[DownloadBuildArtifactsV0] Add clean up logic of destination folder

Tasks/DownloadBuildArtifactsV0/Strings/resources.resjson/en-US/resources.resjson

@@ -29,6 +29,8 @@
   "loc.input.help.itemPattern": "Specify files to be downloaded as multi line minimatch pattern. [More Information](https://aka.ms/minimatchexamples) <p>The default pattern (\\*\\*) will download all files across all artifacts in the build if \"Specific files\" option is selected. To download all files within artifact drop use drop/**.</p>",
   "loc.input.label.downloadPath": "Destination directory",
   "loc.input.help.downloadPath": "Path on the agent machine where the artifacts will be downloaded",
+  "loc.input.label.cleanDestinationFolder": "Clean destination folder",
+  "loc.input.help.cleanDestinationFolder": "Delete all existing files in destination folder before artifact download",
   "loc.input.label.parallelizationLimit": "Parallelization limit",
   "loc.input.help.parallelizationLimit": "Number of files to download simultaneously",
   "loc.input.label.checkDownloadedFiles": "Check downloaded files",
@@ -63,5 +65,6 @@
   "loc.messages.IntegrityCheckNotPassed": "Artifact items integrity check failed",
   "loc.messages.IntegrityCheckPassed": "Artifact items integrity check successfully finished",
   "loc.messages.TarExtractionNotSupportedInWindows": "Tar extraction is not supported on Windows",
-  "loc.messages.NoTarsFound": "No tar archives were found to extract"
+  "loc.messages.NoTarsFound": "No tar archives were found to extract",
+  "loc.messages.CleaningDestinationFolder": "Cleaning destination folder: %s"
 }

Tasks/DownloadBuildArtifactsV0/main.ts

@@ -80,6 +80,7 @@ async function main(): Promise<void> {
         var allowPartiallySucceededBuilds: boolean = tl.getBoolInput("allowPartiallySucceededBuilds", false);
         var branchName: string = tl.getInput("branchName", false);
         var downloadPath: string = path.normalize(tl.getInput("downloadPath", true));
+        var cleanDestinationFolder: boolean = tl.getBoolInput("cleanDestinationFolder", false);
         var downloadType: string = tl.getInput("downloadType", true);
         var tagFiltersInput: string = tl.getInput("tags", false);
         var tagFilters = [];
@@ -109,6 +110,37 @@ async function main(): Promise<void> {
         });
         var artifacts = [];
 
+        // Clean destination folder if requested
+        if (cleanDestinationFolder) {
+            console.log(tl.loc('CleaningDestinationFolder', downloadPath));
+
+            // stat the destination folder (downloadPath) path
+            let destinationFolderStats: tl.FsStats;
+            try {
+                destinationFolderStats = tl.stats(downloadPath);
+            }
+            catch (err) {
+                if (err.code != 'ENOENT') {
+                    throw err;
+                }
+            }
+
+            if (destinationFolderStats) {
+                if (destinationFolderStats.isDirectory()) {
+                    // delete the child items
+                    fs.readdirSync(downloadPath)
+                        .forEach((item: string) => {
+                            let itemPath = path.join(downloadPath, item);
+                            tl.rmRF(itemPath);
+                        });
+                }
+                else {
+                    // destination folder is not a directory. delete it.
+                    tl.rmRF(downloadPath);
+                }
+            }
+        }
+
         if (isCurrentBuild) {
             projectId = tl.getVariable("System.TeamProjectId");
             definitionId = '';

Tasks/DownloadBuildArtifactsV0/task.json

@@ -9,8 +9,8 @@
     "author": "Microsoft Corporation",
     "version": {
         "Major": 0,
-        "Minor": 188,
-        "Patch": 3
+        "Minor": 190,
+        "Patch": 0
     },
     "groups": [
         {
@@ -170,6 +170,13 @@
             "required": true,
             "helpMarkDown": "Path on the agent machine where the artifacts will be downloaded"
         },
+        {
+            "name": "cleanDestinationFolder",
+            "type":"boolean",
+            "label": "Clean destination folder",
+            "defaultValue": false,
+            "helpMarkDown": "Delete all existing files in destination folder before artifact download"
+        },
         {
             "name": "parallelizationLimit",
             "type": "string",
@@ -288,7 +295,8 @@
         "IntegrityCheckNotPassed": "Artifact items integrity check failed",
         "IntegrityCheckPassed": "Artifact items integrity check successfully finished",
         "TarExtractionNotSupportedInWindows": "Tar extraction is not supported on Windows",
-        "NoTarsFound": "No tar archives were found to extract"
+        "NoTarsFound": "No tar archives were found to extract",
+        "CleaningDestinationFolder": "Cleaning destination folder: %s"
     },
     "outputVariables": [
         {

Tasks/DownloadBuildArtifactsV0/task.loc.json

@@ -9,8 +9,8 @@
   "author": "Microsoft Corporation",
   "version": {
     "Major": 0,
-    "Minor": 188,
-    "Patch": 3
+    "Minor": 190,
+    "Patch": 0
   },
   "groups": [
     {
@@ -170,6 +170,13 @@
       "required": true,
       "helpMarkDown": "ms-resource:loc.input.help.downloadPath"
     },
+    {
+      "name": "cleanDestinationFolder",
+      "type": "boolean",
+      "label": "ms-resource:loc.input.label.cleanDestinationFolder",
+      "defaultValue": false,
+      "helpMarkDown": "ms-resource:loc.input.help.cleanDestinationFolder"
+    },
     {
       "name": "parallelizationLimit",
       "type": "string",
@@ -288,7 +295,8 @@
     "IntegrityCheckNotPassed": "ms-resource:loc.messages.IntegrityCheckNotPassed",
     "IntegrityCheckPassed": "ms-resource:loc.messages.IntegrityCheckPassed",
     "TarExtractionNotSupportedInWindows": "ms-resource:loc.messages.TarExtractionNotSupportedInWindows",
-    "NoTarsFound": "ms-resource:loc.messages.NoTarsFound"
+    "NoTarsFound": "ms-resource:loc.messages.NoTarsFound",
+    "CleaningDestinationFolder": "ms-resource:loc.messages.CleaningDestinationFolder"
   },
   "outputVariables": [
     {