Enable task hubs for Durable E2E tests (#631)

Author: Francisco-Gamino

test/E2E/Start-E2ETest.ps1

@@ -8,6 +8,55 @@ param
     $UseCoreToolsBuildFromIntegrationTests
 )
 
+function NewTaskHubName
+{
+    param(
+        [int]$Length = 45
+    )
+
+    <#
+    Task hubs are identified by a name that conforms to these rules:
+      - Contains only alphanumeric characters
+      - Starts with a letter
+      - Has a minimum length of 3 characters, maximum length of 45 characters
+
+    doc: According to the documentation here https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-task-hubs?tabs=csharp
+    #>
+
+    $min = 20
+    $max = 45
+
+    if ($length -lt $min -or $Length -gt $max)
+    {
+        throw "Length must be between $min and $max characters. Provided value: $length"
+    }
+
+    $letters = 'a'..'z' + 'A'..'Z'
+    $numbers = 0..9
+    $alphanumeric = $letters + $numbers
+
+    # First value is a letter
+    $sb = [System.Text.StringBuilder]::new()
+    $value = $letters | Get-Random
+    $sb.Append($value) | Out-Null
+
+    # Add the date and time as part of the name. This way, we can delete older versions.
+    # Example: 202104251929 is for 2021-04-25:1929 (this value is 12 characters long)
+    $value = Get-Date -Format "yyyyMMddHHmm"
+    $sb.Append($value) | Out-Null
+
+    # The remaining of the characters are random alphanumeric values
+    for ($index = 13; $index -lt $length; $index++)
+    {
+        $value = $alphanumeric | Get-Random
+        $sb.Append($value) | Out-Null
+    }
+
+    $sb.ToString()
+}
+
+$taskHubName = NewTaskHubName -Length 45
+
 $FUNC_RUNTIME_VERSION = '3'
 $NETCOREAPP_VERSION = '3.1'
 $POWERSHELL_VERSION = '7'
@@ -68,6 +117,7 @@ if (-not $UseCoreToolsBuildFromIntegrationTests.IsPresent)
 
 Write-Host "Starting Functions Host..."
 
+$Env:TestTaskHubName = $taskHubName
 $Env:FUNCTIONS_WORKER_RUNTIME = "powershell"
 $Env:FUNCTIONS_WORKER_RUNTIME_VERSION = $POWERSHELL_VERSION
 $Env:AZURE_FUNCTIONS_ENVIRONMENT = "development"

test/E2E/TestFunctionApp/host.json

@@ -6,5 +6,10 @@
     "extensionBundle": {
         "id": "Microsoft.Azure.Functions.ExtensionBundle",
         "version": "[2.*, 3.0.0)"
-    }
+    },
+    "extensions": {
+        "durableTask": {
+          "hubName": "%TestTaskHubName%"
+        }
+      }
 }