Use telegram Markdown v2 API; properly escape text; do not send error…

…s using telegram

flaskalert.py

@@ -15,6 +15,7 @@
 from flask import render_template
 from flask import current_app as app
 from flask_basicauth import BasicAuth
+from jinja2.runtime import Undefined
 
 LOG_LEVEL = logging.getLevelName(os.getenv('LOG_LEVEL', 'INFO').upper())
 logging.basicConfig(level=LOG_LEVEL, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
@@ -47,6 +48,17 @@ def get_env_var(env_variable_name='', default='', required=False):
     app.logger.info('Basic Auth is disabled')
 
 
+@app.template_filter()
+def escape_telegram_markdown(item):
+    """
+    Escapes characters in text as Telegram Bot API requires.
+    Info:
+      * https://core.telegram.org/bots/api#markdownv2-style
+      * https://python-telegram-bot.readthedocs.io/en/stable/telegram.utils.helpers.html#telegram.utils.helpers.escape_markdown
+    """
+    return telegram.utils.helpers.escape_markdown(text=str(item), version=2)
+
+
 @app.route('/', methods=['POST'])
 def post_alertmanager():
     """
@@ -69,7 +81,7 @@ def post_alertmanager():
     try:
         content = json.loads(request.get_data())
     except Exception as exc:
-        app.logger.error("Cannot parse JSON data: {}.\n  Error message: {}".format(pformat(request.get_data()), str(exc)))
+        app.logger.error("Cannot parse JSON data: {}.\n  Error message: {}".format(pformat(request.get_data()), pformat(str(exc))))
         return "Alert FAIL", 500
 
     try:
@@ -85,12 +97,20 @@ def post_alertmanager():
                 timediff = None
 
             alert['startsAt'] = alert['startsAt'].strftime(app.time_format)
+    except Exception as exc:
+        app.logger.error("Cannot parse date/time in the message:\n message={}".format(pformat(str(exc))), pformat(alert))
+        return "Alert FAIL", 500
 
-            message = render_template("alert.j2", alert=alert, duration=timediff)
-            app.logger.debug('Rendered the message: {}'.format(pformat(message)))
+    try:
+        message = render_template("alert.j2", alert=alert, duration=timediff)
+        app.logger.debug('Rendered the message: {}'.format(pformat(message)))
+    except Exception as exc:
+        app.logger.error("Cannot render a message:\n message={}\n".format(pformat(alert), pformat(str(exc))))
+        return "Alert FAIL", 500
 
-            app.bot.sendMessage(chat_id=chat_id, text=message, parse_mode=telegram.ParseMode.MARKDOWN)
-            return "Alert OK", 200
+    try:
+        app.bot.sendMessage(chat_id=chat_id, text=message, parse_mode=telegram.ParseMode.MARKDOWN_V2)
+        return "Alert OK", 200
     except Exception as exc:
         app.logger.error("Cannot send the message:\n  chat_id={}\n  message={}".format(chat_id, pformat(str(exc))))
         return "Alert FAIL", 500

templates/alert.j2

@@ -3,16 +3,16 @@
 {% elif alert['status'] == 'resolved' -%}
 *✅ RESOLVED ✅*
 {% else -%}
-*[{{ alert['labels']['severity']|upper }}] {{ alert['status']|upper }}*
+*[{{ alert['labels']['severity']|upper|escape_telegram_markdown }}] {{ alert['status']|upper|escape_telegram_markdown }}*
 {% endif -%}
 
-*{{ alert['labels']['alertname'] }}*
-{{ alert['annotations']['message']|default('') }}
+*{{ alert['labels']['alertname']|escape_telegram_markdown }}*
+{{ alert['annotations']['message']|default('')|escape_telegram_markdown }}
 
-{{ alert['annotations']['description'] -}}
+{{ alert['annotations']['description']|escape_telegram_markdown -}}
 
-{% if alert['startsAt'] is defined %}*Occurred at:* {{ alert['startsAt'] }}{% endif %}
+{% if alert['startsAt'] is defined %}*Occurred at:* {{ alert['startsAt']|escape_telegram_markdown }}{% endif %}
 {% if alert['status'] == 'resolved' -%}
-{% if alert['endsAt'] is defined %}*Resolved at:* {{ alert['endsAt'] }}{%- endif %}
-{% if duration is defined %}*Duration*: {{ duration }}{%- endif %}
+{% if alert['endsAt'] is defined %}*Resolved at:* {{ alert['endsAt']|escape_telegram_markdown }}{%- endif %}
+{% if duration is defined %}*Duration*: {{ duration|escape_telegram_markdown }}{%- endif %}
 {% endif -%}

tests/firing.sh

@@ -2,5 +2,5 @@
 
 curl \
 --request POST \
---data '{"receiver":"telegram","status":"firing","alerts":[{"status":"firing","labels":{"alertname":"Fire","severity":"critical"},"annotations":{"message":"Something is on fire"},"startsAt":"2018-11-04T22:43:58.283995108+01:00","endsAt":"2018-11-04T22:46:58.283995108+01:00","generatorURL":"http://localhost:9090/graph?g0.expr=vector%28666%29\u0026g0.tab=1"}],"groupLabels":{"alertname":"Fire"},"commonLabels":{"alertname":"Fire","severity":"critical"},"commonAnnotations":{"message":"Something is on fire"},"externalURL":"http://localhost:9093","version":"4","groupKey":"{}:{alertname=\"Fire\"}"}' \
+--data '{"receiver":"telegram","status":"firing","alerts":[{"status":"firing","labels":{"alertname":"Fire detected on * host_name (escape test)","severity":"critical"},"annotations":{"message":"Something is on fire"},"startsAt":"2018-11-04T22:43:58.283995108+01:00","endsAt":"2018-11-04T22:46:58.283995108+01:00","generatorURL":"http://localhost:9090/graph?g0.expr=vector%28666%29\u0026g0.tab=1"}],"groupLabels":{"alertname":"Fire"},"commonLabels":{"alertname":"Fire","severity":"critical"},"commonAnnotations":{"message":"Something is on fire"},"externalURL":"http://localhost:9093","version":"4","groupKey":"{}:{alertname=\"Fire\"}"}' \
 localhost:8080

tests/resolved.sh

@@ -2,5 +2,5 @@
 
 curl \
 --request POST \
---data '{"receiver":"telegram","status":"resolved","alerts":[{"status":"resolved","labels":{"alertname":"Fire","severity":"critical"},"annotations":{"message":"Something is on fire"},"startsAt":"2018-11-04T22:43:58.283995108+01:00","endsAt":"2018-11-04T22:48:13.283995108+01:00","generatorURL":"http://localhost:9090/graph?g0.expr=vector%28666%29\u0026g0.tab=1"}],"groupLabels":{"alertname":"Fire"},"commonLabels":{"alertname":"Fire","severity":"critical"},"commonAnnotations":{"message":"Something is on fire"},"externalURL":"http://localhost:9093","version":"4","groupKey":"{}:{alertname=\"Fire\"}"}' \
+--data '{"receiver":"telegram","status":"resolved","alerts":[{"status":"resolved","labels":{"alertname":"Fire extinguished on * host_name (escape test)","severity":"critical"},"annotations":{"message":"Something is on fire"},"startsAt":"2018-11-04T22:43:58.283995108+01:00","endsAt":"2018-11-04T22:48:13.283995108+01:00","generatorURL":"http://localhost:9090/graph?g0.expr=vector%28666%29\u0026g0.tab=1"}],"groupLabels":{"alertname":"Fire"},"commonLabels":{"alertname":"Fire","severity":"critical"},"commonAnnotations":{"message":"Something is on fire"},"externalURL":"http://localhost:9093","version":"4","groupKey":"{}:{alertname=\"Fire\"}"}' \
 localhost:8080