♻️ Move version numbers to their individual build stage for better caching

Dockerfile

@@ -3,26 +3,19 @@ RUN apk add curl git
 ARG BUILDARCH TARGETARCH
 ENV BUILDARCH=$BUILDARCH \
     CGO_ENABLED=0 \
-    COMPOSE_VERSION=2.1.1 \
     GOARCH=$TARGETARCH \
-    HELM_VERSION=3.7.1 \
-    JID_VERSION=0.7.6 \
-    KUBECTL_VERSION=1.22.2 \
-    KUBELINTER_VERSION=0.2.5 \
-    KUBESEAL_VERSION=0.16.0 \
-    KUSTOMIZE_VERSION=4.4.1 \
-    REGCLIENT_VERSION=0.3.9 \
-    SHIP_VERSION=0.51.3 \
-    STERN_VERSION=1.20.1 \
-    TARGETARCH=$TARGETARCH \
-    TILT_VERSION=0.23.0
+    TARGETARCH=$TARGETARCH
 COPY helper-* /bin
 
+# https://github.com/docker/compose/releases
 FROM builder AS compose
+ENV COMPOSE_VERSION=2.1.1
 RUN helper-curl bin docker-compose \
     https://github.com/docker/compose/releases/download/v${COMPOSE_VERSION}/docker-compose-linux-@UARCH
 
+# https://github.com/helm/helm/releases
 FROM builder AS helm
+ENV HELM_VERSION=3.7.1
 RUN helper-curl tar "--strip-components=1 linux-@GOARCH/helm" \
     https://get.helm.sh/helm-v${HELM_VERSION}-linux-@GOARCH.tar.gz
 
@@ -33,55 +26,80 @@ WORKDIR httping
 RUN sed -i s/60/0/ utils.c
 RUN make install BINDIR=/usr/local/bin
 
+# https://github.com/simeji/jid/releases
 FROM builder AS jid
+ENV JID_VERSION=0.7.6
 RUN go install github.com/simeji/jid/cmd/jid@v$JID_VERSION
 RUN cp $(find bin -name jid) /usr/local/bin
 
+# https://github.com/derailed/k9s/releases
 FROM builder AS k9s
 RUN helper-curl tar k9s \
     https://github.com/derailed/k9s/releases/latest/download/k9s_Linux_@WTFARCH.tar.gz
 
+# https://github.com/kubernetes/kompose/releases
 FROM builder AS kompose
 RUN helper-curl bin kompose \
     https://github.com/kubernetes/kompose/releases/latest/download/kompose-linux-@GOARCH
 
+# https://github.com/kubernetes/kubernetes/releases
 FROM builder AS kubectl
+ENV KUBECTL_VERSION=1.22.3
 RUN helper-curl bin kubectl \
     https://storage.googleapis.com/kubernetes-release/release/v${KUBECTL_VERSION}/bin/linux/@GOARCH/kubectl 
 
+# https://github.com/stackrox/kube-linter/releases
 FROM builder AS kube-linter
+ENV KUBELINTER_VERSION=0.2.5
 RUN go install golang.stackrox.io/kube-linter/cmd/kube-linter@$KUBELINTER_VERSION
 RUN cp $(find bin -name kube-linter) /usr/local/bin
 
+# https://github.com/bitnami-labs/sealed-secrets/releases
 FROM builder AS kubeseal
+ENV KUBESEAL_VERSION=0.16.0
 RUN helper-curl bin kubeseal \
     https://github.com/bitnami-labs/sealed-secrets/releases/download/v$KUBESEAL_VERSION/kubeseal-@KSARCH
 
+# https://github.com/kubernetes-sigs/kustomize/releases
 FROM builder AS kustomize
+ENV KUSTOMIZE_VERSION=4.4.1
 RUN helper-curl tar kustomize \
     https://github.com/kubernetes-sigs/kustomize/releases/download/kustomize/v$KUSTOMIZE_VERSION/kustomize_v${KUSTOMIZE_VERSION}_linux_@GOARCH.tar.gz
 
+# https://github.com/derailed/popeye/releases
 FROM builder AS popeye
 RUN helper-curl tar popeye \
     https://github.com/derailed/popeye/releases/latest/download/popeye_Linux_@WTFARCH.tar.gz
 
+# https://github.com/regclient/regclient/releases
 FROM builder AS regctl
+ENV REGCLIENT_VERSION=0.3.9
 RUN helper-curl bin regctl \
     https://github.com/regclient/regclient/releases/download/v$REGCLIENT_VERSION/regctl-linux-@GOARCH
 
+# This tool is still used in the kustomize section, but we will probably
+# deprecate it eventually as we only use a tiny feature that doesn't seem
+# to be available anymore in more recent versions (or requires some work
+# to adapt). Also, it's not available on all platforms and doesn't compile.
 FROM builder AS ship
+ENV SHIP_VERSION=0.51.3
 RUN helper-curl tar ship \
     https://github.com/replicatedhq/ship/releases/download/v${SHIP_VERSION}/ship_${SHIP_VERSION}_linux_@GOARCH.tar.gz
 
+# https://github.com/GoogleContainerTools/skaffold/releases/tag/v1.34.0
 FROM builder AS skaffold
 RUN helper-curl bin skaffold \
     https://storage.googleapis.com/skaffold/releases/latest/skaffold-linux-@GOARCH
 
+# https://github.com/stern/stern/releases
 FROM builder AS stern
+ENV STERN_VERSION=1.20.1
 RUN helper-curl tar "--strip-components=1 stern_${STERN_VERSION}_linux_@GOARCH/stern" \
     https://github.com/stern/stern/releases/download/v${STERN_VERSION}/stern_${STERN_VERSION}_linux_@GOARCH.tar.gz
 
+# https://github.com/tilt-dev/tilt/releases/
 FROM builder AS tilt
+ENV TILT_VERSION=0.23.0
 RUN helper-curl tar tilt \
     https://github.com/tilt-dev/tilt/releases/download/v${TILT_VERSION}/tilt.${TILT_VERSION}.linux.@WTFARCH.tar.gz