Comment and optimize Dockerfile

Dockerfile

@@ -1,7 +1,13 @@
+# Use ubuntu:20.04 as base for builder stage image
 FROM ubuntu:20.04 as builder
 
+# Set Monero branch/tag to be used for monerod compilation
+ARG MONERO_BRANCH=release-v0.17
+
+# Added DEBIAN_FRONTEND=noninteractive to workaround tzdata prompt on installation
 ENV DEBIAN_FRONTEND="noninteractive"
 
+# Install dependencies for monerod and xmrblocks compilation
 RUN apt-get update && apt install -y --no-install-recommends \
     git \
     build-essential \
@@ -23,42 +29,65 @@ RUN apt-get update && apt install -y --no-install-recommends \
     libsodium-dev \
     libhidapi-dev \
     libhidapi-libusb0 \
+    && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
+# Set compilation environment variables
+ENV CFLAGS='-fPIC'
+ENV CXXFLAGS='-fPIC'
+ENV USE_SINGLE_BUILDDIR 1
+ENV BOOST_DEBUG         1
+
 WORKDIR /root
 
-RUN git clone --recursive -b release-v0.17 https://github.com/monero-project/monero.git \
+# Clone and compile monerod with all available threads
+ARG MONERO_BRANCH
+ARG NPROC
+RUN git clone --recursive --branch ${MONERO_BRANCH} https://github.com/monero-project/monero.git \
     && cd monero \
-    && USE_SINGLE_BUILDDIR=1 make
+    && test -z "$NPROC" && nproc > /nproc || echo -n "$NPROC" > /nproc && make -j"$(cat /nproc)"
 
+# Copy and cmake xmrblocks
 COPY . /root/onion-monero-blockchain-explorer/
 WORKDIR /root/onion-monero-blockchain-explorer/build
 RUN cmake ..
-RUN make
 
-# use ldd and awk to bundle up dynamic libraries for the final image
+# Compile xmrblocks with all available threads
+RUN test -z "$NPROC" && nproc > /nproc || echo -n "$NPROC" > /nproc && make -j"$(cat /nproc)"
+
+# Use ldd and awk to bundle up dynamic libraries for the final image
 RUN zip /lib.zip $(ldd xmrblocks | grep -E '/[^\ ]*' -o)
 
+# Use ubuntu:20.04 as base for final image
 FROM ubuntu:20.04
 
+# Added DEBIAN_FRONTEND=noninteractive to workaround tzdata prompt on installation
 ENV DEBIAN_FRONTEND="noninteractive"
+
+# Install unzip to handle bundled libs from builder stage
 RUN apt-get update && apt-get install -y --no-install-recommends \
     unzip \
+    && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
 COPY --from=builder /lib.zip .
 RUN unzip -o lib.zip && rm -rf lib.zip
 
+# Add user and setup directories for monerod and xmrblocks
 RUN useradd -ms /bin/bash monero \
     && mkdir -p /home/monero/.bitmonero \
     && chown -R monero:monero /home/monero/.bitmonero
 USER monero
-WORKDIR /home/monero
 
+# Switch to home directory and install newly built xmrblocks binary
+WORKDIR /home/monero
 COPY --chown=monero:monero --from=builder /root/onion-monero-blockchain-explorer/build/xmrblocks .
 COPY --chown=monero:monero --from=builder /root/onion-monero-blockchain-explorer/build/templates ./templates/
 
+# Expose volume used for lmdb access by xmrblocks
 VOLUME /home/monero/.bitmonero
+
+# Expose default explorer http port
 EXPOSE 8081
 
 ENTRYPOINT ["/bin/sh", "-c", "./xmrblocks"]