Improvements to the file storage format

.gitignore

@@ -1,3 +1,4 @@
+datastore
 www/bower_components/*
 node_modules
 /config.js

NetfluxWebsocketSrv.js

@@ -33,7 +33,11 @@ const sendChannelMessage = function (ctx, channel, msgStruct) {
       }
     });
     if (USE_HISTORY_KEEPER && msgStruct[2] === 'MSG') {
-        ctx.store.message(channel.id, JSON.stringify(msgStruct), function () { });
+        ctx.store.message(channel.id, JSON.stringify(msgStruct), function (err) {
+            if (err) {
+                console.log("Error writing message: " + err);
+            }
+        });
     }
 };
 
@@ -90,7 +94,11 @@ const getHistory = function (ctx, channelName, handler, cb) {
     var messageBuf = [];
     ctx.store.getMessages(channelName, function (msgStr) {
         messageBuf.push(JSON.parse(msgStr));
-    }, function () {
+    }, function (err) {
+        if (err) {
+            console.log("Error getting messages " + err.stack);
+            // TODO: handle this better
+        }
         var startPoint;
         var cpCount = 0;
         var msgBuff2 = [];

storage/file.js

@@ -1,128 +1,167 @@
 var Fs = require("fs");
 var Path = require("path");
+var nThen = require("nthen");
 
-//function will check if a directory exists, and create it if it doesn't
+var mkPath = function (env, channelId) {
-var checkDir = function (dir, cb) {
+    return Path.join(env.root, channelId.slice(0, 2), channelId) + '.ndjson';
-    Fs.stat(dir, function(err, stats) {
-        //Check if error defined and the error code is "not exists"
-        if (err) {
-            //Create the directory, call the callback.
-            Fs.mkdir(dir, cb);
-        } else {
-            //just in case there was a different error:
-            cb(err);
-        }
-    });
 };
 
-var checkFile = function (path, cb) {
+var readMessages = function (path, msgHandler, cb) {
-    Fs.stat(path, function (err, stats) {
-        if (err) {
-            if (err.code === 'ENOENT') {
-                return cb(null, false);
-            } else {
-                return cb(err);
-            }
-        }
-        return cb(null, stats.isFile());
-    });
-};
-
-var separate = function (channel) {
-    return {
-        first: channel.slice(0, 2),
-        rest: channel.slice(2),
-    };
-};
-
-var Channel = function (env, id, filepath, cb) {
-    if (!env.channels[id]) {
-        return (env.channels[id] = {
-            atime: +new Date(),
-            queue: [],
-            stream: Fs.createWriteStream(filepath, {
-                flags: 'a'
-            }).on('open', function () {
-                cb(null, env.channels[id]);
-            }).on('error', function (err) {
-                cb(err);
-            })
-        });
-    }
-    cb(null, env.channels[id]);
-};
-
-var insert = function (env, channelName, content, cb) {
-    var parts = separate(channelName);
-
-    var dirpath = Path.join(env.root, parts.first);
-    checkDir(dirpath, function (e) {
-        if (e) { throw new Error(e); }
-
-        var filepath = Path.join(env.root, parts.first, parts.rest);
-        checkFile(filepath, function (err, isFile) {
-            Channel(env, channelName, filepath, function (err, channel) {
-                if (err) {
-                    console.error(err);
-                    return cb();
-                }
-
-                var doIt = function () {
-                    channel.locked = true;
-                    channel.atime = +new Date();
-                    channel.stream.write(JSON.stringify(content) + '\n');
-
-                    if (!channel.queue.length) {
-                        channel.locked = false;
-                        cb();
-                        return;
-                    }
-
-                    channel.queue.shift()();
-                    cb();
-                };
-
-                if (channel.locked) {
-                    channel.queue.push(doIt);
-                } else {
-                    doIt();
-                }
-            });
-        });
-    });
-};
-
-var getMessages = function (env, channelName, msgHandler, cb) {
-    var parts = separate(channelName);
-
-    var filepath = Path.join(env.root, parts.first, parts.rest);
-
     var remainder = '';
-    var newlines = /[\n\r]+/;
+    var stream = Fs.createReadStream(path, 'utf8');
+    var complete = function (err) {
+        var _cb = cb;
+        cb = undefined;
+        if (_cb) { _cb(err); }
+    };
+    stream.on('data', function (chunk) {
+        var lines = chunk.split('\n');
+        lines[0] = remainder + lines[0];
+        remainder = lines.pop();
+        lines.forEach(msgHandler);
+    });
+    stream.on('end', function () {
+        msgHandler(remainder);
+        complete();
+    });
+    stream.on('error', function (e) { complete(e); });
+};
 
-    var stream = Fs.createReadStream(filepath, 'utf-8')
+var checkPath = function (path, callback) {
-        .on('data', function (chunk) {
+    Fs.stat(path, function (err, stats) {
-            var lines = chunk.split(newlines);
+        if (!err) {
-            lines[0] = remainder + lines[0];
+            callback(undefined, true);
-            remainder = lines.pop();
+            return;
-            lines.forEach(function (line) {
+        }
-                msgHandler(JSON.parse(line));
+        if (err.code !== 'ENOENT') {
-            });
+            callback(err);
-        })
+            return;
-        .on('end', function () { cb(); })
+        }
-        .on('error', function (e) { cb(); });
+        var dirPath = path.replace(/\/[^\/]*$/, '/');
+        Fs.mkdir(dirPath, function (err) {
+            if (err && err !== 'EEXIST') {
+                callback(err);
+                return;
+            }
+            callback(undefined, false);
+        });
+    });
+};
+
+var getChannel = function (env, id, callback) {
+    if (env.channels[id]) {
+        var chan = env.channels[id];
+        if (chan.whenLoaded) {
+            chan.whenLoaded.push(callback);
+        } else {
+            callback(undefined, chan);
+        }
+        return;
+    }
+    var channel = env.channels[id] = {
+        atime: +new Date(),
+        messages: [],
+        writeStream: undefined,
+        whenLoaded: [ callback ],
+        onError: [ ]
+    };
+    var complete = function (err) {
+        var whenLoaded = channel.whenLoaded;
+        // no guarantee stream.on('error') will not cause this to be called multiple times
+        if (!whenLoaded) { return; }
+        channel.whenLoaded = undefined;
+        if (err) {
+            delete env.channels[id];
+        }
+        whenLoaded.forEach(function (wl) { wl(err, (err) ? undefined : channel); });
+    }
+    var path = mkPath(env, id);
+    var fileExists;
+    nThen(function (waitFor) {
+        checkPath(path, waitFor(function (err, exists) {
+            if (err) {
+                waitFor.abort();
+                complete(err);
+                return;
+            }
+            fileExists = exists;
+        }));
+    }).nThen(function (waitFor) {
+        if (!fileExists) { return; }
+        readMessages(path, function (msg) {
+            channel.messages.push(msg);
+        }, waitFor(function (err) {
+            if (err) {
+                waitFor.abort();
+                complete(err);
+            }
+        }));
+    }).nThen(function (waitFor) {
+        var stream = channel.writeStream = Fs.createWriteStream(path, { flags: 'a' });
+        stream.on('open', waitFor());
+        stream.on('error', function (err) {
+            // this might be called after this nThen block closes.
+            if (channel.whenLoaded) {
+                complete(err);
+            } else {
+                channel.onError.forEach(function (handler) {
+                    handler(err);
+                });
+            }
+        });
+    }).nThen(function (waitFor) {
+        complete();
+    });
+};
+
+var message = function (env, chanName, msg, cb) {
+    getChannel(env, chanName, function (err, chan) {
+        if (err) {
+            cb(err);
+            return;
+        }
+        var complete = function (err) {
+            var _cb = cb;
+            cb = undefined;
+            if (_cb) { _cb(err); }
+        };
+        chan.onError.push(complete);
+        chan.writeStream.write(msg + '\n', function () {
+            chan.onError.splice(chan.onError.indexOf(complete) - 1, 1);
+            if (!cb) { return; }
+            chan.messages.push(msg);
+            chan.atime = +new Date();
+            complete();
+        });
+    });
+};
+
+var getMessages = function (env, chanName, handler, cb) {
+    getChannel(env, chanName, function (err, chan) {
+        if (err) {
+            cb(err);
+            return;
+        }
+        chan.messages.forEach(handler);
+        chan.atime = +new Date();
+        cb();
+    });
 };
 
 module.exports.create = function (conf, cb) {
     var env = {
-        root: conf.filePath,
+        root: conf.filePath || './datastore',
         channels: { },
     };
-
+    console.log('storing data in ' + env.root);
-    checkDir(env.root, function (e, data) {
+    Fs.mkdir(env.root, function (err) {
+        if (err && err.code !== 'EEXIST') {
+            // TODO: somehow return a nice error
+            throw err;
+        }
         cb({
             message: function (channelName, content, cb) {
-                insert(env, channelName, content, cb);
+                message(env, channelName, content, cb);
             },
             getMessages: function (channelName, msgHandler, cb) {
                 getMessages(env, channelName, msgHandler, cb);
@@ -132,17 +171,5 @@ module.exports.create = function (conf, cb) {
                 cb();
             },
         });
-
-        setInterval(function () {
-            var now = +new Date();
-            Object.keys(env.channels).forEach(function (id) {
-                var channel = env.channels[id];
-                if (now - channel.atime > (1000 * 60)) {
-                    //console.log("Cleaning up idle channel [%s]", id);
-                    channel.stream.close();
-                    delete env.channels[id];
-                }
-            });
-        }, 60 * 1000);
     });
 };