Helm install check (#359)

Issue #, if available:  aws-controllers-k8s/community#1436

Description of changes:
- Add helm version check function
- Add helm installation helper script
- Modify k8s_controller_gen_version_equals function and its comment

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: kskzk

scripts/build-controller-release.sh

@@ -25,6 +25,12 @@ if ! k8s_controller_gen_version_equals "$CONTROLLER_TOOLS_VERSION"; then
     exit 1
 fi
 
+if ! helm_version_equals_or_greater "$HELM_VERSION"; then
+    echo "FATAL: Existing version of helm "`helm version --template='Version: {{.Version}}'`", required version is $HELM_VERSION."
+    echo "FATAL: Please update helm, or uninstall helm and install the required version with scripts/install-helm.sh."
+    exit 1
+fi
+
 ACK_GENERATE_CACHE_DIR=${ACK_GENERATE_CACHE_DIR:-"$HOME/.cache/aws-controllers-k8s"}
 # The ack-generate code generator is in a separate source code repository,
 # typically at $GOPATH/src/github.com/aws-controllers-k8s/code-generator

scripts/install-helm.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+# ./scripts/install-helm.sh
+#
+# Installs the latest version helm if not installed.
+#
+# NOTE: helm will be installed to /usr/local/bin/helm
+
+set -eo pipefail
+
+SCRIPTS_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+ROOT_DIR="$SCRIPTS_DIR/.."
+
+source "$SCRIPTS_DIR/lib/common.sh"
+
+if ! is_installed helm ; then
+    __helm_url="https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3"
+    echo -n "installing helm from $__helm_url ... "
+    curl --silent "$__helm_url" | bash 1>/dev/null
+    echo "ok."
+fi

scripts/lib/common.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 
 CONTROLLER_TOOLS_VERSION="v0.7.0"
+HELM_VERSION="v3.7"
 
 # setting the -x option if debugging is true
 if [[ "${DEBUG:-"false"}" = "true" ]]; then
@@ -91,25 +92,41 @@ debug_msg() {
     echo "$__debug_prefix$__indent$__msg"
 }
 
-# controller_gen_version_equals accepts a string version and returns 0 if the
+# k8s_controller_gen_version_equals accepts a string version and returns 0 if the
 # installed version of controller-gen matches the supplied version, otherwise
 # returns 1
 #
 # Usage:
 #
-#   if controller_gen_version_equals "v0.4.0"; then
+#   if k8s_controller_gen_version_equals "v0.4.0"; then
 #       echo "controller-gen is at version 0.4.0"
 #   fi
 k8s_controller_gen_version_equals() {
-    currentver="$(controller-gen --version | cut -d' ' -f2 | tr -d '\n')";
-    requiredver="$1";
+    local currentver="$(controller-gen --version | cut -d' ' -f2 | tr -d '\n')";
+    local requiredver="$1";
     if [ "$currentver" = "$requiredver" ]; then
         return 0
     else
         return 1
     fi;
 }
 
+# helm_version_equals_or_greater accepts a string version and returns 0 if the
+# installed version of helm matches or greater than the supplied version, 
+# otherwise returns 1
+#
+# Usage:
+#
+#   if helm_version_equals_or_greater "v3.9.0"; then
+#       echo "Installed helm version is greater than or equal to version v3.9.0"
+#   fi
+helm_version_equals_or_greater() {
+    local currentver="$(helm version --template='Version: {{.Version}}'| cut -d' ' -f2 | tr -d '\n')"
+    local requiredver="$1"
+    printf '%s\n%s\n' $requiredver $currentver | sort -C -V
+    return $?
+}
+
 # is_public_ecr_logged_in returns 0 if the Docker client is authenticated
 # with ECR public and therefore can pull and push to ECR public, otherwise
 # returns 1