Adding a second Dockerfile supporting C++20 for cmake C++20 tests

ci/Dockerfile

@@ -9,6 +9,7 @@ ADD install_bazelisk.sh /setup-ci
 ADD install_protobuf.sh /setup-ci
 ADD install_format_tools.sh /setup-ci
 
+
 RUN /setup-ci/setup_ci_environment.sh \
   && /setup-ci/setup_cmake.sh \
   && /setup-ci/install_gcc48.sh \

ci/README.md

@@ -16,4 +16,7 @@ CI tests can be run on docker by invoking the script `./ci/run_docker.sh ./ci/do
 * `code.coverage`: build cmake targets and run tests. Then upload coverage report to [codecov.io](https://codecov.io/).
 
 Additionally, `./ci/run_docker.sh` can be invoked with no arguments to get a docker shell where tests
-can be run manually.
+can be run manually, except for `cmake.c++20.test`.
+
+Note that `cmake.c++20.test` can only run in a Ubuntu version 20+ container, as earlier versions of Ubuntu do not support C++20 or g++-10.
+To run said test, you must run it in the specified Ubuntu 20.04 container by invoking `./ci/run_docker.sh ./ci/do_ci.sh cmake.c++20.test`.

ci/cpp20/Dockerfile

@@ -0,0 +1,20 @@
+FROM ubuntu:20.04
+
+WORKDIR /setup-ci
+
+ADD setup_ci_environment.sh /setup-ci
+ADD setup_cmake.sh /setup-ci
+ADD install_format_tools.sh /setup-ci
+
+ENV DEBIAN_FRONTEND noninteractive
+ENV DEBCONF_NONINTERACTIVE_SEEN true
+
+RUN echo "tzdata tzdata/Areas select US" > /tmp/preseed.txt; \
+    echo "tzdata tzdata/Zones/US select Chicago" >> /tmp/preseed.txt; \
+    debconf-set-selections /tmp/preseed.txt && \
+    apt-get update && \
+    apt-get install -y tzdata
+
+RUN /setup-ci/setup_ci_environment.sh \
+  && /setup-ci/setup_cmake.sh \
+  && /setup-ci/install_format_tools.sh

ci/cpp20/install_format_tools.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -e
+
+apt install -y clang-format-8 python3-pip git curl
+pip3 install cmake_format==0.6.5
+curl -L -o /usr/local/bin/buildifier https://github.com/bazelbuild/buildtools/releases/download/2.2.1/buildifier
+chmod +x /usr/local/bin/buildifier

ci/cpp20/setup_ci_environment.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -e
+apt-get update
+apt-get install --no-install-recommends --no-install-suggests -y \
+                build-essential \
+                ca-certificates \
+                wget \
+                git \
+                g++-10 
+apt-get install -y lcov

ci/cpp20/setup_cmake.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -e
+
+apt-get install --no-install-recommends --no-install-suggests -y \
+                cmake \
+                libbenchmark-dev \
+                libgtest-dev
+
+# Follows these instructions for setting up gtest
+# https://www.eriksmistad.no/getting-started-with-google-test-on-ubuntu/
+pushd /usr/src/gtest
+cmake CMakeLists.txt
+make
+cp *.a /usr/lib || cp lib/*.a /usr/lib
+popd

ci/do_ci.sh

@@ -21,6 +21,7 @@ if [[ "$1" == "cmake.test" ]]; then
   make test
   exit 0
 elif [[ "$1" == "cmake.c++20.test" ]]; then
+  echo "${BUILD_DIR}"
   cd "${BUILD_DIR}"
   rm -rf *
   cmake -DCMAKE_BUILD_TYPE=Debug  \

ci/run_docker.sh

@@ -3,12 +3,20 @@
 set -e
 
 BUILD_IMAGE=opentelemetry-cpp-build
-docker image inspect "$BUILD_IMAGE" &> /dev/null || {
-  docker build -t "$BUILD_IMAGE" ci
-}
+BUILD_IMAGEcpp20=opentelemetry-cpp20-build
 
-if [[ $# -ge 1 ]]; then
-  docker run -v "$PWD":/src -w /src -it "$BUILD_IMAGE" "$@"
+if [[ $2 == cmake.c++20.test ]]; then
+  docker image inspect "$BUILD_IMAGEcpp20" &> /dev/null || {
+    docker build -t "$BUILD_IMAGEcpp20" ci/cpp20
+  }
+  docker run -v "$PWD":/src -w /src -it "$BUILD_IMAGEcpp20" "$@"
 else
-  docker run -v "$PWD":/src -w /src --privileged -it "$BUILD_IMAGE" /bin/bash -l
-fi
+  docker image inspect "$BUILD_IMAGE" &> /dev/null || {
+    docker build -t "$BUILD_IMAGE" ci
+  }
+  if [[ $# -ge 1 ]]; then
+    docker run -v "$PWD":/src -w /src -it "$BUILD_IMAGE" "$@"
+  else
+    docker run -v "$PWD":/src -w /src --privileged -it "$BUILD_IMAGE" /bin/bash -l
+  fi
+fi