Change tracing example to use OpenTelemetry SDK

[artursouza]

Describe the proposal

Current example for tracing uses OpenCensus SDK: https://github.com/dapr/python-sdk/blob/master/examples/w3c-tracing/invoke-caller.py

OpenTelemetry is the new industry standard. We should use that instead: https://opentelemetry.io/docs/instrumentation/python/cookbook/#manually-setting-span-context

[berndverst]

https://opentelemetry-python.readthedocs.io/en/latest/exporter/zipkin/zipkin.html

Probably need:

opentelemetry-sdk==1.14.0
opentelemetry-api==1.14.0
opentelemetry-exporter-zipkin==1.14.0

But couldn't immediately figure out how to set up the same sampling etc

Would be great if someone with OpenTelemetry experience could take a look here.

[berndverst]

Using this guide https://logz.io/blog/python-opentelemetry-auto-instrumentation/#run

Combined with the following config (to use the zipkin exporter) helps to get started with a local dev setup:

receivers:  
  otlp:
    protocols:
      grpc:
      http:

exporters:
  zipkin:
    endpoint: "http://localhost:9411/api/v2/spans"

processors:
  batch:

extensions:
  pprof:
    endpoint: :1777
  zpages:
    endpoint: :55679
  health_check:

service:
  extensions: [health_check, pprof, zpages]
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [zipkin]

[berndverst]

Another note to self:

The following Python script works by itself for sending data to Zipkin directly (without Dapr). No need to run any collector service etc.

requirements:

opentelemetry-api==1.14.0
opentelemetry-exporter-zipkin==1.14.0
opentelemetry-exporter-zipkin-json==1.14.0
opentelemetry-exporter-zipkin-proto-http==1.14.0
opentelemetry-sdk==1.14.0

from flask import Flask

from opentelemetry import trace
from opentelemetry.exporter.zipkin.json import ZipkinExporter
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import (
    BatchSpanProcessor,
)

zipkin_exporter = ZipkinExporter(
    endpoint="http://localhost:9411/api/v2/spans",
)

provider = TracerProvider()
processor = BatchSpanProcessor(zipkin_exporter)
provider.add_span_processor(processor)

# Sets the global default tracer provider
trace.set_tracer_provider(provider)

# Creates a tracer from the global tracer provider
tracer = trace.get_tracer(__name__)
 
app = Flask(__name__)
 
@app.route('/')
def index():
    with tracer.start_as_current_span("span-name") as span:
        current_span = trace.get_current_span()
        current_span.set_attribute("operation.value", 1)
        current_span.set_attribute("operation.name", "Saying hello!")
        current_span.set_attribute("operation.other-stuff", [1, 2, 3])
        current_span.add_event("Gonna try it!")
        return 'Web App with Python Flask!'
 
app.run(host='0.0.0.0', port=5000)

[berndverst]

The ecosystem for otel in Python is rough. It does not seem that many Python users utilize this and no examples can easily be found.

I am inclined to close this PR, and actually remove the telemetry example from Python.

[berndverst]

#664