fix: require python 3.7+ (#410)

* chore(python): drop python 3.6

Source-Link: googleapis/synthtool@4f89b13
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:e7bb19d47c13839fe8c147e50e02e8b6cf5da8edd1af8b82208cd6f66cc2829c

* require python 3.7+ in setup.py

* remove python 3.6 sample configs

* exclude templated README

* remove python 3.6 from noxfile

* remove python 3.6 from remaining files

* remove testing/constraints-3.6.txt

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Anthonios Partheniou <partheniou@google.com>

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:81ed5ecdfc7cac5b699ba4537376f3563f6f04122c4ec9e735d3b3dc1d43dd32
-# created: 2022-05-05T22:08:23.383410683Z
+  digest: sha256:e7bb19d47c13839fe8c147e50e02e8b6cf5da8edd1af8b82208cd6f66cc2829c
+# created: 2022-07-05T18:31:20.838186805Z

.github/sync-repo-settings.yaml

@@ -11,12 +11,10 @@ branchProtectionRules:
     # No Kokoro:  the following are Github actions
     - 'lint'
     - 'mypy'
-    - 'unit-3.6'
     - 'unit-3.7'
     - 'unit-3.8'
     - 'unit-3.9'
     - 'unit-3.10'
-    - 'unit_wo_grpc-3.6'
     - 'unit_wo_grpc-3.10'
     - 'cover'
     - 'docs'

.github/workflows/unittest.yml

@@ -13,7 +13,6 @@ jobs:
       matrix:
         option: ["", "_wo_grpc"]
         python:
-          - "3.6"
           - "3.7"
           - "3.8"
           - "3.9"

.kokoro/continuous/prerelease-deps.cfg

@@ -0,0 +1,7 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Only run this nox session.
+env_vars: {
+    key: "NOX_SESSION"
+    value: "prerelease_deps"
+}

.kokoro/presubmit/prerelease-deps.cfg

@@ -0,0 +1,7 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Only run this nox session.
+env_vars: {
+    key: "NOX_SESSION"
+    value: "prerelease_deps"
+}

.kokoro/test-samples-impl.sh

@@ -33,7 +33,7 @@ export PYTHONUNBUFFERED=1
 env | grep KOKORO
 
 # Install nox
-python3.6 -m pip install --upgrade --quiet nox
+python3.9 -m pip install --upgrade --quiet nox
 
 # Use secrets acessor service account to get secrets
 if [[ -f "${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" ]]; then
@@ -76,7 +76,7 @@ for file in samples/**/requirements.txt; do
     echo "------------------------------------------------------------"
 
     # Use nox to execute the tests for the project.
-    python3.6 -m nox -s "$RUN_TESTS_SESSION"
+    python3.9 -m nox -s "$RUN_TESTS_SESSION"
     EXIT=$?
 
     # If this is a periodic build, send the test log to the FlakyBot.

CONTRIBUTING.rst

@@ -21,7 +21,7 @@ In order to add a feature:
   documentation.
 
 - The feature must work fully on the following CPython versions:
-  3.6, 3.7, 3.8, 3.9, and 3.10 on both UNIX and Windows.
+  3.7, 3.8, 3.9, and 3.10 on both UNIX and Windows.
 
 - The feature must not add unnecessary dependencies (where
   "unnecessary" is of course subjective, but new dependencies should
@@ -197,13 +197,11 @@ Supported Python Versions
 
 We support:
 
--  `Python 3.6`_
 -  `Python 3.7`_
 -  `Python 3.8`_
 -  `Python 3.9`_
 -  `Python 3.10`_
 
-.. _Python 3.6: https://docs.python.org/3.6/
 .. _Python 3.7: https://docs.python.org/3.7/
 .. _Python 3.8: https://docs.python.org/3.8/
 .. _Python 3.9: https://docs.python.org/3.9/
@@ -215,18 +213,6 @@ Supported versions can be found in our ``noxfile.py`` `config`_.
 .. _config: https://github.com/googleapis/python-api-core/blob/main/noxfile.py
 
 
-We also explicitly decided to support Python 3 beginning with version 3.6.
-Reasons for this include:
-
--  Encouraging use of newest versions of Python 3
--  Taking the lead of `prominent`_ open-source `projects`_
--  `Unicode literal support`_ which allows for a cleaner codebase that
-   works in both Python 2 and Python 3
-
-.. _prominent: https://docs.djangoproject.com/en/1.9/faq/install/#what-python-version-can-i-use-with-django
-.. _projects: http://flask.pocoo.org/docs/0.10/python3/
-.. _Unicode literal support: https://www.python.org/dev/peps/pep-0414/
-
 **********
 Versioning
 **********

README.rst

@@ -16,13 +16,16 @@ common helpers used by all Google API clients. For more information, see the
 
 Supported Python Versions
 -------------------------
-Python >= 3.6
+Python >= 3.7
 
 
 Unsupported Python Versions
 ---------------------------
 
-Python == 2.7, Python == 3.5.
+Python == 2.7, Python == 3.5, Python == 3.6.
 
 The last version of this library compatible with Python 2.7 and 3.5 is
 `google-api-core==1.31.1`.
+
+The last version of this library compatible with Python 3.6 is
+`google-api-core==2.8.2`.

google/api_core/grpc_helpers_async.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""AsyncIO helpers for :mod:`grpc` supporting 3.6+.
+"""AsyncIO helpers for :mod:`grpc` supporting 3.7+.
 
 Please combine more detailed docstring in grpc_helpers.py to use following
 functions. This module is implementing the same surface with AsyncIO semantics.

mypy.ini

@@ -1,4 +1,4 @@
 [mypy]
-python_version = 3.6
+python_version = 3.7
 namespace_packages = True
 ignore_missing_imports = True

noxfile.py

@@ -43,14 +43,14 @@
 ]
 
 
-def _greater_or_equal_than_36(version_string):
+def _greater_or_equal_than_37(version_string):
     tokens = version_string.split(".")
     for i, token in enumerate(tokens):
         try:
             tokens[i] = int(token)
         except ValueError:
             pass
-    return tokens >= [3, 6]
+    return tokens >= [3, 7]
 
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)
@@ -122,9 +122,9 @@ def default(session, install_grpc=True):
         ),
     ]
 
-    # Inject AsyncIO content and proto-plus, if version >= 3.6.
+    # Inject AsyncIO content and proto-plus, if version >= 3.7.
     # proto-plus is needed for a field mask test in test_protobuf_helpers.py
-    if _greater_or_equal_than_36(session.python):
+    if _greater_or_equal_than_37(session.python):
         session.install("asyncmock", "pytest-asyncio", "proto-plus")
 
         # Having positional arguments means the user wants to run specific tests.
@@ -136,28 +136,27 @@ def default(session, install_grpc=True):
     session.run(*pytest_args)
 
 
-@nox.session(python=["3.6", "3.7", "3.8", "3.9", "3.10"])
+@nox.session(python=["3.7", "3.8", "3.9", "3.10"])
 def unit(session):
     """Run the unit test suite."""
     default(session)
 
 
-@nox.session(python=["3.6", "3.10"])
+@nox.session(python=["3.8", "3.10"])
 def unit_wo_grpc(session):
     """Run the unit test suite w/o grpcio installed"""
     default(session, install_grpc=False)
 
 
-@nox.session(python="3.6")
+@nox.session(python="3.8")
 def lint_setup_py(session):
     """Verify that setup.py is valid (including RST check)."""
 
     session.install("docutils", "Pygments")
     session.run("python", "setup.py", "check", "--restructuredtext", "--strict")
 
 
-# No 3.7 because pytype supports up to 3.6 only.
-@nox.session(python="3.6")
+@nox.session(python="3.8")
 def pytype(session):
     """Run type-checking."""
     session.install(".[grpc]", "pytype >= 2019.3.21")
@@ -178,7 +177,7 @@ def mypy(session):
     session.run("mypy", "google", "tests")
 
 
-@nox.session(python="3.6")
+@nox.session(python="3.8")
 def cover(session):
     """Run the final coverage report.
 

owlbot.py

@@ -30,6 +30,7 @@
     ".coveragerc",  # layout
     "CONTRIBUTING.rst",  # no systests
     ".github/workflows/unittest.yml", # exclude unittest gh action
+    "README.rst",
 ]
 templated_files = common.py_library(microgenerator=True, cov_level=100)
 s.move(templated_files, excludes=excludes)

scripts/readme-gen/templates/install_deps.tmpl.rst

@@ -12,7 +12,7 @@ Install Dependencies
    .. _Python Development Environment Setup Guide:
        https://cloud.google.com/python/setup
 
-#. Create a virtualenv. Samples are compatible with Python 3.6+.
+#. Create a virtualenv. Samples are compatible with Python 3.7+.
 
     .. code-block:: bash
 

setup.cfg

@@ -1,5 +1,5 @@
 [pytype]
-python_version = 3.6
+python_version = 3.7
 inputs =
     google/
 exclude =

setup.py

@@ -80,7 +80,6 @@
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
@@ -93,7 +92,7 @@
     namespace_packages=namespaces,
     install_requires=dependencies,
     extras_require=extras,
-    python_requires=">=3.6",
+    python_requires=">=3.7",
     include_package_data=True,
     zip_safe=False,
 )