Pure-Python otlp-proto-common encoding (no protobuf) [2/4 RFC]

.changelog/5503.changed

@@ -0,0 +1 @@
+`opentelemetry-proto`: replace the protobuf dependency with a pure-Python wire-format implementation, so opentelemetry-proto and the OTLP exporters no longer require the protobuf package

.changelog/5504.changed

@@ -0,0 +1 @@
+`opentelemetry-exporter-otlp-proto-common`: move the OTLP encoders into a private `opentelemetry.exporter.otlp._proto.common` package, re-exported from the unchanged public `opentelemetry.exporter.otlp.proto.common` API

.codespellrc

@@ -1,4 +1,4 @@
 [codespell]
 # skipping auto generated folders
 skip = ./.tox,./.mypy_cache,./docs/_build,./target,*/LICENSE,./venv,.git,./opentelemetry-semantic-conventions,*-requirements*.txt
-ignore-words-list = ans,ue,ot,hist,ro,astroid
+ignore-words-list = ans,ue,ot,hist,ro,astroid,nd

.pylintrc

@@ -11,7 +11,7 @@ ignore=CVS,gen,proto,proto_json
 
 # Add files or directories matching the regex patterns to be excluded. The
 # regex matches against base names, not paths.
-ignore-patterns=^models\.py$
+ignore-patterns=^models\.py$,.*_pb2.*\.py$
 
 # Python code to execute, usually for sys.path manipulation such as
 # pygtk.require().
@@ -174,7 +174,7 @@ contextmanager-decorators=contextlib.contextmanager, _agnosticcontextmanager
 # List of members which are set dynamically and missed by pylint inference
 # system, and so shouldn't trigger E1101 when accessed. Python regular
 # expressions are accepted.
-generated-members=zipkin_pb2.*
+generated-members=zipkin_pb2.*,descriptor_pb2.*,google.protobuf.descriptor_pb2.*
 
 # Tells whether missing members accessed in mixin class should be ignored. A
 # mixin class is detected if its name ends with "mixin" (case insensitive).

codegen/opentelemetry-codegen-pyproto/README.rst

@@ -0,0 +1,21 @@
+opentelemetry-codegen-pyproto
+=============================
+
+A ``protoc`` plugin that generates pure-Python, encode-only protobuf-wire
+message classes for the OpenTelemetry proto definitions.
+
+The generated classes reproduce the behaviour of the hand-written
+``opentelemetry._proto.*_pb2`` modules: every message inherits the
+``Message`` base from ``opentelemetry._proto._pyprotobuf.message`` and
+implements ``SerializeToString`` using the field helpers in
+``opentelemetry._proto._pyprotobuf.fields``.
+
+Usage
+-----
+
+Install the plugin so ``protoc-gen-pyproto`` is on ``PATH``, then run::
+
+    python -m grpc_tools.protoc \
+        -I /path/to/opentelemetry-proto \
+        --pyproto_out=OUTPUT_DIR \
+        /path/to/opentelemetry-proto/opentelemetry/proto/common/v1/common.proto

codegen/opentelemetry-codegen-pyproto/pyproject.toml

@@ -0,0 +1,49 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "opentelemetry-codegen-pyproto"
+version = "0.0.0" # Not published to PyPI
+description = "Protobuf plugin to generate pure-Python encode-only wire serializers for OpenTelemetry protobuf messages"
+readme = "README.rst"
+license = "Apache-2.0"
+requires-python = ">=3.10"
+authors = [
+    { name = "OpenTelemetry Authors", email = "cncf-opentelemetry-contributors@lists.cncf.io" },
+]
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "Framework :: OpenTelemetry",
+    "Intended Audience :: Developers",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
+    "Private :: Do Not Upload",
+]
+dependencies = [
+    "protobuf>=4.25.3",
+    "types-protobuf>=4.24",
+]
+
+[project.scripts]
+protoc-gen-pyproto = "opentelemetry.codegen.pyproto.plugin:main"
+
+[project.urls]
+Homepage = "https://github.com/open-telemetry/opentelemetry-python/tree/main/codegen/opentelemetry-codegen-pyproto"
+Repository = "https://github.com/open-telemetry/opentelemetry-python"
+
+[tool.hatch.version]
+path = "src/opentelemetry/codegen/pyproto/version/__init__.py"
+
+[tool.hatch.build.targets.sdist]
+include = [
+    "/src",
+]
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/opentelemetry"]

codegen/opentelemetry-codegen-pyproto/src/opentelemetry/codegen/pyproto/__init__.py

@@ -0,0 +1,2 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0