Initial commit

.dockerignore

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+**/__pycache__
+**/.classpath
+**/.dockerignore
+**/.env
+**/.git
+**/.gitignore
+**/.project
+**/.settings
+**/.toolstarget
+**/.vs
+**/.vscode
+**/*.*proj.user
+**/*.dbmdl
+**/*.jfm
+**/azds.yaml
+**/bin
+**/charts
+**/docker-compose*
+**/Dockerfile*
+**/node_modules
+**/npm-debug.log
+**/obj
+**/secrets.dev.yaml
+**/values.dev.yaml
+README.md

.gitignore

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+.pyenv/

Dockerfile

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+# For more information, please refer to https://aka.ms/vscode-docker-python
+FROM python:3.8-slim-buster
+
+# Keeps Python from generating .pyc files in the container
+ENV PYTHONDONTWRITEBYTECODE 1
+
+# Turns off buffering for easier container logging
+ENV PYTHONUNBUFFERED 1
+
+# Install pip requirements
+ADD requirements.txt .
+RUN python -m pip install -r requirements.txt
+
+WORKDIR /app
+ADD alertify.py /app
+
+# Switching to a non-root user, please refer to https://aka.ms/vscode-docker-python-user-rights
+# RUN useradd appuser && chown -R appuser /app
+# USER appuser
+
+EXPOSE 8080
+
+# During debugging, this entry point will be overridden. For more information, please refer to https://aka.ms/vscode-docker-python-debug
+CMD ["python", "alertify.py"]
+
+HEALTHCHECK --interval=30s --timeout=3s --retries=1 \
+  CMD python3 /app/alertify.py --healthcheck

alertify.py

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+#!/usr/bin/env python3
+"""
+Module to act as a Prometheus Exporter for Docker containers with a
+    healthcheck configured
+"""
+
+import argparse
+import http.client
+import json
+import logging
+import os
+import sys
+from http.server import HTTPServer, SimpleHTTPRequestHandler
+
+LISTEN_PORT = 8080
+
+logger = logging.getLogger()
+logger.setLevel(logging.DEBUG)
+
+
+class HTTPHandler(SimpleHTTPRequestHandler):
+    """
+    Class to encompass the requirements of a Prometheus Exporter
+        for Docker containers with a healthcheck configured
+    """
+
+    # Override built-in method
+    # pylint: disable=invalid-name
+    def do_GET(self):
+        """
+        Method to handle GET requests
+        """
+        if self.path == '/healthcheck':
+            self._healthcheck()
+
+    # Override built-in method
+    # pylint: disable=invalid-name
+    def do_POST(self):
+        """
+        Method to handle POST requests from AlertManager
+        """
+        if self.path == '/alert':
+            self._alerts()
+
+    def _healthcheck(self, message=True):
+        """
+        Method to return 200 or 500 response and an optional message
+        """
+        if not healthy():
+            self.send_response(500)
+            self.end_headers()
+            if message:
+                self.wfile.write(b'ERR')
+            return False
+
+        self.send_response(200)
+        self.end_headers()
+        if message:
+            self.wfile.write(b'OK')
+        return True
+
+    def _alerts(self):
+        """
+        Method to handle the request for alerts
+        """
+        if not self._healthcheck(message=False):
+            return
+            
+        content_length = int(self.headers['Content-Length'])
+        rawdata = self.rfile.read(content_length)
+
+        alert = json.loads(rawdata.decode())
+
+        gotify_msg = {
+            'message': '{}: {}'.format(
+                alert['commonLabels']['severity'].capitalize(),
+                alert['commonAnnotations']['description']
+            ),
+            'priority': int(alert['commonLabels']['priority']) or 5
+        }
+
+        (status, reason) = gotify_send(
+            os.environ['GOTIFY_SERVER'],
+            os.environ['GOTIFY_PORT'],
+            os.environ['GOTIFY_KEY'],
+            gotify_msg
+        )
+
+        self.wfile.write(f'Status: {status}, Reason: {reason}'.encode())
+
+
+def gotify_send(server, port, authkey, payload):
+    """
+    Function to POST data to a Gotify server
+    """
+
+    gotify = http.client.HTTPConnection(server, port)
+    headers = {
+        'X-Gotify-Key': authkey,
+        'Content-type': 'application/json',
+    }
+
+    gotify.request('POST', '/message', json.dumps(payload), headers)
+    response = gotify.getresponse()
+
+    return (response.status, response.reason)
+
+
+def healthy():
+    """
+    Simple funtion to return if all the requirements are met
+    """
+    return all([
+        'GOTIFY_SERVER' in os.environ,
+        'GOTIFY_PORT' in os.environ,
+        'GOTIFY_KEY' in os.environ,
+    ])
+
+
+if __name__ == '__main__':
+    def cli_parse():
+        """
+        Function to parse the CLI
+        """
+        parser = argparse.ArgumentParser()
+
+        parser.add_argument(
+            '-H', '--healthcheck',
+            action='store_true',
+            help='Simply exit with 0 for healthy or 1 when unhealthy',
+        )
+
+        return parser.parse_args()
+
+    def main():
+        """
+        main()
+        """
+        args = cli_parse()
+
+        if args.healthcheck:
+            # Invert the sense of 'healthy' for Unix CLI usage
+            return not healthy()
+
+        HTTPServer(('', LISTEN_PORT), HTTPHandler).serve_forever()
+
+        return 0
+
+    sys.exit(main())

requirements.txt

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+# To ensure app dependencies are ported from your virtual environment/host machine into your container, run 'pip freeze > requirements.txt' in the terminal to overwrite this file
+docker
+prometheus_client