How to add foreach-object -parallel output to a dictionary/arraylist - powershell

Question

I'm trying to get all the stale branches from Azure DevOps to nag the developers to remove them.
If I use this script below, I get all the results I want, but it takes ages to process.
$resultlist = New-Object System.Collections.ArrayList
function Get-StaleBranches {
$dateString = (Get-Date).AddDays(-90).ToString("MM/dd/yyyy HH:mm:ss")
$date = [datetime]::parseexact($dateString, 'MM/dd/yyyy HH:mm:ss', $null)
$reposArray | ForEach-Object {
$repo = $PSItem
$refsUri = "url"
$refs = (Invoke-RestMethod -Uri $refsUri -Method get -Headers $AzureDevOpsAuthenicationHeader).value
foreach($branch in $refs){
$splitName = $branch.name.Substring(11)
$commitUri = $using:OrgUri + "url"
$commits = (Invoke-RestMethod -Uri $commitUri -Method get -Headers $AzureDevOpsAuthenicationHeader).value
$commitDate = [datetime]::parseexact($commits.author.date, 'MM/dd/yyyy HH:mm:ss', $null)
if($commitDate -lt $date -and $splitName -notlike "develop" -and $splitName -notlike "release" -and $splitName -notlike "master")
{
$result = #{}
$result.repo = $repo
$result.branch = $splitName
$result.date = $commitDate
$result.author = $commits.author.name
$result.email = $commits.author.email
$resultlist.Add((New-Object PsObject -Property $result)) | Out-Null
}
}
}
}
Get-StaleBranches
To speed it up, I tried using the foreach-object -parallel functionality like this:
$threadSafeDictionary = [System.Collections.Concurrent.ConcurrentDictionary[string,object]]::new()
function Get-StaleBranches {
$dateString = (Get-Date).AddDays(-90).ToString("MM/dd/yyyy HH:mm:ss")
$date = [datetime]::parseexact($dateString, 'MM/dd/yyyy HH:mm:ss', $null)
$reposArray | ForEach-Object -Parallel {
$dict = $using:threadSafeDictionary
$repo = $PSItem
$dict.$repo = #()
$refsUri = "url"
$refs = (Invoke-RestMethod -Uri $refsUri -Method get -Headers $using:AzureDevOpsAuthenicationHeader).value
foreach($branch in $refs){
$splitName = $branch.name.Substring(11)
$commitUri = "url"
$commits = (Invoke-RestMethod -Uri $commitUri -Method get -Headers $using:AzureDevOpsAuthenicationHeader).value
$commitDate = [datetime]::parseexact($commits.author.date, 'MM/dd/yyyy HH:mm:ss', $null)
if($commitDate -lt $using:date -and $splitName -notlike "develop" -and $splitName -notlike "release" -and $splitName -notlike "master")
{
$dict.$repo += [PSCustomObject]#{
Branch = $splitName
Date = $commitDate
Author = $commits.author.name
Email = $commits.author.email
}
}
}
}
}
Get-StaleBranches
However, now all branches in the dictionary are doubled. Did I make a mistake somewhere? Is there any other way to approach this?
Any help will be appreciated.

Answer 1

I have no explanation for your symptom, but I recommend simplifying your code as follows, which will also speed it up:
Avoid the explicit use of (synchronized) data structures and instead let PowerShell collect loop output in an array for you, as described in this answer, which works with any command output (and therefore also with ForEach-Object [-Parallel] and a foreach loop statement).
The following simplified example shows how to do that:
function Get-StaleBranches {
# Implicitly output what the ForEach-Object -Parallel script block outputs.
(1..5).ForEach({ 'repo' + $_ }) | ForEach-Object -Parallel {
# Create and implicitly output a custom object for each repo.
[pscustomobject] #{
Repo = $PSItem
Results = foreach ($branch in (1..3).ForEach({ 'branch' + $_ })) {
# Create and implicitly output a custom object; all such objects
# created in this `foreach` loop are collected in the .Results property.
[pscustomobject] #{
Branch = $branch
Date = Get-Date
}
}
}
}
}
Note:
Calling Get-StaleBranches outputs a stream of (nested) [pscustomobject] instances, which, when captured in a variable, become an [object[]] array.
Display output:
Repo Result
---- ------
repo1 {#{Branch=branch1; Date=2/6/2023 11:53:33 AM}, #{Branch=branch2; Date=2/6/2023 11:53:33 AM}, #{Branch=branch3; Date=2/6/2023 11:53:33 AM}}
repo2 {#{Branch=branch1; Date=2/6/2023 11:53:33 AM}, #{Branch=branch2; Date=2/6/2023 11:53:33 AM}, #{Branch=branch3; Date=2/6/2023 11:53:33 AM}}
repo3 {#{Branch=branch1; Date=2/6/2023 11:53:33 AM}, #{Branch=branch2; Date=2/6/2023 11:53:33 AM}, #{Branch=branch3; Date=2/6/2023 11:53:33 AM}}
repo4 {#{Branch=branch1; Date=2/6/2023 11:53:33 AM}, #{Branch=branch2; Date=2/6/2023 11:53:33 AM}, #{Branch=branch3; Date=2/6/2023 11:53:33 AM}}
repo5 {#{Branch=branch1; Date=2/6/2023 11:53:33 AM}, #{Branch=branch2; Date=2/6/2023 11:53:33 AM}, #{Branch=branch3; Date=2/6/2023 11:53:33 AM}}
This isn't the same as returning a dictionary keyed by branch names, but it isn't hard to adapt the solution to do that:
$dict = #{} # initialize output dictionary (hashtable)
Get-StaleBranches |
ForEach-Object {
# Create an entry for the repo at hand.
$dict[$_.Repo] = $_.Results
}
# Output the resulting dictionary.
$dict
Display output (the Name column contains the dictionary's key values):
Name Value
---- -----
repo4 {#{Branch=branch1; Date=2/6/2023 12:01:42 PM}, #{Branch=branch2; Date=2/6/2023 12:01:42 PM}, #{Branch=branch3; Date=2/6/2023 12:01:42 PM}}
repo2 {#{Branch=branch1; Date=2/6/2023 12:01:42 PM}, #{Branch=branch2; Date=2/6/2023 12:01:42 PM}, #{Branch=branch3; Date=2/6/2023 12:01:42 PM}}
repo5 {#{Branch=branch1; Date=2/6/2023 12:01:42 PM}, #{Branch=branch2; Date=2/6/2023 12:01:42 PM}, #{Branch=branch3; Date=2/6/2023 12:01:42 PM}}
repo3 {#{Branch=branch1; Date=2/6/2023 12:01:42 PM}, #{Branch=branch2; Date=2/6/2023 12:01:42 PM}, #{Branch=branch3; Date=2/6/2023 12:01:42 PM}}
repo1 {#{Branch=branch1; Date=2/6/2023 12:01:42 PM}, #{Branch=branch2; Date=2/6/2023 12:01:42 PM}, #{Branch=branch3; Date=2/6/2023 12:01:42 PM}}