Fix remarks reported by Sunil Arora such as : 1) use temp dir, 2) che…

…ck os, hw and exists if non supported, 3) add prereq - curl, tar, if kubebuilder folder is empty

scripts/install.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 #
 # This file will be  fetched as: curl -L https://git.io/getLatestKubebuilder | sh -
@@ -8,13 +8,13 @@
 # It lets users to do curl -L https://git.io//getLatestKubebuilder | KUBEBUILDER_VERSION=1.0.5 sh -
 # for instance to change the version fetched.
 
-OS="$(uname)"
-if [ "x${OS}" = "xDarwin" ] ; then
-  OSEXT="darwin"
-else
-  OSEXT="linux"
-fi
-ARCH=amd64
+# Check if the program is installed, otherwise exit
+function command_exists () {
+  if ! [ -x "$(command -v $1)" ]; then
+    echo "Error: $1 program is not installed." >&2
+    exit 1
+  fi
+}
 
 if [ "x${KUBEBUILDER_VERSION}" = "x" ] ; then
   KUBEBUILDER_VERSION=$(curl -L -s https://api.github.com/repos/kubernetes-sigs/kubebuilder/releases/latest | \
@@ -23,18 +23,56 @@ fi
 
 KUBEBUILDER_VERSION=${KUBEBUILDER_VERSION#"v"}
 KUBEBUILDER_VERSION_NAME="kubebuilder_${KUBEBUILDER_VERSION}"
+KUBEBUILDER_DIR=/usr/local/kubebuilder
+
+# Check if folder containing kubebuilder executable exists and is not empty
+if [ -d "$KUBEBUILDER_DIR" ]; then
+  if [ "$(ls -A $KUBEBUILDER_DIR)" ]; then
+    echo "\n/usr/local/kubebuilder folder is not empty. Please delete or backup it before to install ${KUBEBUILDER_VERSION_NAME}"
+    exit 1
+  fi
+fi
+
+# Check if curl, tar commands/programs exist
+command_exists curl
+command_exists tar
+
+# Determine OS
+OS="$(uname)"
+case $OS in
+  Darwin)
+    OSEXT="darwin"
+    ;;
+  Linux)
+    OSEXT="linux"
+    ;;
+  *)
+    echo "Only OSX and Linux OS are supported !"
+    exit 1
+    ;;
+esac
+
+HW=$(uname -m)
+case $HW in
+    x86_64)
+      ARCH=amd64 ;;
+    *)
+      echo "Only x86_64 machines are supported !"
+      exit 1
+      ;;
+esac
+
+TMP_DIR=$(mktemp -d)
+
+# Downloading Kuberbuilder compressed file using curl program
 URL="https://github.com/kubernetes-sigs/kubebuilder/releases/download/v${KUBEBUILDER_VERSION}/${KUBEBUILDER_VERSION_NAME}_${OSEXT}_${ARCH}.tar.gz"
-echo "Downloading ${KUBEBUILDER_VERSION_NAME} from $URL ..."
-curl -L "$URL" | tar xz
-
-echo "Downloaded these executable files into $NAME: "
-ls "${KUBEBUILDER_VERSION_NAME}_${OSEXT}_${ARCH}/bin"
-mv ${KUBEBUILDER_VERSION_NAME}_${OSEXT}_${ARCH} kubebuilder && sudo mv -f kubebuilder /usr/local/
-RETVAL=$?
-
-if [ $RETVAL -eq 0 ]; then
-  echo "Add kubebuilder to your path; e.g copy paste in your shell and/or ~/.profile:"
-  echo "export PATH=\$PATH:/usr/local/kubebuilder/bin"
-else
-  echo "\n/usr/local/kubebuilder folder is not empty. Please delete or backup it before to install ${KUBEBUILDER_VERSION_NAME}"
-fi
+echo "Downloading ${KUBEBUILDER_VERSION_NAME}\nfrom $URL\n"
+curl -L "$URL"| tar xz -C $TMP_DIR
+
+echo "Downloaded executable files"
+ls "$TMP_DIR/${KUBEBUILDER_VERSION_NAME}_${OSEXT}_${ARCH}/bin"
+
+echo "Moving files to $KUBEBUILDER_DIR folder\n"
+mv $TMP_DIR/${KUBEBUILDER_VERSION_NAME}_${OSEXT}_${ARCH} $TMP_DIR/kubebuilder && sudo mv -f $TMP_DIR/kubebuilder /usr/local/
+
+rm -rf $TMP_DIR