AWS Developer Blog

Listing Cmdlets by Service

by Steve Roberts | on | in .NET | Permalink | Comments |  Share

In this post, we discussed a new cmdlet you can use to navigate your way around the cmdlets in the AWS Tools for Windows PowerShell module. This cmdlet enables you to search for cmdlets that implemented a service API by answering questions like, "Which cmdlet implements the Amazon EC2 ‘RunInstances’ API?" It can also do a simple translation of AWS CLI commands you might have found in example documentation to give you the equivalent cmdlet.

In the 3.1.21.0 version of the tools, we extended this cmdlet. Now you can use it to get a list of all cmdlets belonging to a service based on words that appear in the service name or the prefix code we use to namespace the cmdlets by service. You could, of course, do something similar by using the PowerShell Get-Command cmdlet and supplying the -Noun parameter with a value that is the prefix with a wildcard (for example, Get-Command -Module AWSPowerShell -Noun EC2*). The problem here is that you need to know the prefix before you can run the command. Although we try to choose memorable and easily guessable prefixes, sometimes the association can be subtle and searching based on one or more words in the service name is more useful.

To list cmdlets by service you supply the -Service parameter. The value for this parameter is always treated as a case-insensitive regular expression and is used to match against cmdlets using both their ‘namespace’ prefix and full name. For example:

PS C:> Get-AWSCmdletName -Service compute

CmdletName                      ServiceOperation             ServiceName
----------                      ----------------             -----------
Add-EC2ClassicLinkVpc           AttachClassicLinkVpc         Amazon Elastic Compute Cloud
Add-EC2InternetGateway          AttachInternetGateway        Amazon Elastic Compute Cloud
Add-EC2NetworkInterface         AttachNetworkInterface       Amazon Elastic Compute Cloud
Add-EC2Volume                   AttachVolume                 Amazon Elastic Compute Cloud
...
Stop-EC2SpotInstanceRequest     CancelSpotInstanceRequests   Amazon Elastic Compute Cloud
Unregister-EC2Address           DisassociateAddress          Amazon Elastic Compute Cloud
Unregister-EC2Image             DeregisterImage              Amazon Elastic Compute Cloud
Unregister-EC2PrivateIpAddress  UnassignPrivateIpAddresses   Amazon Elastic Compute Cloud
Unregister-EC2RouteTable        DisassociateRouteTable       Amazon Elastic Compute Cloud

When a match for the parameter value is found, the output contains a collection of PSObject instances. Each instance has members detailing the cmdlet name, service operation, and service name. You can see the assigned prefix code in the cmdlet name. If the search term fails to match any supported service, you’ll see an error message in the output.

You might be asking yourself why we output the service name. We do this because the parameter value is treated as a regular expression and it attempts to match against two pieces of metadata in the module’s cmdlets (service and prefix). It is therefore possible that a term can match more than one service. For example:

PS C:> Get-AWSCmdletName -Service EC2

CmdletName                      ServiceOperation           ServiceName
----------                      ----------------           -----------
Add-EC2ClassicLinkVpc           AttachClassicLinkVpc       Amazon Elastic Compute Cloud
Add-EC2InternetGateway          AttachInternetGateway      Amazon Elastic Compute Cloud
...
Unregister-EC2RouteTable        DisassociateRouteTable     Amazon Elastic Compute Cloud
Get-ECSClusterDetail            DescribeClusters           Amazon EC2 Container Service
Get-ECSClusters                 ListClusters               Amazon EC2 Container Service
Get-ECSClusterService           ListServices               Amazon EC2 Container Service
...
Unregister-ECSTaskDefinition    DeregisterTaskDefinition   Amazon EC2 Container Service
Update-ECSContainerAgent        UpdateContainerAgent       Amazon EC2 Container Service
Update-ECSService               UpdateService              Amazon EC2 Container Service

You’ll see the result set contains cmdlets for both Amazon EC2 and Amazon EC2 Container Service. This is because the search term ‘EC2’ matched the noun prefix for the cmdlets exposing the Amazon EC2 service API as well as the service name for the container service.

We hope you find this new capability useful. You can get the new version as a Windows Installer package here or through the PowerShell Gallery.

If you have suggestions for other features, let us know in the comments!