handle cases when kubectl returns an empty string

reactive/kubernetes_control_plane.py

@@ -2639,7 +2639,7 @@ def _wait_for_svc_ip():
             "-l",
             "cdk-restart-on-ca-change=true",
         ).decode("UTF-8")
-        deployments = json.loads(output)["items"]
+        deployments = json.loads(output)["items"] if output else {}
 
         # Now restart the addons
         for deployment in deployments:
@@ -2812,7 +2812,7 @@ def get_pods(namespace="default"):
         output = kubectl(
             "get", "po", "-n", namespace, "-o", "json", "--request-timeout", "10s"
         ).decode("UTF-8")
-        result = json.loads(output)
+        result = json.loads(output) if output else None
     except CalledProcessError:
         hookenv.log("failed to get {} pod status".format(namespace))
         return None
@@ -2825,7 +2825,7 @@ def get_svcs(namespace="default"):
         output = kubectl(
             "get", "svc", "-n", namespace, "-o", "json", "--request-timeout", "10s"
         ).decode("UTF-8")
-        result = json.loads(output)
+        result = json.loads(output) if output else None
     except CalledProcessError:
         hookenv.log("failed to get {} service status".format(namespace))
         return None
@@ -2893,7 +2893,7 @@ def poke_network_unavailable():
 
     try:
         output = kubectl("get", "nodes", "-o", "json").decode("utf-8")
-        nodes = json.loads(output)["items"]
+        nodes = json.loads(output)["items"] if output else {}
     except CalledProcessError:
         hookenv.log("failed to get kube-system nodes")
         return
@@ -3470,7 +3470,7 @@ def restart_addons_for_ca():
             "-l",
             "cdk-restart-on-ca-change=true",
         ).decode("UTF-8")
-        deployments = json.loads(output)["items"]
+        deployments = json.loads(output)["items"] if output else {}
 
         # Get ServiceAccounts
         service_account_names = set(
@@ -3487,8 +3487,9 @@ def restart_addons_for_ca():
             output = kubectl(
                 "get", "ServiceAccount", name, "-o", "json", "-n", namespace
             ).decode("UTF-8")
-            service_account = json.loads(output)
-            service_accounts.append(service_account)
+            if output:
+                service_account = json.loads(output)
+                service_accounts.append(service_account)
 
         # Get ServiceAccount secrets
         secret_names = set()
@@ -3501,8 +3502,9 @@ def restart_addons_for_ca():
             output = kubectl(
                 "get", "Secret", name, "-o", "json", "-n", namespace
             ).decode("UTF-8")
-            secret = json.loads(output)
-            secrets.append(secret)
+            if output:
+                secret = json.loads(output)
+                secrets.append(secret)
 
         # Check secrets have updated CA
         with open(ca_crt_path, "rb") as f: