On Tuesday I posted about the new Digipede SnapIn for PowerShell.
One question I didn’t get into is, why write a SnapIn when PowerShell supports full scripting for .NET APIs? The short answer is that we can provide a better command-line experience with PowerShell cmdlets than the “out of the box” PowerShell experience. Windows PowerShell Architect, Jeffrey Snover, did a great post on this a few months back: Cmdlets vs. APIs.
I thought I’d give an example of the difference as it relates to the new Digipede SnapIn.
For example, suppose you want to enumerate the pools on a Digipede Network. Natively in PowerShell, you can do the following:
[System.Reflection.Assembly]::LoadFrom("C:\\Program Files\\Digipede" +
"\\Framework SDK\\v2.0\\Net2.0\\Digipede.Framework.dll")
$DigipedeClient = New-Object -TypeName Digipede.Framework.Api.DigipedeClient
$DigipedeClient.SetUrlFromHost("MYSERVER")
$DigipedeClient.Management.GetPools() | ft
That is pretty verbose (note the first line is split in two to improve readability in my blog). This same operation becomes much simpler with the Digipede SnapIn:
Add-PSSnapIn DigipedeSnapIn $DigipedeClient = New-DNClient -Network MYSERVER Get-DNPool
And what about the output? Without any extra information, PowerShell will format output on its own — a very cool feature. The former example produces a default table output:
IsReadO PoolId Name Descrip Collect Schedul Potenti TotalCo JobTota TaskTot
nly tion ion ingAlgo alGhz mputeRe lComple alCompl
rithm sources ted eted
------- ------ ---- ------- ------- ------- ------- ------- ------- -------
True 1 Mast... Mast... {Mas... ...rity 66 19 665 57584
True 601 Fifo {Mas... ...tOut 18 3 0 0
PowerShell can’t determine which properties should be included, so it makes a guess. The DigipedeSnapIn includes formatting information to give much more readable (and useful) default output:
PoolId Name Description Resources Potential GHzH ------ ---- ----------- --------- --------- 1 Master Pool Master Pool 19 66 601 Fifo 3 18
So, the SnapIn definitely provides a better command-line experience. And the great thing? These two worlds are not mutually exclusive. For example, suppose you want to specify the default pool for a DigipedeClient object? We haven’t exposed that as a property on New-DNClient nor provided a cmdlet for this purpose, but the API includes the PoolId property. Just do this:
$DigipedeClient.PoolId = (Get-DNPool -Name "Fifo").PoolId
Now, the default pool is a pool named “FIFO”.
This brings me back to something I wrote in my previous post: PowerShell is cool.