snmp.py: improve daemon startup

The previous implementation used a hardcoded 2 seconds sleep until the
daemon configuration was rendered by snmpd (user/password stuff).

Waiting 2 seconds is error prone and was replaced by reading the
configuration file until it shows a marker indicating that the file was
properly processed by snmpd.

1 files changed, 11 insertions, 4 deletions

diff --git a/src/conf_mode/snmp.py b/src/conf_mode/snmp.py
index a4e776d49..3eb2935be 100755
--- a/src/conf_mode/snmp.py
+++ b/src/conf_mode/snmp.py
@@ -21,7 +21,6 @@ import os
 import shutil
 import stat
 import pwd
-import time
 
 import jinja2
 import random
@@ -771,9 +770,17 @@ def apply(snmp):
         # start SNMP daemon
         os.system("sudo systemctl restart snmpd.service")
 
-        # the passwords are not available immediately so this is a workaround
-        # and should be changed to polling
-        time.sleep(2)
+        # Passwords are not available immediately in the configuration file,
+        # after daemon startup - we wait until they have been processed by
+        # snmpd, which we see when a magic line appears in this file.
+        snmpReady = False
+        while not snmpReady:
+            with open(config_file_user, 'r') as f:
+                for line in f:
+                    # Search for our magic string inside the file
+                    if '**** DO NOT EDIT THIS FILE ****' in line:
+                        snmpReady = True
+                        break
 
         # Back in the Perl days the configuration was re-read and any
         # plaintext password inside the configuration was replaced by