Create a latest tag in docker hub for new releases

scripts/manifest

@@ -7,10 +7,36 @@ fi
 
 set -e -x
 
-export REPO="rancher/k3s"
-export DRONE_TAG=$(echo "${DRONE_TAG}" | sed -e 's/+/-/g')
-export PLUGIN_TARGET="${REPO}:${DRONE_TAG}"
-export PLUGIN_TEMPLATE="${REPO}:${DRONE_TAG}-ARCH"
+REPO="rancher/k3s"
+
+# docker can not contain '+' in the tag, so transform '+' to '-'
+DOCKER_TAG=$(echo "${DRONE_TAG}" | sed -e 's/+/-/g')
+
+# export variables for drone-manifest
+export PLUGIN_TEMPLATE="${REPO}:${DOCKER_TAG}-ARCH"
 export PLUGIN_PLATFORMS="linux/amd64,linux/arm64,linux/arm"
 
-drone-manifest
+# push current version manifest tag to docker hub
+PLUGIN_TARGET="${REPO}:${DOCKER_TAG}" drone-manifest
+
+# do not tag in docker as latest if the github tag contains a '-'
+if echo "${DRONE_TAG}" | grep -q '-'; then
+  exit 0
+fi
+
+# get latest released version from github
+GITHUB_URL=https://github.com/rancher/k3s/releases
+VERSION_K3S=$(curl -w '%{url_effective}' -I -L -s -S ${GITHUB_URL}/latest -o /dev/null | sed -e 's|.*/||')
+
+# function for comparing versions
+version_ge() {
+  [ "$1" = "$2" ] || [ "$(printf '%s\n' "$@" | sort -V | head -n 1)" != "$1" ]
+}
+
+# do not tag in docker as latest if we are not greater than or equal to the latest github tag
+if ! version_ge "${DRONE_TAG}" "${VERSION_K3S}"; then
+  exit 0
+fi
+
+# push latest manifest tag to docker hub
+PLUGIN_TARGET="${REPO}:latest" drone-manifest