chore: migrate to owl bot (#89)

This PR migrates from autosynth to [owl bot](https://github.com/googleapis/repo-automation-bots/tree/master/packages/owl-bot).  owl bot will save time for maintainers as it will automatically open PRs when there are updates in [googleapis-gen](https://github.com/googleapis/googleapis-gen/tree/master/google) without requiring maintainers to run `synthtool` to build the client from protos. Additionally, similar to autosynth, PRs will be automatically opened when there are template updates.

.github/.OwlBot.lock.yaml

@@ -0,0 +1,4 @@
+docker:
+  digest: sha256:457583330eec64daa02aeb7a72a04d33e7be2428f646671ce4045dcbc0191b1e
+  image: gcr.io/repo-automation-bots/owlbot-python:latest  
+

.github/.OwlBot.yaml

@@ -0,0 +1,26 @@
+# Copyright 2021 Google LLC
+#
+# 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.
+
+docker:
+  image: gcr.io/repo-automation-bots/owlbot-python:latest
+
+deep-remove-regex:
+  - /owl-bot-staging
+
+deep-copy-regex:
+  - source: /google/cloud/billing/budgets/(v.*)/.*-py/(.*)
+    dest: /owl-bot-staging/$1/$2
+
+begin-after-commit-hash: 6a5da3f1274b088752f074da5bc9e30bd1beb27e
+

.pre-commit-config.yaml

@@ -26,6 +26,6 @@ repos:
     hooks:
     - id: black
 -   repo: https://gitlab.com/pycqa/flake8
-    rev: 3.9.0
+    rev: 3.9.1
     hooks:
     - id: flake8

CONTRIBUTING.rst

@@ -160,21 +160,7 @@ Running System Tests
   auth settings and change some configuration in your project to
   run all the tests.
 
-- System tests will be run against an actual project and
-  so you'll need to provide some environment variables to facilitate
-  authentication to your project:
-
-  - ``GOOGLE_APPLICATION_CREDENTIALS``: The path to a JSON key file;
-    Such a file can be downloaded directly from the developer's console by clicking
-    "Generate new JSON key". See private key
-    `docs <https://cloud.google.com/storage/docs/authentication#generating-a-private-key>`__
-    for more details.
-
-- Once you have downloaded your json keys, set the environment variable 
-  ``GOOGLE_APPLICATION_CREDENTIALS`` to the absolute path of the json file::
-
-   $ export GOOGLE_APPLICATION_CREDENTIALS="/Users/<your_username>/path/to/app_credentials.json"
-
+- System tests will be run against an actual project. You should use local credentials from gcloud when possible. See `Best practices for application authentication <https://cloud.google.com/docs/authentication/best-practices-applications#local_development_and_testing_with_the>`__. Some tests require a service account. For those tests see `Authenticating as a service account <https://cloud.google.com/docs/authentication/production>`__.
 
 *************
 Test Coverage

noxfile.py

@@ -62,16 +62,9 @@ def lint(session):
     session.run("flake8", "google", "tests")
 
 
-@nox.session(python="3.6")
+@nox.session(python=DEFAULT_PYTHON_VERSION)
 def blacken(session):
-    """Run black.
-
-    Format code to uniform standard.
-
-    This currently uses Python 3.6 due to the automated Kokoro run of synthtool.
-    That run uses an image that doesn't have 3.6 installed. Before updating this
-    check the state of the `gcp_ubuntu_config` we use for that Kokoro run.
-    """
+    """Run black. Format code to uniform standard."""
     session.install(BLACK_VERSION)
     session.run(
         "black", *BLACK_PATHS,
@@ -131,9 +124,6 @@ def system(session):
     # Check the value of `RUN_SYSTEM_TESTS` env var. It defaults to true.
     if os.environ.get("RUN_SYSTEM_TESTS", "true") == "false":
         session.skip("RUN_SYSTEM_TESTS is set to false, skipping")
-    # Sanity check: Only run tests if the environment variable is set.
-    if not os.environ.get("GOOGLE_APPLICATION_CREDENTIALS", ""):
-        session.skip("Credentials must be set via environment variable")
     # Install pyopenssl for mTLS testing.
     if os.environ.get("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false") == "true":
         session.install("pyopenssl")

synth.py → owlbot.py

@@ -20,31 +20,22 @@
 
 logging.basicConfig(level=logging.DEBUG)
 
-gapic = gcp.GAPICBazel()
 common = gcp.CommonTemplates()
 
-# ----------------------------------------------------------------------------
-# Generate billing budgets GAPIC layer
-# ----------------------------------------------------------------------------
-versions = ["v1beta1", "v1"]
-for version in versions:
-    library = gapic.py_library(
-        service="billing_budgets",
-        version=f"{version}",
-        bazel_target=f"//google/cloud/billing/budgets/{version}:billing-budgets-{version}-py",
-        include_protos=True,
-        proto_output_path=f"google/cloud/billing/budgets_{version}/proto"
-    )
+default_version = "v1"
 
+for library in s.get_staging_dirs(default_version):
     excludes = [
         "nox.py",
         "setup.py",
         "README.rst",
-        library / "docs/index.rst",
+        "docs/index.rst",
     ]
 
     s.move(library, excludes=excludes)
 
+s.remove_staging_dirs()
+
 # ----------------------------------------------------------------------------
 # Add templated files
 # ----------------------------------------------------------------------------