Test the setup_default_tracing()

This resulted in some fix to the configuration too,
as consuming OTEL_SERVICE_NAME was not being done correctly

It does involve some messy reaching into otel internals though

jobrunner/tracing.py

@@ -17,19 +17,20 @@
 
 logger = logging.getLogger(__name__)
 
-# https://github.com/open-telemetry/semantic-conventions/tree/main/docs/resource#service
-resource = Resource.create(
-    attributes={
-        "service.name": "jobrunner",
-        "service.namespace": os.environ.get("BACKEND", "unknown"),
-        "service.version": config.VERSION,
-    }
-)
-provider = TracerProvider(resource=resource)
-trace.set_tracer_provider(provider)
-
-
-def add_exporter(exporter, processor=BatchSpanProcessor):
+
+def get_provider():
+    # https://github.com/open-telemetry/semantic-conventions/tree/main/docs/resource#service
+    resource = Resource.create(
+        attributes={
+            "service.name": os.environ.get("OTEL_SERVICE_NAME", "jobrunner"),
+            "service.namespace": os.environ.get("BACKEND", "unknown"),
+            "service.version": config.VERSION,
+        }
+    )
+    return TracerProvider(resource=resource)
+
+
+def add_exporter(provider, exporter, processor=BatchSpanProcessor):
     """Utility method to add an exporter.
 
     We use the BatchSpanProcessor by default, which is the default for
@@ -43,18 +44,24 @@ def add_exporter(exporter, processor=BatchSpanProcessor):
     provider.add_span_processor(processor(exporter))
 
 
-def setup_default_tracing():
+def setup_default_tracing(set_global=True):
     """Inspect environment variables and set up exporters accordingly."""
+
+    provider = get_provider()
+
     if "OTEL_EXPORTER_OTLP_HEADERS" in os.environ:
-        if "OTEL_SERVICE_NAME" not in os.environ:
-            os.environ["OTEL_SERVICE_NAME"] == "jobrunner"
         if "OTEL_EXPORTER_OTLP_ENDPOINT" not in os.environ:
             os.environ["OTEL_EXPORTER_OTLP_ENDPOINT"] = "https://api.honeycomb.io"
 
-        add_exporter(OTLPSpanExporter())
+        add_exporter(provider, OTLPSpanExporter())
 
     if "OTEL_EXPORTER_CONSOLE" in os.environ:
-        add_exporter(ConsoleSpanExporter())
+        add_exporter(provider, ConsoleSpanExporter())
+
+    if set_global:
+        trace.set_tracer_provider(provider)
+
+    return provider
 
 
 @warn_assertions

tests/conftest.py

@@ -19,9 +19,11 @@
 from jobrunner.lib.subprocess_utils import subprocess_run
 
 
-# set up tracing
+# set up test tracing
+provider = tracing.get_provider()
+tracing.trace.set_tracer_provider(provider)
 test_exporter = InMemorySpanExporter()
-tracing.add_exporter(test_exporter, processor=SimpleSpanProcessor)
+tracing.add_exporter(provider, test_exporter, processor=SimpleSpanProcessor)
 
 
 def pytest_configure(config):

tests/test_tracing.py

@@ -1,13 +1,68 @@
 import os
 import time
 
+import opentelemetry.exporter.otlp.proto.http.trace_exporter
 from opentelemetry import trace
+from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
+from opentelemetry.sdk.trace.export import ConsoleSpanExporter
 
 from jobrunner import config, models, tracing
 from tests.conftest import get_trace
 from tests.factories import job_factory, job_request_factory, job_results_factory
 
 
+def test_setup_default_tracing_empty_env(monkeypatch):
+    env = {}
+    monkeypatch.setattr(os, "environ", env)
+    provider = tracing.setup_default_tracing(set_global=False)
+    assert provider._active_span_processor._span_processors == ()
+
+
+def test_setup_default_tracing_console(monkeypatch):
+    env = {"OTEL_EXPORTER_CONSOLE": "1"}
+    monkeypatch.setattr(os, "environ", env)
+    provider = tracing.setup_default_tracing(set_global=False)
+
+    processor = provider._active_span_processor._span_processors[0]
+    assert isinstance(processor.span_exporter, ConsoleSpanExporter)
+
+
+def test_setup_default_tracing_otlp_defaults(monkeypatch):
+    env = {"OTEL_EXPORTER_OTLP_HEADERS": "foo=bar"}
+    monkeypatch.setattr(os, "environ", env)
+    monkeypatch.setattr(
+        opentelemetry.exporter.otlp.proto.http.trace_exporter, "environ", env
+    )
+    provider = tracing.setup_default_tracing(set_global=False)
+    assert provider.resource.attributes["service.name"] == "jobrunner"
+
+    exporter = provider._active_span_processor._span_processors[0].span_exporter
+    assert isinstance(exporter, OTLPSpanExporter)
+    assert exporter._endpoint == "https://api.honeycomb.io/v1/traces"
+    assert exporter._headers == {"foo": "bar"}
+    assert env["OTEL_EXPORTER_OTLP_ENDPOINT"] == "https://api.honeycomb.io"
+
+
+def test_setup_default_tracing_otlp_with_env(monkeypatch):
+    env = {
+        "OTEL_EXPORTER_OTLP_HEADERS": "foo=bar",
+        "OTEL_SERVICE_NAME": "service",
+        "OTEL_EXPORTER_OTLP_ENDPOINT": "https://endpoint",
+    }
+    monkeypatch.setattr(os, "environ", env)
+    monkeypatch.setattr(
+        opentelemetry.exporter.otlp.proto.http.trace_exporter, "environ", env
+    )
+    provider = tracing.setup_default_tracing(set_global=False)
+    assert provider.resource.attributes["service.name"] == "service"
+
+    exporter = provider._active_span_processor._span_processors[0].span_exporter
+
+    assert isinstance(exporter, OTLPSpanExporter)
+    assert exporter._endpoint == "https://endpoint/v1/traces"
+    assert exporter._headers == {"foo": "bar"}
+
+
 def test_trace_attributes(db):
     jr = job_request_factory(
         original=dict(