docker: refactor and update docker image build

Makefile

@@ -10,7 +10,7 @@
 # with this name, it will be used.
 #
 # The convention here is tailscale-android-build-amd64-<date>
-DOCKER_IMAGE := tailscale-android-build-amd64-031325-1
+DOCKER_IMAGE := tailscale-android-build-amd64-041425-1
 export TS_USE_TOOLCHAIN=1
 
 # Auto-select an NDK from ANDROID_HOME (choose highest version available)
@@ -355,13 +355,12 @@ docker-remove-build-image: ## Removes the current docker build image
 docker-all: docker-build-image docker-run-build $(DOCKER_IMAGE)
 
 .PHONY: docker-shell
-docker-shell: ## Builds a docker image with the android build env and opens a shell
-	docker build -f docker/DockerFile.amd64-shell -t tailscale-android-shell-amd64 .
-	docker run --rm -v $(CURDIR):/build/tailscale-android -it tailscale-android-shell-amd64
+docker-shell: docker-build-image ## Builds a docker image with the android build env and opens a shell
+	docker run --rm -v $(CURDIR):/build/tailscale-android -it $(DOCKER_IMAGE) /bin/bash
 
 .PHONY: docker-remove-shell-image
 docker-remove-shell-image: ## Removes all docker shell image
-	docker rmi --force tailscale-android-shell-amd64
+	@echo "docker-remove-shell-image retained for backward compatibility, but is a no-op; docker-shell now uses build image"
 
 .PHONY: clean
 clean: ## Remove build artifacts. Does not purge docker build envs. Use dockerRemoveEnv for that.

docker/DockerFile.amd64-build

@@ -3,31 +3,30 @@
 
 FROM --platform=linux/amd64 eclipse-temurin:21
 
-# To enable running android tools such as aapt
-RUN apt-get update && apt-get -y upgrade
-RUN apt-get install -y libz1 libstdc++6 unzip zip
-# For Go:
-RUN apt-get -y --no-install-recommends install curl gcc
-RUN apt-get -y --no-install-recommends install ca-certificates libc6-dev git
-
-RUN apt-get -y install make
-
-RUN mkdir -p build
 ENV HOME /build
-
-# Make android sdk location, the later make step will populate it.
-RUN mkdir android-sdk
 ENV ANDROID_HOME $HOME/android-sdk
 ENV ANDROID_SDK_ROOT $ANDROID_HOME
 ENV PATH $PATH:$HOME/bin:$ANDROID_HOME/platform-tools
 
+RUN mkdir -p \
+    ${HOME} \
+    /android-sdk \
+    ${ANDROID_HOME} \
+    $HOME/tailscale-android
+
+# To enable running android tools such as aapt
+COPY scripts/docker-build-apt-get.sh /tmp
+RUN chmod 755 /tmp/docker-build-apt-get.sh && \
+    /tmp/docker-build-apt-get.sh && \
+    rm -f /tmp/docker-build-apt-get.sh
+
 # We need some version of Go new enough to support the "embed" package
 # to run "go run tailscale.com/cmd/printdep" to figure out which Tailscale Go
 # version we need later, but otherwise this toolchain isn't used:
-RUN curl -L https://go.dev/dl/go1.23.0.linux-amd64.tar.gz | tar -C /usr/local -zxv
-RUN ln -s /usr/local/go/bin/go /usr/bin
+RUN \
+    curl -L https://go.dev/dl/go1.24.1.linux-amd64.tar.gz | tar -C /usr/local -zxv && \
+    ln -s /usr/local/go/bin/go /usr/bin
 
-RUN mkdir -p $HOME/tailscale-android
 RUN git config --global --add safe.directory $HOME/tailscale-android
 WORKDIR $HOME/tailscale-android
 
@@ -37,10 +36,11 @@ COPY Makefile Makefile
 RUN make androidsdk
 
 # Preload Gradle
-COPY android/gradlew android/gradlew
+COPY android/gradlew android/build.gradle android
 COPY android/gradle android/gradle
-RUN ./android/gradlew
+
+RUN chmod 755 android/gradlew && \
+    ./android/gradlew
 
 # Build the android app, bump the playstore version code, and make the tv release
 CMD make clean && make release && make bump_version_code && make release-tv
-

scripts/docker-build-apt-get.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+#
+# Copyright (c) Tailscale Inc & AUTHORS
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# docker-build-apt-get.sh runs 'apt'-related commands inside
+# the environment that /builds the docker image/
+set -x
+set -e
+
+apt-get update
+apt-get -y upgrade
+
+apt-get -y install \
+        \
+	libstdc++6 \
+	libz1 \
+	make \
+	unzip \
+	zip \
+	\
+	# end of sort region
+
+apt-get -y --no-install-recommends install \
+    \
+    ca-certificates \
+    curl \
+    gcc \
+    git \
+    libc6-dev \
+    \
+    # end of sort region
+
+apt-get -y clean
+
+rm -rf \
+   /var/cache/debconf \
+   /var/lib/apt/lists \
+   /var/lib/apt/dpkg