scripts/bazel_from_source

# Copyright 2018 The Bazel Authors. All rights reserved.
#
# 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.
#!/usr/bin/env bash
# Note: Written on a mac please make it compatible with linux if needed.
set -o errexit

# The script assumes that the bazel source code is checked out in the GOPATH
: ${BAZEL_SOURCE:=${GOPATH?GOPATH not set}/src/github.com/bazelbuild/bazel}
# The version of the jdk to use target javabase. The path of the jdk is set as the JAVA_HOME
: ${JAVA_BASE_VERSION:="1.8"}
# The version of the jdk to use as the host_javabase. The path of the jdk is Passed as a startup flag.
: ${HOST_JAVA_BASE_VERSION:="9"}

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
WORKSPACE_DIR=$(dirname ${SCRIPT_DIR})
BAZEL_RC=${WORKSPACE_DIR}/.bazelrc

function _exit { echo $1; exit 1; }
function _jdk_path { /usr/libexec/java_home -v $1; }

function _head_bazel {
    local head_bazel=${BAZEL_SOURCE}/bazel-bin/src/bazel
    if [ ! -f  ${head_bazel} ]; then _exit "bazel binary not found at ${head_bazel} run ${0} _build"; fi

    local hjb="$(_jdk_path ${HOST_JAVA_BASE_VERSION})"
    export JAVA_HOME="$(_jdk_path ${JAVA_BASE_VERSION})"

    ${head_bazel}\
        --host_javabase=${hjb}\
        --bazelrc=${BAZEL_RC}\
        --max_idle_secs=600\
        ${1} $2
}

function _build_head_bazel {
    pushd ${BAZEL_SOURCE}
    bazel build //src:bazel
    if [ $? -ne 0 ]; then _exit "could not build bazel"; fi
    bazel shutdown
}

function _main {
    if [ ! -d ${BAZEL_SOURCE} ]; then _exit "bazel source directory does not exist ${BAZEL_SOURCE}"; fi

    local CMD=$1
    shift 1

    case ${CMD} in
        # compile bazel from head
        _build)
            _build_head_bazel
            ;;
        _cd)
            cd ${BAZEL_SOURCE}
            ;;
        _pull)
            pushd ${BAZEL_SOURCE}
            git fetch
            git pull origin master
            ;;
        *)
            _head_bazel ${CMD} $@
            ;;
    esac
}

_main $@