cluster: reset handle index on close

It allows reopening a server after it has been closed.

Fixes: https://github.com/nodejs/node/issues/6693
PR-URL: https://github.com/nodejs/node/pull/6981
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ron Korving <ron@ronkorving.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/cluster.js

@@ -564,18 +564,18 @@ function workerInit() {
 
   // obj is a net#Server or a dgram#Socket object.
   cluster._getServer = function(obj, options, cb) {
-    const key = [ options.address,
+    const indexesKey = [ options.address,
-                options.port,
+                         options.port,
-                options.addressType,
+                         options.addressType,
-                options.fd ].join(':');
+                         options.fd ].join(':');
-    if (indexes[key] === undefined)
+    if (indexes[indexesKey] === undefined)
-      indexes[key] = 0;
+      indexes[indexesKey] = 0;
     else
-      indexes[key]++;
+      indexes[indexesKey]++;
 
     const message = util._extend({
       act: 'queryServer',
-      index: indexes[key],
+      index: indexes[indexesKey],
       data: null
     }, options);
 
@@ -585,9 +585,9 @@ function workerInit() {
       if (obj._setServerData) obj._setServerData(reply.data);
 
       if (handle)
-        shared(reply, handle, cb);  // Shared listen socket.
+        shared(reply, handle, indexesKey, cb);  // Shared listen socket.
       else
-        rr(reply, cb);              // Round-robin.
+        rr(reply, indexesKey, cb);              // Round-robin.
     });
     obj.once('listening', function() {
       cluster.worker.state = 'listening';
@@ -599,7 +599,7 @@ function workerInit() {
   };
 
   // Shared listen socket.
-  function shared(message, handle, cb) {
+  function shared(message, handle, indexesKey, cb) {
     var key = message.key;
     // Monkey-patch the close() method so we can keep track of when it's
     // closed. Avoids resource leaks when the handle is short-lived.
@@ -607,6 +607,7 @@ function workerInit() {
     handle.close = function() {
       send({ act: 'close', key: key });
       delete handles[key];
+      delete indexes[indexesKey];
       return close.apply(this, arguments);
     };
     assert(handles[key] === undefined);
@@ -615,7 +616,7 @@ function workerInit() {
   }
 
   // Round-robin. Master distributes handles across workers.
-  function rr(message, cb) {
+  function rr(message, indexesKey, cb) {
     if (message.errno)
       return cb(message.errno, null);
 
@@ -636,6 +637,7 @@ function workerInit() {
       if (key === undefined) return;
       send({ act: 'close', key: key });
       delete handles[key];
+      delete indexes[indexesKey];
       key = undefined;
     }
 

test/parallel/test-cluster-server-restart-none.js

@@ -0,0 +1,37 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cluster = require('cluster');
+
+cluster.schedulingPolicy = cluster.SCHED_NONE;
+
+if (cluster.isMaster) {
+  const worker1 = cluster.fork();
+  worker1.on('listening', common.mustCall(() => {
+    const worker2 = cluster.fork();
+    worker2.on('exit', (code, signal) => {
+      assert.strictEqual(code, 0, 'worker2 did not exit normally');
+      assert.strictEqual(signal, null, 'worker2 did not exit normally');
+      worker1.disconnect();
+    });
+  }));
+
+  worker1.on('exit', common.mustCall((code, signal) => {
+    assert.strictEqual(code, 0, 'worker1 did not exit normally');
+    assert.strictEqual(signal, null, 'worker1 did not exit normally');
+  }));
+} else {
+  const net = require('net');
+  const server = net.createServer();
+  server.listen(common.PORT, common.mustCall(() => {
+    if (cluster.worker.id === 2) {
+      server.close(() => {
+        server.listen(common.PORT, common.mustCall(() => {
+          server.close(() => {
+            process.disconnect();
+          });
+        }));
+      });
+    }
+  }));
+}

test/parallel/test-cluster-server-restart-rr.js

@@ -0,0 +1,37 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cluster = require('cluster');
+
+cluster.schedulingPolicy = cluster.SCHED_RR;
+
+if (cluster.isMaster) {
+  const worker1 = cluster.fork();
+  worker1.on('listening', common.mustCall(() => {
+    const worker2 = cluster.fork();
+    worker2.on('exit', (code, signal) => {
+      assert.strictEqual(code, 0, 'worker2 did not exit normally');
+      assert.strictEqual(signal, null, 'worker2 did not exit normally');
+      worker1.disconnect();
+    });
+  }));
+
+  worker1.on('exit', common.mustCall((code, signal) => {
+    assert.strictEqual(code, 0, 'worker1 did not exit normally');
+    assert.strictEqual(signal, null, 'worker1 did not exit normally');
+  }));
+} else {
+  const net = require('net');
+  const server = net.createServer();
+  server.listen(common.PORT, common.mustCall(() => {
+    if (cluster.worker.id === 2) {
+      server.close(() => {
+        server.listen(common.PORT, common.mustCall(() => {
+          server.close(() => {
+            process.disconnect();
+          });
+        }));
+      });
+    }
+  }));
+}