[SPARK-1517] Refactor release scripts to facilitate nightly publishing

This update contains some code changes to the release scripts that allow easier nightly publishing. I've been using these new scripts on Jenkins for cutting and publishing nightly snapshots for the last month or so, and it has been going well. I'd like to get them merged back upstream so this can be maintained by the community.

The main changes are:
1. Separates the release tagging from various build possibilities for an already tagged release (`release-tag.sh` and `release-build.sh`).
2. Allow for injecting credentials through the environment, including GPG keys. This is then paired with secure key injection in Jenkins.
3. Support for copying build results to a remote directory, and also "rotating" results, e.g. the ability to keep the last N copies of binary or doc builds.

I'm happy if anyone wants to take a look at this - it's not user facing but an internal utility used for generating releases.

Author: Patrick Wendell <patrick@databricks.com>

Closes #7411 from pwendell/release-script-updates and squashes the following commits:

74f9beb [Patrick Wendell] Moving maven build command to a variable
233ce85 [Patrick Wendell] [SPARK-1517] Refactor release scripts to facilitate nightly publishing

1 files changed, 79 insertions, 0 deletions

diff --git a/dev/create-release/release-tag.sh b/dev/create-release/release-tag.sh
new file mode 100755
index 0000000000..b0a3374bec
--- /dev/null
+++ b/dev/create-release/release-tag.sh
@@ -0,0 +1,79 @@
+#!/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.
+#
+
+function exit_with_usage {
+  cat << EOF
+usage: tag-release.sh
+Tags a Spark release on a particular branch.
+
+Inputs are specified with the following environment variables:
+ASF_USERNAME - Apache Username
+ASF_PASSWORD - Apache Password
+GIT_NAME - Name to use with git
+GIT_EMAIL - E-mail address to use with git
+GIT_BRANCH - Git branch on which to make release
+RELEASE_VERSION - Version used in pom files for release
+RELEASE_TAG - Name of release tag
+NEXT_VERSION - Development version after release
+EOF
+  exit 1
+}
+
+set -e
+
+if [[ $@ == *"help"* ]]; then
+  exit_with_usage
+fi
+
+for env in ASF_USERNAME ASF_PASSWORD RELEASE_VERSION RELEASE_TAG NEXT_VERSION GIT_EMAIL GIT_NAME GIT_BRANCH; do
+  if [ -z "${!env}" ]; then
+    echo "$env must be set to run this script"
+    exit 1
+  fi
+done
+
+ASF_SPARK_REPO="git-wip-us.apache.org/repos/asf/spark.git"
+MVN="build/mvn --force"
+
+rm -rf spark
+git clone https://$ASF_USERNAME:$ASF_PASSWORD@$ASF_SPARK_REPO -b $GIT_BRANCH
+cd spark
+
+git config user.name "$GIT_NAME"
+git config user.email $GIT_EMAIL
+
+# Create release version
+$MVN versions:set -DnewVersion=$RELEASE_VERSION | grep -v "no value" # silence logs
+git commit -a -m "Preparing Spark release $RELEASE_TAG"
+echo "Creating tag $RELEASE_TAG at the head of $GIT_BRANCH"
+git tag $RELEASE_TAG
+
+# TODO: It would be nice to do some verifications here
+#       i.e. check whether ec2 scripts have the new version
+
+# Create next version
+$MVN versions:set -DnewVersion=$NEXT_VERSION | grep -v "no value" # silence logs
+git commit -a -m "Preparing development version $NEXT_VERSION"
+
+# Push changes
+git push origin $RELEASE_TAG
+git push origin HEAD:$GIT_BRANCH
+
+cd ..
+rm -rf spark