Break get_time_elapsed into misc_helper (#10)

lib/utilities/misc_helper.py

@@ -1,6 +1,7 @@
 import logging
 import os
 import subprocess
+from datetime import datetime
 
 logger = logging.getLogger()
 
@@ -55,3 +56,33 @@ def file_exists_in_mounts(filepath):
                     possible_mount_path = os.path.join(root, mount, filepath.split(component)[-1].lstrip('/'))
                     if os.path.exists(possible_mount_path):
                         return possible_mount_path
+
+
+def get_time_elapsed(start_time=None, end_time=None):
+
+    from string import Template
+
+    class DeltaTemplate(Template):
+        delimiter = "%"
+
+    def strfdelta(tdelta, fmt='%H:%M:%S'):
+        d = {"D": tdelta.days}
+        hours, rem = divmod(tdelta.seconds, 3600)
+        minutes, seconds = divmod(rem, 60)
+        d["H"] = '{:02d}'.format(hours)
+        d["M"] = '{:02d}'.format(minutes)
+        d["S"] = '{:02d}'.format(seconds)
+        t = DeltaTemplate(fmt)
+        return t.substitute(**d)
+
+    # calculate elapsed time
+    elapsed_time = None
+
+    if start_time:
+        if end_time:
+            elapsed_time = end_time - start_time
+        else:
+            elapsed_time = datetime.now() - start_time
+
+    elapsed_time_string = strfdelta(elapsed_time) if elapsed_time else None
+    return elapsed_time_string