Make a couple of changes to the Dockerfile

1. Update the base image from 8.2 -> 8.3
2. Remove the complicated build steps (used to optimize layer caching and build times) which is largely replaced by sccache
3. Combine a couple RUN commands together to shave off ~10MiB from the final image

Signed-off-by: Jacob Hull <jacob@planethull.com>

Dockerfile

@@ -15,38 +15,6 @@ ENV SCCACHE_REGION=${SCCACHE_REGION}
 # Create the directory for agent repo
 WORKDIR /opt/logdna-agent-v2
 
-# Only add dependency lists first for caching
-COPY Cargo.lock                     .
-COPY Cargo.toml                     .
-COPY bin/Cargo.toml                 bin/Cargo.toml
-COPY common/config-macro/Cargo.toml common/config-macro/
-COPY common/config/Cargo.toml       common/config/
-COPY common/fs/Cargo.toml           common/fs/
-COPY common/http/Cargo.toml         common/http/
-COPY common/journald/Cargo.toml     common/journald/
-COPY common/k8s/Cargo.toml          common/k8s/
-COPY common/metrics/Cargo.toml      common/metrics/
-COPY common/middleware/Cargo.toml   common/middleware/
-COPY common/source/Cargo.toml       common/source/
-
-# Create required scaffolding for dependencies
-SHELL ["/bin/bash", "-o", "pipefail", "-c"]
-RUN LIBDIRS=$(find . -name Cargo.toml -type f -mindepth 2 | sed 's/Cargo.toml//') \
-    && for LIBDIR in ${LIBDIRS}; do \
-        mkdir "${LIBDIR}/src" \
-        && touch "${LIBDIR}/src/lib.rs"; \
-    done \
-    && echo "fn main() {}" > bin/src/main.rs
-
-# Build cached dependencies
-RUN --mount=type=secret,id=aws,target=/root/.aws/credentials \
-    if [ -z "$SCCACHE_BUCKET" ]; then unset RUSTC_WRAPPER; fi; \
-    cargo build --release && sccache --show-stats
-
-# Delete all cached deps that are local libs
-RUN grep -aL "github.com" target/release/deps/* | xargs rm \
-  && rm target/release/deps/libconfig_macro*.so
-
 # Add the actual agent source files
 COPY . .
 
@@ -57,7 +25,7 @@ RUN --mount=type=secret,id=aws,target=/root/.aws/credentials \
     sccache --show-stats
 
 # Use Red Hat Universal Base Image Minimal as the final base image
-FROM registry.access.redhat.com/ubi8/ubi-minimal:8.2
+FROM registry.access.redhat.com/ubi8/ubi-minimal:8.3
 
 ARG REPO
 ARG BUILD_TIMESTAMP
@@ -82,17 +50,16 @@ ENV DEBIAN_FRONTEND=noninteractive
 ENV _RJEM_MALLOC_CONF="narenas:1,tcache:false,dirty_decay_ms:0,muzzy_decay_ms:0"
 ENV JEMALLOC_SYS_WITH_MALLOC_CONF="narenas:1,tcache:false,dirty_decay_ms:0,muzzy_decay_ms:0"
 
-RUN microdnf update -y \
-    && microdnf install ca-certificates libcap shadow-utils.x86_64 -y \
-    && rm -rf /var/cache/yum
-
 # Copy the agent binary from the build stage
 COPY --from=build /opt/logdna-agent-v2/target/release/logdna-agent /work/
 WORKDIR /work/
-RUN chmod -R 777 .
 
-RUN setcap "cap_dac_read_search+eip" /work/logdna-agent
-RUN groupadd -g 5000 logdna && \
-useradd -u 5000 -g logdna logdna
+RUN microdnf update -y \
+    && microdnf install ca-certificates libcap shadow-utils.x86_64 -y \
+    && rm -rf /var/cache/yum \
+    && chmod -R 777 . \
+    && setcap "cap_dac_read_search+eip" /work/logdna-agent \
+    && groupadd -g 5000 logdna \
+    && useradd -u 5000 -g logdna logdna
 
 CMD ["./logdna-agent"]