refactor(linux): address code review comments

Also some cleanup.

resources/docker-images/android/Dockerfile

@@ -47,6 +47,9 @@ VOLUME /home/build/build
 WORKDIR /home/build/build
 
 # Pre-install gradle. This will put files in ~/.gradle which will speed up builds.
+# Note it would be safer to copy these files directly from our repo rather than
+# getting it over the Internet, but Docker doesn't allow us to copy files
+# from outside the current directory when building the image.
 RUN mkdir -p $HOME/tmp/gradle/wrapper && \
   # KMEA uses gradle-7.6.4-bin
   curl --location --output $HOME/tmp/gradle/wrapper/gradle-wrapper.jar https://raw.githubusercontent.com/keymanapp/keyman/master/android/KMEA/gradle/wrapper/gradle-wrapper.jar && \

resources/docker-images/base/Dockerfile

@@ -32,6 +32,7 @@ RUN echo "build ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
 RUN <<EOF cat > /usr/bin/bashwrapper
 #!/bin/bash
 export KEYMAN_USE_NVM=1
+export DOCKER_RUNNING=true
 EOF
 
 # Install NVM

resources/docker-images/build.sh

@@ -49,7 +49,9 @@ _add_build_args() {
 _convert_parameters_to_build_args() {
   build_args=()
   build_version=
-  local required_node_version="$(_print_expected_node_version)"
+  local required_node_version
+  # shellcheck disable=SC2034
+  required_node_version="$(_print_expected_node_version)"
 
   _add_build_args UBUNTU_VERSION               KEYMAN_DEFAULT_VERSION_UBUNTU_CONTAINER  ""
   _add_build_args JAVA_VERSION                 KEYMAN_VERSION_JAVA                      java
@@ -82,8 +84,9 @@ build_action() {
     OPTION_NO_CACHE="--no-cache"
   fi
 
+  # shellcheck disable=SC2164
   cd "${platform}"
-  # shellcheck disable=SC2248
+  # shellcheck disable=SC2248,SC2086
   docker build ${OPTION_NO_CACHE:-} --platform amd64 -t "keymanapp/keyman-${platform}-ci:${build_version}" "${build_args[@]}" .
   # If the user didn't specify particular versions we will additionaly create an image
   # with the tag 'default'.
@@ -91,7 +94,8 @@ build_action() {
     builder_echo debug "Setting default tag for ${platform}"
     docker build --platform amd64 -t "keymanapp/keyman-${platform}-ci:default" "${build_args[@]}" .
   fi
-  cd - || true
+  # shellcheck disable=SC2164,SC2103
+  cd -
   builder_echo success "Docker image 'keymanapp/keyman-${platform}-ci:${build_version}' built"
 }
 
@@ -99,7 +103,7 @@ test_action() {
   local platform=$1
 
   builder_echo debug "Testing image for ${platform}"
-  ./run.sh ${platform} -- ./build.sh configure,build,test:${platform}
+  ./run.sh "${platform}" -- ./build.sh configure,build,test:"${platform}"
 }
 
 if builder_has_action build; then

resources/docker-images/linux/run-tests.sh

@@ -1,6 +1,11 @@
 #!/usr/bin/env bash
 set -e
 
+if [[ -z "${DOCKER_RUNNING:-}" ]]; then
+  echo "This script is intended to be run inside a docker container."
+  exit 0
+fi
+
 # Start system dbus
 sudo dbus-daemon --system --fork
 

resources/docker-images/run.sh

@@ -21,37 +21,37 @@ builder_describe \
 builder_parse "$@"
 
 run_android() {
-  docker run -it --rm -v ${KEYMAN_ROOT}:/home/build/build \
-    -v ${KEYMAN_ROOT}/core/build/docker-core:/home/build/build/core/build \
+  docker run -it --rm -v "${KEYMAN_ROOT}":/home/build/build \
+    -v "${KEYMAN_ROOT}/core/build/docker-core":/home/build/build/core/build \
     keymanapp/keyman-android-ci:default \
     "${builder_extra_params[@]}"
 }
 
 run_core() {
-  docker run -it --rm -v ${KEYMAN_ROOT}:/home/build/build \
-    -v ${KEYMAN_ROOT}/core/build/docker-core:/home/build/build/core/build \
+  docker run -it --rm -v "${KEYMAN_ROOT}":/home/build/build \
+    -v "${KEYMAN_ROOT}/core/build/docker-core":/home/build/build/core/build \
     keymanapp/keyman-core-ci:default \
     "${builder_extra_params[@]}"
 }
 
 run_linux() {
-  mkdir -p ${KEYMAN_ROOT}/linux/build/docker-linux
-  docker run -it --privileged --rm -v ${KEYMAN_ROOT}:/home/build/build \
-    -v ${KEYMAN_ROOT}/core/build/docker-core:/home/build/build/core/build \
-    -v ${KEYMAN_ROOT}/linux/build/docker-linux:/home/build/build/linux/build \
+  mkdir -p "${KEYMAN_ROOT}/linux/build/docker-linux"
+  docker run -it --privileged --rm -v "${KEYMAN_ROOT}":/home/build/build \
+    -v "${KEYMAN_ROOT}/core/build/docker-core":/home/build/build/core/build \
+    -v "${KEYMAN_ROOT}/linux/build/docker-linux":/home/build/build/linux/build \
     -e DESTDIR=/tmp \
     keymanapp/keyman-linux-ci:default \
     "${builder_extra_params[@]}"
 }
 
 run_web() {
-  docker run -it --privileged --rm -v ${KEYMAN_ROOT}:/home/build/build \
-    -v ${KEYMAN_ROOT}/core/build/docker-core:/home/build/build/core/build \
+  docker run -it --privileged --rm -v "${KEYMAN_ROOT}":/home/build/build \
+    -v "${KEYMAN_ROOT}/core/build/docker-core":/home/build/build/core/build \
     keymanapp/keyman-web-ci:default \
     "${builder_extra_params[@]}"
 }
 
-mkdir -p ${KEYMAN_ROOT}/core/build/docker-core
+mkdir -p "${KEYMAN_ROOT}/core/build/docker-core"
 
 builder_run_action android  run_android
 builder_run_action core     run_core

resources/docker-images/web/run-tests.sh

@@ -1,4 +1,9 @@
 #!/usr/bin/env bash
+if [[ -z "${DOCKER_RUNNING:-}" ]]; then
+  echo "This script is intended to be run inside a docker container."
+  exit 0
+fi
+
 set -e
 echo "Starting Xvfb..."
 Xvfb -screen 0 1024x768x24 :33 &> /dev/null &