[stable/Influxdb] make mounting of GSA key optional for backups to GCS (#20780)

stable/influxdb/Chart.yaml

 apiVersion: v1
 name: influxdb
-version: 4.0.1
+version: 4.1.0
 appVersion: 1.7.6
 description: Scalable datastore for metrics, events, and real-time analytics.
 keywords:
@@ -15,4 +15,6 @@ maintainers:
   email: jack@influxdb.com
 - name: aisuko
   email: urakiny@gmail.com
+- name: naseemkullah
+  email: naseem@transit.app
 engine: gotpl

stable/influxdb/OWNERS

 approvers:
 - jackzampolin
 - aisuko
+- naseemkullah
 reviewers:
 - jackzampolin
 - aisuko
+- naseemkullah

stable/influxdb/templates/backup-cronjob.yaml

@@ -22,11 +22,13 @@ spec:
           volumes:
           - name: backups
             emptyDir: {}
-          {{- if and .Values.backup.gcs }}
+          {{- if .Values.backup.gcs }}
+          {{- if .Values.backup.gcs.serviceAccountSecret }}
           - name: google-cloud-key
             secret:
               secretName: {{ .Values.backup.gcs.serviceAccountSecret | quote }}
           {{- end }}
+          {{- end }}
           serviceAccountName: {{ include "influxdb.serviceAccountName" . }}
           initContainers:
           - name: influxdb-backup
@@ -41,7 +43,7 @@ spec:
             - |
               influxd backup -host {{ template "influxdb.fullname" . }}.{{ .Release.Namespace }}.svc:{{ .Values.config.rpc.bind_address }} -portable /backups/backup_$(date +%Y%m%d_%H%M%S)
           containers:
-          {{- if .Values.backup.gcs}}
+          {{- if .Values.backup.gcs }}
           - name: gsutil-cp
             image: google/cloud-sdk:alpine
             command:
@@ -49,20 +51,26 @@ spec:
             args:
             - '-c'
             - |
-              gcloud auth activate-service-account --key-file $KEY_FILE
+              if [ -n "$KEY_FILE" ]; then
+                gcloud auth activate-service-account --key-file $KEY_FILE
+              fi
               gsutil -m cp -r "$SRC_URL" "$DST_URL"
             volumeMounts:
             - name: backups
               mountPath: /backups
+            {{- if .Values.backup.gcs.serviceAccountSecretKey}}
             - name: google-cloud-key
               mountPath: /var/secrets/google/
+            {{- end }}
             env:
               - name: SRC_URL
                 value: /backups
               - name: DST_URL
                 value: {{ .Values.backup.gcs.destination}}
+              {{- if .Values.backup.gcs.serviceAccountSecretKey}}
               - name: KEY_FILE
                 value: /var/secrets/google/{{ .Values.backup.gcs.serviceAccountSecretKey }}
+              {{- end }}
           {{- end }}
           {{- if .Values.backup.azure }}
           - name: azure-cli