Added config.getString() method to check if kubernetes.config has googleServiceAccount property

Signed-off-by: armandocomellas1 <cgarmando@google.com>

docs/features/kubernetes/configuration.md

@@ -341,6 +341,7 @@ For example:
 - type: 'gke'
   projectId: 'gke-clusters'
   region: 'europe-west1' # optional
+  authProvider: 'google' # optional
   skipTLSVerify: false # optional
   skipMetricsLookup: false # optional
   exposeDashboard: false # optional
@@ -365,6 +366,18 @@ The Google Cloud project to look for Kubernetes clusters in.
 The Google Cloud region to look for Kubernetes clusters in. Defaults to all
 regions.
 
+##### `authProvider` (optional)
+
+Set the authentication method for discovering clusters and gathering information
+about resources.
+
+Defaults to `google` which leverages the logged in user's Google OAuth credentials.
+
+Set to `googleServiceAccount` to leverage
+Application Default Credentials (https://cloud.google.com/docs/authentication/application-default-credentials).
+To use a service account JSON key (not recommended), set the `GOOGLE_APPLICATION_CREDENTIALS` environment variable
+on the Backstage backend to the path of the service account key file.
+
 ##### `skipTLSVerify` (optional)
 
 This determines whether the Kubernetes client verifies the TLS certificate

plugins/kubernetes-backend/src/cluster-locator/GkeClusterLocator.ts

@@ -29,6 +29,7 @@ interface MatchResourceLabelEntry {
 
 type GkeClusterLocatorOptions = {
   projectId: string;
+  authProvider: string;
   region?: string;
   skipTLSVerify?: boolean;
   skipMetricsLookup?: boolean;
@@ -54,8 +55,21 @@ export class GkeClusterLocator implements KubernetesClustersSupplier {
         return { key: mrl.getString('key'), value: mrl.getString('value') };
       }) ?? [];
 
+    let storeAuthProviderString: string;
+    let getGkeProperty;
+    try {
+      getGkeProperty = config.getString('authProvider');
+    } catch (err) {
+      getGkeProperty = 'google';
+    }
+    if (getGkeProperty === 'googleServiceAccount') {
+      storeAuthProviderString = 'googleServiceAccount';
+    } else {
+      storeAuthProviderString = 'google';
+    }
     const options = {
       projectId: config.getString('projectId'),
+      authProvider: storeAuthProviderString,
       region: config.getOptionalString('region') ?? '-',
       skipTLSVerify: config.getOptionalBoolean('skipTLSVerify') ?? false,
       skipMetricsLookup:
@@ -97,6 +111,7 @@ export class GkeClusterLocator implements KubernetesClustersSupplier {
     const {
       projectId,
       region,
+      authProvider,
       skipTLSVerify,
       skipMetricsLookup,
       exposeDashboard,
@@ -121,7 +136,7 @@ export class GkeClusterLocator implements KubernetesClustersSupplier {
           // TODO filter out clusters which don't have name or endpoint
           name: r.name ?? 'unknown',
           url: `https://${r.endpoint ?? ''}`,
-          authMetadata: { [ANNOTATION_KUBERNETES_AUTH_PROVIDER]: 'google' },
+          authMetadata: { [ANNOTATION_KUBERNETES_AUTH_PROVIDER]: authProvider },
           skipTLSVerify,
           skipMetricsLookup,
           ...(exposeDashboard