PYTHON-6065 Benchmark OpenTelemetry support

.evergreen/generated_configs/variants.yml

@@ -468,6 +468,18 @@ buildvariants:
       - windows-2022-latest-small
     batchtime: 1440
 
+  # Otel tests
+  - name: otel-rhel8
+    tasks:
+      - name: .test-non-standard .standalone-noauth-nossl
+    display_name: OTel RHEL8
+    run_on:
+      - rhel8.10-small
+    expansions:
+      TEST_NAME: otel
+      COVERAGE: "1"
+    tags: [pr]
+
   # Perf tests
   - name: performance-benchmarks
     tasks:

.evergreen/scripts/generate_config.py

@@ -514,6 +514,21 @@ def create_doctests_variants():
     ]
 
 
+def create_otel_variants():
+    host = DEFAULT_HOST
+    # Merge otel's coverage into the combined report; see setup_tests.py's COVERAGE handling.
+    expansions = dict(TEST_NAME="otel", COVERAGE="1")
+    return [
+        create_variant(
+            [".test-non-standard .standalone-noauth-nossl"],
+            get_variant_name("OTel", host),
+            host=host,
+            tags=["pr"],
+            expansions=expansions,
+        )
+    ]
+
+
 def create_atlas_connect_variants():
     host = DEFAULT_HOST
     return [

.evergreen/scripts/setup_tests.py

@@ -46,6 +46,7 @@
     "enterprise_auth": "gssapi",
     "kms": "encryption",
     "ocsp": "ocsp",
+    "otel": "opentelemetry",
     "pyopenssl": "ocsp",
 }
 
@@ -502,6 +503,16 @@ def handle_test_env() -> None:
     if test_name == "numpy":
         UV_ARGS.append("--with numpy")
 
+    if test_name == "otel":
+        # The SDK is test-only tooling (for the in-memory span exporter); the driver
+        # itself must not depend on it, only on opentelemetry-api (the "opentelemetry" extra).
+        # The lower bound matters: under --resolution=lowest-direct an unpinned
+        # --with dependency resolves to its oldest version (1.0.0), which pins
+        # opentelemetry-api==1.0.0 and drags the API below the driver's floor
+        # (>=1.20.0 in requirements/opentelemetry.txt). Keep the SDK's floor in
+        # sync with that file when bumping the supported API version.
+        UV_ARGS.append("--with opentelemetry-sdk>=1.20.0")
+
     if test_name == "perf":
         data_dir = ROOT / "specifications/source/benchmarking/data"
         if not data_dir.exists():
@@ -527,9 +538,10 @@ def handle_test_env() -> None:
         else:
             TEST_ARGS = f"test/performance/async_perf_test.py {TEST_ARGS}"
 
-    # Add coverage if requested.
+    # Add coverage if requested, either via --cov or a pre-set COVERAGE expansion
+    # (e.g. a buildvariant that wants its coverage merged into the combined report).
     # Only cover CPython. PyPy reports suspiciously low coverage.
-    if opts.cov and platform.python_implementation() == "CPython":
+    if (opts.cov or is_set("COVERAGE")) and platform.python_implementation() == "CPython":
         # Keep in sync with combine-coverage.sh.
         # coverage >=5 is needed for relative_files=true.
         UV_ARGS.append("--group coverage")

.evergreen/scripts/utils.py

@@ -47,6 +47,7 @@ class Distro:
     "load_balancer": "load_balancer",
     "mockupdb": "mockupdb",
     "ocsp": "ocsp",
+    "otel": "otel",
     "perf": "perf",
     "sfp": "sfp",
     "numpy": "",

.gitignore

@@ -30,6 +30,7 @@ expansion.yml
 .evergreen/scripts/test-env.sh
 specifications/
 results.json
+otel-bench-results/
 .synchro-modified
 .evergreen/atlas_x509_dev_client_certificate.pem
 .evergreen/atlas_x509_sfp_client_certificate.pem

doc/changelog.rst

@@ -196,6 +196,12 @@ PyMongo 4.18 brings a number of changes including:
   :meth:`~pymongo.synchronous.database.Database.aggregate`, and
   :meth:`~pymongo.asynchronous.collection.AsyncCollection.list_search_indexes`
   and :meth:`~pymongo.synchronous.collection.Collection.list_search_indexes`.
+- Added optional OpenTelemetry command-span support, conforming to the
+  `OpenTelemetry driver specification <https://github.com/mongodb/specifications/blob/master/source/open-telemetry/open-telemetry.md>`_.
+  Enable it with the ``tracing`` :class:`~pymongo.mongo_client.MongoClient`
+  option or the ``OTEL_PYTHON_INSTRUMENTATION_MONGODB_ENABLED`` environment
+  variable. Install the ``opentelemetry-api`` package, or use the
+  ``pymongo[opentelemetry]`` extra, to enable this feature.
 
 Changes in Version 4.17.0 (2026/04/20)
 --------------------------------------

justfile

@@ -2,7 +2,7 @@
 set shell := ["bash", "-c"]
 
 # Commonly used command segments.
-typing_run := "uv run --group typing --extra aws --extra encryption --with numpy --extra ocsp --extra snappy --extra test --extra zstd"
+typing_run := "uv run --group typing --extra aws --extra encryption --with numpy --extra ocsp --extra opentelemetry --with opentelemetry-sdk --extra snappy --extra test --extra zstd"
 docs_run := "uv run --extra docs"
 doc_build := "./doc/_build"
 mypy_args := "--install-types --non-interactive"