From ced0f36cbf7983853a9d7060694b9c58818e6d6b Mon Sep 17 00:00:00 2001
From: AJ ONeal <awesome@coolaj86.com>
Date: Sat, 25 Jul 2015 12:06:12 -0600
Subject: [PATCH] add README.md

---
 README.md | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 README.md

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..1bfeca7
--- /dev/null
+++ b/README.md
@@ -0,0 +1,115 @@
+memstore Cluster
+================
+
+A very simple in-memory object store for use with node cluster
+(or even completely and unrelated node processes).
+
+Node.js runs on a single core, which isn't very effective.
+
+You can run multiple Node.js instances to take advantage of multiple cores,
+but if you do that, you can't share memory between processes.
+
+This module will either run client-server style in environments that benefit from it
+(such as the Raspberry Pi 2 with 4 cores), or in-process for environments that don't
+(such as the Raspberry Pi B and B+).
+
+**Note**: Most people would probably prefer to just use Redis rather than
+wrap a dumb memstore as a service... but I am not most people.
+
+Also works with **level-session-store** (leveldb), **connect-session-knex** (SQLite3),
+**session-file-store** (fs), and any other embedded / in-process store.
+
+Usage
+=====
+
+The default behavior is to try to connect to a master and, if that fails, to become the master.
+
+However, if you are in fact using the `cluster` rather than spinning up random instances,
+you'll probably prefer to use this pattern:
+
+```js
+var cluster = require('cluster');
+var store = require('memstore-cluster');
+var numCores = require('os').cpus().length;
+
+var opts = {
+  sock: '/tmp/mydb.memstore.sock'
+
+  // If left 'null' or 'undefined' this defaults to a similar memstore
+  // with no special logic for 'cookie' or 'expires'
+, store: cluster.isMaster && new require('express-session/session/memory')()
+
+  // a good default to use for instances where you might want
+  // to cluster or to run standalone, but with the same API
+, serve: cluster.isMaster
+, connect: cluster.isWorker
+, standalone: (1 === numCores) // overrides serve and connect
+};
+
+memstore.create(opts).then(function (store) {
+  // same api as new sqlite3.Database(options.filename)
+
+  store.get(id, function (err, data) {
+    console.log(data);
+  });
+
+  // app.use(expressSession({ secret: 'keyboard cat', store: store }));
+});
+
+process.on('unhandledPromiseRejection', function (err) {
+  console.error('Unhandled Promise Rejection');
+  console.error(err);
+  console.error(err.stack);
+
+  throw err;
+});
+```
+
+If you wish to always use clustering, even on a single core system, see `test-cluster.js`.
+
+Likewise, if you wish to use standalone mode in a particular worker process see `test-standalone.js`.
+
+API
+===
+
+This is modeled after Express'
+[Session Store Implementation](https://github.com/expressjs/session#session-store-implementation)
+
+**Note**: These are only exposed if the underlying store supports them.
+
+CRUD methods
+------------
+
+* `store.set(id, data, fn)    => (error)`
+* `store.get(id, fn)          => (error, data)`
+* `store.touch(id, data, fn)  => (error)`
+* `store.destroy(id, fn)      => (error)`
+
+Helpers
+-------
+
+* `store.all(fn)              => (error, array)`
+* `store.clear(fn)            => (error)`
+* `store.length(fn)           => (error, length)`
+
+See <https://github.com/expressjs/session#session-store-implementation>@4.x for full details
+
+Standalone / Master Mode is in-process
+========================
+
+The `master` in the cluster (meaning `opts.serve = true`) will directly hold the `express-session/session/memory`
+memory store.
+
+Likewise, when only one process is being used (`opts.standalone = true`) the listener is
+not started and API is completely in-process.
+
+If you take a look at `wrapper.js` you'll see that it's a rather simple memory store instance.
+
+Security Warning
+================
+
+Note that any application on the system could connect to the socket.
+
+In the future I may add a `secret` field in the options object to be
+used for authentication across processes. This would not be difficult,
+it's just not necessary for my use case at the moment.