Category: Powershell

Garry Bargsley has gone through twelve days of the dbatools module’s functionality:

The final day is upon us and I have saved the best for last and one you can take in to the holiday season as a present from our fearless leader of dbatools.  The Start-DbaMigration is where the dbatools module started years ago.  Who of us have not said “I really should automate this tedious SQL migration stuff” so I do not forget a step when I have not had enough coffee.  Well Chrissy LeMaire (b | t) not only said it, but made it reality.  This early work has grown in to the dbatools module that we know today and has grown in to a multi-tool toolkit that help the DBA expand their skills without having the burden of learning a scripting language and the complexity that goes with hooking it to your SQL Server.

This tool has literally changed my life since finding it a couple years ago.  Not only am I doing work in PowerShell, I am automating work processes.  Also, this has contributed to my personal growth.  Chrissy and team has such a welcoming atmosphere and inclusion around the project, it has guided me to contribute to an open source project as well as guided me to presenting at SQL Saturdays events.

Read the whole thing. And if you missed parts of the series, they’re all up on Garry’s blog.

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Max Trinidad walks us through an issue with Powershell Core Preview 3:

Just in case you haven’t try to install PowerShell Core Preview.3, in Windows, which became available on the evening of the 10th of December. If are doing a clean installation, meaning that it was previously manually uninstall, or that this is your first installation, then you are fine.
The issue with installing PowerShell Core Preview.3 is when you do an upgrade over a previous version: either Preview.1 or Preview.2.

That’s a common occupational hazard when working with preview tools.  But Max has your solution.

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Andy Levy shows how to use the PoshRSJob module to implement multithreaded Powershell solutions:

Let’s say you’ve got a lot of RSJobs. Or maybe long-running RSJobs. Wouldn’t a nice, user-friendly view of the progress be handy? You bet it would!

This is both dense and verbose, but I wrote it really quickly and it works (but not just for this post, I’ve used it in production), so I’m not tinkering too much with it right now. Once the jobs are created (and a few have started), this script runs a loop watching the output of Get-RSJob and updates a progress bar to reflect where we are. It also takes care of receiving and removing the completed jobs.

This is pretty easy to work with—or at least Andy makes it look that way.

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Jess Pomfret shows us an example of creating mandatory parameters but also having a default set:

I came across a situation this week where I wanted to add the option of running an existing script,  for a specific server/database combination.  The script currently has no parameters and runs against all servers in the environment from a scheduled task.  I wanted to make sure that behavior didn’t change. The other requirement was that if I specified Server, Database should be a mandatory parameter and vice versa.
The final solution was to add the two parameters to a parameter set and make them both mandatory.  I also had to add a different DefaultParameterSet (thanks to Andrew for this idea), otherwise it defaulted to the defined parameter set, meaning the script always required both Server and Database parameters.

Click through for a demo.

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Adam Bertram has a paean in honor of Tee-Object:

What does Tee-Object  do anyway? Tee-Object basically kills two birds with one stone. This cmdlet redirects output from a PowerShell command and either saves it to a file or to a variable while also returning the output to the pipeline. It allows a scripter to save the output and send the output across the pipeline all in one shot.
Let’s say a scripter wants to send some text to a file and then perform kind of task on that same text afterward. Perhaps we’re pulling a list of Windows services from a computer and saving that output to a text file to create a snapshot of the before state before we attempt to start the services. This task can be done in two separate steps or with a single one with Tee-Object .

I’ve used it several times in Powershell as well as the tee command in Linux.  It’s great when you need to do several things with the same data but don’t want to break out of your pipeline.

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Chrissy LeMaire has found a technique to reduce the load time for dbatools:

I don’t know the in-depth internals of Import-Module, but I know that importing a DLL filled with C# cmdlets is extremely fast. For instance, Microsoft’s SqlServer module imports 100 commands in less than a second. Sometimes it’s closer to half a second!
I wondered if we could somehow compile our commands into a C# binary but that seemed far-fetched. One thing we could do, though, is use compression! It works for SQL Server backups, could it work for PowerShell?

Spoilers:  the answer is “yes.”  Read on to see how much faster the initial import gets.

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