Make open-telemetry a soft dependency [RHELDST-27627]

Several client tools (e.g. rhsm-tools) make use of various parts of
pubtools for interaction with pulp. This has caused issues with
rcm-dev, as we have specifically avoided making open-telemetry
packages available for CLI clients.

This change introduces a new TracingWrapper class that acts as a pass
through for when opentelemetry isn't installed.

requirements.txt

@@ -1,4 +1,2 @@
 pluggy
 setuptools
-opentelemetry-api
-opentelemetry-sdk

setup.py

@@ -54,6 +54,9 @@ def get_requirements():
         "Topic :: Software Development :: Libraries :: Python Modules",
     ],
     install_requires=get_requirements(),
+    extras_require={
+        "tracing": ["opentelemetry-api", "opentelemetry-sdk"],
+    },
     python_requires=">=3.6",
     project_urls={
         "Documentation": "https://release-engineering.github.io/pubtools/",

src/pubtools/_impl/tracing.py

@@ -12,14 +12,20 @@ def func():
 import os
 import threading
 
-from opentelemetry import baggage, context, trace
-from opentelemetry.baggage.propagation import W3CBaggagePropagator
-from opentelemetry.propagate import set_global_textmap
-from opentelemetry.sdk.resources import SERVICE_NAME, Resource
-from opentelemetry.sdk.trace import TracerProvider
-from opentelemetry.sdk.trace.export import BatchSpanProcessor, ConsoleSpanExporter
-from opentelemetry.trace import Status, StatusCode
-from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator
+try:
+    from opentelemetry import baggage, context, trace
+    from opentelemetry.baggage.propagation import W3CBaggagePropagator
+    from opentelemetry.propagate import set_global_textmap
+    from opentelemetry.sdk.resources import SERVICE_NAME, Resource
+    from opentelemetry.sdk.trace import TracerProvider
+    from opentelemetry.sdk.trace.export import BatchSpanProcessor, ConsoleSpanExporter
+    from opentelemetry.trace import Status, StatusCode
+    from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator
+    OPENTELEMETRY_AVAILABLE = True
+except ImportError:  # pragma: no cover
+    # Clients aren't expected to have open-telemetry. This flag will be used in
+    # TracingWrapper to provide pass through functions.
+    OPENTELEMETRY_AVAILABLE = False
 
 from pubtools.pluggy import pm
 
@@ -60,7 +66,11 @@ def _reset(self):
         # trace.set_tracer_provider global singleton set below can *never* be set up
         # more than once in a single process.
 
-        self._enabled_trace = os.getenv("OTEL_TRACING", "").lower() == "true"
+        self._enabled_trace = (os.getenv("OTEL_TRACING", "").lower() == "true") \
+                              and OPENTELEMETRY_AVAILABLE
+        if (os.getenv("OTEL_TRACING", "").lower() == "true") and not OPENTELEMETRY_AVAILABLE:
+            log.debug("Tracing is enabled but the open telemetry package is "
+                      "unavailable. Tracing functionality will be disabled.")
         if self._enabled_trace and not self._processor:
             log.info("Creating TracingWrapper instance")
             exporter = pm.hook.otel_exporter() or ConsoleSpanExporter()
@@ -87,8 +97,6 @@ def instrument_func(self, span_name=None, carrier=None, args_to_attr=False):
         Returns:
             The decorated function
         """
-        tracer = trace.get_tracer(__name__)
-
         def _instrument_func(func):
             @functools.wraps(func)
             def wrap(*args, **kwargs):
@@ -104,6 +112,7 @@ def wrap(*args, **kwargs):
                 if not self._enabled_trace:
                     return func(*args, **kwargs)
 
+                tracer = trace.get_tracer(__name__)
                 trace_ctx = None
                 token = None
                 if not context.get_current():

test-requirements.in

@@ -1,2 +1,4 @@
 pytest
 pytest-cov
+opentelemetry-api
+opentelemetry-sdk

test-requirements.txt

@@ -701,6 +701,7 @@ opentelemetry-api==1.20.0 \
     --hash=sha256:06abe351db7572f8afdd0fb889ce53f3c992dbf6f6262507b385cc1963e06983 \
     --hash=sha256:982b76036fec0fdaf490ae3dfd9f28c81442a33414f737abc687a32758cdcba5
     # via
+    #   -r test-requirements.in
     #   opentelemetry-exporter-otlp-proto-grpc
     #   opentelemetry-exporter-otlp-proto-http
     #   opentelemetry-sdk
@@ -735,6 +736,7 @@ opentelemetry-sdk==1.20.0 \
     --hash=sha256:702e432a457fa717fd2ddfd30640180e69938f85bb7fec3e479f85f61c1843f8 \
     --hash=sha256:f2230c276ff4c63ea09b3cb2e2ac6b1265f90af64e8d16bbf275c81a9ce8e804
     # via
+    #   -r test-requirements.in
     #   opentelemetry-exporter-otlp-proto-grpc
     #   opentelemetry-exporter-otlp-proto-http
     #   pubtools
@@ -898,9 +900,9 @@ pyrsistent==0.20.0 \
     --hash=sha256:f920385a11207dc372a028b3f1e1038bb244b3ec38d448e6d8e43c6b3ba20e98 \
     --hash=sha256:fed2c3216a605dc9a6ea50c7e84c82906e3684c4e80d2908208f662a6cbf9022
     # via pubtools-quay
-pyspnego[kerberos]==0.11.1 \
-    --hash=sha256:129a4294f2c4d681d5875240ef87accc6f1d921e8983737fb0b59642b397951e \
-    --hash=sha256:e92ed8b0a62765b9d6abbb86a48cf871228ddb97678598dc01c9c39a626823f6
+pyspnego[kerberos]==0.11.2 \
+    --hash=sha256:74abc1fb51e59360eb5c5c9086e5962174f1072c7a50cf6da0bda9a4bcfdfbd4 \
+    --hash=sha256:994388d308fb06e4498365ce78d222bf4f3570b6df4ec95738431f61510c971b
     # via requests-kerberos
 pytest==8.3.3 \
     --hash=sha256:70b98107bd648308a7952b06e6ca9a50bc660be218d53c257cc1fc94fda10181 \
@@ -1165,9 +1167,9 @@ tenacity==9.0.0 \
     --hash=sha256:807f37ca97d62aa361264d497b0e31e92b8027044942bfa756160d908320d73b \
     --hash=sha256:93de0c98785b27fcf659856aa9f54bfbd399e29969b0621bc7f762bd441b4539
     # via iiblib
-tomli==2.0.2 \
-    --hash=sha256:2ebe24485c53d303f690b0ec092806a085f07af5a5aa1464f3931eec36caaa38 \
-    --hash=sha256:d46d457a85337051c36524bc5349dd91b1877838e2979ac5ced3e710ed8a60ed
+tomli==2.1.0 \
+    --hash=sha256:3f646cae2aec94e17d04973e4249548320197cfabdf130015d023de4b74d8ab8 \
+    --hash=sha256:a5c57c3d1c56f5ccdf89f6523458f60ef716e210fc47c4cfb188c5ba473e0391
     # via
     #   coverage
     #   pytest

tests/tracing/test_instrument_tracing.py

@@ -5,7 +5,9 @@
 from opentelemetry.trace.status import StatusCode
 
 from pubtools._impl.tracing import TracingWrapper
+from pubtools._impl import tracing
 from pubtools.tracing import get_trace_wrapper
+import logging
 
 
 def test_instrument_func_in_context(monkeypatch, fake_span_exporter):
@@ -154,3 +156,20 @@ def foo():
 
     assert foo() == 1
     assert tw.provider is None
+
+def test_otel_not_available(caplog, monkeypatch):
+    monkeypatch.setenv("OTEL_TRACING", "true")
+    monkeypatch.setattr(tracing, "OPENTELEMETRY_AVAILABLE", False)
+    caplog.set_level(logging.DEBUG)
+
+    # Recreate an instance of TracingWrapper
+    tw = TracingWrapper()
+
+    @tw.instrument_func()
+    def foo():
+        return 1
+
+    assert foo() == 1
+    assert tw.provider is None
+    assert "Tracing is enabled but the open telemetry package is unavailable. " \
+           "Tracing functionality will be disabled." in caplog.text