core: only rebuild on changes

mod/core/Dockerfile

@@ -28,7 +28,7 @@ RUN apt-get install -y supervisor apt-transport-https equivs libreoffice haveged
 # bbb repo & packages
 RUN LC_CTYPE=C.UTF-8 add-apt-repository ppa:bigbluebutton/support
 RUN sh -c 'wget https://ubuntu.bigbluebutton.org/repo/bigbluebutton.asc -O- | apt-key add -' \
-    && sh -c 'echo "deb https://packages-eu.bigbluebutton.org/xenial-22 bigbluebutton-xenial main" > /etc/apt/sources.list.d/bigbluebutton.list'
+    && sh -c 'echo "deb https://ubuntu.bigbluebutton.org/xenial-22 bigbluebutton-xenial main" > /etc/apt/sources.list.d/bigbluebutton.list'
 
 # create dummy packages to satisfy dependencies
 RUN equivs-control redis-server.control \
@@ -37,6 +37,10 @@ RUN equivs-control redis-server.control \
     && dpkg -i /*.deb \
     && rm /*.deb
 
+# this variable is not used, but it triggers
+# rebuilding from here on if changed
+ENV VERSION v2.2.21
+
 RUN apt-get update && apt-get install -y bbb-web \
                     bbb-fsesl-akka bbb-apps-akka bbb-transcode-akka bbb-apps \
                     bbb-apps-video bbb-apps-screenshare bbb-apps-video-broadcast

scripts/upgrade

@@ -13,6 +13,9 @@ then
     RESTARTED=1 ./scripts/upgrade
 
 else
+    # update changed environment variable
+    sed -i 's/EXTERNAL_IP=/EXTERNAL_IPv4=/' .env
+
     echo ""
     echo "# pull newest bbb-webrtc-sfu"
     git submodule update --remote 
@@ -25,13 +28,8 @@ else
     echo ""
     echo "# rebuild images"
 
-    # rebuild core without caching, since the deb-packages might have changed
-    ./scripts/compose build --pull --no-cache core
-
-    # rebuild everything else only when modified
-    ./scripts/compose build --pull
-
-    sed -i 's/EXTERNAL_IP=/EXTERNAL_IPv4=/' .env
+    # rebuild everything which got modified
+    ./scripts/compose build --pull    
 
     COMMIT_HASH=$(git rev-parse --short HEAD)
     BRANCH_NAME=$(git rev-parse --abbrev-ref HEAD)