Cmdlets for Azure Data Lake Storage

Build 24.0.9060

Establishing a Connection

With the CData Cmdlets users can install a data module, set the connection properties, and start scripting. This section provides examples of using our ADLS Cmdlets with native PowerShell cmdlets, like the CSV import and export cmdlets.

Installing and Connecting

If you have PSGet, installing the cmdlets can be accomplished from the PowerShell Gallery with the following command. You can also obtain a setup from the CData site. 

Install-Module ADLSCmdlets

The following line is then added to your profile, loading the cmdlets on the next session: 

Import-Module ADLSCmdlets;

You can then use the Connect-ADLS cmdlet to create a connection object that can be passed to other cmdlets: 

$conn = Connect-ADLS -Account "MyStorageAccount" -FileSystem "MyBlobContainer" -AccessKey "MyAccessKey"

Connecting to CData Cmdlets PowerShell Module 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 Cmdlets PowerShell Module for Azure Data Lake Storage Gen 2

CData Cmdlets PowerShell Module 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 cmdlet opens Azure Data Lake Storage's OAuth endpoint in your default browser. Log in and grant permissions to the application.

The cmdlet 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 cmdlet 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 cmdlet 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 cmdlet. 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 cmdlet 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 cmdlet 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.

Retrieving Data

The Select-ADLS cmdlet provides a native PowerShell interface for retrieving data: 

$results = Select-ADLS -Connection $conn -Table "Resources" -Columns @("FullPath, Permission") -Where "Type='FILE'"
The Invoke-ADLS cmdlet provides an SQL interface. This cmdlet can be used to execute an SQL query via the Query parameter.

Piping Cmdlet Output

The cmdlets return row objects to the pipeline one row at a time. The following line exports results to a CSV file: 

Select-ADLS -Connection $conn -Table Resources -Where "Type = 'FILE'" | Select -Property * -ExcludeProperty Connection,Table,Columns | Export-Csv -Path c:\myResourcesData.csv -NoTypeInformation

You will notice that we piped the results from Select-ADLS into a Select-Object cmdlet and excluded some properties before piping them into an Export-CSV cmdlet. We do this because the CData Cmdlets append Connection, Table, and Columns information onto each row object in the result set, and we do not necessarily want that information in our CSV file.

However, this makes it easy to pipe the output of one cmdlet to another. The following is an example of converting a result set to JSON: 

 
PS C:\> $conn  = Connect-ADLS -Account "MyStorageAccount" -FileSystem "MyBlobContainer" -AccessKey "MyAccessKey"
PS C:\> $row = Select-ADLS -Connection $conn -Table "Resources" -Columns (FullPath, Permission) -Where "Type = 'FILE'" | select -first 1
PS C:\> $row | ConvertTo-Json
{
  "Connection":  {

  },
  "Table":  "Resources",
  "Columns":  [

  ],
  "FullPath":  "MyFullPath",
  "Permission":  "MyPermission"
}

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Build 24.0.9060