Merge pull request #13390 from lujun9972/add-MjAxOTA0MjIgVHJhY2tpbmcgdGhlIHdlYXRoZXIgd2l0aCBQeXRob24gYW5kIFByb21ldGhldXMubWQK

选题: 20190422 Tracking the weather with Python and Prometheus

sources/tech/20190422 Tracking the weather with Python and Prometheus.md

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+[#]: collector: (lujun9972)
+[#]: translator: ( )
+[#]: reviewer: ( )
+[#]: publisher: ( )
+[#]: url: ( )
+[#]: subject: (Tracking the weather with Python and Prometheus)
+[#]: via: (https://opensource.com/article/19/4/weather-python-prometheus)
+[#]: author: (Moshe Zadka  https://opensource.com/users/moshez)
+
+Tracking the weather with Python and Prometheus
+======
+Create a custom Prometheus integration to keep track of the biggest
+cloud provider of all: Mother Earth.
+![Tree clouds][1]
+
+Open source monitoring system [Prometheus][2] has integrations to track many types of time-series data, but if you want an integration that doesn't yet exist, it's easy to build one. An often-used example is a custom integration with a cloud provider that uses the provider's APIs to grab specific metrics. In this example, though, we will integrate with the biggest cloud provider of all: Earth.
+
+Luckily, the US government already measures the weather and provides an easy API for integrations. Getting the weather forecast for the next hour at Red Hat headquarters is simple.
+
+
+```
+import requests
+HOURLY_RED_HAT = "<https://api.weather.gov/gridpoints/RAH/73,57/forecast/hourly>"
+def get_temperature():
+result = requests.get(HOURLY_RED_HAT)
+return result.json()["properties"]["periods"][0]["temperature"]
+```
+
+Now that our integration with Earth is done, it's time to make sure Prometheus can understand what we are saying. We can use the [Prometheus Python library][3] to create a registry with one _gauge_ : the temperature at Red Hat HQ.
+
+
+```
+from prometheus_client import CollectorRegistry, Gauge
+def prometheus_temperature(num):
+registry = CollectorRegistry()
+g = Gauge("red_hat_temp", "Temperature at Red Hat HQ", registry=registry)
+g.set(num)
+return registry
+```
+
+Finally, we need to connect this to Prometheus in some way. That depends a little on the network topology for Prometheus: whether it is easier for Prometheus to talk to our service, or whether the reverse is easier.
+
+The first case is the one usually recommended, if possible, so we need to build a web server exposing the registry and then configure Prometheus to _scrape_ it.
+
+We can build a simple web server with [Pyramid][4].
+
+
+```
+from pyramid.config import Configurator
+from pyramid.response import Response
+from prometheus_client import generate_latest, CONTENT_TYPE_LATEST
+def metrics_web(request):
+registry = prometheus_temperature(get_temperature())
+return Response(generate_latest(registry),
+content_type=CONTENT_TYPE_LATEST)
+config = Configurator()
+config.add_route('metrics', '/metrics')
+config.add_view(metrics_web, route_name='metrics')
+app = config.make_wsgi_app()
+```
+
+This can be run with any Web Server Gateway Interface (WSGI) server. For example, we can use **python -m twisted web --wsgi earth.app** to run it, assuming we put the code in **earth.py**.
+
+Alternatively, if it is easier for our code to connect to Prometheus, we can push it to Prometheus's [Push gateway][5] periodically.
+
+
+```
+import time
+from prometheus_client import push_to_gateway
+def push_temperature(url):
+while True:
+registry = prometheus_temperature(get_temperature())
+push_to_gateway(url, "temperature collector", registry)
+time.sleep(60*60)
+```
+
+The URL is the one for the Push gateway; it often ends in **:9091**.
+
+Good luck building your own custom Prometheus integration so you can track all the things!
+
+--------------------------------------------------------------------------------
+
+via: https://opensource.com/article/19/4/weather-python-prometheus
+
+作者：[Moshe Zadka ][a]
+选题：[lujun9972][b]
+译者：[译者ID](https://github.com/译者ID)
+校对：[校对者ID](https://github.com/校对者ID)
+
+本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
+
+[a]: https://opensource.com/users/moshez
+[b]: https://github.com/lujun9972
+[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/life_tree_clouds.png?itok=b_ftihhP (Tree clouds)
+[2]: https://prometheus.io/
+[3]: https://github.com/prometheus/client_python
+[4]: https://trypyramid.com/
+[5]: https://github.com/prometheus/pushgateway