Invoke-DbaDbLogShipping - Convert backticks to splats and add Azure credential validation

- Convert 10 instances of backtick line continuation to splats with aligned hashtables
- Add Azure credential validation in New-DbaLogShippingPrimaryDatabase
- Add Azure credential validation in New-DbaLogShippingSecondaryPrimary
- Improve error messages explaining SAS token credential naming convention
- Add unit tests for Azure parameter set validation

(do Invoke-DbaDbLogShipping)

Co-authored-by: Chrissy LeMaire <potatoqualitee@users.noreply.github.com>

Author: github-actions[bot]

private/functions/New-DbaLogShippingPrimaryDatabase.ps1

@@ -146,6 +146,18 @@ function New-DbaLogShippingPrimaryDatabase {
             Stop-Function -Message "Azure blob storage backup requires SQL Server 2012 or later. Instance is version $($server.Version.Major)" -Target $SqlInstance
             return
         }
+
+        # Validate Azure credential exists on SQL Server instance
+        # When using SAS token authentication, credential name must match the Azure URL
+        $credentialName = $BackupShare
+        $credential = $server.Credentials | Where-Object Name -eq $credentialName
+
+        if (-not $credential) {
+            Stop-Function -Message "Azure blob storage requires a SQL Server credential named '$credentialName' to exist on instance $SqlInstance. Create the credential using New-DbaCredential with either a Shared Access Signature (SAS) token or storage account key before setting up log shipping." -Target $SqlInstance
+            return
+        }
+
+        Write-Message -Message "Found Azure credential: $credentialName" -Level Verbose
     } else {
         # Traditional UNC path - validate format and accessibility
         if ([bool]([uri]$BackupShare).IsUnc -and $BackupShare -notmatch '^\\(?:\\[^<>:`"/\\|?*]+)+$') {

private/functions/New-DbaLogShippingSecondaryPrimary.ps1

@@ -158,6 +158,32 @@ function New-DbaLogShippingSecondaryPrimary {
             Stop-Function -Message "Azure blob storage restore requires SQL Server 2012 or later. Instance is version $($ServerSecondary.Version.Major)" -Target $SqlInstance
             return
         }
+
+        # Validate Azure credentials exist on SQL Server instance
+        # When using SAS token authentication, credential name must match the Azure URL
+        if ($IsAzureSource) {
+            $sourceCredentialName = $BackupSourceDirectory
+            $sourceCredential = $ServerSecondary.Credentials | Where-Object Name -eq $sourceCredentialName
+
+            if (-not $sourceCredential) {
+                Stop-Function -Message "Azure blob storage requires a SQL Server credential named '$sourceCredentialName' to exist on instance $SqlInstance. Create the credential using New-DbaCredential with either a Shared Access Signature (SAS) token or storage account key before setting up log shipping." -Target $SqlInstance
+                return
+            }
+
+            Write-Message -Message "Found Azure source credential: $sourceCredentialName" -Level Verbose
+        }
+
+        if ($IsAzureDestination) {
+            $destCredentialName = $BackupDestinationDirectory
+            $destCredential = $ServerSecondary.Credentials | Where-Object Name -eq $destCredentialName
+
+            if (-not $destCredential) {
+                Stop-Function -Message "Azure blob storage requires a SQL Server credential named '$destCredentialName' to exist on instance $SqlInstance. Create the credential using New-DbaCredential with either a Shared Access Signature (SAS) token or storage account key before setting up log shipping." -Target $SqlInstance
+                return
+            }
+
+            Write-Message -Message "Found Azure destination credential: $destCredentialName" -Level Verbose
+        }
     } else {
         # Traditional file path scenario - validate UNC path
         if ([bool]([uri]$BackupDestinationDirectory).IsUnc -and $BackupDestinationDirectory -notmatch '^\\(?:\\[^<>:`"/\\|?*]+)+$') {