Feature: add feedback for cluster create wait (#273)

* add feedback for cluster create wait

* whitespace

* alphasort imports

cli/spark/endpoints/cluster_create.py

@@ -53,6 +53,11 @@ def execute(args: typing.NamedTuple):
 
     print_cluster_conf(cluster_conf)
 
+    spinner = utils.Spinner()
+
+    log.info("Please wait while your cluster is being provisioned")
+    spinner.start()
+
     if cluster_conf.custom_scripts:
         custom_scripts = []
         for custom_script in cluster_conf.custom_scripts:
@@ -107,6 +112,8 @@ def execute(args: typing.NamedTuple):
             ssh_key=ssh_key
         )
 
+    spinner.stop()
+
     if cluster_conf.wait:
         log.info("Cluster %s created successfully.", cluster.id)
     else:

cli/utils.py

@@ -1,7 +1,9 @@
 import getpass
+import sys
+import threading
 import time
-from typing import List
 from subprocess import call
+from typing import List
 import azure.batch.models as batch_models
 import aztk.spark
 from aztk import error
@@ -219,3 +221,33 @@ def print_batch_exception(batch_exception):
             for mesg in batch_exception.error.values:
                 log.error("%s:\t%s", mesg.key, mesg.value)
     log.error("-------------------------------------------")
+
+
+class Spinner:
+    busy = False
+    delay = 0.1
+
+    @staticmethod
+    def spinning_cursor():
+        while 1: 
+            for cursor in '|/-\\': yield cursor
+
+    def __init__(self, delay=None):
+        self.spinner_generator = self.spinning_cursor()
+        if delay and float(delay): self.delay = delay
+
+    def spinner_task(self):
+        while self.busy:
+            sys.stdout.write(next(self.spinner_generator))
+            sys.stdout.flush()
+            time.sleep(self.delay)
+            sys.stdout.write('\b')
+            sys.stdout.flush()
+
+    def start(self):
+        self.busy = True
+        threading.Thread(target=self.spinner_task, daemon=True).start()
+
+    def stop(self):
+        self.busy = False
+        time.sleep(self.delay)