Add bin/stop-test.js shutdown testing script:

This script launches rippled repeatedly and then issues a stop command
after a variable amount of time. This is to test the shutdown of the
application and catch errors.

bin/stop-test.js

@@ -0,0 +1,133 @@
+/* -------------------------------- REQUIRES -------------------------------- */
+
+var child = require("child_process");
+var assert = require("assert");
+
+/* --------------------------------- CONFIG --------------------------------- */
+
+if (process.argv[2] == null) {
+  [
+   'Usage: ',
+   '',
+   '  `node bin/stop-test.js i,j [rippled_path] [rippled_conf]`',
+   '',
+   '  Launch rippled and stop it after n seconds for all n in [i, j}',
+   '  For all even values of n launch rippled with `--fg`',
+   '  For values of n where n % 3 == 0 launch rippled with `--fg`\n',
+   'Examples: ',
+   '',
+   '  $ node bin/stop-test.js 5,10',
+   ('  $ node bin/stop-test.js 1,4 ' +
+      'build/clang.debug/rippled $HOME/.confs/rippled.cfg')
+   ]
+      .forEach(function(l){console.log(l)});
+
+  process.exit();
+} else {
+  var testRange = process.argv[2].split(',').map(Number);
+  var rippledPath = process.argv[3] || 'build/rippled'
+  var rippledConf = process.argv[4] || 'rippled.cfg'
+}
+
+var options = {
+  env: process.env,
+  stdio: 'ignore' // we could dump the child io when it fails abnormally
+};
+
+// default args
+var conf_args = ['--conf='+rippledConf];
+var start_args  = conf_args.concat([/*'--net'*/])
+var stop_args = conf_args.concat(['stop']);
+
+/* --------------------------------- HELPERS -------------------------------- */
+
+function start(args) {
+    return child.spawn(rippledPath, args, options);
+}
+function stop(rippled) { child.execFile(rippledPath, stop_args, options)}
+function secs_l8r(ms, f) {setTimeout(f, ms * 1000); }
+
+function show_results_and_exit(results) {
+  console.log(JSON.stringify(results, undefined, 2));
+  process.exit();
+}
+
+var timeTakes = function (range) {
+  function sumRange(n) {return (n+1) * n /2}
+  var ret = sumRange(range[1]);
+  if (range[0] > 1) {
+    ret = ret - sumRange(range[0] - 1)
+  }
+  var stopping = (range[1] - range[0]) * 0.5;
+  return ret + stopping;
+}
+
+/* ---------------------------------- TEST ---------------------------------- */
+
+console.log("Test will take ~%s seconds", timeTakes(testRange));
+
+(function oneTest(n /* seconds */, results) {
+  if (n >= testRange[1]) {
+    // show_results_and_exit(results);
+    console.log(JSON.stringify(results, undefined, 2));
+    oneTest(testRange[0], []);
+    return;
+  }
+
+  var args = start_args;
+  if (n % 2 == 0) {args = args.concat(['--fg'])}
+  if (n % 3 == 0) {args = args.concat(['--net'])}
+
+  var result = {args: args, alive_for: n};
+  results.push(result);
+
+  console.log("\nLaunching `%s` with `%s` for %d seconds",
+                rippledPath, JSON.stringify(args), n);
+
+  rippled = start(args);
+  console.log("Rippled pid: %d", rippled.pid);
+
+  // defaults
+  var b4StopSent = false;
+  var stopSent = false;
+  var stop_took = null;
+
+  rippled.once('exit', function(){
+    if (!stopSent && !b4StopSent) {
+      console.warn('\nRippled exited itself b4 stop issued');
+      process.exit();
+    };
+
+    // The io handles close AFTER exit, may have implications for
+    // `stdio:'inherit'` option to `child.spawn`.
+    rippled.once('close', function() {
+      result.stop_took = (+new Date() - stop_took) / 1000; // seconds
+      console.log("Stopping after %d seconds took %s seconds",
+                   n, result.stop_took);
+      oneTest(n+1, results);
+    });
+  });
+
+  secs_l8r(n, function(){
+    console.log("Stopping rippled after %d seconds", n);
+
+    // possible race here ?
+    // seems highly unlikely, but I was having issues at one point
+    b4StopSent=true;
+    stop_took = (+new Date());
+    // when does `exit` actually get sent?
+    stop();
+    stopSent=true;
+
+    // Sometimes we want to attach with a debugger.
+    if (process.env.ABORT_TESTS_ON_STALL != null) {
+      // We wait 30 seconds, and if it hasn't stopped, we abort the process
+      secs_l8r(30, function() {
+        if (result.stop_took == null) {
+          console.log("rippled has stalled");
+          process.exit();
+        };
+      });
+    }
+  })
+}(testRange[0], []));