140 lines
3.9 KiB
Python
140 lines
3.9 KiB
Python
import logging
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import time
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import gunicorn.app.base
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from prometheus_client import CONTENT_TYPE_LATEST, Summary, Counter, generate_latest
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from werkzeug.routing import Map, Rule
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from werkzeug.wrappers import Request, Response
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from werkzeug.exceptions import InternalServerError
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from .collector import collect_europapark
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class EuropaParkExporterApplication:
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"""
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Europa Park prometheus collector HTTP handler.
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"""
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# pylint: disable=no-self-use
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def __init__(self, duration, errors):
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self._duration = duration
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self._errors = errors
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self._log = logging.getLogger(__name__)
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def on_europapark(self, module='default'):
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"""
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Request handler for /europapark route
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"""
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start = time.time()
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output = collect_europapark()
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response = Response(output)
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response.headers['content-type'] = CONTENT_TYPE_LATEST
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self._duration.labels(module).observe(time.time() - start)
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return response
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def on_metrics(self):
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"""
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Request handler for /metrics route
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"""
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response = Response(generate_latest())
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response.headers['content-type'] = CONTENT_TYPE_LATEST
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return response
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def on_index(self):
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"""
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Request handler for index route (/).
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"""
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response = Response(
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"""<html>
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<head><title>Europa Park Exporter</title></head>
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<body>
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<h1>Europa Park Exporter</h1>
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<p>Visit <code>/europapark</code> to use.</p>
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</body>
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</html>"""
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)
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response.headers['content-type'] = 'text/html'
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return response
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def view(self, endpoint, values, args):
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"""
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Werkzeug views mapping method.
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"""
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view_registry = {
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'index': self.on_index,
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'metrics': self.on_metrics,
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'europapark': self.on_europapark,
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}
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params = dict(values)
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try:
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return view_registry[endpoint](**params)
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except Exception as error: # pylint: disable=broad-except
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self._log.exception("Exception thrown while rendering view")
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self._errors.labels(args.get('module', 'default')).inc()
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raise InternalServerError from error
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@Request.application
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def __call__(self, request):
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url_map = Map([
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Rule('/', endpoint='index'),
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Rule('/metrics', endpoint='metrics'),
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Rule('/europapark', endpoint='europapark'),
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])
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urls = url_map.bind_to_environ(request.environ)
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view_func = lambda endpoint, values: self.view(endpoint, values, request.args)
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return urls.dispatch(view_func, catch_http_exceptions=True)
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class StandaloneGunicornApplication(gunicorn.app.base.BaseApplication):
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"""
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Copy-paste from https://docs.gunicorn.org/en/stable/custom.html
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"""
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# 'init' and 'load' methods are implemented by WSGIApplication.
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# pylint: disable=abstract-method
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def __init__(self, app, options=None):
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self.options = options or {}
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self.application = app
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super().__init__()
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def load_config(self):
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config = {key: value for key, value in self.options.items()
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if key in self.cfg.settings and value is not None}
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for key, value in config.items():
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self.cfg.set(key.lower(), value)
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def load(self):
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return self.application
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def start_http_server(gunicorn_options):
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"""
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Start a HTTP API server for Europa Park prometheus collector.
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"""
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duration = Summary(
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'europapark_collection_duration_seconds',
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'Duration of collections by the Europa Park exporter',
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['module'],
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)
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errors = Counter(
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'europapark_request_errors_total',
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'Errors in requests to Europa Park exporter',
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['module'],
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)
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app = EuropaParkExporterApplication(duration, errors)
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StandaloneGunicornApplication(app, gunicorn_options).run()
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