Update AzMig_Dependencies.psm1 (Azure#320)

* Update AzMig_Dependencies.psm1

Changed TokenCache behaviour now that is depricated and removed redundant assignment of the TokenCacheItem variable.

* Update AzMig_Dependencies.psm1

Changed to use token directly from Get-AzAccessToken and removed redundant code.

* Update AzMig_Dependencies.psm1

Added verification for Az.Accounts module to be at least 2.2.0.

* Update README.md

Added requirement for Az.Accounts 2.2.0 or higher.

Author: martyncoup

azure-migrate/dependencies-at-scale/AzMig_Dependencies.psm1

@@ -17,6 +17,10 @@ function GetRequestProperties()
         Import-Module Az.Accounts
     }
 
+    if ((Get-Module Az.Accounts).Version -lt "2.2.0") {
+        throw "At least Az.Accounts 2.2.0 is required, please update before continuing."
+    }
+    
     $CurrentContext = Get-AzContext
     if (-not $CurrentContext) {
         throw "Not logged in. Use Connect-AzAccount to log in"
@@ -44,35 +48,12 @@ function GetRequestProperties()
 		New-Variable -Name ResourceURL -Value "https://management.core.windows.net/" -Option Constant
 	}
 
-    $TokenCache = $CurrentContext.TokenCache
-    if (-not $TokenCache) {
-        throw "Missing or incomaptible module version. Get the latest version of the Az.Accounts module"
-    }
-
-    $TokenCacheItem = $TokenCache.ReadItems() |
-                      Where-Object -Property TenantId -eq $TenantId |
-                      Where-Object -Property DisplayableId -eq $UserId |
-                      Where-Object -Property Resource -eq $ResourceURL
-    if (-not $TokenCacheItem) {
-        throw "Something went wrong. Open a new PowerShell session, login with Connect-AzAccount and then try again"
-    }
-
-    $authorityURL = $CurrentContext.Environment.ActiveDirectoryAuthority +$TenantId
-    $AuthContext = [Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext]::new($authorityURL, $TokenCache)
-
-    if (-not $AuthContext) {
-        throw "Couldn't get Auth Context. ADAL Library version missing or incompatible. Get the latest version of the Az.Accounts module"
-    }  
-
-    $Task = $AuthContext.AcquireTokenSilentAsync($ResourceURL, "1950a258-227b-4e31-a9cf-717495945fc2") 
-    while (-not $Task.AsyncWaitHandle.WaitOne(200)) {}
-    $Result = $Task.GetAwaiter().GetResult()
-
-    if((-not $Result) -or (-not $Result.AccessToken)) {
-        throw "Something went wrong while fetching access token"
+    $Token = (Get-AzAccessToken -ResourceUrl $ResourceURL -TenantId $TenantId).Token
+    if (-not $Token) {
+        throw "Missing token, please make sure you are signed in."
     }
 
-    $AuthorizationHeader = "Bearer " + $Result.AccessToken
+    $AuthorizationHeader = "Bearer " + $Token
     $Headers = [ordered]@{Accept = "application/json"; Authorization = $AuthorizationHeader} 
 
 	if($Environment -eq "AzureUSGovernment") {

azure-migrate/dependencies-at-scale/README.md

@@ -19,7 +19,8 @@ Before you get started, you need to do the following:
 - Ensure that VMware Tools (later than 10.2) is installed on each VM you want to analyze.
 - Ensure you have downloaded the AzMig_Dependencies powershell module in this folder.
 - Ensure you have PowerShell available. It is recommended you use the [latest version of PowerShell](https://docs.microsoft.com/powershell/scripting/install/installing-powershell).
-- Ensure you have the [Azure PowerShell](https://docs.microsoft.com/powershell/azure/install-az-ps) module installed. 
+- Ensure you have the [Azure PowerShell](https://docs.microsoft.com/powershell/azure/install-az-ps) module installed.
+- The Az.Accounts module is required and must be at least version 2.2.0 or higher.
 
 ## Log in to Azure
 
@@ -96,4 +97,4 @@ The Network Connections chart and the Source server name, Destination server nam
 4. Visualize the map of network connections filtering by servers and processes.
 > Below is an example output when the data is visualized within PowerBI
 
-![PowerShell Output](images/PowerBI_example_output.jpg)
+![PowerShell Output](images/PowerBI_example_output.jpg)