, Azure Active Directory OAuth (AzureAD), and Managed Service Identity (AzureMSI).

Access Key

To connect using an access key, you must first obtain an available access key for the ADLS Gen2 storage account.

At the Azure portal:

1. Go to your ADLS Gen2 Storage Account.
2. Under Settings, select Access keys.
3. Copy the value for one of the available access keys to the AccessKey connection property.

When you are ready to connect, set these properties:

• AuthScheme: AccessKey.
• AccessKey: The access key value you just retrieved from the Azure Portal.

Shared Access Signature (SAS)

To connect using a Shared Access Signature, you must first generate one using the Azure Storage Explorer tool.

When you are ready to connect, set these properties:

• AuthScheme: SAS.
• SharedAccessSignature: The value of the Shared Access Signature you just generated.

Azure AD

Azure AD is Microsoft’s multi-tenant, cloud-based directory and identity management service. It is user-based authentication that requires that you set AuthScheme to AzureAD.

Authentication to Azure AD over a Web application always requires the creation of a custom OAuth application. For details, see Creating an Azure AD Application.

Desktop Applications

CData provides an embedded OAuth application that simplifies connection to Azure AD from a Desktop application.

You can also authenticate from a desktop application using a custom OAuth application. (For further information, see Creating an Azure AD Application.) To authenticate via Azure AD, set these parameters:

• AuthScheme: AzureAD.

• Custom applications only:

  • OAuthClientId: The client Id assigned when you registered your custom OAuth application.
  • OAuthClientSecret: The client secret assigned when you registered your custom OAuth application.
  • CallbackURL: The redirect URI you defined when you registered your custom OAuth application.

When you connect, the connector opens Azure Data Lake Storage's OAuth endpoint in your default browser. Log in and grant permissions to the application.

The connector completes the OAuth process, obtaining an access token from Azure Data Lake Storage and using it to request data. The OAuth values are saved in the path specified in OAuthSettingsLocation. These values persist across connections.

When the access token expires, the connector refreshes it automatically.

Headless Machines

To configure the driver with a user account on a headless machine, you must authenticate on another device that has an internet browser.

You can do this in either of the following ways:

• Obtain the OAuthVerifier value as described below in Option 1: Obtain and Exchange a Verifier Code.
• Install the connector on another machine as described below in Option 2: Transfer OAuth Settings. After you authenticate via the usual browser-based flow, transfer the OAuth authentication values.

Option 1: Obtain and Exchange a Verifier Code

1. Find the authorization endpoint.

   Custom applications only: Set these properties to create the Authorization URL:

   • OAuthClientId: The client Id assigned when you registered your application.
   • OAuthClientSecret: The client secret assigned when you registered your application.

   Custom and embedded applications: Call the GetOAuthAuthorizationURL stored procedure.

   1. Open the URL returned by the stored procedure in a browser.
   2. Log in and grant permissions to the connector. You are redirected to the callback URL, which contains the verifier code.
   3. Save the value of the verifier code. You will use this later to set the OAuthVerifier connection property.

2. Exchange the OAuth verifier code for OAuth refresh and access tokens.

   At the headless machine, set these properties:

   • AuthScheme: AzureAD.
   • OAuthVerifier: The verifier code.
   • OAuthSettingsLocation: The location of the file that holds the OAuth token values that persist across connections.

   • Custom applications only:

     • OAuthClientId: The client Id in your custom OAuth application settings.
     • OAuthClientSecret: The client secret in the custom OAuth application settings.

3. After the OAuth settings file is generated, reset the following properties to connect:

   • OAuthSettingsLocation: The location containing the encrypted OAuth authentication values. Make sure this location grants read and write permissions to the connector to enable the automatic refreshing of the access token.

   • Custom applications only:

     • OAuthClientId: The client Id assigned when you registered your application.
     • OAuthClientSecret: The client secret assigned when you registered your application.

Option 2: Transfer OAuth Settings

Before you can connect via a headless machine, you must create and install a connection with the driver on a device that supports an internet browser. Set the connection properties as described above, in Desktop Applications.

After you complete the instructions in Desktop Applications, the resulting authentication values are encrypted and written to the location specified by OAuthSettingsLocation. The default filename is OAuthSettings.txt.

Once you have successfully tested the connection, copy the OAuth settings file to your headless machine.

At the headless machine, set these properties:

• AuthScheme: AzureAD.
• OAuthSettingsLocation: The location of your OAuth settings file. Make sure this location gives read and write permissions to the connector to enable the automatic refreshing of the access token.

• Custom applications only:

  • OAuthClientId: The client Id assigned when you registered your application.
  • OAuthClientSecret: The client secret assigned when you registered your application.

Managed Service Identity (MSI)

If you are running Azure Data Lake Storage on an Azure VM and want to leverage MSI to connect, set AuthScheme to AzureMSI.

User-Managed Identities

To obtain a token for a managed identity, use the OAuthClientId property to specify the managed identity's "client_id".

When your VM has multiple user-assigned managed identities, you must also specify OAuthClientId.