minor improvements to load generator script --no-deploy

tests/load_generator.py

@@ -1,5 +1,8 @@
 import sys
+import datetime
 import subprocess
+from pprint import pprint
+from collections import defaultdict
 
 
 def main(num_processes):
@@ -10,10 +13,24 @@ def main(num_processes):
         processes[process_num] = subprocess.Popen([
             'nslookup', '-port=10053', 'foobar.com', '-', '127.0.0.1'
         ], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    start_time = datetime.datetime.now()
     print('waiting for processes to terminate')
+    stats = defaultdict(int)
     for process_num, process in processes.items():
         returncode = process.wait()
-        print(f'{process_num}: returncode {returncode} output {process.stdout.read()}')
+        output = process.stdout.read().decode()
+        if returncode == 0:
+            if 'Address: 127.0.0.1' in output:
+                stats['success'] += 1
+            else:
+                raise Exception(f'Success with unknown output: {output}')
+        elif 'connection timed out; no servers could be reached' in output:
+            stats['timed out'] += 1
+            if not stats['seconds to first timeout']:
+                stats['seconds to first timeout'] = (datetime.datetime.now() - start_time).total_seconds()
+        else:
+            raise Exception(f'Failed with unknown output: {output}')
+    pprint(dict(stats))
 
 
 main(*sys.argv[1:])