Add a default Dockerfile for Python testing

templates/tools/dockerfile/test/python_stretch_default_x64/Dockerfile.template

@@ -0,0 +1,37 @@
+%YAML 1.2
+--- |
+  # Copyright 2018 The gRPC 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.
+
+  <%include file="../../python_stretch.include"/>
+
+  RUN apt-get install -y jq zlib1g-dev libssl-dev
+  RUN apt-get install -y jq build-essential libffi-dev
+
+  RUN cd /tmp && ${'\\'}
+    wget -q https://github.com/python/cpython/archive/v3.6.9.tar.gz && ${'\\'}
+    tar xzvf v3.6.9.tar.gz && ${'\\'}
+    cd cpython-3.6.9 && ${'\\'}
+    ./configure && ${'\\'}
+    make install
+
+  RUN apt-get update && apt-get -t buster install -y python3.7 python3-all-dev
+  RUN curl https://bootstrap.pypa.io/get-pip.py | python3.7
+
+  # for Python test coverage reporting
+  RUN python3.7 -m ensurepip && ${'\\'}
+      python3.7 -m pip install coverage
+
+  RUN python3.6 -m ensurepip && ${'\\'}
+      python3.6 -m pip install coverage

tools/dockerfile/test/python_stretch_default_x64/Dockerfile

@@ -0,0 +1,88 @@
+# Copyright 2018 The gRPC 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 debian:stretch
+  
+# Install Git and basic packages.
+RUN apt-get update && apt-get install -y \
+  autoconf \
+  autotools-dev \
+  build-essential \
+  bzip2 \
+  ccache \
+  curl \
+  dnsutils \
+  gcc \
+  gcc-multilib \
+  git \
+  golang \
+  gyp \
+  lcov \
+  libc6 \
+  libc6-dbg \
+  libc6-dev \
+  libgtest-dev \
+  libtool \
+  make \
+  perl \
+  strace \
+  python-dev \
+  python-setuptools \
+  python-yaml \
+  telnet \
+  unzip \
+  wget \
+  zip && apt-get clean
+
+#================
+# Build profiling
+RUN apt-get update && apt-get install -y time && apt-get clean
+
+# Google Cloud platform API libraries
+RUN apt-get update && apt-get install -y python-pip && apt-get clean
+RUN pip install --upgrade google-api-python-client oauth2client
+
+# Install Python 2.7
+RUN apt-get update && apt-get install -y python2.7 python-all-dev
+RUN curl https://bootstrap.pypa.io/get-pip.py | python2.7
+
+# Add Debian 'buster' repository, we will need it for installing newer versions of python
+RUN echo 'deb http://ftp.de.debian.org/debian buster main' >> /etc/apt/sources.list
+RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
+
+RUN mkdir /var/local/jenkins
+
+# Define the default command.
+CMD ["bash"]
+
+
+RUN apt-get install -y jq zlib1g-dev libssl-dev
+RUN apt-get install -y jq build-essential libffi-dev
+
+RUN cd /tmp && \
+  wget -q https://github.com/python/cpython/archive/v3.6.9.tar.gz && \
+  tar xzvf v3.6.9.tar.gz && \
+  cd cpython-3.6.9 && \
+  ./configure && \
+  make install
+
+RUN apt-get update && apt-get -t buster install -y python3.7 python3-all-dev
+RUN curl https://bootstrap.pypa.io/get-pip.py | python3.7
+
+# for Python test coverage reporting
+RUN python3.7 -m ensurepip && \
+    python3.7 -m pip install coverage
+
+RUN python3.6 -m ensurepip && \
+    python3.6 -m pip install coverage

tools/run_tests/run_tests.py

@@ -761,7 +761,7 @@ class PythonLanguage(object):
         elif self.args.compiler == 'python3.4':
             return 'jessie'
         else:
-            return 'stretch_3.7'
+            return 'stretch_default'
 
     def _get_pythons(self, args):
         """Get python runtimes to test with, based on current platform, architecture, compiler etc."""