win_robocopy add md5 checksum check for copy

lib/ansible/modules/windows/win_robocopy.ps1

@@ -8,6 +8,7 @@
 $params = Parse-Args $args -supports_check_mode $true
 $check_mode = Get-AnsibleParam -obj $params -name "_ansible_check_mode" -type "bool" -default $false
 
+$checksum = Get-AnsibleParam -obj $params -name "checksum" -type "bool" -default $false
 $src = Get-AnsibleParam -obj $params -name "src" -type "path" -failifempty $true
 $dest = Get-AnsibleParam -obj $params -name "dest" -type "path" -failifempty $true
 $purge = Get-AnsibleParam -obj $params -name "purge" -type "bool" -default $false
@@ -75,6 +76,80 @@ if ($null -eq $flags) {
 $result.flags = $flags
 $result.cmd = "$robocopy $robocopy_opts"
 
+$checksum_output=@()
+if ($checksum -eq $true){
+    $checksum_output+="md5 checksum enabled for existing destination files, changed files:"
+    $excludelist=@()
+    if ($flags -match '/xf') {
+        $excludes=($flags -Split "/xf ")[1]
+        $excludelist=$excludes.Split(' ')
+    }
+    $checksum_output+="-------------------------------------------------------------------------------"
+    function Get-FileMD5 {
+        Param([string]$file)
+        $md5 = [System.Security.Cryptography.HashAlgorithm]::Create("MD5")
+        $IO = New-Object System.IO.FileStream($file, [System.IO.FileMode]::Open)
+        $StringBuilder = New-Object System.Text.StringBuilder
+        $md5.ComputeHash($IO) | ForEach-Object { [void] $StringBuilder.Append($_.ToString("x2")) }
+        $hash = $StringBuilder.ToString()
+        $IO.Dispose()
+        return $hash
+    }
+    function CheckifExcluded($file, $excludelist){
+        $excludelist | Foreach-Object {
+            if($file -match $_){
+                return $true
+            }
+        }
+        return $false
+    }
+    $SourceFiles = Get-ChildItem -Recurse $src `
+      | Where-Object { $_.PSIsContainer -eq $false } `
+      | Where-Object { -not (CheckifExcluded -file $_.FullName -excludelist $excludelist) }
+
+    $cfiles = @()
+    # loop through the source dir files
+    $SourceFiles | Foreach-object {
+        $fres = @{
+            src=[string]$_.FullName.Replace('\','\\');
+            src_md5=$null;
+            dest=[string]($_.FullName -replace $src.Replace('\','\\'),$dest);
+            dest_md5=$null;
+            changed=$false
+          }
+
+        $cpy = $false
+        #if file exists in destination folder check MD5 hash
+        if (test-path $fres.dest) {
+            $cpy = $true
+
+            $srcMD5 = Get-FileMD5 -file $fres.src
+            $fres.src_md5 = $srcMD5
+            $destMD5 = Get-FileMD5 -file $fres.dest
+            $fres.dest_md5 = $destMD5
+
+            #if the MD5 hashes match then the files are the same
+            if ($fres.src_md5 -eq $fres.dest_md5) {
+                $cpy = $false
+            }
+        }
+
+        #copy the file if file exists and the hash is different
+        if ($cpy -eq $true) {
+            $fres.changed = $true
+            if (!(test-path $fres.dest)) {
+                New-Item -ItemType "File" -Path $fres.dest -Force
+            }
+            Copy-Item -Path $fres.src -Destination $fres.dest -Force
+        }
+        $cfiles += $fres
+    }
+    $cfiles | Where-Object { $_.changed -eq $true } | Foreach-Object {
+        $checksum_output+="* File: $($_.dest.replace($dest, ''))"
+        $checksum_output+="`tOld md5: $($_.dest_md5)`tNew md5: $($_.src_md5)"
+    }
+}
+
 Try {
     $robocopy_output = &robocopy $robocopy_opts
     $rc = $LASTEXITCODE
@@ -83,7 +158,7 @@ Try {
 }
 
 $result.msg = "Success"
-$result.output = $robocopy_output
+$result.output = $checksum_output + $robocopy_output
 $result.return_code = $rc # Backward compatibility
 $result.rc = $rc
 

lib/ansible/modules/windows/win_robocopy.py

@@ -44,6 +44,12 @@
     - If C(flags) is set, this will be ignored.
     type: bool
     default: no
+  checksum:
+    version_added: '2.9'
+    description:
+    - Use md5 checksum hash on existing dest files to compare with the src files.
+    type: bool
+    default: no
   flags:
     description:
       - Directly supply Robocopy flags.
@@ -72,6 +78,13 @@
     dest: C:\DirectoryTwo
     recurse: yes
 
+- name: Sync the contents of one directory to another, including subdirectories, using md5 checksum hash on destination files
+  win_robocopy:
+    checksum: true
+    src: C:\DirectoryOne
+    dest: C:\DirectoryTwo
+    recurse: yes
+
 - name: Sync the contents of one directory to another, and remove any files/directories found in destination that do not exist in the source
   win_robocopy:
     src: C:\DirectoryOne