Commit to Github Using API from Powershell

Continuing my search for doing automation in Powershell with as few dependencies as possible I turned to committing code to Github via the API.  I found various posts that outlined the basic process but not very good examples of getting it done, certainly none in Powershell.  So I extended the Powershell module I had already been working on, UMN-GitHub, to add support.  The short version is, just run the function Update-GitHubRepo.

The reference for master is ”refs/heads/master” however I would recommend committing to a test branch at a minimum and doing a pull request after that.  Github has plenty of content on best practices around all that and is outside the scope of this post. (use Get-GitHubRepoRef to get a list of refs, choose the one you want)

Lets dig in a bit to what the function actually does.

Run $headers = New-GitHubHeader [token or credential switch] first to get the header you will need.

# Get reference to head of ref and record Sha
$reference = Get-GitHubRepoRef -headers $headers -Repo $Repo -Org $Org -server $server -ref $ref
$sha = $reference.object.sha
# get commit for that ref and store Sha
$commit = Get-GitHubCommit -headers $headers -Repo $Repo -Org $Org -server $server -sha $sha
$treeSha = $commit.tree.sha
# Creat Blob
$blob = New-GitHubBlob -headers $headers -Repo $Repo -Org $Org -server $server -filePath $filePath
# create new Tree
$tree = New-GitHubTree -headers $headers -Repo $Repo -Org $Org -server $server -path $path -blobSha $blob.sha -baseTree $treeSha -mode 100644 -type 'blob'
# create new commit
$newCommit = New-GitHubCommit -headers $headers -Repo $Repo -Org $Org -server $server -message $message -tree $tree.sha -parents @($sha)
# update head to point at new commint
Set-GitHubCommit -headers $headers -Repo $Repo -Org $Org -server $server -ref $ref -sha $newCommit.sha

One thing to note, if you open up New-GitHubBlob you’ll notice I converted the file contents to base64.  Since the contents need to be sent as text via json data …. there wasn’t a good way to define a boundary and say “this is the file contents” without it blowing up.  Its not like you can attach a file.  So converting it to base64 solved a lot of problems.

This first version of New-GitHubTree is not very advanced and only takes in one file.  Future version may take in multiple version.

Powershell and the VMWare 6.5 RestAPI

VMWare has released a RestAPI to be an alternative to powercli and their other SDKs.  Once of the best ways to peek at the API is via the API Explorer.  In a browser, open the web page to your vcenter server/appliance: https://<vcenter-FQDN>/apiexplorer/

I found plenty of references to using the API is other languages/formats …… but as usual powershell was harder to come by.  Also, in general I found examples to be overly simplified and vmware’s explanation of what data should look like to be lacking.  So after a fair amount of trial and error I put together a number of basic functions and put them in a module.  They are public in Github.

The module is not (as of yet anyways) a complete covering of everything.  It covers basics around creating and removing VMs, tagging, and of course Authenticating.  The number of options around things like creating the vm are numerous therefore I did use some defaults.  That being said,  if you look at the code in the functions along with the apiexplorer you should have a good bases for making changes to make it do what you want.  This applies to all the functions.  As with most RestAPIs, once you figure out the basic structure of the various methods (GET,POST,DELETE,PUT,PATCH) and how to construct the body (in this case its just JSON), expanding to consume any part of the api becomes much easier.

 

Emergency! We need that patched!

Infrastructure is never a perfect world when it comes to Microsoft patch management. Is your WSUS service healthy? Is it integrated to SCCM as a software update point? Are you free of errors, but still not sure? Did that security patch really go out?

Your security monitoring, SCOM, or log analytics tool might tell you otherwise; and what are you left to do?

Do you believe the SCCM deployment reports, or your monitoring that says a critical patch is missing?

No matter the case of what, or why – sometimes there comes a point where you just need to brute force install a patch. Also, you need it, like, NOW.

You’ve got options if you’re prepared with DSC, but this is production, and we need them patched now – reboot later! Business requirements… alas.

Hopefully you can pull a dynamic list of systems from SCOM, SCCM, VMWare, Hyper-V, AD, or where ever… and just pipe it through. Obviously, if you need to reboot now as well, that is easy enough to modify from this little one-off.

Prep:
1. Get a list of systems you need to apply the patch to.
2. Extract the .cab of the KB you download from Microsoft.
3. Assumes you have remote powerShell / Admin access.

$listOfComputers| foreach {
$session = new-pssession $_
copy 'path to patchKB.cab' 'path to patchKB.cab' -tosession $session

Invoke-Command -session $session -scriptBlock {
## Check if KB is already installed
$KB = get-hotfix |where{$_.hotfixid -eq 'KB#####'}
if (!$KB) {

## Just in case you need to verify the OS version ##
$os = (Get-WmiObject -class Win32_OperatingSystem).version

## dism... I know -- allows for remote execution using no new processes, or EULA to the KB ##
dism.exe /online /add-package /PackagePath:c:\windows\temp\patchKB.cab /norestart
}

Else {write-host 'KB previously installed'}}}

DIY Continous Integration with GitHub Webhooks, Azure, and Docker Containers Part 1

There are plenty of tools out there focused on CI (Continuous Integration), not all of which play nice with Microsoft or are for some reason inaccessible ($$, IT management, etc).  This is one approach I’ve used based of the tools available to me.  Maybe some part of it will be of value to you.

The Main components are Github, Azure Runbooks, and Docker.  The overall process is this.  You make a commit in github, then github will send a bunch of data over to Azure to be processed.  Azure will spin up a docker container and dump your code onto the container.  I chose Azure for two reasons.  The cost to run the runbooks is very small.  You get 500 minutes Free!  After that its still only $0.002 / minute.  The second reason is that all the work has been done for you by Azure.  You don’t have to set anything up or manage another server.  We all have better things to do.

I’m actually going to start with the Azure Runbook because without that you can’t really create the webhook.  Create a Powershell Runbook and edit it.  Copy and paste the following for the first few lines.

param ([object]$WebHookData)
$WebhookBody = $WebhookData.RequestBody
$Inputs = ConvertFrom-JSON $WebhookBody
#$Inputs# here for debug, it will output to the ouput section of the job in Azure
#$Inputs.head_commit.modified
$authorEmail = $Inputs.head_commit.author.email
$ref = (($Inputs.ref).Split('/'))[-1]
$user = $Inputs.head_commit.committer.name
$message = $Inputs.head_commit.message
$message += "`n"
$files = $Inputs.head_commit.modified
$files = $files + $Inputs.head_commit.added
"Files changed/added $files"
$repo = $Inputs.repository.name
$org = $Inputs.repository.owner.name

There is plenty of additional information in $WebhookData.RequestBody, but this list grabs some of the key elements you need: what changed, by who, and what org/repo the changes were made in.  This is also a good starting point.  From here we need to add a Listener, aka Webhook.  Go ahead and publish what you have so far.  Back on the main page for the runbook under “RESOURCES” is a link to Webhooks.  Click on that and click to Add a webhook.  Create a new Webhook.  Give it a name and this is key YOU MUST COPY THE URL NOW.  Once you create it you can NOT go back and see the URL again.   Paste it someplace handy so you don’t lose it.  Almost done.  Click on OK and then click on “Modify run settings”.  The default is to Run on Azure.  Now this is also a great alternative and you can build automation around Azure vms and apply most of what will follow.  However, since I have access to on-prem equipment its cheaper to run everything local.  You will need to set up a Hybrid runbook worker  (This process is outside the scope of this post).  Don’t worry you can finish creating the Webhook now, leaving it on Azure, and come back later to switch over to your Hybrid Worker.

Now on to github.  To set up a repository webhook on GitHub, head over to the Settings page of your repository, and click on Webhooks & services. After that, click on Add webhook.  Take the URL you copied earlier and paste it into “Payload URL”.  You can leave the rest as defaults, make sure Content type is application/json.  Click on “Add Webhook”

Now you’re ready to start some basic testing.  If you don’t already have a dev/test branch for your repo, go ahead and create one.  Make a commit to your test branch.  Head back over to the Azure runbook.  This time under “RESOURCES” click on “Jobs”.   You should see a completed job (possibly In Queue or Running if you are quick).  Click on the Job.

Now you can click on the Output button and you should see some useful information.  If you go back to your runbook editor and start removing comments you will get even more information.  Remove the comment from $Inputs to see everything.  Use this part to get familiar with the data coming from github to determine what you consider to be valuable.

Part II will cover some decision making and spinning up the Container.

Install chef client on Windows Container and Connect to Chef Server

With a traditional windows machine the traditional “knife bootstrap windows winrm …” approach to bootstrapping works fine.  It is not however so straight forward for a container.  When you first spin up a container (assume a blank server core)  you have two methods to interact with it, Direct Powershell from the container host or the docker client, neither of which work with “knife” (in so far as I know).  You also don’t know the admin password.  There are going to be different methods to solving this problem, this is just one example that I have found to be simple and easy.  I am assuming you already have a chef server setup and have a minimal amount of familiarity with it.

Step one: Download the Validation key into a file named “validation.pem” and store it in an empty folder.  Then create a file ‘first-boot.json’ in that same folder. Contents:

{“run_list”:[]}

Of course you can add additional parameters to this file as you see fit.

You’ll also need to know your ‘chef_server_url’ and ‘validation_client_name’ (which you can get from “Generate knife Config” in the chef server.

Step two:  Spin up a container (more details on this here)

$ps = "Invoke-WebRequest -Uri 'https://raw.githubusercontent.com/Microsoft/Virtualization-Documentation/master/windows-server-container-tools/Wait-Service/Wait-Service.ps1' -OutFile 'c:\Wait-Service.ps1';c:\Wait-Service.ps1 -ServiceName WinRm -AllowServiceRestart"
($cid = docker run -d microsoft/windowsservercore powershell.exe -executionpolicy bypass $ps)

Step three: Install the chef client and connect to chef server.  There are 3 lines to update with your specific info

Invoke-Command -ContainerId $cid -RunAsAdministrator -ScriptBlock{Invoke-WebRequest -uri "https://omnitruck.chef.io/install.ps1" -OutFile c:\install.ps1;c:\install.ps1;Install}
$cPath = 'c:\'
$local = '' # update this from above
docker cp -L $local $cid`:$cPath
$chefURL = '' # update with your chef server URL
$validationClientName = '' # update this with your info
Invoke-Command -ContainerId $cid -RunAsAdministrator -ScriptBlock{
@" chef_server_url '$using:chefURL'
validation_client_name '$using:validationClientName'
file_cache_path 'c:/chef/cache'
file_backup_path 'c:/chef/backup'
cache_options ({:path => 'c:/chef/cache/checksums', :skip_expires => true})
node_name '$env:COMPUTERNAME'
log_level :info log_location STDOUT "@ | Out-File 'c:\chef\client.rb' -Encoding utf8 -Force
chef-client -c c:/chef/client.rb -j c:/chef/first-boot.json
}

That's it.  Run the following if you want to inspect the client.rb that is create for troubleshooting

$name = (((docker ps --no-trunc -a| Select-String $cid).ToString()).Normalize()).Split(" ")[-1]
$ps = "get-content c:\chef\client.rb"
docker exec $($name) powershell.exe -executionpolicy bypass $ps

Keep a Windows Container Running -Docker

The nature of a docker container is to start up, run a task, then go away.  It is uninterested in whatever service you want to run that is expected to be available to clients.  In order to keep the container running you need to give it something to do when you create the container.  This can be done with 2 simple lines of powershell.

## This string, when run by the container, will grab a script from microsoft and run it.
$ps = "Invoke-WebRequest -Uri 'https://raw.githubusercontent.com/Microsoft/Virtualization-Documentation/master/windows-server-container-tools/Wait-Service/Wait-Service.ps1' -OutFile 'c:\Wait-Service.ps1';c:\Wait-Service.ps1 -ServiceName WinRm -AllowServiceRestart"
## This will start the container and feed it the string above then while capturing the containerID that you'll want for later
($cid = docker run -d microsoft/windowsservercore powershell.exe -executionpolicy bypass $ps)
## While were at it, lets get the name of the container, it will come in handy as well
($name = (((docker $dkrRemote ps --no-trunc -a| Select-String $cid).ToString()).Normalize()).Split(" ")[-1])

The Wait-Service.ps1 file is provided by Microsoft via github.  Since this is a hosted file and could change, I would recommend downloading it and storing it on a web server you control to avoid unplanned changes.  Another alternative is to download the file and include it as part of your image build process and skipping the Invoke-webrequest part.

The variable $cid holds the ContainerID which is very useful for copying over files and restarting a container, etc.

You of course can substitute in any container image you like.  I prefer to work with a clean container.

Powershell: Finding All Traverse Groups

When it comes to managing file shares one of the larger issues I deal with on a regular basis is identifying all the traverse groups that lead to a specific folder.

The first thing to do is identify what makes a traverse ACL.  Where I work we simply use Read and Execute rights and then apply them to the folder only, not inheriting further down the tree.

I first build those into variables I can use later on:

# Build tests for traverse group
$TravRights = [System.Security.AccessControl.FileSystemRights]"ReadAndExecute,Synchronize"
$TravInheritanceFlag = [System.Security.AccessControl.InheritanceFlags]::None
$TravPropagationFlag = [System.Security.AccessControl.PropagationFlags]::None
$TravType = [System.Security.AccessControl.AccessControlType]::Allow

In order to properly handle the full path we’ll identify the root of the path.  When it’s a network share that’s grabbing the third entry of the array created from the “string”.split(“\”) as the first two entries are blank from the front double backslashes.  Otherwise I’m assuming it’s a normal filesystem provider which can simply have it’s qualifier split from the path.

# Get the root of the path
if($Path.StartsWith("\\")) {
    $RootPath = "\\" + [string]::Join("\",$Path.Split("\")[2])
} else {
    $RootPath = Split-Path -Path $Path -Qualifier
}

Next, you need to build a list of the directories leading to the directory in question.  The first thing I do is pull apart the string using String.Split().  Next I use the Split-Path cmdlet to identify the root drive.  We also need to pull out the root of the drive so all we’re getting is a list of the directories in order.

Also, we’ll create a path’s arraylist which we’ll use to parse through the directories and create a list of all thee paths not just the directories.  So if we pass into the function C:\Foo\Bar we get “C:\Foo”, “C:\Foo\Bar back as an array list.

# Split up paths and pull the root
$spath = $Path.Replace("$RootPath\", "").Split("\")
$Paths = New-Object System.Collections.ArrayList

# Build a list of all the directories that lead to the target directory
for($i = 0; $i -le $spath.Length; $i++) {
    if($spath[$i] -ne $null) {
        $PathToAdd = ""
        for($j = 0; $j -le $i; $j++) {
            $PathToAdd += "$($spath[$j])\"
        }
        # Add the new path to our list of paths
        $Paths.Add("$RootPath\$PathToAdd") | Out-Null
    }
}

Once we have our list of paths to check we can simply loop through the paths then gett the ACL for each path.  Once we have the ACL we can loop through the Access rules in each ACL and then check the access rule against the flags we defined earlier which are what we’re looking for.

# Loop through the paths and determine which contain a traverse group
foreach($item in $Paths) {
    $itemacl = Get-Acl -Path $item
        foreach($acl in $itemacl.Access) {
        # Check the acl for the traverse permissions defined earlier
        if(($acl.InheritanceFlags -eq $travInheritanceFlag) -and ($acl.PropagationFlags -eq $travPropagationFlag) -and ($acl.FileSystemRights -eq $travRights) -and ($acl.AccessControlType -eq $travType) -and ($acl.IsInherited -eq $false)) {
            # We've now found a traverse group
            $SamAccountName = $acl.IdentityReference.ToString().Split("\")[1]

            # Make sure the account name isn't null, then get the group make sure it exists in AD then add the path to the group output object.
            if($null -ne $SamAccountName) {
                $ADObject = Get-ADGroup -Identity $SamAccountName
                if($ADObject -ne $null) {
                    $TraverseGroups += $ADObject | Add-Member -MemberType NoteProperty -Name TraversePath -Value $item -Force -PassThru
                }
            }
        }
    }
}

Once we’ve identified that we’ve found exactly what we’re looking for and that the account name isn’t null we can add it to our $TraverseGroups array.

The full code can be obtained from my GitHub repository Find-TraverseGroups.