Initial code

Signed-off-by: Julien Riou <julien@riou.xyz>

.pre-commit-config.yaml

@@ -0,0 +1,29 @@
+---
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: master
+    hooks:
+      - id: check-executables-have-shebangs
+      - id: check-merge-conflict
+      - id: double-quote-string-fixer
+      - id: end-of-file-fixer
+      - id: fix-encoding-pragma
+        args: ['--remove']
+      - id: requirements-txt-fixer
+      - id: trailing-whitespace
+  - repo: https://gitlab.com/pycqa/flake8
+    rev: master
+    hooks:
+      - id: flake8
+        args: ['--max-line-length=120']
+  - repo: https://github.com/FalconSocial/pre-commit-python-sorter
+    rev: master
+    hooks:
+      - id: python-import-sorter
+        args: ['--silent-overwrite']
+  - repo: https://github.com/chewse/pre-commit-mirrors-pydocstyle
+    rev: master
+    hooks:
+      - id: pydocstyle
+        args: ['--config=.pydocstyle', '--match="(?!test_).*\.py"']
+  - repo: https://github.com/jumanjihouse/pre-commit-hooks

.pydocstyle

@@ -0,0 +1,2 @@
+[pydocstyle]
+ignore = D100,D104,D400,D203,D204,D101,D213,D202

README.md

@@ -1,2 +1,58 @@
 # notify-by-telegram
-Send Nagios notifications to a Telegram channel
+Send Nagios notifications to a Telegram channel.
+
+
+## Telegram bot
+
+This [tutorial](https://takersplace.de/2019/12/19/telegram-notifications-with-nagios/) explains how to create a Telegram bot. You'll need the *chat_id* and *auth_key* for the next section.
+
+## Installation
+
+_This guide has been written for [Debian](https://www.debian.org/). Some commands might slightly change depending on your distribution._
+
+Clone the repository:
+```
+git clone https://github.com/jouir/notify-by-telegram.git
+sudo cp -p notify-by-telegram.py /usr/lib/nagios/plugins/notify-by-telegram.py
+sudo chmod 755 /usr/lib/nagios/plugins/notify-by-telegram.py
+sudo chown root:root /usr/lib/nagios/plugins/notify-by-telegram.py
+```
+
+Install dependencies using the package manager:
+```
+sudo apt install python3-jinja2 python3-requests
+```
+
+## Configuration
+
+Copy and update the configuration file example:
+```
+sudo cp -p config.json.example /etc/nagios/telegram.json
+sudo chmod 640 root:nagios /etc/nagios/telegram.json
+```
+
+Add Nagios configurations:
+```
+sudo cp -p nagios.cfg /etc/nagios4/conf.d/telegram.cfg
+```
+
+Ensure Nagios reads the configuration file:
+```
+grep cfg_dir=/etc/nagios4/conf.d /etc/nagios4/nagios.cfg
+```
+
+Then reload service:
+```
+systemctl reload nagios4
+```
+
+## Logs
+
+Errors logs can be set with the `--logfile` argument.
+
+Example:
+```
+tail -f /var/log/nagios4/telegram.log
+```
+
+Log level can be raised using `--verbose` or even more with `--debug` arguments.

config.json.example

@@ -0,0 +1,4 @@
+{
+  "chat_id": 99,
+  "auth_key": "hash"
+}

nagios.cfg

@@ -0,0 +1,9 @@
+define command {
+    command_name    notify-host-by-telegram
+    command_line    /usr/lib/nagios/plugins/notify-by-telegram.py -c /etc/nagios/telegram.json --logfile /var/log/nagios4/telegram.log host --notification-type "$NOTIFICATIONTYPE$" --service-desc "$SERVICEDESC$" --host-name "$HOSTNAME$" --host-state "$HOSTSTATE$" --host-address "$HOSTADDRESS$" --host-output "$HOSTOUTPUT$" --long-date-time "$LONGDATETIME$"
+}
+
+define command {
+    command_name    notify-service-by-telegram
+    command_line    /usr/lib/nagios/plugins/notify-by-telegram.py -c /etc/nagios/telegram.json --logfile /var/log/nagios4/telegram.log service --notification-type "$NOTIFICATIONTYPE$" --service-desc "$SERVICEDESC$" --host-alias "$HOSTALIAS$" --host-address "$HOSTADDRESS$" --service-state "$SERVICESTATE$" --long-date-time "$LONGDATETIME$" --service-output "$SERVICEOUTPUT$"
+}

notify-by-telegram.py

@@ -0,0 +1,150 @@
+#!/usr/bin/env python3
+import argparse
+import json
+import logging
+import os
+
+import requests
+from jinja2 import Template
+
+logger = logging.getLogger(__name__)
+
+
+class InvalidConfigException(Exception):
+    pass
+
+
+def parse_arguments():
+    parser = argparse.ArgumentParser()
+    # base arguments
+    parser.add_argument('-v', '--verbose', dest='loglevel', action='store_const', const=logging.INFO,
+                        help='Print more output')
+    parser.add_argument('-d', '--debug', dest='loglevel', action='store_const', const=logging.DEBUG,
+                        default=logging.WARNING, help='Print even more output')
+    parser.add_argument('-c', '--config', help='Configuration file location', required=True)
+    parser.add_argument('-o', '--logfile', help='Logging file location')
+    subparsers = parser.add_subparsers(title='commands', dest='command', help='Nagios notification type')
+
+    # host notifications
+    host_parser = subparsers.add_parser('host')
+    host_parser.add_argument('--notification-type', help='Nagios $NOTIFICATIONTYPE$', required=True)
+    host_parser.add_argument('--service-desc', help='Nagios $SERVICEDESC$', required=True)
+    host_parser.add_argument('--host-name', help='Nagios $HOSTNAME$', required=True)
+    host_parser.add_argument('--host-state', help='Nagios $HOSTSTATE$', required=True)
+    host_parser.add_argument('--host-address', help='Nagios $HOSTADDRESS$', required=True)
+    host_parser.add_argument('--host-output', help='Nagios $HOSTOUTPUT$', required=True)
+    host_parser.add_argument('--long-date-time', help='Nagios $LONGDATETIME$', required=True)
+
+    # service notifications
+    service_parser = subparsers.add_parser('service')
+    service_parser.add_argument('--notification-type', help='Nagios $NOTIFICATIONTYPE$', required=True)
+    service_parser.add_argument('--service-desc', help='Nagios $SERVICEDESC$', required=True)
+    service_parser.add_argument('--host-alias', help='Nagios $HOSTALIAS$', required=True)
+    service_parser.add_argument('--host-address', help='Nagios $HOSTADDRESS$', required=True)
+    service_parser.add_argument('--service-state', help='Nagios $SERVICESTATE$', required=True)
+    service_parser.add_argument('--long-date-time', help='Nagios $LONGDATETIME$', required=True)
+    service_parser.add_argument('--service-output', help='Nagios $SERVICEOUTPUT$', required=True)
+
+    args = parser.parse_args()
+    return args
+
+
+def read_config(filename=None):
+    if filename and os.path.isfile(filename):
+        with open(filename, 'r') as fd:
+            return json.load(fd)
+    else:
+        return {}
+
+
+def validate_config(config):
+    if config is None:
+        raise InvalidConfigException('Config is not a dict')
+    for key in ['chat_id', 'auth_key']:
+        if key not in config:
+            raise InvalidConfigException(f'Missing "{key}" key in config')
+
+
+def setup_logging(args):
+    logging.basicConfig(format='%(levelname)s: %(message)s', level=args.loglevel, filename=args.logfile)
+
+
+def markdown_escape(text):
+    for special_char in ['\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '#', '+', '-', '.', '!']:
+        text = text.replace(special_char, fr'\{special_char}')
+    return text
+
+
+def generate_host_payload(chat_id, args):
+    payload = {'chat_id': chat_id, 'parse_mode': 'MarkdownV2'}
+    text = r"""\*\*\*\*\* Nagios \*\*\*\*\*
+*Notification Type:* {{notification_type}}
+*Host:* {{host_name}}
+*State:* {{host_state}}
+*Address:* {{host_address}}
+*Info:* {{host_output}}
+*Date/Time:* {{long_date_time}}
+"""
+    template = Template(text)
+    text = template.render(notification_type=markdown_escape(args.notification_type),
+                           host_name=markdown_escape(args.host_name), host_state=markdown_escape(args.host_state),
+                           host_address=markdown_escape(args.host_address),
+                           host_output=markdown_escape(args.host_output),
+                           long_date_time=markdown_escape(args.long_date_time))
+    payload['text'] = text
+    return payload
+
+
+def generate_service_payload(chat_id, args):
+    payload = {'chat_id': chat_id, 'parse_mode': 'MarkdownV2'}
+    text = r"""\*\*\*\*\* Nagios \*\*\*\*\*
+*Notification Type:* {{notification_type}}
+*Service:* {{service_desc}}
+*Host:* {{host_alias}}
+*Address:* {{host_address}}
+*State:* {{service_state}}
+*Date/Time:* {{long_date_time}}
+*Additional Info:*
+{{service_output}}
+"""
+    template = Template(text)
+    text = template.render(notification_type=markdown_escape(args.notification_type),
+                           service_desc=markdown_escape(args.service_desc), host_alias=markdown_escape(args.host_alias),
+                           host_address=markdown_escape(args.host_address),
+                           service_state=markdown_escape(args.service_state),
+                           long_date_time=markdown_escape(args.long_date_time),
+                           service_output=markdown_escape(args.service_output))
+    payload['text'] = text
+    return payload
+
+
+def send_message(auth_key, payload):
+    r = requests.post(f'https://api.telegram.org/bot{auth_key}/sendMessage', json=payload)
+    if r.status_code != requests.codes.ok:
+        description = r.json().get('description')
+        logger.error(f'{r.status_code}: {description}')
+        logger.debug(payload)
+
+
+def main():
+    args = parse_arguments()
+    setup_logging(args)
+    logger.info(f'reading configuration file {args.config}')
+    config = read_config(args.config)
+    logger.info('validating configuration')
+    validate_config(config)
+
+    logger.info('generating payload')
+    if args.command == 'host':
+        payload = generate_host_payload(chat_id=config['chat_id'], args=args)
+    elif args.command == 'service':
+        payload = generate_service_payload(chat_id=config['chat_id'], args=args)
+    else:
+        raise NotImplementedError(f'Command {args.command} not supported')
+
+    logger.info('sending message to telegram api')
+    send_message(auth_key=config['auth_key'], payload=payload)
+
+
+if __name__ == '__main__':
+    main()