Implement optional BASEIMAGE_ONLY builds

hack/bootstrap_tfw_dev.sh

@@ -27,13 +27,18 @@ run()
 
     check_dependencies
     clone_repos_ask_ssh_or_https
-    TAG="$(fetch_latest_tag)"
+    TAG="${BASEIMAGE_ONLY:-$(fetch_latest_tag)}"
     TAG=$TAG pin_latest_baseimage
     TAG=$TAG build_latest_baseimage
-    install_frontend_deps
-    if [ "$TFWDEV" == "0" ]; then
-        cleanup_repos
-        merge_repos
+
+    if [ -z "${BASEIMAGE_ONLY:-}" ]; then
+        install_frontend_deps
+        if [ "$TFWDEV" == "0" ]; then
+            cleanup_repos
+            merge_repos
+        fi
+    else
+        delete_repos
     fi
 
     echo 
@@ -43,7 +48,7 @@ run()
 handle_exit()
 {
     if [[ $? -ne 0 ]]; then
-        err_cleanup
+        delete_repos
         showlog
     fi
     cleanlog
@@ -51,7 +56,7 @@ handle_exit()
 
 showlog() { echo && echo "Error! Showing logs:" && cat $LOGFILE; }
 cleanlog() { rm $LOGFILE; }
-err_cleanup() { cd "$BASEDIR" && rm -rf "$BASEIMAGE" "$FRONTEND" "$TEST"; }
+delete_repos() { pushd "$BASEDIR" && rm -rf "$BASEIMAGE" "$FRONTEND" "$TEST" && popd; }
 
 check_dependencies()
 {
@@ -122,7 +127,7 @@ fetch_latest_tag()
 
 pin_latest_baseimage()
 {
-    echo -n "Pinning latest TFW baseimage version... "
+    echo -n "Pinning TFW baseimage version... "
     echo -n "which is ${TAG}... "
     sed -i "1 s/.*/&:${TAG}/" "${TEST}/solvable/Dockerfile"
     echo "Done!"