commit d5a422ca10ef1366ba574496df22305fa51eea00
Author: Scott Wallace <scott@wallace.sh>
Date:   Tue Aug 3 15:56:28 2021 +0100

    Initial code commit

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
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+.vscode/
+__pycache__/
+.pyenv/
diff --git a/Dockerfile b/Dockerfile
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+++ b/Dockerfile
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+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
+
+ADD requirements.txt .
+RUN python -m pip install -r requirements.txt
+
+WORKDIR /app
+COPY main.py /app
+
+RUN useradd appuser && chown -R appuser /app
+USER appuser
+
+EXPOSE 5000
+
+ENTRYPOINT ["python", "main.py"]
diff --git a/README.md b/README.md
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+# Carbon Exporter
+Pulls carbon intensity data from [carbonintensity.org.uk](https://carbonintensity.org.uk) and provides it in Prometheus-style exporter format over HTTP.
+
+Used to monitor a UK region's carbon intensity over time.
diff --git a/docker-compose.yaml b/docker-compose.yaml
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+++ b/docker-compose.yaml
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+---
+version: '3.7'
+services:
+  carbon-exporter:
+    image: carbon-exporter:latest
+    container_name: carbon-exporter
+    environment:
+      - CARBON_POSTCODE=<first 3 characters of UK postcode>
+    restart: unless-stopped
diff --git a/main.py b/main.py
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+++ b/main.py
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+"""
+Present observational weather data to Prometheus
+"""
+
+import json
+import os
+from typing import Dict, List
+
+import requests  # type: ignore
+from flask import Flask, Response  # type: ignore
+
+app = Flask(__name__)
+
+
+def fetch_carbon_data(postcode: str) -> Dict:
+    """
+    Fetch current data for the carbon intensity of the provided region
+    """
+
+    obs_data = requests.get(
+        f'https://api.carbonintensity.org.uk/regional/postcode/{postcode}'
+    )
+
+    return json.loads(obs_data.content)
+
+
+@app.route('/metrics')
+def metrics():
+    """
+    Output Prometheus-style metrics
+    """
+    postcode = os.environ.get('CARBON_POSTCODE')
+
+    latest_data = fetch_carbon_data(postcode)['data'][0]
+
+    ret_data: List = list()
+    for generation in latest_data['data'][0]['generationmix']:
+        ret_data.append(
+            {
+                'key': f'sensor_carbon_generation_{generation["fuel"]}_perc',
+                'labels': {
+                    'region': latest_data['dnoregion'],
+                },
+                'type': 'gauge',
+                'value': float(generation['perc'])
+            }
+        )
+
+    ret_data.append(
+        {
+            'key': 'sensor_carbon_intensity_forecast',
+            'labels': {
+                'region': latest_data['dnoregion'],
+            },
+            'type': 'gauge',
+            'value': float(latest_data['data'][0]['intensity']['forecast']),
+        }
+    )
+
+    ret_strs = list()
+    for item in ret_data:
+        ret_strs.append(f'# HELP {item["key"]} Carbon metric')
+        ret_strs.append(f'# TYPE {item["key"]} {item["type"]}')
+        ret_strs.append(
+            item["key"]
+            + '{'
+            + " ".join([f'{key}="{val}"' for key, val in item["labels"].items()])
+            + '} '
+            + str(item["value"])
+        )
+
+    resp = Response('\n'.join(ret_strs))
+    resp.headers['Content-type'] = 'text/plain'
+
+    return resp
+
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0')
diff --git a/requirements.txt b/requirements.txt
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+++ b/requirements.txt
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+flask
+requests