|
| 1 | +import time |
| 2 | +import logging |
| 3 | +from typing import Text |
| 4 | + |
| 5 | +from flask import Blueprint, Response, request |
| 6 | +from pyms.flask.services.driver import DriverService |
| 7 | + |
| 8 | +from prometheus_client import generate_latest |
| 9 | +from opentelemetry import metrics |
| 10 | +from opentelemetry.exporter.prometheus import PrometheusMetricsExporter |
| 11 | +from opentelemetry.sdk.metrics import Counter, ValueRecorder, MeterProvider |
| 12 | +from opentelemetry.sdk.metrics.export.controller import PushController |
| 13 | +from opentelemetry.instrumentation.requests import RequestsInstrumentor |
| 14 | + |
| 15 | +# Based on https://github.com/sbarratt/flask-prometheus |
| 16 | +# and https://github.com/korfuri/python-logging-prometheus/ |
| 17 | + |
| 18 | +# Set meter provider |
| 19 | +metrics.set_meter_provider(MeterProvider()) |
| 20 | +meter = metrics.get_meter(__name__) |
| 21 | +# Set main exporter |
| 22 | +exporter = PrometheusMetricsExporter() |
| 23 | +# Ser interval to generate metrics |
| 24 | +INTERVAL = 1 |
| 25 | +# Instrument requests |
| 26 | +instrumentor = RequestsInstrumentor() |
| 27 | +instrumentor.instrument() |
| 28 | +PushController(instrumentor.meter, exporter, INTERVAL) |
| 29 | +# Generate the custom metrics |
| 30 | +PushController(meter, exporter, INTERVAL) |
| 31 | + |
| 32 | + |
| 33 | +FLASK_REQUEST_LATENCY = meter.create_metric( |
| 34 | + "http_server_requests_seconds", |
| 35 | + "Flask Request Latency", |
| 36 | + "http_server_requests_seconds", |
| 37 | + float, |
| 38 | + ValueRecorder, |
| 39 | + ("service", "method", "uri", "status"), |
| 40 | +) |
| 41 | +FLASK_REQUEST_COUNT = meter.create_metric( |
| 42 | + "http_server_requests_count", |
| 43 | + "Flask Request Count", |
| 44 | + "http_server_requests_count", |
| 45 | + int, |
| 46 | + Counter, |
| 47 | + ["service", "method", "uri", "status"], |
| 48 | +) |
| 49 | +LOGGER_TOTAL_MESSAGES = meter.create_metric( |
| 50 | + "logger_messages_total", |
| 51 | + "Count of log entries by service and level.", |
| 52 | + "logger_messages_total", |
| 53 | + int, |
| 54 | + Counter, |
| 55 | + ["service", "level"], |
| 56 | +) |
| 57 | + |
| 58 | + |
| 59 | +class FlaskMetricsWrapper(): |
| 60 | + def __init__(self, app_name): |
| 61 | + self.app_name = app_name |
| 62 | + |
| 63 | + def before_request(self): # pylint: disable=R0201 |
| 64 | + request.start_time = time.time() |
| 65 | + |
| 66 | + def after_request(self, response): |
| 67 | + if hasattr(request.url_rule, "rule"): |
| 68 | + path = request.url_rule.rule |
| 69 | + else: |
| 70 | + path = request.path |
| 71 | + request_latency = time.time() - request.start_time |
| 72 | + labels = { |
| 73 | + "service": self.app_name, |
| 74 | + "method": str(request.method), |
| 75 | + "uri": path, |
| 76 | + "status": str(response.status_code), |
| 77 | + } |
| 78 | + |
| 79 | + FLASK_REQUEST_LATENCY.record(request_latency, labels) |
| 80 | + FLASK_REQUEST_COUNT.add(1, labels) |
| 81 | + |
| 82 | + return response |
| 83 | + |
| 84 | + |
| 85 | +class Service(DriverService): |
| 86 | + """ |
| 87 | + Adds [Prometheus](https://prometheus.io/) metrics using the [Opentelemetry Client Library](https://opentelemetry-python.readthedocs.io/en/latest/exporter/prometheus/prometheus.html). |
| 88 | + """ |
| 89 | + config_resource: Text = "metrics" |
| 90 | + |
| 91 | + def __init__(self, *args, **kwargs): |
| 92 | + super().__init__(*args, **kwargs) |
| 93 | + |
| 94 | + self.metrics_blueprint = Blueprint("metrics", __name__) |
| 95 | + self.serve_metrics() |
| 96 | + |
| 97 | + @staticmethod |
| 98 | + def monitor(app_name, app): |
| 99 | + metric = FlaskMetricsWrapper(app_name) |
| 100 | + app.before_request(metric.before_request) |
| 101 | + app.after_request(metric.after_request) |
| 102 | + |
| 103 | + def serve_metrics(self): |
| 104 | + @self.metrics_blueprint.route("/metrics", methods=["GET"]) |
| 105 | + def metrics(): # pylint: disable=unused-variable |
| 106 | + return Response( |
| 107 | + generate_latest(), |
| 108 | + mimetype="text/print()lain", |
| 109 | + content_type="text/plain; charset=utf-8", |
| 110 | + ) |
| 111 | + |
| 112 | + @staticmethod |
| 113 | + def add_logger_handler(logger, service_name): |
| 114 | + logger.addHandler(MetricsLogHandler(service_name)) |
| 115 | + return logger |
| 116 | + |
| 117 | + |
| 118 | +class MetricsLogHandler(logging.Handler): |
| 119 | + """A LogHandler that exports logging metrics for Prometheus.io.""" |
| 120 | + |
| 121 | + def __init__(self, app_name): |
| 122 | + super().__init__() |
| 123 | + self.app_name = str(app_name) |
| 124 | + |
| 125 | + def emit(self, record): |
| 126 | + labels = {"service": self.app_name, "level": record.levelname} |
| 127 | + LOGGER_TOTAL_MESSAGES.add(1, labels) |
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