Add public symbols checker script

scripts/public_symbols_checker.py

@@ -0,0 +1,97 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from difflib import unified_diff
+from os import getcwd
+from pathlib import Path
+from re import match
+
+from git import Repo
+
+repo = Repo(getcwd())
+
+active_branch = repo.active_branch.name
+diff_index = repo.commit("main").diff(repo.active_branch.name)
+
+symbol = r"[a-zA-Z][_\w]+"
+
+file_path_symbols = {}
+
+
+def get_symbols(change_type, diff_lines_getter, prefix):
+    for diff_lines in diff_index.iter_change_type(change_type):
+
+        b_file_path = diff_lines.b_blob.path
+
+        if (
+            Path(b_file_path).suffix != ".py"
+            or "opentelemetry" not in b_file_path
+        ):
+            continue
+
+        for diff_line in diff_lines_getter(diff_lines):
+            matching_line = match(
+                r"{prefix}({symbol})\s=\s.+|"
+                r"{prefix}def\s({symbol})|"
+                r"{prefix}class\s({symbol})".format(
+                    symbol=symbol, prefix=prefix
+                ),
+                diff_line,
+            )
+
+            if matching_line is not None:
+                if b_file_path not in file_path_symbols.keys():
+                    file_path_symbols[b_file_path] = []
+
+                file_path_symbols[b_file_path].append(
+                    next(filter(bool, matching_line.groups()))
+                )
+
+
+def a_diff_lines_getter(diff_lines):
+    return diff_lines.b_blob.data_stream.read().decode("utf-8").split("\n")
+
+
+def m_diff_lines_getter(diff_lines):
+    return unified_diff(
+        diff_lines.a_blob.data_stream.read().decode("utf-8").split("\n"),
+        diff_lines.b_blob.data_stream.read().decode("utf-8").split("\n"),
+    )
+
+
+get_symbols("A", a_diff_lines_getter, r"")
+get_symbols("M", m_diff_lines_getter, r"\+")
+
+if file_path_symbols:
+    print(
+        "The {} branch adds the following public symbols:".format(
+            active_branch
+        )
+    )
+    print()
+    for file_path, symbols in file_path_symbols.items():
+        print("- {}".format(file_path))
+        for symbol in symbols:
+            print("\t{}".format(symbol))
+        print()
+
+    print(
+        "Please make sure that all of them are strictly necessary, if not, "
+        "please consider prefixing them with an underscore to make them "
+        "private."
+    )
+else:
+    print(
+        "The {} branch does not add any public symbols".format(active_branch)
+    )

tox.ini

@@ -33,7 +33,7 @@ envlist =
 
     ; opentelemetry-exporter-jaeger-proto-grpc
     py3{6,7,8,9}-test-exporter-jaeger-proto-grpc
-    
+
     ; opentelemetry-exporter-jaeger-thrift
     py3{6,7,8,9}-test-exporter-jaeger-thrift
 
@@ -78,6 +78,7 @@ envlist =
     mypy,mypyinstalled
     docs
     docker-tests
+    public-symbols-check
 
 [testenv]
 deps =
@@ -186,6 +187,7 @@ deps =
   psutil
   readme_renderer
   httpretty
+  GitPython
 
 commands_pre =
   python -m pip install -e {toxinidir}/opentelemetry-api[test]
@@ -268,3 +270,11 @@ commands =
   pytest {posargs}
 commands_post =
   docker-compose down -v
+
+[testenv:public-symbols-check]
+basepython: python3.8
+recreate = True
+deps =
+  GitPython
+commands =
+  python {toxinidir}/scripts/public_symbols_checker.py