Add **simple** client/server examples (#191)

examples/trace/client.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+#
+# Copyright 2019, OpenTelemetry 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.
+
+import requests
+
+from opentelemetry import trace
+from opentelemetry.ext import http_requests
+from opentelemetry.sdk.trace import Tracer
+from opentelemetry.sdk.trace.export import (
+    ConsoleSpanExporter,
+    SimpleExportSpanProcessor,
+)
+
+# The preferred tracer implementation must be set, as the opentelemetry-api
+# defines the interface with a no-op implementation.
+trace.set_preferred_tracer_implementation(lambda T: Tracer())
+tracer = trace.tracer()
+
+# Integrations are the glue that binds the OpenTelemetry API and the
+# frameworks and libraries that are used together, automatically creating
+# Spans and propagating context as appropriate.
+http_requests.enable(tracer)
+
+# SpanExporter receives the spans and send them to the target location.
+span_processor = SimpleExportSpanProcessor(ConsoleSpanExporter())
+tracer.add_span_processor(span_processor)
+
+response = requests.get(url="http://127.0.0.1:5000/")
+span_processor.shutdown()

examples/trace/server.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+#
+# Copyright 2019, OpenTelemetry 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.
+
+import flask
+import requests
+
+from opentelemetry import trace
+from opentelemetry.ext import http_requests
+from opentelemetry.ext.wsgi import OpenTelemetryMiddleware
+from opentelemetry.sdk.trace import Tracer
+from opentelemetry.sdk.trace.export import (
+    ConsoleSpanExporter,
+    SimpleExportSpanProcessor,
+)
+
+# The preferred tracer implementation must be set, as the opentelemetry-api
+# defines the interface with a no-op implementation.
+trace.set_preferred_tracer_implementation(lambda T: Tracer())
+
+# Integrations are the glue that binds the OpenTelemetry API and the
+# frameworks and libraries that are used together, automatically creating
+# Spans and propagating context as appropriate.
+http_requests.enable(trace.tracer())
+
+# SpanExporter receives the spans and send them to the target location.
+span_processor = SimpleExportSpanProcessor(ConsoleSpanExporter())
+trace.tracer().add_span_processor(span_processor)
+
+app = flask.Flask(__name__)
+app.wsgi_app = OpenTelemetryMiddleware(app.wsgi_app)
+
+
+@app.route("/")
+def hello():
+    with trace.tracer().start_span("parent"):
+        requests.get("https://www.wikipedia.org/wiki/Rabbit")
+    return "hello"
+
+
+if __name__ == "__main__":
+    app.run(debug=True)
+    span_processor.shutdown()