more readable script, added simple recovery mechanic

scripts/sync-latest-with-local.sh

@@ -3,37 +3,128 @@
 # Prerequisites: this scripts requires the gh client to work
 # Use this script to sync the latest build of the mediasuite-website to a local folder
 
+GITHUB_REPO=github.com/beeldengeluid/mediasuite-website
 VERSION_FILE=./latest
 WEBSITE_DIR=./website
+EXTRACTION_DIR=_site
 ARTEFACT_FILENAME=_site.tar.gz
-LATEST=`gh release view --json name --jq .name`
-DOWLOAD=false
 
-echo "laatste versie was: $LATEST"
+# PATHs
+EXTRACTION_PATH="${WEBSITE_DIR}/${EXTRACTION_DIR}"
+ARTEFACT_PATH="${WEBSITE_DIR}/${ARTEFACT_FILENAME}"
 
-# first compare the latest tag with whatever was recored in ./latest
-if [ ! -f $VERSION_FILE ]; then
-    echo "No latest version yet"
-    DOWNLOAD=true
-elif [ `cat $VERSION_FILE` == $LATEST ]; then
-    echo "yay"
-else
-    DOWNLOAD=true
-fi
+# backup PATHs
+OLD_EXTRACTION_PATH="${WEBSITE_DIR}/${EXTRACTION_DIR}__OLD"
+OLD_ARTEFACT_PATH="${WEBSITE_DIR}/${ARTEFACT_FILENAME}.old"
+
+# Uses the gh client to get the latest release version number
+get_gh_version(){
+    echo `gh release view --json name --jq .name` && return
+}
+
+# Obtains the downloaded version from VERSION_FILE (if it exists)
+get_download_version(){
+    if [ ! -f $VERSION_FILE ]; then
+        echo "Unknown" && return
+    fi
+    echo `cat $VERSION_FILE` && return
+}
+
+
+DOWNLOAD_VERSION=`get_download_version`
+GH_VERSION=`get_gh_version`
+echo "Last version in GH: $GH_VERSION; last version downloaded: $DOWNLOAD_VERSION"
+
+requires_download(){
 
-# now go ahead and download if necessary
-if [ "$DOWNLOAD" = true ]; then
-    echo "A new version was found: $LATEST, removing the old site first"
-    rm "$WEBSITE_DIR/$ARTEFACT_FILENAME"
+    if [  $DOWNLOAD_VERSION == $GH_VERSION ]; then
+        echo "Download version is up-to-date ($DOWNLOAD_VERSION), no download needed"
+        false
+        return
+    else
+        echo "Download needed since $DOWNLOAD_VERSION != $GH_VERSION"
+        true
+        return
+    fi
+}
+
+# before downloading a new version backup the old site data
+backup_old_site(){
+    echo "Backing up previously downloaded site"
+    if [ -d $EXTRACTION_PATH ] && [ -f $ARTEFACT_PATH ]; then
+        mv $EXTRACTION_PATH $OLD_EXTRACTION_PATH && \
+        mv $ARTEFACT_PATH $OLD_ARTEFACT_PATH && \
+        echo "Successfully renamed $EXTRACTION_PATH -> $OLD_EXTRACTION_PATH" && \
+        echo "Successfully renamed $ARTEFACT_PATH -> $OLD_ARTEFACT_PATH" && \
+        return
+    elif [ -d $OLD_EXTRACTION_PATH ] && [ -f $OLD_ARTEFACT_PATH ]; then
+        echo "Backup already exists, skipping" && return
+    fi
+    false
+}
+
+# the backup is only valuable before we're sure the latest version was downloaded successfully
+delete_previous_backup(){
+    if [ -d $OLD_EXTRACTION_PATH ] && [ -f $OLD_ARTEFACT_PATH ]; then
+        rm -rf $OLD_EXTRACTION_PATH && \
+        rm -f $OLD_ARTEFACT_PATH && \
+        echo "Successfully deleted $OLD_EXTRACTION_PATH" && \
+        echo "Successfully deleted $OLD_ARTEFACT_PATH" && \
+        return
+    fi
+    echo "Failed to find or delete backup data"
+    false
+}
+
+# in case download fails, restore the previous version
+restore_backup(){
+    if [ -d $OLD_EXTRACTION_DIR ] && [ -f $OLD_ARTEFACT_PATH ]; then
+        mv $OLD_EXTRACTION_PATH $EXTRACTION_PATH && \
+        mv $OLD_ARTEFACT_PATH $ARTEFACT_PATH && \
+        echo "Successfully renamed $OLD_EXTRACTION_PATH -> $EXTRACTION_PATH" && \
+        echo "Successfully renamed $OLD_ARTEFACT_PATH -> $ARTEFACT_PATH" && \
+        return
+    fi
+    echo "Critical: Failed to restore backup data!"
+    false
+}
+
+download_from_gh(){
     echo "Downloading latest version into $WEBSITE_DIR"
-    gh -R github.com/beeldengeluid/mediasuite-website release download --pattern '*.tar.gz' -O $WEBSITE_DIR/$ARTEFACT_FILENAME
+    gh -R $GITHUB_REPO release download --pattern '*.tar.gz' -O $ARTEFACT_PATH && return
+    false
+}
+
+# download the latest version and make sure the old version is backed up in case of failure
+download_latest_from_gh(){
+    # first check if there is an old backup & delete it
+    delete_previous_backup
+
+    # then create a new backup of the current site data
+    echo "A new version was found: $GH_VERSION, backing up the old site data first"
+    if ! backup_old_site; then
+        echo "Could not rename old data, quitting" && return
+    fi
+
+    # now download the latest version from GH
+    if download_from_gh ; then
+        # set the current version in ./latest
+        echo $GH_VERSION > $VERSION_FILE
 
-    # set the current version in ./latest
-    echo $LATEST > $VERSION_FILE
+        # unpack the website
+        cd $WEBSITE_DIR
+        tar -xvvzf $ARTEFACT_FILENAME
+        return
+    else
+        echo "Download failed, restoring old site"
+        restore_backup
+        return
+    fi
+}
 
-    # unpack the website
-    cd $WEBSITE_DIR
-    tar -xvvzf $ARTEFACT_FILENAME
+# main
+if requires_download ; then
+    download_latest_from_gh
 else
     echo "No download needed"
 fi