Allow simultaneous initialization of common html volume

Signed-off-by: John Molakvoæ <[email protected]>

docker-entrypoint.sh

@@ -101,15 +101,37 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
         else
             rsync_options="-rlD"
         fi
-        rsync $rsync_options --delete --exclude-from=/upgrade.exclude /usr/src/nextcloud/ /var/www/html/
 
-        for dir in config data custom_apps themes; do
-            if [ ! -d "/var/www/html/$dir" ] || directory_empty "/var/www/html/$dir"; then
-                rsync $rsync_options --include "/$dir/" --exclude '/*' /usr/src/nextcloud/ /var/www/html/
-            fi
+        # If another process is syncing the html folder, wait for
+        # it to be done, then escape initalization
+        lock=/tmp/nextcloud-init-sync.lock
+        count=0
+        until [ ! -f "$lock"]
+        do
+            skipInit=1
+            count=$((count+1))
+            wait=$((count*10))
+            echo "Another process is initializing Nextcloud. Waiting $wait seconds..."
+            sleep $wait
         done
-        rsync $rsync_options --include '/version.php' --exclude '/*' /usr/src/nextcloud/ /var/www/html/
-        echo "Initializing finished"
+
+        if [ -n "$skipInit" ]; then
+            echo "The other process is done, assuming complete initialization"
+        else
+            # Prevent multiple images syncing simultaneously
+            touch $lock
+            rsync $rsync_options --delete --exclude-from=/upgrade.exclude /usr/src/nextcloud/ /var/www/html/
+
+            for dir in config data custom_apps themes; do
+                if [ ! -d "/var/www/html/$dir" ] || directory_empty "/var/www/html/$dir"; then
+                    rsync $rsync_options --include "/$dir/" --exclude '/*' /usr/src/nextcloud/ /var/www/html/
+                fi
+            done
+            rsync $rsync_options --include '/version.php' --exclude '/*' /usr/src/nextcloud/ /var/www/html/
+
+            rm $lock
+            echo "Initializing finished"
+        fi
 
         #install
         if [ "$installed_version" = "0.0.0.0" ]; then