oteltest

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Table of Contents

• Installation
• License

Installation

pip install oteltest

Overview

The oteltest package contains utilities for testing OpenTelemetry Python scenarios.

oteltest

The oteltest command runs black box tests against Python scripts that send telemetry.

Execution

With the virtual environment (into which you've installed oteltest) active, run oteltest as a shell command and provide a directory as an argument:

oteltest my_script_dir

This will attempt to run all oteltest-eligible scripts in my_script_dir, non-recursively.

Operation

Running oteltest against a directory containing only my_script.py

1. Starts an OTLP or HTTP listener (otelsink)
2. Creates a new Python virtual environment with requirements()
3. In that environment, starts running my_script.py in a subprocess
4. Calls on_start()
5. Depending on the return value from on_start(), waits for my_script.py to complete
6. Stops otelsink
7. Calls on_stop() with otelsink's received telemetry and script output
8. Writes the telemetry to a .json file next to the script (script name but with ".{number}.json" instead of ".py")

Script Eligibility

For a Python script to be runnable by oteltest, it must implement the OtelTest abstract base class, either formally by inheriting from OtelTest, or informally by merely containing the name "OtelTest" and implementing the methods. The script below has an implementation called MyOtelTest:

import time

from opentelemetry import trace

SERVICE_NAME = "my-otel-test"
NUM_ADDS = 12

if __name__ == "__main__":
    tracer = trace.get_tracer("my-tracer")
    for i in range(NUM_ADDS):
        with tracer.start_as_current_span("my-span"):
            print(f"simple_loop.py: {i+1}/{NUM_ADDS}")
            time.sleep(0.5)


# Since we're not inheriting from the OtelTest base class (to avoid depending on it) we make sure our class name
# contains "OtelTest".
class MyOtelTest:
    def requirements(self):
        return "opentelemetry-distro", "opentelemetry-exporter-otlp-proto-grpc"

    def environment_variables(self):
        return {"OTEL_SERVICE_NAME": SERVICE_NAME}

    def wrapper_command(self):
        return "opentelemetry-instrument"

    def on_start(self):
        return None

    def on_stop(self, telemetry, stdout: str, stderr: str, returncode: int) -> None:
        print(f"script completed with return code {returncode}")

    def is_http(self) -> bool:
        return False

Here's a client-server example:

import time
from typing import Mapping, Optional, Sequence


PORT = 8002
HOST = "127.0.0.1"


if __name__ == "__main__":
    from flask import Flask

    app = Flask(__name__)

    @app.route("/")
    def home():
        return "hello"

    app.run(port=PORT, host=HOST)


# Since we're not inheriting from the OtelTest base class (to avoid depending on it) we make sure our class name
# contains "OtelTest".
class FlaskOtelTest:
    def environment_variables(self) -> Mapping[str, str]:
        return {}

    def requirements(self) -> Sequence[str]:
        return (
            "flask",
            "opentelemetry-distro",
            "opentelemetry-exporter-otlp-proto-grpc",
            "opentelemetry-instrumentation-flask",
        )

    def wrapper_command(self) -> str:
        return "opentelemetry-instrument"

    def on_start(self) -> Optional[float]:
        import http.client

        # Todo: replace this sleep with a liveness check!
        time.sleep(10)

        conn = http.client.HTTPConnection(HOST, PORT)
        conn.request("GET", "/")
        print("response:", conn.getresponse().read().decode())
        conn.close()

        # The return value of on_script_start() tells oteltest the number of seconds to wait for the script to complete.
        # In this case, we indicate 30 (seconds), which, once elapsed, will cause the script to be terminated, if it's
        # still running. If we return `None` then the script will run indefinitely.
        return 30

    def on_stop(self, telemetry, stdout: str, stderr: str, returncode: int) -> None:
        # you can do something with the telemetry here, e.g. make assertions etc.
        print("done")

    def is_http(self) -> bool:
        return False

otelsink

otelsink is a gRPC (or HTTP) server that listens for OTel metrics, traces, and logs.

Operation

You can run otelsink either from the command line by using the otelsink command (installed when you pip install oteltest), or programmatically.

Either way, otelsink runs a gRPC server listening on 0.0.0.0:4317 by default. To run an HTTP server listening on 4318, use the --http flag.

Command Line

% otelsink
starting otelsink
- Set up grpc sink at address 0.0.0.0:4317

% otelsink --http
- Set up http sink on port 4318

Programmatic

from oteltest.sink import GrpcSink, RequestHandler

class MyHandler(RequestHandler):
    def handle_logs(self, request, headers):
        print(f"received log request: {request}")

    def handle_metrics(self, request, headers):
        print(f"received metrics request: {request}")

    def handle_trace(self, request, headers):
        print(f"received trace request: {request}")


sink = GrpcSink(MyHandler())
sink.start()
sink.wait_for_termination()

License

oteltest is distributed under the terms of the Apache-2.0 license.