def requests(self, session: requests.Session) -> requests.Session:
"""
A backoff factor to apply between attempts after the second try (most errors are resolved immediately by a
second try without a delay). urllib3 will sleep for: {backoff factor} * (2 ^ ({number of total retries} - 1))
seconds. If the backoff_factor is 0.1, then sleep() will sleep for [0.0s, 0.2s, 0.4s, ...] between retries.
It will never be longer than Retry.BACKOFF_MAX. By default, backoff is disabled (set to 0).
:param session:
:return:
"""
session_r = session or requests.Session()
max_retries = Retry(
total=self.retries,
read=self.retries,
connect=self.retries,
backoff_factor=0.3,
status_forcelist=self.status_retries,
)
adapter = HTTPAdapter(max_retries=max_retries)
session_r.mount("http://", adapter)
session_r.mount("https://", adapter)
metrics_enabled = get_conf(service=get_service_name(service="metrics"), empty_init=True)
if metrics_enabled:
session_r.hooks["response"] = [self.observe_requests]
return session_r
def init_jaeger_tracer(self):
"""This scaffold is configured whith `Jeager <https://github.com/jaegertracing/jaeger>`_ but you can use
one of the `opentracing tracers <http://opentracing.io/documentation/pages/supported-tracers.html>`_
:param service_name: the name of your application to register in the tracer
:return: opentracing.Tracer
"""
check_package_exists("jaeger_client")
Config = import_from("jaeger_client", "Config")
host = {}
if self.host:
host = {'local_agent': {'reporting_host': self.host}}
metrics_config = get_conf(service=get_service_name(service="metrics"),
empty_init=True)
metrics = ""
if metrics_config:
service_name = self.component_name.lower().replace("-",
"_").replace(
" ", "_")
metrics = PrometheusMetricsFactory(service_name_label=service_name)
config = Config(config={
**{
'sampler': {
'type': 'const',
'param': 1,
},
'propagation': 'b3',
'logging': True
},
**host
},
service_name=self.component_name,
metrics_factory=metrics,
validate=True)
return config.initialize_tracer()
def create_app(self):
"""Initialize the Flask app, register blueprints and initialize
all libraries like Swagger, database,
the trace system...
return the app and the database objects.
:return:
"""
config = get_conf(service=self.service)
app = connexion.App(__name__,
specification_dir=os.path.join(
self.path, 'swagger'))
app.add_api('swagger.yaml',
arguments={'title': config.APP_NAME},
base_path=config.APPLICATION_ROOT)
self.application = app.app
self.application._connexion_app = app
self.application.config.from_object(config)
self.application.tracer = None
# Initialize Blueprints
self.application.register_blueprint(healthcheck_blueprint)
self.init_libs()
self.add_error_handlers()
# Inject Modules
formatter = CustomJsonFormatter(
'(timestamp) (level) (name) (module) (funcName) (lineno) (message)'
)
if not self.application.config["TESTING"]:
log_handler = logging.StreamHandler()
self.application.tracer = FlaskTracer(init_jaeger_tracer(), True,
self.application)
formatter.add_service_name(self.application.config["APP_NAME"])
formatter.add_trace_span(self.application.tracer)
log_handler.setFormatter(formatter)
self.application.logger.addHandler(log_handler)
self.application.logger.propagate = False
self.application.logger.setLevel(logging.INFO)
return self.application
import logging
import time
from flask import Blueprint, Flask, Response, request
from prometheus_client import REGISTRY, CollectorRegistry, Counter, Histogram, generate_latest, multiprocess
from pyms.flask.services.driver import DriverService, get_service_name
from pyms.config.conf import get_conf
# Based on https://github.com/sbarratt/flask-prometheus
# and https://github.com/korfuri/python-logging-prometheus/
METRICS_CONFIG = get_conf(service=get_service_name(service="metrics"),
empty_init=True)
FLASK_REQUEST_COUNT = Counter("http_server_requests_count",
"Flask Request Count",
["service", "method", "uri", "status"])
FLASK_REQUEST_LATENCY = Histogram("http_server_requests_seconds",
"Flask Request Latency",
["service", "method", "uri", "status"])
LOGGER_TOTAL_MESSAGES = Counter(
"logger_messages_total",
"Count of log entries by service and level.",
["service", "level"],
)
class FlaskMetricsWrapper:
def __init__(self, service: Text, path=__file__):
self.service = service
self.path = os.path.dirname(path)
self.config = get_conf(service=self.service)
self.init_services()
def __init__(self, service=None):
self.service = (service if service else SERVICE_BASE)
self.config = get_conf(service=self.service, empty_init=True)
def __init__(self, service, *args, **kwargs):
self.service = ".".join([service, self.service])
self.config = get_conf(service=self.service, empty_init=True)