Merge pull request Yelp#2438 from gza/fix_pipe_to_command

Fix command alert with piped match data

Author: Qmando

elastalert/alerts.py

@@ -918,10 +918,10 @@ def alert(self, matches):
 
             if self.rule.get('pipe_match_json'):
                 match_json = json.dumps(matches, cls=DateTimeEncoder) + '\n'
-                stdout, stderr = subp.communicate(input=match_json)
+                stdout, stderr = subp.communicate(input=match_json.encode())
             elif self.rule.get('pipe_alert_text'):
                 alert_text = self.create_alert_body(matches)
-                stdout, stderr = subp.communicate(input=alert_text)
+                stdout, stderr = subp.communicate(input=alert_text.encode())
             if self.rule.get("fail_on_non_zero_exit", False) and subp.wait():
                 raise EAException("Non-zero exit code while running command %s" % (' '.join(command)))
         except OSError as e: