[BEAM-9175] Add pre-commit Jenkins job

.test-infra/jenkins/job_PreCommit_PythonAutoformatter.groovy

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import PrecommitJobBuilder
+
+PrecommitJobBuilder builder = new PrecommitJobBuilder(
+    scope: this,
+    nameBase: 'PythonFormatter',
+    gradleTask: ':pythonFormatterPreCommit',
+    triggerPathPatterns: [
+      '^sdks/python/apache_beam/.*$',
+    ]
+)
+builder.build()

build.gradle

@@ -219,6 +219,10 @@ task pythonLintPreCommit() {
   dependsOn ":sdks:python:test-suites:tox:py37:lint"
 }
 
+task pythonFormatterPreCommit() {
+  dependsOn 'sdks:python:test-suites:tox:py37:formatter'
+}
+
 task python2PostCommit() {
   dependsOn ":sdks:python:test-suites:portable:py2:crossLanguageTests"
   dependsOn ":sdks:python:test-suites:dataflow:py2:postCommitIT"

sdks/python/test-suites/tox/py37/build.gradle

@@ -35,6 +35,9 @@ lint.dependsOn lintPy37
 toxTask "mypyPy37", "py37-mypy"
 lint.dependsOn mypyPy37
 
+toxTask "formatter", "py3-yapf-check"
+check.dependsOn formatter
+
 // TODO(BEAM-3713): Migrate to -pytest env variant.
 toxTask "testPython37", "py37"
 test.dependsOn testPython37

sdks/python/tox.ini

@@ -349,3 +349,10 @@ deps =
 commands =
   yapf --version
   time yapf --in-place --parallel --recursive apache_beam
+
+[testenv:py3-yapf-check]
+deps =
+  yapf==0.29.0
+commands =
+  yapf --version
+  time yapf --diff --parallel --recursive apache_beam