Add postfix_valid_config_check

postfix_valid_config_check.py

@@ -0,0 +1,132 @@
+#!/usr/bin/env python3
+#
+# Name:        postfix_valid_config_check.py
+# Date:        2021-03-08
+# Author:      dalibor.aleksic@atomia.com
+# Version:     1.0
+# Parameters:
+#              --ignore-warnings   Report OK status even when warnings are found
+#              --quiet             Surpress errors/warrings messages
+#              --postfix-path      Overide default postfix path
+#
+# Returns:
+#              0 - OK
+#              1 - WARNING
+#              2 - CRITICAL
+#              3 - UNKNOWN
+#
+# Description: Nagios plugin that alerts when postfix configuration is not valid.
+#              It executes "postfix check" command and parses output for errors.
+#
+import argparse
+import subprocess
+
+
+nagios_status_exit_code = {
+    'OK': 0,
+    'WARNING': 1,
+    'CRITICAL': 2,
+    'UNKNOWN': 3
+}
+
+
+def load_arguments():
+    """
+    Parses script arguments
+    """
+    global args
+    parser = argparse.ArgumentParser('Postfix valid config check')
+    parser.add_argument('--ignore-warnings',
+                        action='store_true',
+                        help="Ignore warnings in configuration")
+    parser.add_argument('--postfix-path',
+                        default='/usr/sbin/postfix',
+                        help="Path to postfix bin (default: /usr/sbin/postfix)")
+    parser.add_argument('-q', '--quiet',
+                        action='store_true',
+                        help="Surpress error and warning details")
+    args = parser.parse_args()
+
+
+def exec_postfix_check():
+    """
+    Executes 'postfix check' command and returns output
+    """
+    # Workaround:
+    # postfix doesn't display output when detects that stdout/stderr
+    # are not attached to console. Using 'script' command it emulates
+    # that postfix is run inside console aka stdout/stderr are attached to console
+    process_info = subprocess.run(["script --quiet --return --command '%s check' /dev/null" % args.postfix_path],
+                                  stdout=subprocess.PIPE,
+                                  stderr=subprocess.STDOUT,
+                                  shell=True,
+                                  universal_newlines=True)
+    return {
+        'returncode': process_info.returncode,
+        'output_lines': process_info.stdout.splitlines()
+    }
+
+
+def run_nagios_check():
+    """
+    Parses output from 'postfix check' and returns appropriate nagios result
+    """
+    # Fetch output from postfix check
+    postfix_check_result = exec_postfix_check()
+
+    # Return UNKNOWN status if postfix is not installed
+    if postfix_check_result['returncode'] == 127:
+        print("POSTFIX CONFIG: postfix not installed or --postfix-path=%s invalid" %
+              args.postfix_path)
+        if not args.quiet:
+            print('\n'.join(postfix_check_result['output_lines']))
+        exit(nagios_status_exit_code['UNKNOWN'])
+
+    # Classify lines from output
+    fatal_lines = []
+    error_lines = []
+    warning_lines = []
+    other_lines = []
+    for line in postfix_check_result['output_lines']:
+        if 'fatal:' in line:
+            fatal_lines.append(line)
+        elif 'error:' in line:
+            error_lines.append(line)
+        elif 'warning:' in line:
+            warning_lines.append(line)
+        else:
+            other_lines.append(line)
+
+    # Return CRITICAL if config is invalid
+    if len(fatal_lines) or len(error_lines):
+        print("POSTFIX CONFIG: %d fatal errors; %d errors; %d warnings" %
+              (len(fatal_lines), len(error_lines), len(warning_lines)))
+        if not args.quiet:
+            print('\n'.join(fatal_lines))
+            print('\n'.join(error_lines))
+        exit(nagios_status_exit_code['CRITICAL'])
+
+    # Return WARNING if config is valid but contains warnings. Overridden with --ignore-warnings
+    if len(warning_lines) and not args.ignore_warnings:
+        print("POSTFIX CONFIG: %d warnings" % len(warning_lines))
+        if not args.quiet:
+            print('\n'.join(warning_lines))
+        exit(nagios_status_exit_code['WARNING'])
+
+    # Plugin validation check
+    if postfix_check_result['returncode'] != 0:
+        print("POSTFIX CONFIG: PLUGIN ERROR: Detected OK state, but return code is %d (expected 0)" %
+              postfix_check_result['returncode'])
+        exit(nagios_status_exit_code['CRITICAL'])
+
+    # Return OK if no errors found or warnings are ignored
+    if len(warning_lines) and args.ignore_warnings:
+        print("POSTFIX CONFIG: OK (%d ignored warnings)" % len(warning_lines))
+    else:
+        print("POSTFIX CONFIG: OK")
+    exit(nagios_status_exit_code['OK'])
+
+
+# Main
+load_arguments()
+run_nagios_check()