Cloud Trace Propagator Example

These examples show how to make OpenTelemetry use the X-Cloud-Trace-Context header for context propagation.

Basic Example

To use this feature you first need to:

• Create a Google Cloud project. You can create one here.

• Enable Cloud Trace API (listed in the Cloud Console as Stackdriver Trace API) in the project here. If the page says “API Enabled” then you’re done! No need to do anything.

• Enable Default Application Credentials by creating setting GOOGLE_APPLICATION_CREDENTIALS or by installing gcloud sdk and calling gcloud auth application-default login.

• Installation

pip install opentelemetry-api \
  opentelemetry-sdk \
  opentelemetry-instrumentation-flask \
  opentelemetry-instrumentation-requests \
  opentelemetry-exporter-gcp-trace \
  opentelemetry-propagator-gcp \
  Flask

• Create a server that uses the Cloud Trace header

#!/usr/bin/env python3
# Copyright 2021 The 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.

from opentelemetry.instrumentation.requests import RequestsInstrumentor
from opentelemetry.instrumentation.flask import FlaskInstrumentor
from opentelemetry import trace
from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
from opentelemetry.instrumentation.flask import FlaskInstrumentor
from opentelemetry.propagate import set_global_textmap
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.propagators.cloud_trace_propagator import (
    CloudTraceFormatPropagator,
)

from flask import Flask

# Instrumenting requests
RequestsInstrumentor().instrument()

# Instrumenting flask
app = Flask(__name__)
FlaskInstrumentor().instrument_app(app)

# Tracer boilerplate
trace.set_tracer_provider(TracerProvider())
trace.get_tracer_provider().add_span_processor(
    BatchSpanProcessor(CloudTraceSpanExporter())
)

# Using the X-Cloud-Trace-Context header
set_global_textmap(CloudTraceFormatPropagator())


@app.route("/")
def hello_world():
    tracer = trace.get_tracer(__name__)
    with tracer.start_as_current_span("server_span"):
        return "Hello World!"


if __name__ == "__main__":
    port = 5000
    app.run(port=port)

• Make a client that uses the Cloud Trace header

#!/usr/bin/env python3
# Copyright 2021 The 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.

from opentelemetry.instrumentation.requests import RequestsInstrumentor
import requests
from opentelemetry import trace
from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
from opentelemetry.propagate import set_global_textmap
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.propagators.cloud_trace_propagator import (
    CloudTraceFormatPropagator,
)

# Instrumenting requests
RequestsInstrumentor().instrument()

# Tracer boilerplate
trace.set_tracer_provider(TracerProvider())
trace.get_tracer_provider().add_span_processor(
    BatchSpanProcessor(CloudTraceSpanExporter())
)

# Using the X-Cloud-Trace-Context header
set_global_textmap(CloudTraceFormatPropagator())

tracer = trace.get_tracer(__name__)
with tracer.start_as_current_span("client_span"):
    response = requests.get("http://localhost:5000/")

Checking Output

After running these examples, you can go to Cloud Trace overview to see the results.