ensure python-docker-py dependency

roles/openshift_health_checker/openshift_checks/etcd_imagedata_size.py

@@ -3,15 +3,25 @@
 """
 
 from openshift_checks import OpenShiftCheck
+from openshift_checks.mixins import DockerHostMixin
 
 
-class EtcdImageDataSize(OpenShiftCheck):
+class EtcdImageDataSize(DockerHostMixin, OpenShiftCheck):
     """Check that total size of OpenShift image data does not exceed the recommended limit in an etcd cluster"""
 
     name = "etcd_imagedata_size"
     tags = ["etcd"]
 
+    dependencies = ["python-docker-py"]
+
     def run(self):
+        msg, failed = self.ensure_dependencies()
+        if failed:
+            return {
+                "failed": True,
+                "msg": "Some dependencies are required in order to check Docker image availability.\n" + msg
+            }
+
         etcd_mountpath = self.find_ansible_mount("/var/lib/etcd")
         etcd_avail_diskspace = etcd_mountpath["size_available"]
         etcd_total_diskspace = etcd_mountpath["size_total"]