refactor(docker): remove redundant cache directory setup

- Eliminate explicit creation and ownership setting for LWD and Zebra cache directories in Dockerfile.
- Introduce default values for cache directories in entrypoint script, allowing for environment variable overrides.

Author: gustavovalverde

docker/Dockerfile

@@ -122,15 +122,6 @@ COPY --from=tianon/gosu:bookworm /gosu /usr/local/bin/
 ENV ZEBRA_CONF_PATH="${HOME}/.config/zebrad.toml"
 COPY --chown=${UID}:${GID} ./docker/default-zebra-config.toml ${ZEBRA_CONF_PATH}
 
-ENV LWD_CACHE_DIR="${HOME}/.cache/lwd"
-RUN mkdir -p ${LWD_CACHE_DIR} && \
-    chown -R ${UID}:${GID} ${LWD_CACHE_DIR}
-
-# Use the same cache dir as in the production environment.
-ENV ZEBRA_CACHE_DIR="${HOME}/.cache/zebra"
-RUN mkdir -p ${ZEBRA_CACHE_DIR} && \
-    chown -R ${UID}:${GID} ${ZEBRA_CACHE_DIR}
-
 # As tests are run as the non-root user, we need to set the correct permissions
 # for the cargo home dir.
 RUN chown -R ${UID}:${GID} "${HOME}" && \
@@ -214,10 +205,6 @@ RUN chown -R ${UID}:${GID} ${HOME}
 ARG ZEBRA_CONF_PATH="${HOME}/.config/zebrad.toml"
 ENV ZEBRA_CONF_PATH=${ZEBRA_CONF_PATH}
 
-ARG ZEBRA_CACHE_DIR="${HOME}/.cache/zebra"
-ENV ZEBRA_CACHE_DIR=${ZEBRA_CACHE_DIR}
-RUN mkdir -p ${ZEBRA_CACHE_DIR} && chown -R ${UID}:${GID} ${ZEBRA_CACHE_DIR}
-
 # We're explicitly NOT using the USER directive here.
 # Instead, we run as root initially and use gosu in the entrypoint.sh
 # to step down to the non-privileged user. This allows us to change permissions

docker/entrypoint.sh

@@ -10,6 +10,15 @@
 
 set -eo pipefail
 
+
+# These are the default cached state directories for Zebra and lightwalletd.
+#
+# They are set to `${HOME}/.cache/zebra` and `${HOME}/.cache/lwd`
+# respectively, but can be overridden by setting the
+# `ZEBRA_CACHE_DIR` and `LWD_CACHE_DIR` environment variables.
+: "${ZEBRA_CACHE_DIR:=${HOME}/.cache/zebra}"
+: "${LWD_CACHE_DIR:=${HOME}/.cache/lwd}"
+
 # Exit early if `ZEBRA_CONF_PATH` does not point to a file.
 if [[ ! -f "${ZEBRA_CONF_PATH}" ]]; then
   echo "ERROR: No Zebra config file found at ZEBRA_CONF_PATH (${ZEBRA_CONF_PATH})."