build-and-push-release-images.sh

#! /usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

# This scripts sets TAG_LATEST based on whether the tag currently being
# built is the highest semantic version tag that's not a pre-release
# (alpha, beta, rc), and calls 'make multiarch-build'.
#
# This script is intended to be run only for tag builds and will no-op
# if GITHUB_REF is not in the format "refs/tags/<tag-name>".
# Ref. https://docs.github.com/en/free-pro-team@latest/actions/reference/environment-variables#default-environment-variables

# Check if the current build is for a tag and exit early if not.
REF_TYPE=$(echo "$GITHUB_REF" | cut -d / -f 2)
if [[ "$REF_TYPE" != "tags" ]]; then
    echo "REF_TYPE \"$REF_TYPE\" is not a tag, exiting"
    exit 0
fi

# Get the current tag name.
CURRENT_TAG=$(echo "$GITHUB_REF" | cut -d / -f 3)
if [[ -z "$CURRENT_TAG" ]]; then
    echo "Error getting current tag name from GITHUB_REF \"$GITHUB_REF\""
    exit 1
fi

# Fetch all tags so we can check if the current tag
# is the highest semver.
git fetch --tags --force

HIGHEST_SEMVER_TAG=""

# The --sort=-v:refname flag treats tag names as versions, so gives
# us semantic sorting rather than lexicographic (alphabetic) sorting.
for t in $(git tag -l --sort=-v:refname); do
    # Skip pre-release tags
    if [[ "$t" == *"beta"* || "$t" == *"alpha"* || "$t" == *"rc"* ]]; then
        continue
    fi
    HIGHEST_SEMVER_TAG="$t"
    break
done

# Set TAG_LATEST based on whether the current tag is the highest semver tag.
if [[ "$CURRENT_TAG" == "$HIGHEST_SEMVER_TAG" ]]; then
    TAG_LATEST="true"
else
    TAG_LATEST="false"
fi

echo "CURRENT_TAG: $CURRENT_TAG"
echo "HIGHEST_SEMVER_TAG: $HIGHEST_SEMVER_TAG"
echo "TAG_LATEST: $TAG_LATEST"

make multiarch-build TAG_LATEST="$TAG_LATEST" PUSH_IMAGE=true