feat(helm): Allow downloading of Helm repo index using a Helm account (…

…#4773)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

clouddriver-artifacts/src/main/java/com/netflix/spinnaker/clouddriver/artifacts/helm/HelmArtifactCredentials.java

@@ -38,10 +38,15 @@
 final class HelmArtifactCredentials extends BaseHttpArtifactCredentials<HelmArtifactAccount>
     implements ArtifactCredentials {
   @Getter private final String name;
-  @Getter private final ImmutableList<String> types = ImmutableList.of("helm/chart");
+  @Getter private final ImmutableList<String> types = ImmutableList.of("helm/chart", "helm/index");
 
   @JsonIgnore private final IndexParser indexParser;
 
+  @Override
+  public boolean handlesType(String type) {
+    return types.contains(type);
+  }
+
   HelmArtifactCredentials(HelmArtifactAccount account, OkHttpClient okHttpClient) {
     super(okHttpClient, account);
     this.name = account.getName();
@@ -52,6 +57,10 @@ final class HelmArtifactCredentials extends BaseHttpArtifactCredentials<HelmArti
   public InputStream download(Artifact artifact) throws IOException {
     InputStream index = downloadIndex();
 
+    if ("helm/index".equals(artifact.getType())) {
+      return index;
+    }
+
     List<String> urls = indexParser.findUrls(index, artifact.getName(), artifact.getVersion());
     ResponseBody downloadResponse;
     for (String url : urls) {