Merge pull request #22 from azuqua/kevin/develop

Kevin/develop

examples/gen_server/dlm/README.md

@@ -0,0 +1,45 @@
+DLM example
+===========
+
+A distributed lock manager `gen_server` implementation for reference, using the [Redlock algorithm](https://redis.io/topics/distlock). May be added into clusterluck as an optional feature if there's community interest.
+
+Example Usage
+-------------
+
+A simple example usage of this `gen_server` follows. For a more detailed integration test on a single node, refer to `test.js`. For a multi-node integration test, refer to `multi_test.js`. In this test, we try to lock the same resource with two different requesters.
+
+``` javascript
+const cl = require("../../index"),
+      os = require("os"),
+      assert = require("chai").assert;
+
+const nodeID = "name",
+      port = 7022,
+      host = os.hostname();
+
+const node = cl.createCluster(nodeID, host, port),
+      gossip = node.gossip(),
+      kernel = node.kernel();
+
+const DLMServer = require("./dlm");
+const dlm = new DLMServer(gossip, kernel, {
+  rquorum: 0.51,
+  wquorum: 0.51
+});
+
+// load node state
+node.load(() => {
+  // first start dlm, then start network kernel
+  dlm.start("locker");
+  node.start("cookie", "ring", () => {
+    console.log("Node %s listening on hostname %s, port %s", nodeID, host, port);
+    dlm.wlock("id", "holder", 30000, (err, nodes) => {
+      assert.notOk(err);
+      assert.isArray(nodes);
+      dlm.wlock("id", "holder", 30000, (err, wNodes) => {
+        assert.ok(err);
+      });
+    });
+  });
+});
+```