Add Bazel build to the ci

.travis.yml

@@ -39,6 +39,12 @@ matrix:
         sources: ['ubuntu-toolchain-r-test']
         packages: ['g++-4.9', 'valgrind', 'ninja-build']
 
+  # Bazel
+  - os: linux
+    compiler: gcc
+    install: ci/travis/install-bazel.sh
+    script: ci/travis/build-bazel.sh
+
   # clang sanitizer
   - os: linux
     compiler: clang
@@ -332,3 +338,31 @@ script:
     brew install nlohmann_json --HEAD ;    
     brew test nlohmann_json ;    
     fi
+
+# The following code is an excerpt from google-cloud-cpp.
+#
+# Copyright 2017 Google Inc.
+#
+# 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.
+
+cache:
+  directories:
+    # Cache the Bazel directories, in builds that do not use Bazel this is
+    # empty and trivial to cache.
+    - $HOME/.cache/bazel
+  timeout: 900
+
+before_cache:
+  # Do not save the Bazel installation, reinstall each time, it fails to install
+  # if the installation is in the cache.
+  - rm -fr ${HOME}/.cache/bazel/_bazel_${USER}/install

NOTICE

@@ -1,6 +1,5 @@
-This product contains modified files from google-cloud-cpp v0.11.0, which is
-available under a "Apache 2.0" License. For details, see
-cmake/CreateBazelConfig.cmake.
+This product contains files and code excerpts from google-cloud-cpp, which is
+available under a "Apache 2.0" License.
 
                                  Apache License
                            Version 2.0, January 2004

ci/travis/build-bazel.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+export PATH=$PATH:$HOME/bin
+
+bazel build --test_output=errors --verbose_failures=true --keep_going -- //...:all

ci/travis/install-bazel.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+#
+# Copyright 2018 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.
+
+set -eu
+
+sudo apt-get update
+sudo apt-get install -y \
+     gcc \
+     g++ \
+     unzip \
+     wget \
+     zip
+
+readonly BAZEL_VERSION=0.24.0
+readonly GITHUB_DL="https://github.com/bazelbuild/bazel/releases/download"
+wget -q "${GITHUB_DL}/${BAZEL_VERSION}/bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh"
+chmod +x "bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh"
+./bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh --user