update script template file

template-update.sh

@@ -0,0 +1,125 @@
+#!/bin/sh
+
+### update script for <ab-container> utility scripts
+# version x.y.z
+# script by Asif Bacchus
+# usage of this script is subject to the license terms found at:
+# https://git.asifbacchus.app/ab-docker/scripts/LICENSE
+
+
+### pre-requisites
+
+# check if wget is installed
+if ! command -v wget > /dev/null 2>&1; then
+    printf "\nSorry, this script requires that 'wget' is installed in order to automatically update files.\nExiting.\n\n"
+    exit 1
+fi
+
+# zero counters
+updatesAvailable=0
+downloadFailed=0
+downloadSuccess=0
+updateFailed=0
+updateSuccess=0
+
+# reference constants
+containerName=''
+server='https://git.asifbacchus.app/ab-docker/scripts/raw/branch/master/'
+checksumFilename='checksums.sha256'
+
+# files to update
+localScriptName='update.sh'
+repoScriptName='template-update.sh'
+updateFiles=""
+
+printf "\n*** Updating %s container service scripts ***\n\n" "$containerName"
+
+
+### download latest checksums
+printf "Getting latest checksums from ab-git server... "
+if ! wget --quiet --tries=3 --timeout=10 -N "${server}${checksumFilename}"; then
+    printf "[ERROR]\n"
+    printf "Unable to download checksums from ab-git server. Try again later.\n\n"
+    exit 1
+else
+    printf "[OK]\n"
+fi
+
+
+### check for updates to this script
+printf "Checking for updates to this script... "
+repoScriptChecksum=$( grep "$repoScriptName" files.sha256 | grep -o '^\S*' )
+localScriptChecksum=$( sha256sum "$localScriptName" | grep -o '^\S*' )
+if [ "$localScriptChecksum" = "$repoScriptChecksum" ]; then
+    printf "[NONE]\n\n"
+else
+    # download updated script
+    if ! wget --quiet --tries=3 --timeout=10 -O $localScriptName "${server}${repoScriptName}"; then
+        printf "[ERROR]\n"
+        printf "Unable to download script update. Try again later.\n\n"
+        exit 1
+    else
+        # verify download
+        localScriptChecksum=$( sha256sum "$localScriptName" | grep -o '^\S*' )
+        if ! [ "$localScriptChecksum" = "$repoScriptChecksum" ]; then
+            printf "[ERROR]\n"
+            printf "Unable to verify checksum of updated script. Try again later.\n\n"
+        else
+        printf "[UPDATED]\n\n"
+        printf "*** This script has been updated. Please re-run it to load the updated version of this file. ***\n\n"
+        exit 0
+        fi
+    fi
+fi
+
+
+### update files
+set -- dummy $updateFiles
+shift
+for file; do
+    updateTarget="$file"
+    printf "Checking '%s' for updates... " "$updateTarget"
+    repoFile=$( grep "$updateTarget" files.sha256 | grep -o '^\S*' )
+    if [ -f "$file" ]; then
+        localFile=$( sha256sum "$updateTarget" | grep -o '^\S*' )
+    else
+        localFile=0
+    fi
+
+    if ! [ "$localFile" = "$repoFile" ]; then
+        printf "[AVAILABLE]\n"
+        updatesAvailable=$((updatesAvailable+1))
+        # download update
+        printf "Downloading updated '%s'... " "$updateTarget"
+        # specify a name here instead of using the server name so that wget
+        # overwrites the file
+        if ! wget --quiet --tries=3 --timeout=10 -O "$updateTarget" "${server}${updateTarget}"; then
+            printf "[ERROR]\n"
+            downloadFailed=$((downloadFailed+1))
+        else
+            printf "[OK]\n"
+            downloadSuccess=$((downloadSuccess+1))
+            # verify download
+            printf "Verifying '%s'... " "$updateTarget"
+            localFile=$( sha256sum "$updateTarget" | grep -o '^\S*' )
+            if ! [ "$localFile" = "$repoFile" ]; then
+                printf "[INVALID]\n"
+                updateFailed=$((updateFailed+1))
+            else
+                printf "[OK]\n"
+                updateSuccess=$((updateSuccess+1))
+            fi
+        fi
+    else
+        printf "[NONE]\n"
+    fi
+done
+
+
+### display results
+printf "\nResults:\n"
+printf "\tUpdates: %s available\n" "$updatesAvailable"
+printf "\tDownloads: %s successful, %s failed\n" "$downloadSuccess" "$downloadFailed"
+printf "\tUpdates: %s applied, %s failed\n" "$updateSuccess" "$updateFailed"
+
+exit 0