chore!: updates as Debian 9 (Stretch) is EOL (#9405)

Debian 9 (Stretch) reached EOL on 2022-06-30. Therefore, we have stopped
testing or supporting this distribution. This was the last distribution
we supported that required GCC < 7.3, and/or CMake < 3.10. Starting with
this release we require GCC >= 7.3 and CMake >= 3.10.

This PR updates the documentation, CI builds and fixes some test problems
that only show up with GCC circa 7.3

CHANGELOG.md

@@ -112,6 +112,13 @@ transition to C++ >= 14 we will, if requested, backport critical fixes to
 v1.42.0 until 2023-07-01.  After 2023-07-01 we will drop all support to v1.42.0
 and earlier versions.
 
+**Debian 9 (Stretch) is EOL**
+
+Debian 9 (Stretch) reached EOL on 2022-06-30. Therefore, we have stopped testing
+or supporting this distribution. This was the last distribution we supported
+that required GCC < 7.3, and/or CMake < 3.10. Starting with this release we
+require CMake >= 3.10, and only test with GCC >= 7.3.
+
 **OTHER CHANGES**
 
 We are introducing a new client library. While we do not anticipate any API

CMakeLists.txt

@@ -14,7 +14,7 @@
 # limitations under the License.
 # ~~~
 
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.10)
 
 # Define the project name and where to report bugs.
 set(PACKAGE_BUGREPORT "https://github.com/googleapis/google-cloud-cpp/issues")
@@ -44,9 +44,9 @@ if (APPLE AND NOT DEFINED CMAKE_CXX_STANDARD)
 endif ()
 
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.3)
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.3)
         message(
-            WARNING "The `google-cloud-cpp` library is tested with GCC >= 6.3."
+            WARNING "The `google-cloud-cpp` library is tested with GCC >= 7.3."
                     " We will consider patches for older versions.")
     endif ()
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")

README.md

@@ -397,7 +397,7 @@ int main(int argc, char* argv[]) {
 ## Support
 
 * This project supports Windows, macOS, Linux
-* This project supports C++14 (and higher) compilers (we test with GCC >= 6.3,
+* This project supports C++14 (and higher) compilers (we test with GCC >= 7.3,
   Clang >= 6.0, and MSVC >= 2017)
 * This project supports Bazel (>= 4.0) and CMake (>= 3.5) builds. See the
   [Quickstart examples](https://github.com/googleapis/google-cloud-cpp#quickstart)

ci/cloudbuild/builds/gcc-63.sh → ci/cloudbuild/builds/gcc-7.3.sh

@@ -20,7 +20,7 @@ source "$(dirname "$0")/../../lib/init.sh"
 source module ci/cloudbuild/builds/lib/cmake.sh
 
 # We run this test in a docker image that includes the oldest GCC that we
-# support, which happens to be 6.3 currently.
+# support, which happens to be 7.3 currently.
 export CC=gcc
 export CXX=g++
 

ci/cloudbuild/dockerfiles/centos-7.Dockerfile

@@ -0,0 +1,167 @@
+# Copyright 2022 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
+#
+#     https://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 centos:7
+
+# First install the development tools and OpenSSL. The development tools
+# distributed with CentOS 7 are too old to build the project. In these
+# instructions, we use `cmake3` and `gcc-7` obtained from
+# [Software Collections](https://www.softwarecollections.org/).
+
+RUN rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
+RUN yum install -y centos-release-scl yum-utils
+RUN yum-config-manager --enable rhel-server-rhscl-7-rpms
+RUN yum makecache && \
+    yum install -y automake ccache cmake3 curl-devel devtoolset-7 gcc gcc-c++ \
+        git libtool make ninja-build openssl-devel patch re2-devel tar wget \
+        which zlib-devel
+RUN ln -sf /usr/bin/cmake3 /usr/bin/cmake && ln -sf /usr/bin/ctest3 /usr/bin/ctest
+
+# In order to use the `devtoolset-7` Software Collection we're supposed to run
+# `scl enable devtoolset-7 bash`, which starts a new shell with the environment
+# configured correctly. However, we can't do that in this Dockerfile, AND we
+# want the instructions that we generate for the user to say the right thing.
+# So this block is ignored, and we manually set some environment variables to
+# make the devtoolset-7 available. After this ignored block, we'll include the
+# correct instructions for the user. NOTE: These env values were obtained by
+# manually running the `scl ...` command (above) then copying the values set in
+# its environment.
+ENV PATH /opt/rh/devtoolset-7/root/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+ENV LD_LIBRARY_PATH /opt/rh/devtoolset-7/root/usr/lib64:/opt/rh/devtoolset-7/root/usr/lib:/opt/rh/devtoolset-7/root/usr/lib64/dyninst:/opt/rh/devtoolset-7/root/usr/lib/dyninst:/opt/rh/devtoolset-7/root/usr/lib64:/opt/rh/devtoolset-7/root/usr/lib
+
+# CentOS-7 ships with `pkg-config` 0.27.1, which has a
+# [bug](https://bugs.freedesktop.org/show_bug.cgi?id=54716) that can make
+# invocations take extremely long to complete.
+
+WORKDIR /var/tmp/build/pkg-config-cpp
+RUN curl -sSL https://pkgconfig.freedesktop.org/releases/pkg-config-0.29.2.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    ./configure --with-internal-glib && \
+    make -j "$(nproc)" && \
+    make install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+# The following steps will install libraries and tools in `/usr/local`. By
+# default, CentOS-7 does not search for shared libraries in these directories,
+# there are multiple ways to solve this problem, the following steps are one
+# solution:
+
+RUN (echo "/usr/local/lib" ; echo "/usr/local/lib64") | \
+    tee /etc/ld.so.conf.d/usrlocal.conf
+ENV PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig
+ENV PATH=/usr/local/bin:${PATH}
+
+WORKDIR /var/tmp/build/abseil-cpp
+RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20211102.0.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    sed -i 's/^#define ABSL_OPTION_USE_\(.*\) 2/#define ABSL_OPTION_USE_\1 0/' "absl/base/options.h" && \
+    cmake \
+      -DCMAKE_BUILD_TYPE=Release \
+      -DBUILD_TESTING=OFF \
+      -DBUILD_SHARED_LIBS=yes \
+      -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out && \
+    cmake --build cmake-out --target install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+WORKDIR /var/tmp/build/protobuf
+RUN curl -sSL https://github.com/protocolbuffers/protobuf/archive/v21.2.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    cmake \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DBUILD_SHARED_LIBS=yes \
+        -Dprotobuf_BUILD_TESTS=OFF \
+        -Dprotobuf_ABSL_PROVIDER=package \
+        -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out && \
+    cmake --build cmake-out --target install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+WORKDIR /var/tmp/build/c-ares
+RUN curl -sSL https://github.com/c-ares/c-ares/archive/cares-1_14_0.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    ./buildconf && ./configure && make -j "$(nproc)" && \
+    make install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+WORKDIR /var/tmp/build/grpc
+RUN curl -sSL https://github.com/grpc/grpc/archive/v1.47.0.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    cmake \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DBUILD_SHARED_LIBS=yes \
+        -DgRPC_INSTALL=ON \
+        -DgRPC_BUILD_TESTS=OFF \
+        -DgRPC_ABSL_PROVIDER=package \
+        -DgRPC_CARES_PROVIDER=package \
+        -DgRPC_PROTOBUF_PROVIDER=package \
+        -DgRPC_RE2_PROVIDER=package \
+        -DgRPC_SSL_PROVIDER=package \
+        -DgRPC_ZLIB_PROVIDER=package \
+        -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out && \
+    cmake --build cmake-out --target install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+WORKDIR /var/tmp/build/crc32c
+RUN curl -sSL https://github.com/google/crc32c/archive/1.1.2.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    cmake \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DBUILD_SHARED_LIBS=yes \
+        -DCRC32C_BUILD_TESTS=OFF \
+        -DCRC32C_BUILD_BENCHMARKS=OFF \
+        -DCRC32C_USE_GLOG=OFF \
+        -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out && \
+    cmake --build cmake-out --target install  && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+WORKDIR /var/tmp/build/json
+RUN curl -sSL https://github.com/nlohmann/json/archive/v3.10.5.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    cmake \
+      -DCMAKE_BUILD_TYPE=Release \
+      -DBUILD_SHARED_LIBS=yes \
+      -DBUILD_TESTING=OFF \
+      -DJSON_BuildTests=OFF \
+      -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out --target install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+# Install googletest, remove the downloaded files and the temporary artifacts
+# after a successful build to keep the image smaller (and with fewer layers)
+WORKDIR /var/tmp/build
+RUN curl -sSL https://github.com/google/googletest/archive/release-1.11.0.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    cmake \
+      -DCMAKE_BUILD_TYPE="Release" \
+      -DBUILD_SHARED_LIBS=yes \
+      -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out --target install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+# Download and compile Google microbenchmark support library:
+WORKDIR /var/tmp/build
+RUN curl -sSL https://github.com/google/benchmark/archive/v1.6.1.tar.gz | \
+    tar -xzf - --strip-components=1 && \
+    cmake \
+        -DCMAKE_BUILD_TYPE="Release" \
+        -DBUILD_SHARED_LIBS=yes \
+        -DBENCHMARK_ENABLE_TESTING=OFF \
+        -GNinja -S . -B cmake-out && \
+    cmake --build cmake-out --target install && \
+    ldconfig && cd /var/tmp && rm -fr build
+
+RUN ldconfig /usr/local/lib*