Decouple exporters from Flask integration (#621)

Author: reyang

contrib/opencensus-ext-azure/examples/custom.py

@@ -0,0 +1,44 @@
+# Copyright 2019, OpenCensus Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from flask import Flask
+from opencensus.ext.flask.flask_middleware import FlaskMiddleware
+
+app = Flask(__name__)
+# TODO:
+# Replace 00000000-0000-0000-0000-000000000000 with your Instrumentation Key
+# https://docs.microsoft.com/en-us/azure/azure-monitor/app/create-new-resource
+app.config['OPENCENSUS'] = {
+    'TRACE': {
+        'SAMPLER': 'opencensus.trace.samplers.ProbabilitySampler(rate=1)',
+        'EXPORTER': '''opencensus.ext.azure.trace_exporter.AzureExporter(
+            opencensus.ext.azure.common.Options(
+                instrumentation_key="00000000-0000-0000-0000-000000000000",
+                timeout=29.9,
+            ))''',
+    },
+}
+middleware = FlaskMiddleware(app)
+
+
+@app.route('/')
+def hello():
+    return 'Hello World!'
+
+
+if __name__ == '__main__':
+    import logging
+    logger = logging.getLogger('werkzeug')
+    logger.setLevel(logging.ERROR)
+    app.run(host='localhost', port=8080, threaded=True)

contrib/opencensus-ext-azure/examples/server.py

@@ -18,15 +18,9 @@
 from opencensus.trace import config_integration
 from opencensus.ext.azure.trace_exporter import AzureExporter
 from opencensus.ext.flask.flask_middleware import FlaskMiddleware
-from opencensus.trace.propagation.trace_context_http_header_format \
-    import TraceContextPropagator
 
 app = Flask(__name__)
-middleware = FlaskMiddleware(
-    app,
-    exporter=AzureExporter(),
-    propagator=TraceContextPropagator(),
-)
+middleware = FlaskMiddleware(app, exporter=AzureExporter())
 
 
 @app.route('/')

contrib/opencensus-ext-flask/CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## Unreleased
+- Decoupled exporter specific logic from configuration
 
 ## 0.2.0
 Released 2019-04-08

contrib/opencensus-ext-flask/README.rst

@@ -20,10 +20,9 @@ Usage
 
     from flask import Flask
     from opencensus.ext.flask.flask_middleware import FlaskMiddleware
-    from opencensus.trace.propagation.trace_context_http_header_format import TraceContextPropagator
     
     app = Flask(__name__)
-    middleware = FlaskMiddleware(app, propagator=TraceContextPropagator(), blacklist_paths=['_ah/health'])
+    middleware = FlaskMiddleware(app, blacklist_paths=['_ah/health'])
     
     @app.route('/')
     def hello():
@@ -34,3 +33,18 @@ Usage
         logger = logging.getLogger('werkzeug')
         logger.setLevel(logging.ERROR)
         app.run(host='localhost', port=8080, threaded=True)
+
+Additional configuration can be provided, please read
+`Customization <https://github.com/census-instrumentation/opencensus-python#customization>`_
+for a complete reference.
+
+.. code:: python
+
+    app.config['OPENCENSUS'] = {
+        'TRACE': {
+            'SAMPLER': 'opencensus.trace.samplers.ProbabilitySampler(rate=1)',
+            'EXPORTER': '''opencensus.ext.ocagent.trace_exporter.TraceExporter(
+                service_name='foobar',
+            )''',
+        }
+    }

contrib/opencensus-ext-flask/examples/simple.py

@@ -14,11 +14,9 @@
 
 from flask import Flask
 from opencensus.ext.flask.flask_middleware import FlaskMiddleware
-from opencensus.trace.propagation.trace_context_http_header_format \
-    import TraceContextPropagator
 
 app = Flask(__name__)
-middleware = FlaskMiddleware(app, propagator=TraceContextPropagator())
+middleware = FlaskMiddleware(app)
 
 
 @app.route('/')

contrib/opencensus-ext-flask/opencensus/ext/flask/flask_middleware.py

@@ -12,14 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import inspect
 import logging
+import six
 import sys
 
 import flask
 from google.rpc import code_pb2
 
-from opencensus.common.transports import sync
+from opencensus.common import configuration
 from opencensus.trace import attributes_helper
 from opencensus.trace import execution_context
 from opencensus.trace import print_exporter
@@ -28,38 +28,20 @@
 from opencensus.trace import status
 from opencensus.trace import tracer as tracer_module
 from opencensus.trace import utils
-from opencensus.trace.propagation import google_cloud_format
-from opencensus.trace.samplers import always_on, probability
+from opencensus.trace.propagation import trace_context_http_header_format
+from opencensus.trace.samplers import always_on
 
 HTTP_METHOD = attributes_helper.COMMON_ATTRIBUTES['HTTP_METHOD']
 HTTP_URL = attributes_helper.COMMON_ATTRIBUTES['HTTP_URL']
 HTTP_STATUS_CODE = attributes_helper.COMMON_ATTRIBUTES['HTTP_STATUS_CODE']
 
 BLACKLIST_PATHS = 'BLACKLIST_PATHS'
-GCP_EXPORTER_PROJECT = 'GCP_EXPORTER_PROJECT'
-SAMPLING_RATE = 'SAMPLING_RATE'
-TRANSPORT = 'TRANSPORT'
-SERVICE_NAME = 'SERVICE_NAME'
-ZIPKIN_EXPORTER_SERVICE_NAME = 'ZIPKIN_EXPORTER_SERVICE_NAME'
-ZIPKIN_EXPORTER_HOST_NAME = 'ZIPKIN_EXPORTER_HOST_NAME'
-ZIPKIN_EXPORTER_PORT = 'ZIPKIN_EXPORTER_PORT'
-ZIPKIN_EXPORTER_PROTOCOL = 'ZIPKIN_EXPORTER_PROTOCOL'
-JAEGER_EXPORTER_HOST_NAME = 'JAEGER_EXPORTER_HOST_NAME'
-JAEGER_EXPORTER_PORT = 'JAEGER_EXPORTER_PORT'
-JAEGER_EXPORTER_AGENT_HOST_NAME = 'JAEGER_EXPORTER_AGENT_HOST_NAME'
-JAEGER_EXPORTER_AGENT_PORT = 'JAEGER_EXPORTER_AGENT_PORT'
-JAEGER_EXPORTER_SERVICE_NAME = 'JAEGER_EXPORTER_SERVICE_NAME'
-OCAGENT_TRACE_EXPORTER_ENDPOINT = 'OCAGENT_TRACE_EXPORTER_ENDPOINT'
 BLACKLIST_HOSTNAMES = 'BLACKLIST_HOSTNAMES'
 
 log = logging.getLogger(__name__)
 
 
 class FlaskMiddleware(object):
-    DEFAULT_SAMPLER = always_on.AlwaysOnSampler
-    DEFAULT_EXPORTER = print_exporter.PrintExporter
-    DEFAULT_PROPAGATOR = google_cloud_format.GoogleCloudFormatPropagator
-
     """Flask middleware to automatically trace requests.
 
     :type app: :class: `~flask.Flask`
@@ -68,24 +50,25 @@ class FlaskMiddleware(object):
     :type blacklist_paths: list
     :param blacklist_paths: Paths that do not trace.
 
-    :type sampler: :class: `type`
-    :param sampler: Class for creating new Sampler objects. It should extend
-                    from the base :class:`.Sampler` type and implement
+    :type sampler: :class:`~opencensus.trace.samplers.base.Sampler`
+    :param sampler: A sampler. It should extend from the base
+                    :class:`.Sampler` type and implement
                     :meth:`.Sampler.should_sample`. Defaults to
                     :class:`.AlwaysOnSampler`. The rest options are
                     :class:`.AlwaysOffSampler`, :class:`.FixedRateSampler`.
 
-    :type exporter: :class: `type`
-    :param exporter: Class for creating new exporter objects. Default to
-                     :class:`.PrintExporter`. The rest option is
-                     :class:`.FileExporter`.
+    :type exporter: :class:`~opencensus.trace.base_exporter.exporter`
+    :param exporter: An exporter. Default to
+                     :class:`.PrintExporter`. The rest options are
+                     :class:`.FileExporter`, :class:`.LoggingExporter` and
+                     trace exporter extensions.
 
-    :type propagator: :class: 'type'
-    :param propagator: Class for creating new propagator objects. Default to
-                       :class:`.GoogleCloudFormatPropagator`. The rest option
+    :type propagator: :class: 'object'
+    :param propagator: A propagator. Default to
+                       :class:`.TraceContextPropagator`. The rest options
                        are :class:`.BinaryFormatPropagator`,
-                       :class:`.TextFormatPropagator` and
-                       :class:`.TraceContextPropagator`.
+                       :class:`.GoogleCloudFormatPropagator` and
+                       :class:`.TextFormatPropagator`.
     """
 
     def __init__(self, app=None, blacklist_paths=None, sampler=None,
@@ -103,92 +86,31 @@ def init_app(self, app):
         self.app = app
 
         # get settings from app config
-        settings = self.app.config.get('OPENCENSUS_TRACE', {})
-
-        self.sampler = (self.sampler
-                        or settings.get('SAMPLER',
-                                        self.DEFAULT_SAMPLER))
-        self.exporter = (self.exporter
-                         or settings.get('EXPORTER',
-                                         self.DEFAULT_EXPORTER))
-        self.propagator = (self.propagator
-                           or settings.get('PROPAGATOR',
-                                           self.DEFAULT_PROPAGATOR))
-
-        # get params from app config
-        params = self.app.config.get('OPENCENSUS_TRACE_PARAMS', {})
-
-        self.blacklist_paths = params.get(BLACKLIST_PATHS,
-                                          self.blacklist_paths)
-
-        # Initialize the sampler
-        if not inspect.isclass(self.sampler):
-            pass  # handling of instantiated sampler
-        elif self.sampler.__name__ == 'ProbabilitySampler':
-            _rate = params.get(SAMPLING_RATE,
-                               probability.DEFAULT_SAMPLING_RATE)
-            self.sampler = self.sampler(_rate)
-        else:
-            self.sampler = self.sampler()
-
-        transport = params.get(TRANSPORT, sync.SyncTransport)
-
-        # Initialize the exporter
-        if not inspect.isclass(self.exporter):
-            pass  # handling of instantiated exporter
-        elif self.exporter.__name__ == 'StackdriverExporter':
-            _project_id = params.get(GCP_EXPORTER_PROJECT, None)
-            self.exporter = self.exporter(
-                project_id=_project_id,
-                transport=transport)
-        elif self.exporter.__name__ == 'JaegerExporter':
-            _service_name = params.get(
-                JAEGER_EXPORTER_SERVICE_NAME,
-                self._get_service_name(params))
-            _jaeger_host_name = params.get(
-                JAEGER_EXPORTER_HOST_NAME, None)
-            _jaeger_port = params.get(
-                JAEGER_EXPORTER_PORT, None)
-            _jaeger_agent_host_name = params.get(
-                JAEGER_EXPORTER_AGENT_HOST_NAME, 'localhost')
-            _jaeger_agent_port = params.get(
-                JAEGER_EXPORTER_AGENT_PORT, 6831)
-            self.exporter = self.exporter(
-                service_name=_service_name,
-                host_name=_jaeger_host_name,
-                port=_jaeger_port,
-                agent_host_name=_jaeger_agent_host_name,
-                agent_port=_jaeger_agent_port,
-                transport=transport)
-        elif self.exporter.__name__ == 'ZipkinExporter':
-            _service_name = self._get_service_name(params)
-            _zipkin_host_name = params.get(
-                ZIPKIN_EXPORTER_HOST_NAME, 'localhost')
-            _zipkin_port = params.get(
-                ZIPKIN_EXPORTER_PORT, 9411)
-            _zipkin_protocol = params.get(
-                ZIPKIN_EXPORTER_PROTOCOL, 'http')
-            self.exporter = self.exporter(
-                service_name=_service_name,
-                host_name=_zipkin_host_name,
-                port=_zipkin_port,
-                protocol=_zipkin_protocol,
-                transport=transport)
-        elif self.exporter.__name__ == 'TraceExporter':
-            _service_name = self._get_service_name(params)
-            _endpoint = params.get(
-                OCAGENT_TRACE_EXPORTER_ENDPOINT, None)
-            self.exporter = self.exporter(
-                service_name=_service_name,
-                endpoint=_endpoint,
-                transport=transport)
-        else:
-            self.exporter = self.exporter(transport=transport)
-
-        self.blacklist_hostnames = params.get(BLACKLIST_HOSTNAMES, None)
-        # Initialize the propagator
-        if inspect.isclass(self.propagator):
-            self.propagator = self.propagator()
+        settings = self.app.config.get('OPENCENSUS', {})
+        settings = settings.get('TRACE', {})
+
+        if self.sampler is None:
+            self.sampler = settings.get('SAMPLER', None) or \
+                always_on.AlwaysOnSampler()
+            if isinstance(self.sampler, six.string_types):
+                self.sampler = configuration.load(self.sampler)
+
+        if self.exporter is None:
+            self.exporter = settings.get('EXPORTER', None) or \
+                print_exporter.PrintExporter()
+            if isinstance(self.exporter, six.string_types):
+                self.exporter = configuration.load(self.exporter)
+
+        if self.propagator is None:
+            self.propagator = settings.get('PROPAGATOR', None) or \
+                trace_context_http_header_format.TraceContextPropagator()
+            if isinstance(self.propagator, six.string_types):
+                self.propagator = configuration.load(self.propagator)
+
+        self.blacklist_paths = settings.get(BLACKLIST_PATHS,
+                                            self.blacklist_paths)
+
+        self.blacklist_hostnames = settings.get(BLACKLIST_HOSTNAMES, None)
 
         self.setup_trace()
 
@@ -280,13 +202,3 @@ def _teardown_request(self, exception):
             tracer.finish()
         except Exception:  # pragma: NO COVER
             log.error('Failed to trace request', exc_info=True)
-
-    def _get_service_name(self, params):
-        _service_name = params.get(
-            SERVICE_NAME, None)
-
-        if _service_name is None:
-            _service_name = params.get(
-                ZIPKIN_EXPORTER_SERVICE_NAME, 'my_service')
-
-        return _service_name