added changeset ps1 script and updated xpack-winlogbeat pipeline

.buildkite/scripts/changesets.psm1

@@ -0,0 +1,73 @@
+OSS_MODULE_PATTERN="^[a-z0-9]+beat/module/([^/]+)/.*"
+XPACK_MODULE_PATTERN="^x-pack/[a-z0-9]+beat/module/([^/]+)/.*"
+
+function ArePathsChanged($patterns) {
+    $changedlist = @()
+    foreach ($pattern in $patterns) {
+        $changedFiles = & git diff --name-only "HEAD@{1}" HEAD | Select-String -Pattern $pattern
+        if ($changedFiles) {
+            $changedlist += $changedFiles
+        }
+    }
+    if ($changedlist) {
+        Write-Output "Files changed:"
+        Write-Output $changedlist
+        return $true
+    }
+    else {
+        Write-Output "No files changed within specified changeset:"
+        Write-Output $patterns
+        return $false
+    }
+}
+
+function AreChangedOnlyPaths($patterns) {
+    $changedFiles = & git diff --name-only "HEAD@{1}" HEAD
+    $matchedFiles = @()
+    foreach ($pattern in $patterns) {
+        $matched = $changedFiles | Select-String -Pattern $pattern
+        if ($matched) {
+            $matchedFiles += $matched
+        }
+    }
+    if (($matchedFiles.Count -eq $changedFiles.Count) -or ($changedFiles.Count -eq 0)) {
+        return $true
+    }
+    return $false
+}
+
+# This function sets a `MODULE` env var, required by IT tests, containing a comma separated list of modules for a given beats project (specified via the first argument).
+# The list is built depending on directories that have changed under `modules/` excluding anything else such as asciidoc and png files.
+# `MODULE` will empty if no changes apply.
+function DefineModuleFromTheChangeSet($projectPath) {
+    $projectPathTransformed = $projectPath -replace '\', '\\'
+    $projectPathExclusion = "((?!^$projectPathTransformed\/).*\$|((?!\/module\/).*\$|.*\.asciidoc|.*\.png)"
+    $exclude = "$projectPathExclusion"
+    $changedModules = ''
+
+    $moduleDirs = Get-ChildItem -Directory "$projectPath\module"
+    foreach($moduleDir in $moduleDirs) {
+        if((ArePathsChanged($moduleDir)) -and !(AreChangedOnlyPaths($exclude))) {
+            if(!$changedModules) {
+                $changedModules = $moduleDir.Name
+            }
+            else {
+                $changedModules += ',' + $moduleDir.Name
+            }
+        }
+    }
+
+    # TODO: remove this conditional when issue https://github.com/elastic/ingest-dev/issues/2993 gets resolved
+    if(!$changedModules) {
+        if($Env:BUILDKITE_PIPELINE_SLUG -eq 'beats-xpack-metricbeat') {
+            $Env:MODULE = "aws"
+        }
+        else {
+            # TODO: once https://github.com/elastic/ingest-dev/issues/2993 gets resolved, this should be the only thing we export
+            $Env:MODULE = "kubernetes"
+        }
+    }
+    else {
+        $Env:MODULE = $changedModules
+    }
+}

.buildkite/scripts/changesets.sh

@@ -56,6 +56,7 @@ defineModuleFromTheChangeSet() {
   else
     local pattern=("$OSS_MODULE_PATTERN")
   fi
+
   local changed_modules=""
   local module_dirs=$(find "$project_path/module" -mindepth 1 -maxdepth 1 -type d)
   for module_dir in $module_dirs; do

.buildkite/x-pack/pipeline.xpack.winlogbeat.yml

@@ -22,6 +22,9 @@ steps:
       - label: ":windows: Xpack/Winlogbeat Win-2019 Unit (MODULE) Tests"
         key: "mandatory-win-2019-module-unit-tests"
         command: |
+          Import-Module .\.buildkite\scripts\changesets.psm1
+          $MODULE = defineModuleFromTheChangeSet ('.\x-pack\winlogbeat')
+          Write-Output "~~~ Will run tests with env var MODULE=$MODULE"
           Set-Location -Path x-pack/winlogbeat
           mage build unitTest
         env: