Make bootstrap script compatible with both variants

Dockerfile

@@ -5,8 +5,6 @@ LABEL maintainer="github.google-sre-ebook@captnemo.in"
 
 ARG DEBIAN_FRONTEND="noninteractive"
 
-COPY . /src/
-
 WORKDIR /src
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
@@ -17,11 +15,17 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ruby-dev \
     wget \
     zlib1g-dev \
+    file \
     && gem install bundler --no-ri --no-rdoc \
-    && bundle install \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
+COPY . /src/
+
+RUN bundle install
+
+ENV NO_BUNDLE_INSTALL=true
+
 ENTRYPOINT ["/src/bootstrap.sh", "docker"]
 
 VOLUME ["/output"]

bootstrap.sh

@@ -29,10 +29,9 @@ wget \
     --recursive             \
     --domains=${IMGS_DOMAIN},landing.google.com ${TOC_URL}
 
-#
-MODE=${1:-}
+: "${NO_BUNDLE_INSTALL:=false}"
 
-if [ "$MODE" != "docker" ];then
+if [ "$NO_BUNDLE_INSTALL" != "true" ];then
     bundle install
 fi
 
@@ -61,10 +60,13 @@ pandoc --from=html --to=epub \
     complete.html
 popd
 
-for EXTENSION in mobi pdf; do
-    ebook-convert ${BOOK_FILE}.epub ${BOOK_FILE}.${EXTENSION}
-done
+if [[ command -v ebook-convert ]]; then
+    for EXTENSION in mobi pdf; do
+        ebook-convert ${BOOK_FILE}.epub ${BOOK_FILE}.${EXTENSION}
+    done
+fi
 
+# TODO: Replace this with a better check
 if [ "$1"=="docker" ]; then
     chown -v $(id -u):$(id -g) ${BOOK_FILE}.*
     mv -f ${BOOK_FILE}.* /output

epub.Dockerfile

@@ -2,7 +2,7 @@ FROM ruby:alpine
 
 LABEL maintainer="docker@captnemo.in"
 
-RUN apk add \
+RUN apk add --no-cache \
     build-base \
     linux-headers \
     wget \
@@ -22,6 +22,8 @@ RUN gem install bundler --no-ri --no-document \
 
 WORKDIR /src
 
-ENTRYPOINT ["/src/bootstrap.sh", "docker", "epub"]
+ENV NO_BUNDLE_INSTALL=true
+
+ENTRYPOINT ["/src/bootstrap.sh", "docker"]
 
 VOLUME ["/output"]