Optimize Dockerfile build

Use a multi-stage build to trim of ~250MB from the exported image.

Author: hholst80

Dockerfile

@@ -5,58 +5,82 @@
 
 ARG PYTHON_VERSION="3.10"
 
-FROM python:${PYTHON_VERSION}-alpine
-
-ARG CLI_VERSION
-
-# Metadata as defined at http://label-schema.org
-ARG BUILD_DATE
+#---------------------------------------------------------------------------------------------
 
-LABEL maintainer="Microsoft" \
-      org.label-schema.schema-version="1.0" \
-      org.label-schema.vendor="Microsoft" \
-      org.label-schema.name="Azure CLI" \
-      org.label-schema.version=$CLI_VERSION \
-      org.label-schema.license="MIT" \
-      org.label-schema.description="The Azure CLI is used for all Resource Manager deployments in Azure." \
-      org.label-schema.url="https://docs.microsoft.com/cli/azure/overview" \
-      org.label-schema.usage="https://docs.microsoft.com/cli/azure/install-az-cli2#docker" \
-      org.label-schema.build-date=$BUILD_DATE \
-      org.label-schema.vcs-url="https://github.com/Azure/azure-cli.git" \
-      org.label-schema.docker.cmd="docker run -v \${HOME}/.azure:/root/.azure -it mcr.microsoft.com/azure-cli:$CLI_VERSION"
+FROM python:${PYTHON_VERSION}-alpine AS common
 
 # bash gcc make openssl-dev libffi-dev musl-dev - dependencies required for CLI
 # openssh - included for ssh-keygen
 # ca-certificates
 
-# curl - required for installing jp
+# curl - required for installing jp, and also a useful tool
 # jq - we include jq as a useful tool
-# pip wheel - required for CLI packaging
-# jmespath-terminal - we include jpterm as a useful tool
 # libintl and icu-libs - required by azure devops artifact (az extension add --name azure-devops)
 
 # We don't use openssl (3.0) for now. We only install it so that users can use it.
 # Once cryptography is bumped to the latest version, openssl1.1-compat should be removed and openssl1.1-compat-dev
 # should be replaced by openssl-dev.
-RUN apk add --no-cache bash openssh ca-certificates jq curl openssl openssl1.1-compat perl git zip \
- && apk add --no-cache --virtual .build-deps gcc make openssl1.1-compat-dev libffi-dev musl-dev linux-headers \
- && apk add --no-cache libintl icu-libs libc6-compat \
- && apk add --no-cache bash-completion \
+
+RUN apk add --no-cache \
+    bash openssh ca-certificates jq curl openssl openssl1.1-compat perl git zip \
+    libintl icu-libs libc6-compat \
+    bash-completion \
  && update-ca-certificates
 
+#---------------------------------------------------------------------------------------------
+
+FROM common AS tools
+
 ARG JP_VERSION="0.1.3"
 
 RUN curl -L https://github.com/jmespath/jp/releases/download/${JP_VERSION}/jp-linux-amd64 -o /usr/local/bin/jp \
  && chmod +x /usr/local/bin/jp
 
+#---------------------------------------------------------------------------------------------
+
+FROM common AS builder
+
+# bash gcc make openssl-dev libffi-dev musl-dev - dependencies required for CLI
+
+RUN apk add --no-cache --virtual .build-deps gcc make openssl1.1-compat-dev libffi-dev musl-dev linux-headers
+
 WORKDIR azure-cli
 COPY . /azure-cli
 
 # 1. Build packages and store in tmp dir
 # 2. Install the cli and the other command modules that weren't included
-RUN ./scripts/install_full.sh \
- && cat /azure-cli/az.completion > ~/.bashrc \
- && runDeps="$( \
+RUN ./scripts/install_full.sh
+
+# Remove CLI source code from the final image and normalize line endings.
+RUN dos2unix az.completion /usr/local/bin/az
+
+#---------------------------------------------------------------------------------------------
+
+FROM common
+
+ARG CLI_VERSION
+
+# Metadata as defined at http://label-schema.org
+ARG BUILD_DATE
+
+LABEL maintainer="Microsoft" \
+      org.label-schema.schema-version="1.0" \
+      org.label-schema.vendor="Microsoft" \
+      org.label-schema.name="Azure CLI" \
+      org.label-schema.version=$CLI_VERSION \
+      org.label-schema.license="MIT" \
+      org.label-schema.description="The Azure CLI is used for all Resource Manager deployments in Azure." \
+      org.label-schema.url="https://docs.microsoft.com/cli/azure/overview" \
+      org.label-schema.usage="https://docs.microsoft.com/cli/azure/install-az-cli2#docker" \
+      org.label-schema.build-date=$BUILD_DATE \
+      org.label-schema.vcs-url="https://github.com/Azure/azure-cli.git" \
+      org.label-schema.docker.cmd="docker run -v \${HOME}/.azure:/root/.azure -it mcr.microsoft.com/azure-cli:$CLI_VERSION"
+
+COPY --from=builder /azure-cli/az.completion /root/.bashrc
+COPY --from=builder /usr/local /usr/local
+COPY --from=tools /usr/local/bin/jp /usr/local/bin/
+
+RUN runDeps="$( \
     scanelf --needed --nobanner --recursive /usr/local \
         | awk '{ gsub(/,/, "\nso:", $2); print "so:" $2 }' \
         | sort -u \
@@ -65,11 +89,5 @@ RUN ./scripts/install_full.sh \
     )" \
  && apk add --virtual .rundeps $runDeps
 
-WORKDIR /
-
-# Remove CLI source code from the final image and normalize line endings.
-RUN rm -rf ./azure-cli && \
-    dos2unix /root/.bashrc /usr/local/bin/az
-
 ENV AZ_INSTALLER=DOCKER
 CMD bash