|
| 1 | +import logging |
| 2 | +import time |
| 3 | +from typing import Text |
| 4 | + |
| 5 | +from flask import Blueprint, Response, request |
| 6 | +from pyms.flask.services.driver import DriverService |
| 7 | + |
| 8 | +from opentelemetry import metrics |
| 9 | +from opentelemetry.exporter.prometheus import PrometheusMetricsExporter |
| 10 | +from opentelemetry.sdk.metrics import Counter, MeterProvider, ValueRecorder |
| 11 | +from opentelemetry.sdk.metrics.export.controller import PushController |
| 12 | +from prometheus_client import generate_latest |
| 13 | + |
| 14 | +# TODO set sane defaults |
| 15 | +# https://github.com/python-microservices/pyms/issues/218 |
| 16 | +# TODO validate config |
| 17 | +# https://github.com/python-microservices/pyms/issues/219 |
| 18 | +PROMETHEUS_CLIENT = "prometheus" |
| 19 | + |
| 20 | + |
| 21 | +class FlaskMetricsWrapper: |
| 22 | + def __init__(self, app_name: str, meter: MeterProvider): |
| 23 | + self.app_name = app_name |
| 24 | + # TODO add Histogram support for flask when available |
| 25 | + # https://github.com/open-telemetry/opentelemetry-python/issues/1255 |
| 26 | + self.flask_request_latency = meter.create_metric( |
| 27 | + "http_server_requests_seconds", |
| 28 | + "Flask Request Latency", |
| 29 | + "http_server_requests_seconds", |
| 30 | + float, |
| 31 | + ValueRecorder, |
| 32 | + ("service", "method", "uri", "status"), |
| 33 | + ) |
| 34 | + self.flask_request_count = meter.create_metric( |
| 35 | + "http_server_requests_count", |
| 36 | + "Flask Request Count", |
| 37 | + "http_server_requests_count", |
| 38 | + int, |
| 39 | + Counter, |
| 40 | + ["service", "method", "uri", "status"], |
| 41 | + ) |
| 42 | + |
| 43 | + def before_request(self): # pylint: disable=R0201 |
| 44 | + request.start_time = time.time() |
| 45 | + |
| 46 | + def after_request(self, response: Response) -> Response: |
| 47 | + if hasattr(request.url_rule, "rule"): |
| 48 | + path = request.url_rule.rule |
| 49 | + else: |
| 50 | + path = request.path |
| 51 | + request_latency = time.time() - request.start_time |
| 52 | + labels = { |
| 53 | + "service": self.app_name, |
| 54 | + "method": str(request.method), |
| 55 | + "uri": path, |
| 56 | + "status": str(response.status_code), |
| 57 | + } |
| 58 | + |
| 59 | + self.flask_request_latency.record(request_latency, labels) |
| 60 | + self.flask_request_count.add(1, labels) |
| 61 | + |
| 62 | + return response |
| 63 | + |
| 64 | + |
| 65 | +class Service(DriverService): |
| 66 | + """ |
| 67 | + Adds [OpenTelemetry](https://opentelemetry.io/) metrics using the [Opentelemetry Client Library](https://opentelemetry-python.readthedocs.io/en/latest/exporter/). |
| 68 | + """ |
| 69 | + |
| 70 | + config_resource: Text = "opentelemetry" |
| 71 | + |
| 72 | + def __init__(self, *args, **kwargs): |
| 73 | + super().__init__(*args, **kwargs) |
| 74 | + self.blueprint = Blueprint("opentelemetry", __name__) |
| 75 | + self.serve_metrics() |
| 76 | + |
| 77 | + def set_metrics_backend(self): |
| 78 | + # Set meter provider |
| 79 | + metrics.set_meter_provider(MeterProvider()) |
| 80 | + self.meter = metrics.get_meter(__name__) |
| 81 | + if self.config.metrics.backend.lower() == PROMETHEUS_CLIENT: |
| 82 | + exporter = PrometheusMetricsExporter() |
| 83 | + else: |
| 84 | + pass |
| 85 | + # Create the push controller that will update the metrics when the |
| 86 | + # interval is met |
| 87 | + PushController(self.meter, exporter, self.config.metrics.interval) |
| 88 | + |
| 89 | + def set_tracing_backend(self): |
| 90 | + pass |
| 91 | + |
| 92 | + def set_logging_backend(self): |
| 93 | + pass |
| 94 | + |
| 95 | + def monitor(self, app_name, app): |
| 96 | + metric = FlaskMetricsWrapper(app_name, self.meter) |
| 97 | + app.before_request(metric.before_request) |
| 98 | + app.after_request(metric.after_request) |
| 99 | + |
| 100 | + def serve_metrics(self): |
| 101 | + @self.blueprint.route("/metrics", methods=["GET"]) |
| 102 | + def metrics(): # pylint: disable=unused-variable |
| 103 | + return Response( |
| 104 | + generate_latest(), |
| 105 | + mimetype="text/print()lain", |
| 106 | + content_type="text/plain; charset=utf-8", |
| 107 | + ) |
| 108 | + |
| 109 | + def add_logger_handler( |
| 110 | + self, logger: logging.Logger, service_name: str |
| 111 | + ) -> logging.Logger: |
| 112 | + logger.addHandler(MetricsLogHandler(service_name, self.meter)) |
| 113 | + return logger |
| 114 | + |
| 115 | + |
| 116 | +class MetricsLogHandler(logging.Handler): |
| 117 | + """A LogHandler that exports logging metrics for OpenTelemetry.""" |
| 118 | + |
| 119 | + def __init__(self, app_name: str, meter: MeterProvider): |
| 120 | + super().__init__() |
| 121 | + self.app_name = str(app_name) |
| 122 | + self.logger_total_messages = meter.create_metric( |
| 123 | + "logger_messages_total", |
| 124 | + "Count of log entries by service and level.", |
| 125 | + "logger_messages_total", |
| 126 | + int, |
| 127 | + Counter, |
| 128 | + ["service", "level"], |
| 129 | + ) |
| 130 | + |
| 131 | + def emit(self, record) -> None: |
| 132 | + labels = {"service": self.app_name, "level": record.levelname} |
| 133 | + self.logger_total_messages.add(1, labels) |
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