.github/workflows/assets/linux.Dockerfile

@@ -1,43 +1,28 @@
 # The Arduino IDE Linux build workflow job runs in this container.
 # syntax=docker/dockerfile:1
 
-FROM ubuntu:18.04
-
-# See: https://unofficial-builds.nodejs.org/download/release/
-ARG node_version="18.17.1"
+# See: https://hub.docker.com/_/ubuntu/tags
+FROM ubuntu:18.10
 
+# This is required in order to use the Ubuntu package repositories for EOL Ubuntu versions:
+# https://help.ubuntu.com/community/EOLUpgrades#Update_sources.list
 RUN \
-  apt-get \
-    --yes \
-    update
+  sed \
+    --in-place \
+    --regexp-extended \
+    --expression='s/([a-z]{2}\.)?archive.ubuntu.com|security.ubuntu.com/old-releases.ubuntu.com/g' \
+    "/etc/apt/sources.list"
 
-# This is required to get add-apt-repository
 RUN \
   apt-get \
     --yes \
-    install \
-      "software-properties-common=0.96.24.32.22"
+    update
 
-# Install Git
-# The PPA is required to get a modern version of Git. The version in the Ubuntu 18.04 package repository is 2.17.1,
-# while action/checkout@v3 requires 2.18 or higher.
 RUN \
-  add-apt-repository \
-    --yes \
-    "ppa:git-core/ppa" && \
-  apt-get \
-    --yes \
-    update && \
-  \
   apt-get \
     --yes \
     install \
-      "git" && \
-  \
-  apt-get \
-    --yes \
-    purge \
-      "software-properties-common"
+      "git"
 
 # The repository path must be added to safe.directory, otherwise any Git operations on it would fail with a
 # "dubious ownership" error. actions/checkout configures this, but it is not applied to containers.
@@ -51,62 +36,28 @@ ENV \
 
 # Install Python
 # The Python installed by actions/setup-python has dependency on a higher version of glibc than available in the
-# ubuntu:18.04 container.
+# container.
 RUN \
   apt-get \
     --yes \
     install \
-      "python3.8-minimal=3.8.0-3ubuntu1~18.04.2" && \
-  \
-  ln \
-    --symbolic \
-    --force \
-    "$(which python3.8)" \
-    "/usr/bin/python3"
+      "python3.7-minimal=3.7.3-2~18.10"
 
 # Install Theia's package dependencies
 # These are pre-installed in the GitHub Actions hosted runner machines.
 RUN \
   apt-get \
     --yes \
     install \
-      "libsecret-1-dev=0.18.6-1" \
-      "libx11-dev=2:1.6.4-3ubuntu0.4" \
+      "libsecret-1-dev=0.18.6-3" \
+      "libx11-dev=2:1.6.7-1" \
       "libxkbfile-dev=1:1.0.9-2"
 
-# Install Node.js
-# It is necessary to use the "unofficial" linux-x64-glibc-217 build because the official Node.js 18.x is dynamically
-# linked against glibc 2.28, while Ubuntu 18.04 has glibc 2.27.
-ARG node_installation_path="/tmp/node-installation"
-ARG artifact_name="node-v${node_version}-linux-x64-glibc-217"
-RUN \
-  mkdir "$node_installation_path" && \
-  cd "$node_installation_path" && \
-  \
-  apt-get \
-    --yes \
-    install \
-      "wget=1.19.4-1ubuntu2.2" && \
-  \
-  archive_name="${artifact_name}.tar.xz" && \
-  wget \
-    "https://unofficial-builds.nodejs.org/download/release/v${node_version}/${archive_name}" && \
-  \
-  apt-get \
-    --yes \
-    purge \
-      "wget" && \
-  \
-  tar \
-    --file="$archive_name" \
-    --extract && \
-  rm "$archive_name"
-ENV PATH="${PATH}:${node_installation_path}/${artifact_name}/bin"
-
-# Install Yarn
-# Yarn is pre-installed in the GitHub Actions hosted runner machines.
+# Target python3 symlink to Python 3.7 installation. It would otherwise target version 3.6 due to the installation of
+# the `python3` package as a transitive dependency.
 RUN \
-  npm \
-    install \
-    --global \
-      "yarn@1.22.19"
+  ln \
+    --symbolic \
+    --force \
+    "$(which python3.7)" \
+    "/usr/bin/python3"