[SPARK-24372][BUILD] Add scripts to help with preparing releases.

The "do-release.sh" script asks questions about the RC being prepared,
trying to find out as much as possible automatically, and then executes
the existing scripts with proper arguments to prepare the release. This
script was used to prepare the 2.3.1 release candidates, so was tested
in that context.

The docker version runs that same script inside a docker image especially
crafted for building Spark releases. That image is based on the work
by Felix C. linked in the bug. At this point is has been only midly
tested.

I also added a template for the vote e-mail, with placeholders for
things that need to be replaced, although there is no automation around
that for the moment. It shouldn't be hard to hook up certain things like
version and tags to this, or to figure out certain things like the
repo URL from the output of the release scripts.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #21515 from vanzin/SPARK-24372.

dev/.rat-excludes

@@ -106,3 +106,4 @@ spark-warehouse
 structured-streaming/*
 kafka-source-initial-offset-version-2.1.0.bin
 kafka-source-initial-offset-future-version.bin
+vote.tmpl

dev/create-release/do-release-docker.sh

@@ -0,0 +1,143 @@
+#!/usr/bin/env bash
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+#
+
+#
+# Creates a Spark release candidate. The script will update versions, tag the branch,
+# build Spark binary packages and documentation, and upload maven artifacts to a staging
+# repository. There is also a dry run mode where only local builds are performed, and
+# nothing is uploaded to the ASF repos.
+#
+# Run with "-h" for options.
+#
+
+set -e
+SELF=$(cd $(dirname $0) && pwd)
+. "$SELF/release-util.sh"
+
+function usage {
+  local NAME=$(basename $0)
+  cat <<EOF
+Usage: $NAME [options]
+
+This script runs the release scripts inside a docker image. The image is hardcoded to be called
+"spark-rm" and will be re-generated (as needed) on every invocation of this script.
+
+Options are:
+
+  -d [path]   : required: working directory (output will be written to an "output" directory in
+                the working directory).
+  -n          : dry run mode. Performs checks and local builds, but do not upload anything.
+  -t [tag]    : tag for the spark-rm docker image to use for building (default: "latest").
+  -j [path]   : path to local JDK installation to use for building. By default the script will
+                use openjdk8 installed in the docker image.
+  -s [step]   : runs a single step of the process; valid steps are: tag, build, docs, publish
+EOF
+}
+
+WORKDIR=
+IMGTAG=latest
+JAVA=
+RELEASE_STEP=
+while getopts "d:hj:ns:t:" opt; do
+  case $opt in
+    d) WORKDIR="$OPTARG" ;;
+    n) DRY_RUN=1 ;;
+    t) IMGTAG="$OPTARG" ;;
+    j) JAVA="$OPTARG" ;;
+    s) RELEASE_STEP="$OPTARG" ;;
+    h) usage ;;
+    ?) error "Invalid option. Run with -h for help." ;;
+  esac
+done
+
+if [ -z "$WORKDIR" ] || [ ! -d "$WORKDIR" ]; then
+  error "Work directory (-d) must be defined and exist. Run with -h for help."
+fi
+
+if [ -d "$WORKDIR/output" ]; then
+  read -p "Output directory already exists. Overwrite and continue? [y/n] " ANSWER
+  if [ "$ANSWER" != "y" ]; then
+    error "Exiting."
+  fi
+fi
+
+cd "$WORKDIR"
+rm -rf "$WORKDIR/output"
+mkdir "$WORKDIR/output"
+
+get_release_info
+
+# Place all RM scripts and necessary data in a local directory that must be defined in the command
+# line. This directory is mounted into the image.
+for f in "$SELF"/*; do
+  if [ -f "$f" ]; then
+    cp "$f" "$WORKDIR"
+  fi
+done
+
+GPG_KEY_FILE="$WORKDIR/gpg.key"
+fcreate_secure "$GPG_KEY_FILE"
+$GPG --export-secret-key --armor "$GPG_KEY" > "$GPG_KEY_FILE"
+
+run_silent "Building spark-rm image with tag $IMGTAG..." "docker-build.log" \
+  docker build -t "spark-rm:$IMGTAG" --build-arg UID=$UID "$SELF/spark-rm"
+
+# Write the release information to a file with environment variables to be used when running the
+# image.
+ENVFILE="$WORKDIR/env.list"
+fcreate_secure "$ENVFILE"
+
+function cleanup {
+  rm -f "$ENVFILE"
+  rm -f "$GPG_KEY_FILE"
+}
+
+trap cleanup EXIT
+
+cat > $ENVFILE <<EOF
+DRY_RUN=$DRY_RUN
+SKIP_TAG=$SKIP_TAG
+RUNNING_IN_DOCKER=1
+GIT_BRANCH=$GIT_BRANCH
+NEXT_VERSION=$NEXT_VERSION
+RELEASE_VERSION=$RELEASE_VERSION
+RELEASE_TAG=$RELEASE_TAG
+GIT_REF=$GIT_REF
+SPARK_PACKAGE_VERSION=$SPARK_PACKAGE_VERSION
+ASF_USERNAME=$ASF_USERNAME
+GIT_NAME=$GIT_NAME
+GIT_EMAIL=$GIT_EMAIL
+GPG_KEY=$GPG_KEY
+ASF_PASSWORD=$ASF_PASSWORD
+GPG_PASSPHRASE=$GPG_PASSPHRASE
+RELEASE_STEP=$RELEASE_STEP
+EOF
+
+JAVA_VOL=
+if [ -n "$JAVA" ]; then
+  echo "JAVA_HOME=/opt/spark-java" >> $ENVFILE
+  JAVA_VOL="--volume $JAVA:/opt/spark-java"
+fi
+
+echo "Building $RELEASE_TAG; output will be at $WORKDIR/output"
+docker run -ti \
+  --env-file "$ENVFILE" \
+  --volume "$WORKDIR:/opt/spark-rm" \
+  $JAVA_VOL \
+  "spark-rm:$IMGTAG"

dev/create-release/do-release.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+#
+
+SELF=$(cd $(dirname $0) && pwd)
+. "$SELF/release-util.sh"
+
+while getopts "bn" opt; do
+  case $opt in
+    b) GIT_BRANCH=$OPTARG ;;
+    n) DRY_RUN=1 ;;
+    ?) error "Invalid option: $OPTARG" ;;
+  esac
+done
+
+if [ "$RUNNING_IN_DOCKER" = "1" ]; then
+  # Inside docker, need to import the GPG key stored in the current directory.
+  echo $GPG_PASSPHRASE | $GPG --passphrase-fd 0 --import "$SELF/gpg.key"
+
+  # We may need to adjust the path since JAVA_HOME may be overridden by the driver script.
+  if [ -n "$JAVA_HOME" ]; then
+    export PATH="$JAVA_HOME/bin:$PATH"
+  else
+    # JAVA_HOME for the openjdk package.
+    export JAVA_HOME=/usr
+  fi
+else
+  # Outside docker, need to ask for information about the release.
+  get_release_info
+fi
+
+function should_build {
+  local WHAT=$1
+  [ -z "$RELEASE_STEP" ] || [ "$WHAT" = "$RELEASE_STEP" ]
+}
+
+if should_build "tag" && [ $SKIP_TAG = 0 ]; then
+  run_silent "Creating release tag $RELEASE_TAG..." "tag.log" \
+    "$SELF/release-tag.sh"
+  echo "It may take some time for the tag to be synchronized to github."
+  echo "Press enter when you've verified that the new tag ($RELEASE_TAG) is available."
+  read
+else
+  echo "Skipping tag creation for $RELEASE_TAG."
+fi
+
+if should_build "build"; then
+  run_silent "Building Spark..." "build.log" \
+    "$SELF/release-build.sh" package
+else
+  echo "Skipping build step."
+fi
+
+if should_build "docs"; then
+  run_silent "Building documentation..." "docs.log" \
+    "$SELF/release-build.sh" docs
+else
+  echo "Skipping docs step."
+fi
+
+if should_build "publish"; then
+  run_silent "Publishing release" "publish.log" \
+    "$SELF/release-build.sh" publish-release
+else
+  echo "Skipping publish step."
+fi