feat: multi platform support

- use build platform argument
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

bitcoind/Dockerfile

@@ -1,5 +1,8 @@
 # Build stage for Bitcoin Core
-FROM alpine as bitcoin-core
+FROM --platform=${TARGETPLATFORM:-${BUILDPLATFORM}} alpine:3.18 as bitcoin-core
+
+ARG TARGETPLATFORM
+
 
 RUN sed -i 's/http\:\/\/dl-cdn.alpinelinux.org/https\:\/\/alpine.global.ssl.fastly.net/g' /etc/apk/repositories
 RUN apk add \
@@ -71,7 +74,7 @@ RUN ./configure LDFLAGS=-L`ls -d /opt/db*`/lib/ CPPFLAGS=-I`ls -d /opt/db*`/incl
     --with-libs \
     --with-sqlite=yes \
     --with-daemon
-RUN make -j`nproc`
+RUN make -j $(nproc)
 RUN make install
 RUN strip ${BITCOIN_PREFIX}/bin/bitcoin-cli
 RUN strip ${BITCOIN_PREFIX}/bin/bitcoin-tx
@@ -79,8 +82,8 @@ RUN strip ${BITCOIN_PREFIX}/bin/bitcoind
 RUN strip ${BITCOIN_PREFIX}/lib/libbitcoinconsensus.a
 RUN strip ${BITCOIN_PREFIX}/lib/libbitcoinconsensus.so.0.0.0
 
-# Build stage for compiled artifacts
-FROM alpine
+# Runtime binaries and setup stage
+FROM --platform=${TARGETPLATFORM:-${BUILDPLATFORM}} alpine:3.18 as runner
 
 ARG UID=100
 ARG GID=101
@@ -100,8 +103,8 @@ RUN apk --no-cache add \
   libzmq
 
 ENV BITCOIN_DATA=/home/bitcoin/.bitcoin
-ENV BITCOIN_VERSION=23.0
-ENV BITCOIN_PREFIX=/opt/bitcoin-${BITCOIN_VERSION}
+ARG BITCOIN_VERSION=23.0
+ARG BITCOIN_PREFIX=/opt/bitcoin-${BITCOIN_VERSION}
 
 COPY --from=bitcoin-core ${BITCOIN_PREFIX}/bin/bitcoin-cli /usr/bin/bitcoin-cli
 COPY --from=bitcoin-core ${BITCOIN_PREFIX}/bin/bitcoin-tx /usr/bin/bitcoin-tx
@@ -115,7 +118,7 @@ COPY assets/bitcoin.conf /bitcoin.conf
 COPY bitcoind/healthcheck.sh /healthcheck.sh
 RUN chmod +x /healthcheck.sh
 
-VOLUME ["/home/bitcoin/.bitcoin"]
+VOLUME ["${BITCOIN_DATA}"]
 
 EXPOSE 8332 8333 18332 18333 18444
 
@@ -124,7 +127,7 @@ RUN chown -R bitcoin:bitcoin "${BITCOIN_DATA}"
 
 USER bitcoin
 
-ENTRYPOINT  ["/entrypoint.sh" ]
+ENTRYPOINT  ["/entrypoint.sh"]
 
 RUN bitcoind -version | grep "Bitcoin Core version v${BITCOIN_VERSION}"