Update Dockerfile for multi-arch building

Dockerfile

@@ -1,7 +1,14 @@
-ARG base_image
+ARG base_image=cgr.dev/chainguard/wolfi-base
 ARG builder_image=concourse/golang-builder
 
-FROM ${builder_image} as builder
+ARG BUILDPLATFORM
+FROM --platform=${BUILDPLATFORM} ${builder_image} AS builder
+
+ARG TARGETOS
+ARG TARGETARCH
+ENV GOOS=$TARGETOS
+ENV GOARCH=$TARGETARCH
+
 WORKDIR /src
 COPY . .
 RUN go mod download
@@ -10,10 +17,27 @@ RUN set -e; for pkg in $(go list ./...); do \
 		go test -o "/tests/$(basename $pkg).test" -c $pkg; \
 	done
 
+FROM ${base_image} AS proxybuilder
+RUN apk --no-cache add \
+    git \
+    gcc \
+    make \
+    openssl-dev
+
+WORKDIR /root
+RUN git clone https://github.com/proxytunnel/proxytunnel.git && \
+    cd proxytunnel && \
+    make -j4 && \
+    install -c proxytunnel /usr/bin/proxytunnel && \
+    cd .. && \
+    rm -rf proxytunnel
+
 FROM ${base_image} AS resource
-USER root
-RUN apt update && apt upgrade -y -o Dpkg::Options::="--force-confdef"
-RUN apt update && apt install -y jq git make g++ libssl-dev openssh-client
+RUN apk --no-cache add \
+    bash \
+    jq \
+    git \
+    openssh-client
 RUN git config --global user.email "git@localhost"
 RUN git config --global user.name "git"
 
@@ -22,15 +46,10 @@ RUN chmod +x /opt/resource/*
 COPY --from=builder /assets /opt/go
 RUN chmod +x /opt/go/out
 
-WORKDIR /root
-RUN git clone https://github.com/proxytunnel/proxytunnel.git && \
-    cd proxytunnel && \
-    make -j4 && \
-    install -c proxytunnel /usr/bin/proxytunnel && \
-    cd .. && \
-    rm -rf proxytunnel
+COPY --from=proxybuilder /usr/bin/proxytunnel /usr/bin/
 
 FROM resource AS tests
+RUN apk --no-cache add git-daemon cmd:ssh-keygen
 COPY --from=builder /tests /go/resource-tests/
 RUN set -e; for test in /go/resource-tests/*.test; do \
 		$test; \
@@ -39,7 +58,7 @@ ADD test/ /opt/resource-tests
 RUN /opt/resource-tests/all.sh
 
 FROM resource AS integrationtests
-RUN apt update && apt install -y squid net-tools
+RUN apk --no-cache add squid net-tools
 ADD test/ /opt/resource-tests/test
 ADD integration-tests /opt/resource-tests/integration-tests
 RUN /opt/resource-tests/integration-tests/integration.sh

README.md

@@ -307,7 +307,7 @@ will stop the build.
 Run the tests with the following command:
 
 ```sh
-docker build -t pool-resource --target tests --build-arg base_image=paketobuildpacks/run-jammy-base:latest .
+docker build -t pool-resource --target tests .
 ```
 
 #### Note about the integration tests
@@ -329,7 +329,7 @@ contents to understand the directory structure expected by the integration tests
 Then run the tests:
 
 ```sh
-docker build -t pool-resource --build-arg base_image=concourse/golang-builder --target integrationtests .
+docker build -t pool-resource --target integrationtests .
 ```
 
 ### Contributing