first commit

core/gekkoStream.js

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+// Small writable stream wrapper that
+// passes data to all `candleConsumers`.
+
+const Writable = require('stream').Writable;
+const _ = require('lodash');
+const async = require('async');
+const moment = require('moment');
+
+const util = require('./util');
+const env = util.gekkoEnv();
+const mode = util.gekkoMode();
+const config = util.getConfig();
+const log = require(util.dirs().core + 'log');
+
+var Gekko = function(plugins) {
+  this.plugins = plugins;
+  this.candleConsumers = plugins
+    .filter(plugin => plugin.processCandle);
+  Writable.call(this, {objectMode: true});
+
+  this.producers = this.plugins
+    .filter(p => p.meta.emits);
+
+  this.finalize = _.bind(this.finalize, this);
+}
+
+Gekko.prototype = Object.create(Writable.prototype, {
+  constructor: { value: Gekko }
+});
+
+if(config.debug && mode !== 'importer') {
+  // decorate with more debug information
+  Gekko.prototype._write = function(chunk, encoding, _done) {
+
+    if(chunk.isFinished) {
+      return this.finalize();
+    }
+
+    const start = moment();
+    var relayed = false;
+    var at = null;
+
+    const timer = setTimeout(() => {
+      if(!relayed)
+        log.error([
+          `The plugin "${at}" has not processed a candle for 1 second.`,
+          `This will cause Gekko to slow down or stop working completely.`
+        ].join(' '));
+    }, 1000);
+
+    const flushEvents = _.after(this.candleConsumers.length, () => {
+      relayed = true;
+      clearInterval(timer);
+      this.flushDefferedEvents();
+      _done();
+    });
+    _.each(this.candleConsumers, function(c) {
+      at = c.meta.name;
+      c.processCandle(chunk, flushEvents);
+    }, this);
+  }
+} else {
+  // skip decoration
+  Gekko.prototype._write = function(chunk, encoding, _done) {
+    if(chunk.isFinished) {
+      return this.finalize();
+    }
+
+    const flushEvents = _.after(this.candleConsumers.length, () => {
+      this.flushDefferedEvents();
+      _done();
+    });
+    _.each(this.candleConsumers, function(c) {
+      c.processCandle(chunk, flushEvents);
+    }, this);
+  }
+}
+
+Gekko.prototype.flushDefferedEvents = function() {
+  const broadcasted = _.find(
+    this.producers,
+    producer => producer.broadcastDeferredEmit()
+  );
+
+  // If we braodcasted anything we might have
+  // triggered more events, recurse until we
+  // have fully broadcasted everything.
+  if(broadcasted)
+    this.flushDefferedEvents();
+}
+
+Gekko.prototype.finalize = function() {
+  var tradingMethod = _.find(
+    this.candleConsumers,
+    c => c.meta.name === 'Trading Advisor'
+  );
+
+  if(!tradingMethod)
+    return this.shutdown();
+
+  tradingMethod.finish(this.shutdown.bind(this));
+}
+
+Gekko.prototype.shutdown = function() {
+  this.end();
+  async.eachSeries(
+    this.plugins,
+    function(c, callback) {
+      if (c.finalize) c.finalize(callback);
+      else callback();
+    },
+    () => {
+      // If we are a child process, we signal to the parent to kill the child once it is done
+      // so that is has time to process all remaining events (and send report data)
+      if (env === 'child-process') process.send('done');
+      else process.exit(0);
+    }
+  );
+};
+
+module.exports = Gekko;