using SSH_AUTH_SOCK (ssh agent forwarding) to pull upm private repos

action/Dockerfile

@@ -14,4 +14,7 @@ ADD steps /steps
 RUN chmod -R +x /steps
 ADD entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
+
+RUN apt-get update && apt-get install -y openssh-client
+
 ENTRYPOINT ["/entrypoint.sh"]

src/index.js

@@ -4,7 +4,7 @@ import { Action, Docker, Input, ImageTag, Output, ResultsCheck } from './model';
 async function action() {
   Action.checkCompatibility();
 
-  const { dockerfile, workspace, actionFolder } = Action;
+  const { dockerfile, workspace, actionFolder, sshAgent } = Action;
   const {
     unityVersion,
     customImage,
@@ -32,6 +32,7 @@ async function action() {
       useHostNetwork,
       customParameters,
       githubToken,
+      sshAgent,
     });
   } finally {
     // Set output

src/model/action.js

@@ -37,6 +37,10 @@ class Action {
     return process.env.GITHUB_WORKSPACE;
   }
 
+  static get sshAgent() {
+    return process.env.SSH_AUTH_SOCK;
+  }
+
   static checkCompatibility() {
     const currentPlatform = process.platform;
     if (!Action.supportedPlatforms.includes(currentPlatform)) {

src/model/docker.js

@@ -27,6 +27,7 @@ class Docker {
       useHostNetwork,
       customParameters,
       githubToken,
+      sshAgent,
     } = parameters;
 
     const command = `docker run \
@@ -42,7 +43,6 @@ class Docker {
         --env TEST_MODE="${testMode}" \
         --env ARTIFACTS_PATH="${artifactsPath}" \
         --env CUSTOM_PARAMETERS="${customParameters}" \
-        --env HOME=/github/home \
         --env GITHUB_REF \
         --env GITHUB_SHA \
         --env GITHUB_REPOSITORY \
@@ -58,10 +58,13 @@ class Docker {
         --env RUNNER_TOOL_CACHE \
         --env RUNNER_TEMP \
         --env RUNNER_WORKSPACE \
+        --env SSH_AUTH_SOCK=/ssh-agent \
         --volume "/var/run/docker.sock":"/var/run/docker.sock" \
-        --volume "/home/runner/work/_temp/_github_home":"/github/home" \
+        --volume "/home/runner/work/_temp/_github_home":"/root" \
         --volume "/home/runner/work/_temp/_github_workflow":"/github/workflow" \
         --volume "${workspace}":"/github/workspace" \
+        --volume "${sshAgent}":"/ssh-agent" \
+        --volume /home/runner/.ssh/known_hosts:/root/.ssh/known_hosts:ro \
         ${useHostNetwork ? '--net=host' : ''} \
         ${githubToken ? '--env USE_EXIT_CODE=false' : '--env USE_EXIT_CODE=true'} \
         ${image}`;