Make setup-node faster and more reliable

We have occasionally seen that setup-node actions failing due to intermittent connection failures between us and nodejs.org.

To alleviate the issue, we could cache our "most-widely-used" Node.js version inside the container image, enabling setup-node to skip access to nodejs.org.

This tries to implements that, in a way so that it becomes resilient to nodejs and tool-cache changes. Just keep updating NODE_VERSION defined in the dockerfile using dependabot or renovate- the rest of the change will just work regardless of the version you want.

Dockerfile.ubuntu20

@@ -65,9 +65,48 @@ RUN export RUNNER_ARCH=${TARGETARCH} \
     && rm -rf docker
 
 # some setup actions store cache into /opt/hostedtoolcache
+ENV RUNNER_TOOL_CACHE /opt/hostedtoolcache
+
 RUN mkdir /opt/hostedtoolcache \
     && chown runner:docker /opt/hostedtoolcache
 
+# We pre-install nodejs to reduce time of setup-node and improve its reliability.
+ENV NODE_VERSION 18.18.2
+
+RUN mkdir -p /opt/hostedtoolcache/node/${NODE_VERSION}/${TARGETARCH} && \
+    curl -s -L https://nodejs.org/dist/v${NODE_VERSION}/node-v${NODE_VERSION}-linux-${TARGETARCH}.tar.gz \
+    | tar xvzf - -C /opt/hostedtoolcache/node/${NODE_VERSION}/${TARGETARCH} \
+    && touch /opt/hostedtoolcache/node/${NODE_VERSION}/${TARGETARCH}.complete \
+    && chown -R runner:docker /opt/hostedtoolcache/node && \
+    ${RUNNER_TOOL_CACHE}/node/${NODE_VERSION}/arm64/node-v${NODE_VERSION}-linux-${TARGETARCH}/bin/node --version
+
+RUN export PATH=$PATH:/home/runner/externals/node20/bin ; export NODE_PATH=/home/runner/externals/node20/lib/node_modules ; \
+    npm install -g @actions/tool-cache && node <<EOF && npm uninstall -g @actions/tool-cache
+const tc = require('@actions/tool-cache');
+const allNodeVersions = tc.findAllVersions('node');
+const expected = ['${NODE_VERSION}'];
+if (expected[0] == '') {
+  console.log('Invalid NODE_VERSION: ' + expected[0]);
+  process.on("exit", function() {
+      process.exit(1);
+  });
+} else if (allNodeVersions.length != expected.length) {
+  console.log('Expected versions of node available: ' + expected);
+  console.log('Actual versions of node available: ' + allNodeVersions);
+  process.on("exit", function() {
+    process.exit(1);
+  });
+} else if (allNodeVersions[0] != expected[0]) {
+  console.log('Expected versions of node available: ' + expected);
+  console.log('Actual versions of node available: ' + allNodeVersions);
+  process.on("exit", function() {
+    process.exit(1);
+  });
+} else {
+  console.log('Versions of node available: ' + allNodeVersions);
+}
+EOF
+
 COPY entrypoint.sh /
 
 VOLUME /var/lib/docker