install ruby if not available

Author: patrickcrocker

src/gem/install.sh

@@ -1,27 +1,84 @@
 #!/usr/bin/env bash
 
-set -eu
-
 : ${GEM:=}
 gems=${GEM//,/ }
 
-if [ -z "${gems}" ]; then
-    echo "No RubyGems specified. Skip installation..."
-    exit 0
-fi
+USERNAME=${USERNAME:-${_REMOTE_USER:-"automatic"}}
+
+set -e
+
+export TMPDIR=$(mktemp -d /tmp/feature.XXXXXX)
+trap "rm -rf $TMPDIR" EXIT
+
+# Clean up
+rm -rf /var/lib/apt/lists/*
 
 if [ "$(id -u)" -ne 0 ]; then
     echo -e 'Script must be run as root. Use sudo, su, or add "USER root" to your Dockerfile before running this script.'
     exit 1
 fi
 
+architecture="$(dpkg --print-architecture)"
+if [ "${architecture}" != "amd64" ] && [ "${architecture}" != "arm64" ]; then
+    echo "(!) Architecture $architecture unsupported"
+    exit 1
+fi
+
+# Determine the appropriate non-root user
+if [ "${USERNAME}" = "auto" ] || [ "${USERNAME}" = "automatic" ]; then
+    USERNAME=""
+    POSSIBLE_USERS=("vscode" "node" "codespace" "$(awk -v val=1000 -F ":" '$3==val{print $1}' /etc/passwd)")
+    for CURRENT_USER in "${POSSIBLE_USERS[@]}"; do
+        if id -u "${CURRENT_USER}" >/dev/null 2>&1; then
+            USERNAME=${CURRENT_USER}
+            break
+        fi
+    done
+    if [ "${USERNAME}" = "" ]; then
+        USERNAME=root
+    fi
+elif [ "${USERNAME}" = "none" ] || ! id -u ${USERNAME} >/dev/null 2>&1; then
+    USERNAME=root
+fi
+
+apt_get_update() {
+    if [ "$(find /var/lib/apt/lists/* | wc -l)" = "0" ]; then
+        echo "Running apt-get update..."
+        apt-get update -y
+    fi
+}
+
+# Checks if packages are installed and installs them if not
+check_packages() {
+    if ! dpkg -s "$@" >/dev/null 2>&1; then
+        apt_get_update
+        apt-get -y install --no-install-recommends "$@"
+    fi
+}
+
 export DEBIAN_FRONTEND=noninteractive
 
+### BEGIN install
+
+if [ -z "${gems}" ]; then
+    echo "No RubyGems specified. Skip installation..."
+    exit 0
+fi
+
+check_packages ruby-full ca-certificates
+echo "Installing gems..."
+
 args=("$gems")
 [ -n "${VERSION:-}" ] && args+=(--version "${VERSION}")
 [ -n "${PRERELEASE:-}" ] && args+=(--prerelease)
 
-echo "Installing gems..."
 gem install "${args[@]}"
 
 echo "Done!"
+
+### END install
+
+# Clean up
+rm -rf /var/lib/apt/lists/*
+
+echo "Done!"

test/gem/test.sh

@@ -2,6 +2,9 @@
 
 set -e
 
+# This test can be run with the following command (from the root of this repo)
+# devcontainer features test --features gem --base-image mcr.microsoft.com/devcontainers/base:ubuntu .
+
 # Import 'check' command
 source dev-container-features-test-lib