feat: make trace demo application use OpenTelemetry (#8428)

removes trace demo application that using OpenCensus from the repo.
makes the removed demo's README file to reference to the active demo.
modifies the OpenTelemetry based demo so it has functional parity with the removed demo.
removes manual span creation that with OT leads to orphan span ingestion.
adds comment explaining needlessness of manual trace context creation.
updates README to refresh the instructions for OT version of the demo app.
refactors `setup.sh` to include building image into the script.
removes container building to improve deployment time and instead uses predeployed (in gcr.io/google_samples) image.
fixes distinct traces by adding request instrumentation.

trace/cloud-trace-demo-app-opentelemetry/README.md

@@ -2,73 +2,120 @@
 
 Open this demo app in [Google Cloud Shell](https://cloud.google.com/shell/docs/). This includes necessary tools.
 
-
 [![Open Cloud Trace Demo APP in Cloud Shell](http://gstatic.com/cloudssh/images/open-btn.svg)](https://console.cloud.google.com/cloudshell/open?cloudshell_git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=trace/cloud-trace-demo-app/README.md&cloudshell_tutorial=trace/cloud-trace-demo-app/README.md)
 
-#### Demo Requirements
+## Demo Requirements
+
 If you are using Cloud Shell, skip to the next section.
 
 1. Install gcloud <https://cloud.google.com/sdk/install>
 2. Install kubectl <https://kubernetes.io/docs/tasks/tools/install-kubectl/>
 3. Install docker <https://docs.docker.com/install/>
 
-
-#### Create a GKE cluster
-
-4. Enable Google Cloud and set up region and zone.
-
-    `gcloud init`
-5. Enable the GKE API & billing:
-
-    `gcloud services enable container.googleapis.com`
-6. Create a GKE cluster named "cloud-trace-demo", replacing `your-gcp-zone`  below
-with the 
-[GCP Zone](https://cloud.google.com/compute/docs/regions-zones) closest in proximity to you:
-
-     ```
-     gcloud container clusters create cloud-trace-demo\`
-     --num-nodes 1 \
-     --enable-basic-auth \
-     --issue-client-certificate \
-     --zone your-gcp-zone
-     ```
-7. Verify that you have access to the cluster:
-
-    `kubectl get nodes`
-
-#### Deploy The Cloud Trace Demo App
-
-8. Build and tag the docker image for demo app:
-
-    `docker build -t gcr.io/${PROJECT_ID}/cloud-trace-demo:v1 .`
-9. Deploy resource to the cluster:
-
-    `kubectl apply -f deployment.yaml`
-10. Track the status of the deployment:
-
-    `kubectl get deployments`
-
-    Deployment is complete when all of the available deployments are ready. 
-11. Run the following command to see the pods the deployment created:
-
-    `kubectl get pods`  
-
-#### Deploy The Cloud Trace Demo Service
-
-12. Create the cloud trace demo service:
-
-    `kubectl apply -f service.yaml`
-13. Get the services IP address by running the following command:
-
-    `kubectl get services`
-14. Send a curl request to the EXTERNAL_IP, replacing `EXTERNAL_IP` with the external IP address found
-in step 13:
-
-    `curl EXTERNAL_IP`
-15. Visit [Trace List](https://console.cloud.google.com/traces/list) to check traces generated.
+## Deploy and run the demo application
+
+1. Enable Google Cloud and set up region and zone.
+
+   ```bash
+   gcloud init
+   ```
+
+1. Enable the GKE API:
+
+   ```bash
+   gcloud services enable container.googleapis.com
+   ```
+
+1. Setup GCP project to `YOUR_PROJECT_ID`. Replace `YOUR_PROJECT_ID` with your GCP project id.
+
+   ```bash
+   gcloud config set project YOUR_PROJECT_ID
+   ```
+
+1. Setup the location of GKE cluster and create a new cluster named
+`cloud-trace-demo`.
+The example below sets the cluster's location to the "us-central1-c" zone.
+You can replace the zone with one which you like. See [zones][] for the full
+list.
+
+   ```bash
+   ZONE=us-central1-c
+   gcloud container clusters create cloud-trace-demo \
+       --zone $ZONE
+   ```
+
+1. Update GKE cluster credentials and verify the access to the cluster:
+
+   ```bash
+   gcloud container clusters get-credentials cloud-trace-demo --zone $ZONE
+   kubectl get nodes
+   ```
+
+   The output is similar to the following:
+
+   ```bash
+   NAME                                              STATUS   ROLES    AGE     VERSION
+   gke-cloud-trace-demo-default-pool-43f3fe97-dnk1   Ready    <none>   5m      v1.23.8-gke.1900
+   gke-cloud-trace-demo-default-pool-43f3fe97-j2b8   Ready    <none>   5m      v1.23.8-gke.1900
+   gke-cloud-trace-demo-default-pool-43f3fe97-znvv   Ready    <none>   5m      v1.23.8-gke.1900
+   ```
+
+1. Download the demo application:
+
+   ```bash
+   git clone https://github.com/GoogleCloudPlatform/python-docs-samples
+   cd python-docs-samples/trace/cloud-trace-demo-app-opentelemetry/
+   ```
+
+1. Setup the application:
+
+   ```bash
+   ./setup.sh
+   ```
+
+   The setup deployes 3 services of the demo application using a pre-built
+   image. If you like, you can build your own container image using
+   [`app/Dockerfile`][dockerfile].
+
+1. Track the status of the deployment:
+
+   ```bash
+   kubectl get deployments
+   ```
+
+   The output is similar to the following:
+
+   ```bash
+   NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
+   cloud-trace-demo-a   1/1     1            1           3m
+   cloud-trace-demo-b   1/1     1            1           3m
+   cloud-trace-demo-c   1/1     1            1           3m
+   ```
+
+1. Send a curl request to the cloud-trace-demo-a:
+
+   ```bash
+   curl $(kubectl get svc -o=jsonpath='{.items[?(@.metadata.name=="cloud-trace-demo-a")].status.loadBalancer.ingress[0].ip}')
+   ```
+
+   The output is similar to the following:
+
+   ```bash
+   Hello, I am service A
+   And I am service B
+   Hello, I am service C
+   ```
+
+1. Visit [Trace List](https://console.cloud.google.com/traces/list) to check traces generated.
     Click on any trace in the graph to see the Waterfall View.
-    
+
     ![Screenshot](example-trace.png)
-16. Clean up GKE cluster/pods/services:
 
-    `gcloud container clusters delete cloud-trace-demo`
+1. To clean up the provisioned resources:
+
+   ```bash
+   gcloud container clusters delete cloud-trace-demo --zone $ZONE
+   ```
+
+[zones]: https://cloud.google.com/compute/docs/regions-zones#zones_and_clusters
+[dockerfile]: https://github.com/GoogleCloudPlatform/python-docs-samples/blob/main/trace/cloud-trace-demo-app-opentelemetry/app/Dockerfile

trace/cloud-trace-demo-app-opentelemetry/app/Dockerfile

@@ -16,12 +16,14 @@
 # https://hub.docker.com/_/python
 FROM python:3.10-slim
 
-# Copy local code to the container image.
+RUN pip3 install --upgrade pip
+
 ENV APP_HOME /app
 WORKDIR $APP_HOME
-COPY . ./
-COPY requirements.txt /app/
-RUN pip install Flask gunicorn
+
+# Copy local code to the container image.
+COPY *.py *.txt ./
+
 RUN pip install -r requirements.txt
 
 CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 app:app

trace/cloud-trace-demo-app-opentelemetry/app/app.py

@@ -11,49 +11,71 @@
 # 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.
+
 """
 A sample app demonstrating CloudTraceSpanExporter
 """
+
+import os
 import random
 import time
 
-# [START trace_demo_imports]
 import flask
-from opentelemetry import propagate, trace
+# [START trace_demo_imports]
+from opentelemetry import trace
 from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
 from opentelemetry.instrumentation.flask import FlaskInstrumentor
+from opentelemetry.instrumentation.requests import RequestsInstrumentor
+from opentelemetry.propagate import set_global_textmap
 from opentelemetry.propagators.cloud_trace_propagator import CloudTraceFormatPropagator
 from opentelemetry.sdk.trace import TracerProvider
-from opentelemetry.sdk.trace.export import SimpleSpanProcessor
-
+from opentelemetry.sdk.trace.export import BatchSpanProcessor
 # [END trace_demo_imports]
-
-app = flask.Flask(__name__)
-FlaskInstrumentor().instrument_app(app)
+import requests
 
 
+# [START trace_demo_create_exporter]
 def configure_exporter(exporter):
-    trace.set_tracer_provider(TracerProvider())
-    trace.get_tracer_provider().add_span_processor(SimpleSpanProcessor(exporter))
-    propagate.set_global_textmap(CloudTraceFormatPropagator())
+    set_global_textmap(CloudTraceFormatPropagator())
+    tracer_provider = TracerProvider()
+    tracer_provider.add_span_processor(BatchSpanProcessor(exporter))
+    trace.set_tracer_provider(tracer_provider)
 
 
 configure_exporter(CloudTraceSpanExporter())
 tracer = trace.get_tracer(__name__)
+# [END trace_demo_create_exporter]
+
+
+# [START trace_demo_middleware]
+app = flask.Flask(__name__)
+FlaskInstrumentor().instrument_app(app)
+RequestsInstrumentor().instrument()
+# [END trace_demo_middleware]
 
 
 @app.route("/")
 def template_test():
     # Sleep for a random time to imitate a random processing time
     time.sleep(random.uniform(0, 0.5))
 
-    with tracer.start_as_current_span("span1"):
-        with tracer.start_as_current_span("span2"):
-            with tracer.start_as_current_span("span3"):
-                print("Hello world from Cloud Trace Exporter!")
-
-    return "Hello World"
+    # If there is an endpoint, send keyword to next service.
+    # Return received input with the keyword
+    keyword = os.getenv("KEYWORD")
+    endpoint = os.getenv("ENDPOINT")
+# [START trace_context_header]
+    if endpoint is not None and endpoint != "":
+        data = {'body': keyword}
+        response = requests.get(
+            endpoint,
+            params=data,
+        )
+        return keyword + "\n" + response.text
+    else:
+        return keyword, 200
+# [END trace_context_header]
 
 
 if __name__ == "__main__":
-    app.run(debug=True, host="0.0.0.0", port=8080)
+    port = os.getenv("PORT")
+    app.run(debug=True, host="0.0.0.0", port=port)

trace/cloud-trace-demo-app-opentelemetry/app/app_test.py

@@ -14,14 +14,20 @@
 """
 A sample app demonstrating Google Cloud Trace
 """
+import os
+
 import mock
 
 import app
 
 
 def test_traces():
+    expected = "Lorem ipsum dolor sit amet"
+    os.environ["KEYWORD"] = expected
+    app.app.testing = True
     exporter = mock.Mock()
     app.configure_exporter(exporter)
     client = app.app.test_client()
     resp = client.get("/")
     assert resp.status_code == 200
+    assert expected in resp.data.decode('utf-8')