How to Generate and Propagate W3C Trace Context Headers in Python

import uuid


def generate_w3c_traceparent(trace_id=None, parent_id=None, flags="01"):
    if trace_id is None:
        trace_id = uuid.uuid4().hex[:32]
    if parent_id is None:
        parent_id = uuid.uuid4().hex[:16]
    return f"00-{trace_id}-{parent_id}-{flags}"


def create_mock_headers(service_name, trace_id=None, parent_id=None):
    traceparent = generate_w3c_traceparent(trace_id, parent_id)
    tracestate = f"{service_name}=mock:{traceparent[:8]}"
    return {
        "traceparent": traceparent,
        "tracestate": tracestate,
    }


def propagate_headers(headers, child_service_name):
    traceparent = headers["traceparent"]
    version, trace_id, _, flags = traceparent.split("-")
    new_parent_id = uuid.uuid4().hex[:16]
    child_traceparent = f"{version}-{trace_id}-{new_parent_id}-{flags}"
    child_tracestate = f"{child_service_name}=mock:{child_traceparent[:8]}"
    return {
        "traceparent": child_traceparent,
        "tracestate": child_tracestate,
    }


if __name__ == "__main__":
    service_a_headers = create_mock_headers("svc-a")
    print("Service A headers:", service_a_headers)

    service_b_headers = propagate_headers(service_a_headers, "svc-b")
    print("Service B headers:", service_b_headers)