diff --git a/builder-create-dokku-image b/builder-create-dokku-image
new file mode 100755
index 0000000..4c7bb5c
--- /dev/null
+++ b/builder-create-dokku-image
@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+export DOCKER_BIN=${DOCKER_BIN:="docker"}
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+source "$PLUGIN_AVAILABLE_PATH/apt/internal-functions"
+
+hook-apt-builder-create-dokku-image() {
+  declare BUILDER_TYPE="$1" APP="$2" SOURCECODE_WORK_DIR="$3" DOKKU_IMAGE="$4"
+  local IMAGE="dokku/$APP" DIR=/tmp/apt
+  local COMMAND CONTENT_SHA DOCKER_COMMIT_LABEL_ARGS DOCKER_RUN_LABEL_ARGS
+
+  if [[ -f "$SOURCECODE_WORK_DIR/dpkg-packages" ]]; then
+    dokku_log_info1 "Rebuilding extended app image due to dpkg-packages usage"
+    return
+  fi
+
+  CONTENT_SHA="$(fn-apt-fetch-sha "$SOURCECODE_WORK_DIR")"
+  if [[ -z "$CONTENT_SHA" ]]; then
+    return
+  fi
+
+  local TMP_WORK_DIR=$(mktemp -d "/tmp/dokku-${DOKKU_PID}-${FUNCNAME[0]}.XXXXXX")
+  trap "rm -rf '$TMP_WORK_DIR' >/dev/null" RETURN
+  fn-apt-populate-work-dir "$SOURCECODE_WORK_DIR" "$TMP_WORK_DIR"
+
+  if [[ "$("$DOCKER_BIN" images --quiet "dokku/$APP:$CONTENT_SHA" 2>/dev/null)" != "" ]]; then
+    dokku_log_info1 "Compatible extended app image found, skipping system package installation"
+    fn-clean-extended-app-images "$APP" "dokku/$APP:$CONTENT_SHA"
+    return
+  fi
+
+  dokku_log_info1 "Creating extended app image with custom system packages"
+  pushd "$TMP_WORK_DIR" >/dev/null
+  CID=$(tar -c . | "$DOCKER_BIN" run "${DOCKER_RUN_LABEL_ARGS[@]}" $DOKKU_GLOBAL_RUN_ARGS -i -a stdin "$DOKKU_IMAGE" /bin/bash -c "mkdir -p /tmp/apt && tar -xC /tmp/apt")
+  popd >/dev/null
+  if test "$("$DOCKER_BIN" wait "$CID")" -ne 0; then
+    dokku_log_warn "Failure extracting apt files"
+    return 1
+  fi
+
+  DOCKER_COMMIT_LABEL_ARGS=("--change" "LABEL org.label-schema.schema-version=1.0" "--change" "LABEL org.label-schema.vendor=dokku" "--change" "LABEL com.dokku.app-name=$APP" "--change" "LABEL $DOKKU_CONTAINER_LABEL=")
+  "$DOCKER_BIN" commit "${DOCKER_COMMIT_LABEL_ARGS[@]}" "$CID" "$IMAGE:apt" >/dev/null
+  "$DOCKER_BIN" rm "$CID" &>/dev/null || true
+
+  COMMAND="$(fn-apt-command "$APP" "$DOKKU_IMAGE" "/tmp/apt")"
+  DOCKER_RUN_LABEL_ARGS="--label=com.dokku.app-name=$APP"
+  CID=$("$DOCKER_BIN" run "${DOCKER_RUN_LABEL_ARGS[@]}" $DOKKU_GLOBAL_RUN_ARGS -d "$IMAGE:apt" /bin/bash -e -c "$COMMAND")
+
+  "$DOCKER_BIN" attach "$CID"
+  if test "$("$DOCKER_BIN" wait "$CID")" -ne 0; then
+    dokku_log_warn "Failure installing system packages"
+    return 1
+  fi
+
+  DOCKER_COMMIT_LABEL_ARGS=("--change" "LABEL org.label-schema.schema-version=1.0" "--change" "LABEL org.label-schema.vendor=dokku" "--change" "LABEL com.dokku.app-name=sha-$APP" "--change" "LABEL $DOKKU_CONTAINER_LABEL=")
+  "$DOCKER_BIN" commit "${DOCKER_COMMIT_LABEL_ARGS[@]}" "$CID" "dokku/$APP:$CONTENT_SHA" >/dev/null
+  "$DOCKER_BIN" rm "$CID" &>/dev/null || true
+  "$DOCKER_BIN" rmi "$IMAGE:apt" &>/dev/null || true
+  fn-clean-extended-app-images "$APP" "dokku/$APP:$CONTENT_SHA"
+}
+
+hook-apt-builder-create-dokku-image "$@"
diff --git a/builder-dokku-image b/builder-dokku-image
new file mode 100755
index 0000000..c5d6328
--- /dev/null
+++ b/builder-dokku-image
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+export DOCKER_BIN=${DOCKER_BIN:="docker"}
+source "$PLUGIN_AVAILABLE_PATH/apt/internal-functions"
+
+hook-apt-builder-dokku-image() {
+  declare BUILDER_TYPE="$1" APP="$2" SOURCECODE_WORK_DIR="$3"
+  local IMAGE="dokku/$APP"
+  local CONTENT_SHA
+
+  if [[ -f "$SOURCECODE_WORK_DIR/dpkg-packages" ]]; then
+    return
+  fi
+
+  CONTENT_SHA="$(fn-apt-fetch-sha "$SOURCECODE_WORK_DIR")"
+  if [[ -z "$CONTENT_SHA" ]]; then
+    return
+  fi
+
+  if [[ "$("$DOCKER_BIN" images --quiet "$IMAGE:$CONTENT_SHA" 2>/dev/null)" != "" ]]; then
+    echo "$IMAGE:$CONTENT_SHA"
+    return
+  fi
+}
+
+hook-apt-builder-dokku-image "$@"
diff --git a/internal-functions b/internal-functions
new file mode 100755
index 0000000..c32e12b
--- /dev/null
+++ b/internal-functions
@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+export DOCKER_BIN=${DOCKER_BIN:="docker"}
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+
+fn-clean-extended-app-images() {
+  declare APP="$1" IMAGE="$2"
+  local images
+
+  # remove dangling extended app images
+  "$DOCKER_BIN" rmi $("$DOCKER_BIN" images --format 'dangling=true' --format "label=com.dokku.app-name=sha-$APP" --quiet) &>/dev/null || true
+
+  images="$("$DOCKER_BIN" images --filter "label=com.dokku.app-name=sha-$APP" --quiet)"
+  for image in $images; do
+    if [[ "$("$DOCKER_BIN" inspect --format '{{(index .RepoTags 0)}}' "$image" 2>/dev/null)" != "$IMAGE" ]]; then
+      "$DOCKER_BIN" rmi "$image" &>/dev/null || true
+    fi
+  done
+}
+
+fn-apt-fetch-sha() {
+  declare SOURCECODE_WORK_DIR="$1"
+  local APT_FILES CONTENT INJECT_PACKAGES file
+
+  if [[ -f "$SOURCECODE_WORK_DIR/dpkg-packages" ]]; then
+    return
+  fi
+
+  APT_FILES=('apt-env' 'apt-preferences' 'apt-sources-list' 'apt-repositories' 'apt-debconf' 'apt-packages')
+  for file in "${APT_FILES[@]}"; do
+    if [[ -f "$SOURCECODE_WORK_DIR/$file" ]]; then
+      INJECT_PACKAGES=true
+      local file_contents=$(<$SOURCECODE_WORK_DIR/$file)
+      CONTENT="${CONTENT}\n${file}\n${file_contents}"
+    fi
+  done
+
+  if [[ "$INJECT_PACKAGES" != "true" ]]; then
+    return
+  fi
+
+  echo -n "$(<$PLUGIN_AVAILABLE_PATH/apt/plugin.toml)$CONTENT" | sha256sum | cut -d " " -f 1
+}
+
+fn-apt-populate-work-dir() {
+  declare SOURCECODE_WORK_DIR="$1" TMP_WORK_DIR="$2"
+  local APT_FILES file
+
+  APT_FILES=('apt-env' 'apt-preferences' 'apt-sources-list' 'apt-repositories' 'apt-debconf' 'apt-packages')
+  for file in "${APT_FILES[@]}"; do
+    if [[ -f "$SOURCECODE_WORK_DIR/$file" ]]; then
+      cp "$SOURCECODE_WORK_DIR/$file" "$TMP_WORK_DIR/$file"
+    fi
+  done
+}
+
+fn-apt-command() {
+  declare APP="$1" DOKKU_IMAGE="$2" DIR="$3"
+  cat <<EOF
+# $APP $DOKKU_IMAGE
+sleep 2
+export DEBIAN_FRONTEND=noninteractive
+if [ -f $DIR/apt-env ]; then
+    echo "-----> Sourcing apt env"
+    source $DIR/apt-env
+fi
+if [ -d $DIR/apt-preferences ]; then
+    echo "-----> Injecting apt preferences"
+    mv -v $DIR/apt-preferences /etc/apt/preferences.d/90customizations
+fi
+if [ -f $DIR/apt-sources-list ]; then
+    echo "-----> Using customized sources.list"
+    mv -v $DIR/apt-sources-list /etc/apt/sources.list
+fi
+if [ -f $DIR/apt-repositories ]; then
+    echo "-----> Updating package list"
+    apt-get update >/dev/null
+    echo "-----> Installing required apt transport packages"
+    apt-get install -y software-properties-common apt-transport-https
+    echo "-----> Installing custom apt repositories"
+    cat "$DIR/apt-repositories" | while read repository; do
+        if [ -n "\$repository" ]; then
+            add-apt-repository -y "\$repository"
+        fi
+    done
+fi
+if [ -f $DIR/apt-debconf ]; then
+    cat "$DIR/apt-debconf" | while read conf; do
+        if [ -n "\$conf" ]; then
+            echo \$conf | debconf-set-selections
+        fi
+    done
+fi
+if [ -f $DIR/apt-packages ]; then
+    PACKAGES=\$(cat "$DIR/apt-packages" | tr "\\n" " ")
+    echo "-----> Updating package list"
+    apt-get update >/dev/null
+    echo "-----> Injecting packages: \$PACKAGES"
+    apt-get install -y \$PACKAGES
+fi
+if [ -d $DIR/dpkg-packages ]; then
+    for pkg in $DIR/dpkg-packages/*.deb; do
+        echo "-----> Injecting package: \$pkg"
+        dpkg -i \$pkg
+    done
+fi
+rm -rf /tmp/apt
+sleep 1 # wait so that docker run has not exited before docker attach
+EOF
+}
diff --git a/pre-build-buildpack b/pre-build-buildpack
index 81eef6a..65748ec 100755
--- a/pre-build-buildpack
+++ b/pre-build-buildpack
@@ -3,122 +3,38 @@ set -eo pipefail
 [[ $DOKKU_TRACE ]] && set -x
 export DOCKER_BIN=${DOCKER_BIN:="docker"}
 source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
-
-fn-clean-extended-app-images() {
-  declare APP="$1" IMAGE="$2"
-  local images
-
-  # remove dangling extended app images
-  "$DOCKER_BIN" rmi $("$DOCKER_BIN" images --format 'dangling=true' --format "label=com.dokku.app-name=sha-$APP" --quiet) &>/dev/null || true
-
-  images="$("$DOCKER_BIN" images --filter "label=com.dokku.app-name=sha-$APP" --quiet)"
-  for image in $images; do
-    if [[ "$("$DOCKER_BIN" inspect --format '{{(index .RepoTags 0)}}' "$image" 2>/dev/null)" != "$IMAGE" ]]; then
-      "$DOCKER_BIN" rmi "$image" &>/dev/null || true
-    fi
-  done
-}
+source "$PLUGIN_AVAILABLE_PATH/apt/internal-functions"
 
 hook-apt-pre-build-buildpack() {
   declare APP="$1" SOURCECODE_WORK_DIR="$2"
   local IMAGE="dokku/$APP" DIR=/app
-  local COMMAND CONTENT CONTENT_SHA INJECT_PACKAGES
+  local CID COMMAND DOCKER_COMMIT_LABEL_ARGS
 
   if [[ -n "$SOURCECODE_WORK_DIR" ]]; then
     pushd "$SOURCECODE_WORK_DIR" >/dev/null
   fi
 
-  local APT_FILES=('apt-env' 'apt-preferences' 'apt-sources-list' 'apt-repositories' 'apt-debconf' 'apt-packages' 'dpkg-packages')
-  for file in "${APT_FILES[@]}"; do
-    if [[ -f "$file" ]]; then
-      INJECT_PACKAGES=true
-      local file_contents=$(<$file)
-      CONTENT="${CONTENT}\n${file}\n${file_contents}"
-      if [[ "$file" == "dpkg-packages" ]]; then
-        CONTENT="${CONTENT}$(date +%s)"
-      fi
-    fi
-  done
+  if [[ ! -f "dpkg-packages" ]]; then
+    return
+  fi
 
   if [[ -n "$SOURCECODE_WORK_DIR" ]]; then
     popd >/dev/null
   fi
 
-  if [[ "$INJECT_PACKAGES" != "true" ]]; then
-    return
-  fi
-
-  COMMAND=$(
-    cat <<EOF
-# $APP $IMAGE
-sleep 2
-export DEBIAN_FRONTEND=noninteractive
-if [ -f $DIR/apt-env ]; then
-    echo "-----> Sourcing apt env"
-    source $DIR/apt-env
-fi
-if [ -d $DIR/apt-preferences ]; then
-    echo "-----> Injecting apt preferences"
-    mv -v $DIR/apt-preferences /etc/apt/preferences.d/90customizations
-fi
-if [ -f $DIR/apt-sources-list ]; then
-    echo "-----> Using customized sources.list"
-    mv -v $DIR/apt-sources-list /etc/apt/sources.list
-fi
-if [ -f $DIR/apt-repositories ]; then
-    echo "-----> Updating package list"
-    apt-get update >/dev/null
-    echo "-----> Installing required apt transport packages"
-    apt-get install -y software-properties-common apt-transport-https
-    echo "-----> Installing custom apt repositories"
-    cat "$DIR/apt-repositories" | while read repository; do
-        if [ -n "\$repository" ]; then
-            add-apt-repository -y "\$repository"
-        fi
-    done
-fi
-if [ -f $DIR/apt-debconf ]; then
-    cat "$DIR/apt-debconf" | while read conf; do
-        if [ -n "\$conf" ]; then
-            echo \$conf | debconf-set-selections
-        fi
-    done
-fi
-if [ -f $DIR/apt-packages ]; then
-    PACKAGES=\$(cat "$DIR/apt-packages" | tr "\\n" " ")
-    echo "-----> Updating package list"
-    apt-get update >/dev/null
-    echo "-----> Injecting packages: \$PACKAGES"
-    apt-get install -y \$PACKAGES
-fi
-if [ -d $DIR/dpkg-packages ]; then
-    for pkg in $DIR/dpkg-packages/*.deb; do
-        echo "-----> Injecting package: \$pkg"
-        dpkg -i \$pkg
-    done
-fi
-sleep 1 # wait so that docker run has not exited before docker attach
-EOF
-  )
+  dokku_log_info1 "Creating extended app image with custom system packages"
+  COMMAND="$(fn-apt-command "$APP" "$IMAGE" "$DIR")"
+  CID=$(docker run -d "$IMAGE" /bin/bash -e -c "$COMMAND")
 
-  CONTENT_SHA="$(echo -n "$CONTENT" | sha256sum | cut -d " " -f 1)"
-  if [[ "$("$DOCKER_BIN" images --quiet "dokku/$APP:$CONTENT_SHA" 2>/dev/null)" != "" ]]; then
-    dokku_log_info1 "Compatible extended app image found, skipping system package installation"
-    "$DOCKER_BIN" tag "dokku/$APP:$CONTENT_SHA" "$IMAGE"
-    fn-clean-extended-app-images "$APP" "dokku/$APP:$CONTENT_SHA"
-    return
+  "$DOCKER_BIN" attach "$CID"
+  if test "$("$DOCKER_BIN" wait "$CID")" -ne 0; then
+    dokku_log_warn "Failure installing system packages"
+    return 1
   fi
 
-  dokku_log_info1 "Extending app image with custom system packages"
-  CID=$("$DOCKER_BIN" run -d "$IMAGE" /bin/bash -e -c "$COMMAND")
-  local DOCKER_COMMIT_LABEL_ARGS=("--change" "LABEL org.label-schema.schema-version=1.0" "--change" "LABEL org.label-schema.vendor=dokku" "--change" "LABEL com.dokku.app-name=sha-$APP" "--change" "LABEL $DOKKU_CONTAINER_LABEL=")
-
-  "$DOCKER_BIN" attach "$CID"
-  test "$("$DOCKER_BIN" wait "$CID")" -eq 0
+  DOCKER_COMMIT_LABEL_ARGS=("--change" "LABEL org.label-schema.schema-version=1.0" "--change" "LABEL org.label-schema.vendor=dokku" "--change" "LABEL com.dokku.app-name=$APP" "--change" "LABEL $DOKKU_CONTAINER_LABEL=")
   "$DOCKER_BIN" commit "${DOCKER_COMMIT_LABEL_ARGS[@]}" "$CID" "$IMAGE" >/dev/null
   "$DOCKER_BIN" rm "$CID" &>/dev/null || true
-  "$DOCKER_BIN" tag "$IMAGE" "dokku/$APP:$CONTENT_SHA"
-  fn-clean-extended-app-images "$APP" "dokku/$APP:$CONTENT_SHA"
 }
 
 hook-apt-pre-build-buildpack "$@"