fix: Remove $SERVICEDESC$ from host notification

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

.pre-commit-config.yaml

@@ -11,6 +11,8 @@ repos:
         args: ['--remove']
       - id: requirements-txt-fixer
       - id: trailing-whitespace
+      - id: check-json
+      - id: check-yaml
   - repo: https://gitlab.com/pycqa/flake8
     rev: master
     hooks:

Dockerfile

@@ -0,0 +1,5 @@
+FROM python:3.8-slim
+RUN apt-get update \
+    && apt-get install -y git \
+    && apt-get autoclean \
+    && pip install pre-commit

README.md

@@ -15,19 +15,25 @@ Clone the repository:
 git clone https://github.com/jouir/notify-by-telegram.git /opt/notify-by-telegram
 ```
 
-Install dependencies using the package manager:
+Install dependencies using pip:
 ```
-sudo apt install python3-jinja2 python3-requests
+pip install -r requirements.txt
+```
+
+Or via the package manager:
+```
+sudo apt install python3-jinja2 python3-requests python3-jsonschema
 ```
 
 ## Configuration
 
 Copy and update the configuration file example:
 ```
-cp -p config.json.example telegram.json
+cp -p config.example.json telegram.json
 vim telegram.json
 sudo mv telegram.json /etc/nagios4/telegram.json
-sudo chmod 640 root:nagios /etc/nagios4/telegram.json
+sudo chown root:nagios /etc/nagios4/telegram.json
+sudo chmod 640 /etc/nagios4/telegram.json
 ```
 
 Ensure Nagios reads the configuration file:
@@ -40,7 +46,16 @@ Then reload service:
 systemctl reload nagios4
 ```
 
-## Logs
+## Configuration file
+
+Format used is JSON with the following keys:
+
+* `chat_id`: where to send message on Telegram
+* `auth_key`: key used to authenticate on Telegram
+* `host_template` (optional): path to Markdown template file used for sending host notifications
+* `service_template` (optional): path to Markdown template file used for sending service notifications
+
+## Logging
 
 Errors logs can be set with the `--logfile` argument.
 
@@ -70,3 +85,37 @@ They can be overriden in the configuration file:
 ```
 
 Both options are optional.
+
+### Host variables
+
+Variables replaced in the host template:
+* `notification_type` (= `$NOTIFICATIONTYPE$`)
+* `host_name` (= `$HOSTNAME$`)
+* `host_state` (= `$HOSTSTATE$`)
+* `host_address` (= `$HOSTADDRESS$`)
+* `host_output` (= `$HOSTOUTPUT$`)
+* `long_date_time` (= `$LONGDATETIME$`)
+
+### Service variables
+
+Variables replaced in the service template:
+* `notification_type` (= `$NOTIFICATIONTYPE$`)
+* `service_desc` (= `$SERVICEDESC$`)
+* `host_alias` (= `$HOSTALIAS$`)
+* `host_address` (= `$HOSTADDRESS$`)
+* `service_state` (= `$SERVICESTATE$`)
+* `long_date_time` (= `$LONGDATETIME$`)
+* `service_output` (= `$SERVICEOUTPUT$`)
+
+## How to contribute
+
+Contributions are welcomed! Feel free to update the code and create a pull-request.
+
+Be sure to lint the code before:
+```
+docker build -t pre-commit .
+docker run -it -v $(pwd):/mnt/ --rm pre-commit bash
+# cd /mnt/
+# pre-commit run --all-files
+# exit
+```

TODO.txt

@@ -1,4 +0,0 @@
-Factorize the template rendering functions
-Use JSON schema to validate configuration file
-Add pre-commit Dockerfile and a doc to easily lint the code
-Add requirements.txt file

config.schema.json

@@ -0,0 +1,21 @@
+{
+  "type": "object",
+  "properties": {
+    "chat_id": {
+      "type": "number"
+    },
+    "auth_key": {
+      "type": "string"
+    },
+    "host_template": {
+      "type": "string"
+    },
+    "service_template": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "chat_id",
+    "auth_key"
+  ]
+}

nagios.cfg

@@ -1,6 +1,6 @@
 define command {
     command_name    notify-host-by-telegram
-    command_line    /opt/notify-by-telegram/notify-by-telegram.py -c /etc/nagios4/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 "$LONGDATETIME$"
+    command_line    /opt/notify-by-telegram/notify-by-telegram.py -c /etc/nagios4/telegram.json --logfile /var/log/nagios4/telegram.log host --notification-type "$NOTIFICATIONTYPE$" --host-name "$HOSTNAME$" --host-state "$HOSTSTATE$" --host-address "$HOSTADDRESS$" --host-output "$HOSTOUTPUT$" --long-date-time "$LONGDATETIME$"
 }
 
 define command {

notify-by-telegram.py

@@ -6,8 +6,10 @@ import os
 
 import requests
 from jinja2 import Environment, FileSystemLoader
+from jsonschema import validate
 
 logger = logging.getLogger(__name__)
+absolute_path = os.path.split(os.path.abspath(__file__))[0]
 
 
 class InvalidConfigException(Exception):
@@ -28,7 +30,6 @@ def parse_arguments():
     # 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)
@@ -60,9 +61,9 @@ def read_config(filename=None):
 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')
+    with open(os.path.join(absolute_path, 'config.schema.json'), 'r') as fd:
+        schema = json.loads(fd.read())
+        validate(instance=config, schema=schema)
 
 
 def setup_logging(args):
@@ -71,48 +72,56 @@ def setup_logging(args):
 
 
 def markdown_escape(text):
-    for special_char in ['\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '#', '+', '-', '.', '!']:
+    for special_char in ['\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '#', '+', '-', '.', '!', '=']:
         text = text.replace(special_char, fr'\{special_char}')
     return text
 
 
-def generate_host_payload(chat_id, args, template_file_name=None):
+def generate_payload(chat_id, message_type, message_variables, template_file_name=None):
     payload = {'chat_id': chat_id, 'parse_mode': 'MarkdownV2'}
+
+    # define jinja template name
     if not template_file_name:
-        absolute_path = os.path.split(os.path.abspath(__file__))[0]
-        template_file_name = os.path.join(absolute_path, 'templates', 'host.md.j2')
+        template_name = 'host.md.j2' if message_type == 'host' else 'service.md.j2'
+        template_file_name = os.path.join(absolute_path, 'templates', template_name)
     template_path = os.path.dirname(os.path.abspath(template_file_name))
     template_name = os.path.basename(os.path.abspath(template_file_name))
+
+    # create a jinja file template
     loader = FileSystemLoader(template_path)
     env = Environment(loader=loader)
     template = env.get_template(template_name)
-    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))
+
+    # escape message variables
+    template_variables = {}
+    for key, value in message_variables.items():
+        template_variables[key] = markdown_escape(value)
+
+    # render template and update payload
+    text = template.render(**template_variables)
     payload['text'] = text
     return payload
 
 
-def generate_service_payload(chat_id, args, template_file_name=None):
-    payload = {'chat_id': chat_id, 'parse_mode': 'MarkdownV2'}
-    if not template_file_name:
-        absolute_path = os.path.split(os.path.abspath(__file__))[0]
-        template_file_name = os.path.join(absolute_path, 'templates', 'service.md.j2')
-    template_path = os.path.dirname(os.path.abspath(template_file_name))
-    template_name = os.path.basename(os.path.abspath(template_file_name))
-    loader = FileSystemLoader(template_path)
-    env = Environment(loader=loader)
-    template = env.get_template(template_name)
-    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 generate_host_payload(chat_id, notification_type, host_name, host_state, host_address, host_output, long_date_time,
+                          template_file_name=None):
+    message_variables = {
+        'notification_type': notification_type, 'host_name': host_name, 'host_state': host_state,
+        'host_address': host_address, 'host_output': host_output, 'long_date_time': long_date_time
+    }
+    return generate_payload(chat_id=chat_id, message_type='host', message_variables=message_variables,
+                            template_file_name=template_file_name)
+
+
+def generate_service_payload(chat_id, notification_type, service_desc, host_alias, host_address, service_state,
+                             long_date_time, service_output, template_file_name=None):
+    message_variables = {
+        'notification_type': notification_type, 'service_desc': service_desc, 'host_alias': host_alias,
+        'host_address': host_address, 'service_state': service_state, 'long_date_time': long_date_time,
+        'service_output': service_output
+    }
+    return generate_payload(chat_id=chat_id, message_type='service', message_variables=message_variables,
+                            template_file_name=template_file_name)
 
 
 def send_message(auth_key, payload):
@@ -134,17 +143,23 @@ def main():
 
         logger.info('generating payload')
         if args.command == 'host':
-            payload = generate_host_payload(chat_id=config['chat_id'], args=args,
+            payload = generate_host_payload(chat_id=config['chat_id'], notification_type=args.notification_type,
+                                            host_name=args.host_name, host_state=args.host_state,
+                                            host_address=args.host_address, host_output=args.host_output,
+                                            long_date_time=args.long_date_time,
                                             template_file_name=config.get('host_template'))
         elif args.command == 'service':
-            payload = generate_service_payload(chat_id=config['chat_id'], args=args,
-                                            template_file_name=config.get('service_template'))
+            payload = generate_service_payload(chat_id=config['chat_id'], notification_type=args.notification_type,
+                                               service_desc=args.service_desc, host_alias=args.host_alias,
+                                               host_address=args.host_address, service_state=args.service_state,
+                                               long_date_time=args.long_date_time, service_output=args.service_output,
+                                               template_file_name=config.get('service_template'))
         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)
-    except Exception as err:
+    except Exception:
         logger.exception('cannot execute program')
 
 

requirements.txt

@@ -0,0 +1,21 @@
+appdirs==1.4.4
+attrs==20.3.0
+certifi==2020.11.8
+cfgv==3.2.0
+chardet==3.0.4
+distlib==0.3.1
+filelock==3.0.12
+identify==1.5.10
+idna==2.10
+Jinja2==2.11.2
+jsonschema==3.2.0
+MarkupSafe==1.1.1
+nodeenv==1.5.0
+pre-commit==2.9.2
+pyrsistent==0.17.3
+PyYAML==5.3.1
+requests==2.25.0
+six==1.15.0
+toml==0.10.2
+urllib3==1.26.2
+virtualenv==20.2.1