compute metadata in the same child process that builds indexes

lib/commands/metadata.js

@@ -18,15 +18,7 @@ Data.getMetadataRaw = function (Env, channel /* channelName */, _cb) {
     }
 
     Env.batchMetadata(channel, cb, function (done) {
-        var ref = {};
-        var lineHandler = Meta.createLineHandler(ref, Env.Log.error);
-        return void Env.msgStore.readChannelMetadata(channel, lineHandler, function (err) {
-            if (err) {
-                // stream errors?
-                return void done(err);
-            }
-            done(void 0, ref.meta);
-        });
+        Env.computeMetadata(channel, done);
     });
 };
 

lib/historyKeeper.js

@@ -247,11 +247,10 @@ module.exports.create = function (config, cb) {
             channelExpirationMs: config.channelExpirationMs,
             verbose: config.verbose,
             openFileLimit: config.openFileLimit,
-        }, w(function (err, computeIndex) {
+        }, w(function (err) {
             if (err) {
                 throw new Error(err);
             }
-            Env.computeIndex = computeIndex;
         }));
     }).nThen(function (w) {
         // create a task store

lib/hk-util.js

@@ -337,7 +337,7 @@ const storeMessage = function (Env, channel, msg, isCp, optionalMessageHash) {
       * -1 if you didn't find it
 
 */
-const getHistoryOffset = (Env, channelName, lastKnownHash, _cb) => {
+const getHistoryOffset = (Env, channelName, lastKnownHash, _cb) => { // XXX child process
     const cb = Util.once(Util.mkAsync(_cb));
     const store = Env.store;
     const Log = Env.Log;
@@ -454,7 +454,7 @@ const getHistoryAsync = (Env, channelName, lastKnownHash, beforeHash, handler, c
     Used by:
     * GET_HISTORY_RANGE
 */
-const getOlderHistory = function (Env, channelName, oldestKnownHash, cb) {
+const getOlderHistory = function (Env, channelName, oldestKnownHash, cb) { // XXX child process
     const store = Env.store;
     const Log = Env.Log;
     var messageBuffer = [];
@@ -833,7 +833,14 @@ HK.initializeIndexWorkers = function (Env, config, _cb) {
         });
 
         worker.on('message', function (res) {
-            if (!res || !res.txid) { return; }
+            if (!res) { return; }
+            if (!res.txid) {
+                // !report errors...
+                if (res.error) {
+                    Env.Log.error(res.error, res.value);
+                }
+                return;
+            }
             //console.log(res);
             try {
                 response.handle(res.txid, [res.error, res.value]);
@@ -860,20 +867,18 @@ HK.initializeIndexWorkers = function (Env, config, _cb) {
     };
 
     var workerIndex = 0;
-    var sendCommand = function (Env, channel, cb) {
+    var sendCommand = function (msg, _cb) {
+        var cb = Util.once(Util.mkAsync(_cb));
+
         workerIndex = (workerIndex + 1) % workers.length;
         if (workers.length === 0 ||
             typeof(workers[workerIndex].send) !== 'function') {
             return void cb("NO_WORKERS");
         }
-        Env.store.getWeakLock(channel, function (next) {
-            const txid = Util.uid();
-            response.expect(txid, Util.both(next, cb), 45000);
-            workers[workerIndex].send({
-                txid: txid,
-                args: channel,
-            });
-        });
+        const txid = Util.uid();
+        msg.txid = txid;
+        response.expect(txid, cb, 45000);
+        workers[workerIndex].send(msg);
     };
 
     nThen(function (w) {
@@ -885,6 +890,30 @@ HK.initializeIndexWorkers = function (Env, config, _cb) {
             }));
         });
     }).nThen(function () {
+        Env.computeIndex = function (Env, channel, cb) {
+            Env.store.getWeakLock(channel, function (next) {
+                sendCommand({
+                    channel: channel,
+                    command: 'COMPUTE_INDEX',
+                }, function (err, index) {
+                    next();
+                    cb(err, index);
+                });
+            });
+        };
+
+        Env.computeMetadata = function (channel, cb) {
+            Env.store.getWeakLock(channel, function (next) {
+                sendCommand({
+                    channel: channel,
+                    command: 'COMPUTE_METADATA',
+                }, function (err, metadata) {
+                    next();
+                    cb(err, metadata);
+                });
+            });
+        };
+
         //console.log("index workers ready");
         cb(void 0, sendCommand);
     });
@@ -925,14 +954,13 @@ HK.initializeValidationWorkers = function (Env) {
 
     var nextWorker = 0;
     const send = function (msg, _cb) {
+        var cb = Util.once(Util.mkAsync(_cb));
         // let's be paranoid about asynchrony and only calling back once..
         nextWorker = (nextWorker + 1) % workers.length;
         if (workers.length === 0 || typeof(workers[nextWorker].send) !== 'function') {
-            console.error(workers);
-            throw new Error("INVALID_WORKERS");
+            return void cb("INVALID_WORKERS");
         }
 
-        var cb = Util.once(Util.mkAsync(_cb));
         var txid = msg.txid = Util.uid();
 
         // expect a response within 15s

lib/workers/compute-index.js

@@ -5,6 +5,7 @@ const HK = require("../hk-util");
 const Store = require("../storage/file");
 const Util = require("../common-util");
 const nThen = require("nthen");
+const Meta = require("../metadata");
 
 const Env = {};
 
@@ -46,7 +47,13 @@ const tryParse = function (Env, str) {
             * including the initial metadata line, if it exists
 
 */
-const computeIndex = function (channelName, cb) {
+const computeIndex = function (data, cb) {
+    if (!data || !data.channel) {
+        return void cb('E_NO_CHANNEL');
+    }
+
+    const channelName = data.channel;
+
     const cpIndex = [];
     let messageBuf = [];
     let i = 0;
@@ -125,45 +132,60 @@ const computeIndex = function (channelName, cb) {
     });
 };
 
+const computeMetadata = function (data, cb, errorHandler) {
+    const ref = {};
+    const lineHandler = Meta.createLineHandler(ref, errorHandler);
+    return void store.readChannelMetadata(data.channel, lineHandler, function (err) {
+        if (err) {
+            // stream errors?
+            return void cb(err);
+        }
+        cb(void 0, ref.meta);
+    });
+};
+
+const COMMANDS = {
+    COMPUTE_INDEX: computeIndex,
+    COMPUTE_METADATA: computeMetadata,
+};
+
 process.on('message', function (data) {
     if (!data || !data.txid) {
         return void process.send({
             error:'E_INVAL'
         });
     }
-    const txid = data.txid;
+
+    const cb = function (err, value) {
+        if (err) {
+            return void process.send({
+                txid: data.txid,
+                error: err,
+            });
+        }
+        process.send({
+            txid: data.txid,
+            value: value,
+        });
+    };
 
     if (!ready) {
         return void init(data.config, function (err) {
-            if (err) {
-                return void process.send({
-                    txid: txid,
-                    error: err,
-                });
-            }
+            if (err) { return void cb(err); }
             ready = true;
-            process.send({txid: txid,});
+            cb();
         });
     }
 
-    const channel = data.args;
-    if (!channel) {
-        return void process.send({
-            error: 'E_NO_CHANNEL',
-        });
+    const command = COMMANDS[data.command];
+    if (typeof(command) !== 'function') {
+        return void cb("E_BAD_COMMAND");
     }
-
-    // computeIndex
-    computeIndex(channel, function (err, index) {
-        if (err) {
-            return void process.send({
-                txid: txid,
-                error: err,
-            });
-        }
-        return void process.send({
-            txid: txid,
-            value: index,
+    command(data, cb, function (label, info) {
+        // for streaming errors
+        process.send({
+            error: label,
+            value: info,
         });
     });
 });