chore: add latest tag action (#11148)

* add latest tag action

* update documentation with latest tag info

* Python in docs doesn't need v3 reference

* add check that latest tag is truly a later version

* remove rc from acceptable tags

* move tag script to seperate file

* add a check that the tag exists

scripts/tag_latest_release.sh

@@ -0,0 +1,128 @@
+#! /bin/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.
+#
+
+run_git_tag () {
+  if [ "$DRY_RUN" = "false" ] && [ "$SKIP_TAG" = "false" ]
+  then
+    git tag -a -f latest "${GITHUB_TAG_NAME}" -m "latest tag"
+    echo "${GITHUB_TAG_NAME} has been tagged 'latest'"
+  fi
+  exit 0
+}
+
+SKIP_TAG=false
+DRY_RUN=false
+
+# get params passed in with script when it was run
+# --dry-run is optional and returns the value of SKIP_TAG, but does not run the git tag statement
+# A tag name is required as a param. A SHA won't work. You must first tag a sha with a release number
+# and then run this script
+while [[ $# -gt 0 ]]
+do
+key="$1"
+
+case $key in
+    --dry-run)
+    DRY_RUN=true
+    shift # past value
+    ;;
+    *)    # this should be the tag name
+    GITHUB_TAG_NAME=$key
+    shift # past value
+    ;;
+esac
+done
+
+if [ -z "${GITHUB_TAG_NAME}" ]; then
+    echo "Missing tag parameter, usage: ./scripts/tag_latest_release.sh <GITHUB_TAG_NAME>"
+    exit 1
+fi
+
+if [ -z "$(git show-ref ${GITHUB_TAG_NAME})" ]; then
+    echo "The tag ${GITHUB_TAG_NAME} does not exist. Please use a different tag."
+    exit 1
+fi
+
+# check that this tag only contains a proper semantic version
+if ! [[ ${GITHUB_TAG_NAME} =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]
+then
+  echo "This tag ${GITHUB_TAG_NAME} is not a valid release version. Not tagging."
+  SKIP_TAG=true
+  exit 0
+fi
+
+## split the current GITHUB_TAG_NAME into an array at the dot
+IFS=$'.'
+THIS_TAG_NAME=(${GITHUB_TAG_NAME})  || echo 'not found'
+
+# look up the 'latest' tag on git
+LATEST_TAG_LIST=$(git show-ref latest && git show --pretty=tformat:%d -s latest | grep tag:) || echo 'not found'
+
+# if 'latest' tag doesn't exist, then set this commit to latest
+if [[ -z "$LATEST_TAG_LIST" ]]
+then
+  # move on to next task
+  echo "there are no latest tags yet, so I'm going to start by tagging this sha as the latest"
+  run_git_tag
+fi
+
+## get all tags that use the same sha as the latest tag. split at comma.
+IFS=$','
+LATEST_TAGS=($LATEST_TAG_LIST)
+
+## loop over those tags and only take action on the one that isn't tagged 'latest'
+## that one will have the version number tag
+for (( i=0; i<${#LATEST_TAGS[@]}; i++ ))
+do
+  if [[ ${LATEST_TAGS[$i]} != *"latest"* ]]
+  then
+    ## extract just the version from this tag
+    LATEST_RELEASE_TAG=$(echo "${LATEST_TAGS[$i]}" | sed -E -e 's/tag:|\(|\)|[[:space:]]*//g')
+
+    # check that this only contains a proper semantic version
+    if ! [[ ${LATEST_RELEASE_TAG} =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]
+    then
+      echo "'Latest' has been associated with tag ${LATEST_RELEASE_TAG} which is not a valid release version. Looking for another."
+      continue
+    fi
+    echo "The current release with the latest tag is version ${LATEST_RELEASE_TAG}"
+
+    ## remove the sha from the latest tag and split into an array- split at the dot
+    IFS=$'.'
+    LATEST_RELEASE_TAG_SPLIT=(${LATEST_RELEASE_TAG})
+
+    for (( j=0; j<${#THIS_TAG_NAME[@]}; j++ ))
+    do
+      ## if this value is greater than the latest release, then tag it, if it's lower, then stop, if it's
+      ## the same then move on to the next index
+      if [[ ${THIS_TAG_NAME[$j]} -gt ${LATEST_RELEASE_TAG_SPLIT[$j]} ]]
+      then
+        echo "This release tag ${GITHUB_TAG_NAME} is the latest. Tagging it"
+        run_git_tag
+
+      elif [[ ${THIS_TAG_NAME[$j]} -lt ${LATEST_RELEASE_TAG_SPLIT[$j]} ]]
+      then
+        continue
+      fi
+    done
+  fi
+done
+
+echo "This release tag ${GITHUB_TAG_NAME} is not the latest. Not tagging."
+# if you've gotten this far, then we don't want to run any tags in the next step
+SKIP_TAG=true