PowerShell SDK

Here's a bit of PS that goes at the head of my scripts for RESTAPI work... uses Credential Manager 2.0 with the restAPI user/key stored in  the windows cred store:

Import-Module     CredentialManager

function          Send-Request               {
    param (
        $cred               ,
        $URL                ,
        $accessid    = $null,
        $accesskey   = $null,
        $data        = $null,
        $version     = '2'  ,
        $httpVerb    = "GET"
    )
    if ( $accessId -eq $null) {
        $accessId    = $cred.UserName
        $accessKey   = $cred.GetNetworkCredential().Password
    }
    # Use TLS 1.2
    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

    # Get current time in milliseconds
    $epoch           = [Math]::Round(
        ( New-TimeSpan `
            -start (Get-Date -Date "1/1/1970") `
            -end (Get-Date).ToUniversalTime()).TotalMilliseconds
        )
    # Concatenate Request Details
    $requestVars     = $httpVerb + $epoch + $data + $resourcePath

    # Construct Signature
    $hmac            = New-Object System.Security.Cryptography.HMACSHA256
    $hmac.Key        = [Text.Encoding]::UTF8.GetBytes( $accessKey )
    $signatureBytes  = $hmac.ComputeHash( [Text.Encoding]::UTF8.GetBytes( $requestVars ) )
    $signatureHex    = [System.BitConverter]::ToString( $signatureBytes ) -replace '-'
    $signature       = [System.Convert]::ToBase64String( [System.Text.Encoding]::UTF8.GetBytes( $signatureHex.ToLower() ) )
    # Construct Headers
    $auth            = 'LMv1 ' + $accessId + ':' + $signature + ':' + $epoch
    $headers         = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
    $headers.Add(      "Authorization", $auth              )
    $headers.Add(      "Content-Type" , 'application/json' )
    # uses version 2 of the API
    $headers.Add(      "X-version"    , $version           )
    
	# Make Request
    try {
        $response        = Invoke-RestMethod  `
            -Uri             $URL             `
            -Method          $httpVerb        `
            -Body            $data            `
            -Header          $headers         `
            -erroraction     stop `
            -warningaction   SilentlyContinue
    } catch {
        $response    = -1
    }
    Return $response
}

function          Get-LMRestAPIObjectListing {
    param (
        $URLBase          ,
        $resourcePathRoot , # "/device/devices"
        $size = 1000      ,
        $accessKey        ,
        $accessId         ,
        $version = '2'
    )

    write-host "Gathering $resourcePathRoot"

    $output  = @()
    $looping = $true
    $counter = 0

    # write-host "Gathering data from $resourcePathRoot"
    while ($looping) {

        # Re-calc offset based on iteration
        $offset = $counter * $size
        $resourcePath    = $resourcePathRoot
        $queryParam      = "?size=$size&offset=$offset"
        $url             = $URLBase + $resourcePath + $queryParam

        # Make Request
        $response        = Send-Request `
            -accesskey    $accessKey    `
            -accessid     $accessId     `
            -URL          $url          `
            -version      $version
        if ( $response.items.count -eq $size ) {
            # Return set is full, more items to retrieve
            $output     += $response.items
            $counter++
        } elseif ( $response.items.count -gt 0 ) {
            # Return set is not full, store date, end loop
            $output     += $response.items
            $looping     = $false
        } else {
            # Return set is empty, no data to store, end loop
            $looping     = $false
        }
    }
    write-output $output
    }

$company        = "<CompanyName>"
$URLBase        = "https://$company.logicmonitor.com/santaba/rest"

# This will resolve to proper values if it's being run from inside LM
$accessID       = "##Logicmonitor.AccessID.key##"
$accessKey      = "##Logicmonitor.AccessKey.key##"

if ( $accessID -like "##*" )       {
    # Not being run from inside LM - populate manually for testing
    Import-Module CredentialManager
    $Cred       = Get-StoredCredential -Target LogicMonitor
    $accessID   = $cred.UserName
    $accessKey  = $Cred.GetNetworkCredential().Password
}

# Get Devices
$resourcePath         = "/device/devices"
$Devices              = Get-LMRestAPIObjectListing `
    -resourcePathRoot $resourcePath                `
    -accessKey        $accessKey                   `
    -accessId         $accessID                    `
    -URLBase          $URLBase

I wrote most of it using the standard "Send-Request" piece from LM's docs and the posts here... but added a bit to work around the request limit to allow me to fill a variable with all of the specific piece I'm looking for.  It also allows for storing creds for dev that are also in LM properties for deployment.  They're stored in a generic windows credential named "LogicMonitor" locally.

To expand what it does, change or duplicate the "Get Devices" section to target a different $resourcePath from the swagger doc for the restAPI.

DISCLAIMER: this code comes with no guarantees from myself or my employers past and present that it is safe in your environment.  Use it with caution as you always should.