Only set proxy environment variables in proxy environments

The approach using /etc/profile.d/ to unset empty variables does not
work, because it is never executed in the devcontainer.

The proposed solution should be more robust, because now the variables
are never present, if not needed and the build will fail, if it is
broken. Files in /etc/bash_completion.d/ will be executed whenever a new
bash instance is spawned and should work as a /etc/profile.d/
replacement.

Author: lurtz

scripts/build.sh

@@ -1,6 +1,9 @@
 #!/usr/bin/env bash
 set -euxo pipefail
 
+SCRIPT_PATH=$(readlink -f "$0")
+SCRIPT_DIR=$(dirname -- "${SCRIPT_PATH}")
+
 if [[ "$#" -lt 1 || "$1" != "--arm64" && "$1" != "--amd64" ]]; then
     echo "Error: First parameter must be --arm64 or --amd64."
     exit 1
@@ -32,6 +35,9 @@ for LABEL in "${LABELS[@]}"; do
     IMAGES+=("--image-name \"ghcr.io/eclipse-score/devcontainer:${LABEL}-${ARCH}\"")
 done
 
+. "${SCRIPT_DIR}/functions.sh"
+set_dockerfile_name
+
 # Prepare devcontainer build command
 DEVCONTAINER_CALL="devcontainer build --workspace-folder src/s-core-devcontainer --cache-from ghcr.io/eclipse-score/devcontainer"
 

scripts/functions.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set_dockerfile_name() {
+    DEVCONTAINER_DOCKERFILE_NAME="Dockerfile"
+
+    # Check if proxies are configured in the environment
+    set +u
+    if [ -n "${HTTP_PROXY}${HTTPS_PROXY}${http_proxy}${https_proxy}${NO_PROXY}${no_proxy}" ]; then
+        DEVCONTAINER_DOCKERFILE_NAME="Dockerfile-with-proxy-vars"
+        echo "Proxy environment detected."
+    fi
+    set -u
+
+    export DEVCONTAINER_DOCKERFILE_NAME
+    echo "Using Dockerfile: ${DEVCONTAINER_DOCKERFILE_NAME}"
+}

scripts/test.sh

@@ -10,6 +10,9 @@ SCRIPT_DIR=$(dirname -- "${SCRIPT_PATH}")
 PROJECT_DIR=$(dirname -- "${SCRIPT_DIR}")
 ID_LABEL="test-container=${IMAGE}"
 
+. "${SCRIPT_DIR}/functions.sh"
+set_dockerfile_name
+
 devcontainer up \
   --id-label "${ID_LABEL}" \
   --workspace-folder "${PROJECT_DIR}/src/${IMAGE}/" \

src/s-core-devcontainer/.devcontainer/Dockerfile

@@ -1,25 +1,5 @@
 FROM buildpack-deps:noble-curl
 
-# Proxy arguments for build-time network access
-ARG HTTP_PROXY=""
-ARG HTTPS_PROXY=""
-ARG http_proxy=""
-ARG https_proxy=""
-ARG NO_PROXY=""
-ARG no_proxy=""
-
-# Set proxy environment variables for the build process
-ENV HTTP_PROXY=${HTTP_PROXY}
-ENV HTTPS_PROXY=${HTTPS_PROXY}
-ENV http_proxy=${http_proxy}
-ENV https_proxy=${https_proxy}
-ENV NO_PROXY=${NO_PROXY}
-ENV no_proxy=${no_proxy}
-
 LABEL dev.containers.features="common"
 
-# Unset proxy variables for all login shells
-COPY unset-proxy.sh /etc/profile.d/unset-proxy.sh
-RUN chmod +x /etc/profile.d/unset-proxy.sh
-
 RUN userdel -f -r ubuntu

src/s-core-devcontainer/.devcontainer/Dockerfile-with-proxy-vars

@@ -0,0 +1,24 @@
+FROM buildpack-deps:noble-curl
+
+# Proxy arguments for build-time network access
+ARG HTTP_PROXY=""
+ARG HTTPS_PROXY=""
+ARG http_proxy=""
+ARG https_proxy=""
+ARG NO_PROXY=""
+ARG no_proxy=""
+
+# Set proxy environment variables for the build process
+ENV HTTP_PROXY=${HTTP_PROXY}
+ENV HTTPS_PROXY=${HTTPS_PROXY}
+ENV http_proxy=${http_proxy}
+ENV https_proxy=${https_proxy}
+ENV NO_PROXY=${NO_PROXY}
+ENV no_proxy=${no_proxy}
+
+LABEL dev.containers.features="common"
+
+# Unset proxy variables for all login shells
+COPY unset-proxy.sh /etc/bash_completion.d/unset-proxy.sh
+
+RUN userdel -f -r ubuntu

src/s-core-devcontainer/.devcontainer/devcontainer.json

@@ -1,7 +1,7 @@
 {
     "build": {
         // Installs latest version from the Distribution
-        "dockerfile": "./Dockerfile",
+        "dockerfile": "./${localEnv:DEVCONTAINER_DOCKERFILE_NAME:Dockerfile}",
         "context": ".",
         "args": {
             "HTTP_PROXY": "${localEnv:HTTP_PROXY}",

src/s-core-devcontainer/.devcontainer/unset-proxy.sh

@@ -1,3 +1,4 @@
+#!/bin/bash
 # /etc/profile.d/unset-proxy.sh
 # Unset proxy variables for all login shells if they are empty
 for var in HTTP_PROXY HTTPS_PROXY http_proxy https_proxy NO_PROXY no_proxy; do

src/s-core-devcontainer/test-project/test.sh

@@ -4,7 +4,7 @@ set -euo pipefail
 SCRIPT_PATH=$(readlink -f "$0")
 SCRIPT_DIR=$(dirname -- "${SCRIPT_PATH}")
 
-source "test-utils.sh" vscode
+source "$SCRIPT_DIR/test-utils.sh" vscode
 
 # C++ tooling
 check "validate clangd is working and has the correct version" bash -c "clangd --version | grep '20.1.8'"
@@ -25,5 +25,14 @@ source /devcontainer/features/s-core-local/tests/test_default.sh
 # Tests from the local bazel feature
 source /devcontainer/features/bazel/tests/test_default.sh
 
+# Check that no environment variables are empty
+. /etc/bash_completion
+for var in $(compgen -e); do
+    if [[ "$var" == "LS_COLORS" ]]; then
+        continue
+    fi
+    check "validate environment variable $var is not empty" bash -c "[ -n \"\${$var}\" ]"
+done
+
 # Report result
 reportResults