Use self update ready entrypoint (#99)

* Use self update ready entrypoint

* Add --once support for runsvc.sh

Run `cd runner; NAME=$DOCKER_USER/actions-runner TAG=dev make docker-build docker-push`,
`kubectl apply -f release/actions-runner-controller.yaml`,
then update the runner image(not the controller image) by updating e.g. `Runner.Spec.Image` to `$DOCKER_USER/actions-runner:$TAG`, for testing.

Co-authored-by: Yusuke Kuoka <ykuoka@gmail.com>

runner/patched/RunnerService.js

@@ -0,0 +1,91 @@
+#!/usr/bin/env node
+// Copyright (c) GitHub. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+var childProcess = require("child_process");
+var path = require("path")
+
+var supported = ['linux', 'darwin']
+
+if (supported.indexOf(process.platform) == -1) {
+    console.log('Unsupported platform: ' + process.platform);
+    console.log('Supported platforms are: ' + supported.toString());
+    process.exit(1);
+}
+
+var stopping = false;
+var listener = null;
+
+var runService = function() {
+    var listenerExePath = path.join(__dirname, '../bin/Runner.Listener');
+    var interactive = process.argv[2] === "interactive";
+
+    if(!stopping) {
+        try {
+            if (interactive) {
+                console.log('Starting Runner listener interactively');
+                listener = childProcess.spawn(listenerExePath, ['run'].concat(process.argv.slice(3)), { env: process.env });
+            } else {
+                console.log('Starting Runner listener with startup type: service');
+                listener = childProcess.spawn(listenerExePath, ['run', '--startuptype', 'service'].concat(process.argv.slice(2)), { env: process.env });
+            }
+
+            console.log('Started listener process');
+
+            listener.stdout.on('data', (data) => {
+                process.stdout.write(data.toString('utf8'));
+            });
+
+            listener.stderr.on('data', (data) => {
+                process.stdout.write(data.toString('utf8'));
+            });
+
+            listener.on('close', (code) => {
+                console.log(`Runner listener exited with error code ${code}`);
+
+                if (code === 0) {
+                    console.log('Runner listener exit with 0 return code, stop the service, no retry needed.');
+                    stopping = true;
+                } else if (code === 1) {
+                    console.log('Runner listener exit with terminated error, stop the service, no retry needed.');
+                    stopping = true;
+                } else if (code === 2) {
+                    console.log('Runner listener exit with retryable error, re-launch runner in 5 seconds.');
+                } else if (code === 3) {
+                    console.log('Runner listener exit because of updating, re-launch runner in 5 seconds.');
+                } else {
+                    console.log('Runner listener exit with undefined return code, re-launch runner in 5 seconds.');
+                }
+
+                if(!stopping) {
+                    setTimeout(runService, 5000);
+                }
+            });
+
+        } catch(ex) {
+            console.log(ex);
+        }
+    }
+}
+
+runService();
+console.log('Started running service');
+
+var gracefulShutdown = function(code) {
+    console.log('Shutting down runner listener');
+    stopping = true;
+    if (listener) {
+        console.log('Sending SIGINT to runner listener to stop');
+        listener.kill('SIGINT');
+
+        // TODO wait for 30 seconds and send a SIGKILL
+    }
+}
+
+process.on('SIGINT', () => {
+    gracefulShutdown(0);
+});
+
+process.on('SIGTERM', () => {
+    gracefulShutdown(0);
+});

runner/patched/runsvc.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+# convert SIGTERM signal to SIGINT
+# for more info on how to propagate SIGTERM to a child process see: http://veithen.github.io/2014/11/16/sigterm-propagation.html
+trap 'kill -INT $PID' TERM INT
+
+if [ -f ".path" ]; then
+    # configure
+    export PATH=`cat .path`
+    echo ".path=${PATH}"
+fi
+
+# insert anything to setup env when running as a service
+
+# run the host process which keep the listener alive
+./externals/node12/bin/node ./bin/RunnerService.js $* &
+PID=$!
+wait $PID
+trap - TERM INT
+wait $PID