Merge pull request #2166 from openedx/hack-and-slash-dev-guide

Hack and slash dev guide

en_us/developers/source/architecture.rst

@@ -1,6 +1,6 @@
-###########################
+#####################
 Open edX Architecture
-###########################
+#####################
 
 The Open edX project is a web-based platform for creating, delivering, and
 analyzing online courses. It is the software that powers edx.org and many other
@@ -21,8 +21,8 @@ the learning management and course authoring applications (LMS and Studio,
 respectively).
 
 This service is supported by a collection of other autonomous web services
-called independently deployed applications (IDAs). Over time, edX plans to
-break out more of the existing edx-platform functions into new IDAs. This
+called independently deployed applications (IDAs). Over time, we plan to
+break out more of the existing edx-platform functions into new IDAs and MFEs. This
 strategy will help manage the complexity of the edx-platform code base to make
 it as easy as possible for developers to approach and contribute to the
 project.
@@ -42,58 +42,6 @@ Key Components
 Learning Management System (LMS)
 ================================
 
-The LMS is the most visible part of the Open edX project. Learners take courses
-using the LMS. The LMS also provides an instructor dashboard that users who
-have the Admin or Staff role can access by selecting **Instructor**.
-
-The LMS uses a number of data stores. Courses are stored in `MongoDB`_, with
-videos served from YouTube or Amazon S3. Per-learner data is stored in MySQL.
-
-As learners move through courses and interact with them, events are published
-to the analytics pipeline for collection, analysis, and reporting.
-
-Front End
-*********
-
-The Django server-side code in the LMS and elsewhere uses `Mako`_ for front-end
-template generation. The browser-side code is written primarily in JavaScript
-with some `CoffeeScript`_ as well (edX is working to replace that code with
-JavaScript). Parts of the client-side code use the `Backbone.js`_ framework,
-and edX is moving more of the code base to use that framework. The Open edX
-project uses `Sass`_ and the `Bourbon framework`_ for CSS code.
-
-Course Browsing
-***************
-
-The Open edX project provides a simple front page for browsing courses. The
-`edx.org`_ site has a separate home page and course discovery site that is not
-open source.
-
-Course Structure
-****************
-
-Open edX courses are composed of units called
-:ref:`XBlocks<xblocktutorial:Open edX XBlock Tutorial>`. Anyone can write new
-XBlocks, allowing educators and technologists to extend the set of components
-for their courses. The edX platform also still contains several XModules, the
-precursors to XBlocks. EdX is working to rewrite the existing XModules as
-XBlocks and remove XModules from our code base.
-
-In addition to XBlocks, there are a few ways to extend course behavior:
-
-* The LMS is an :ref:`LTI<partnercoursestaff:LTI Component>` tool consumer.
-  Course authors can embed LTI tools to integrate other learning tools into an
-  Open edX course.
-
-* Problems can use embedded Python code to either present the problem or assess
-  the learner’s response. Instructor-written Python code is executed in a
-  secure environment called CodeJail.
-
-* JavaScript components can be integrated using
-  :ref:`JS Input<Custom JavaScript Applications>`.
-
-* Courses can be exported and imported using OLX (open learning XML), an XML-
-  based format for courses.
 
 ======
 Studio
@@ -120,42 +68,28 @@ Mobile Apps
 ===========
 
 The Open edX project includes a mobile application, available for iOS and
-Android, that allows learners to watch course videos and more. EdX is actively
+Android, that allows learners to watch course videos and more. Open edX is actively
 enhancing the mobile app.
 
 =========
 Analytics
 =========
 
-Events describing learner behavior are captured by the Open edX analytics
-pipeline. The events are stored as JSON in S3, processed using Hadoop, and then
-digested, aggregated results are published to MySQL. Results are made available
-via a REST API to Insights, an IDA that instructors and administrators use to
-explore data that lets them know what their learners are doing and how their
-courses are being used.
-
-.. image:: ../../shared/images/edx-architecture-analytics.png
-  :width: 700
-  :alt: A diagram of the components and technologies that make up the Open edX
-      analytics architecture.
 
 ===============
 Background Work
 ===============
 
 A number of tasks are large enough that they are performed by separate
 background workers, rather than in the web applications themselves. This work
-is queued and distributed using `Celery`_ and `RabbitMQ`_. Examples of queued
+is queued and distributed using `Celery`_ and `Redis`_. Examples of queued
 work include:
 
 * Grading entire courses
 * Sending bulk emails (with Amazon SES)
 * Generating answer distribution reports
 * Producing end-of-course certificates
 
-The Open edX project includes an IDA called XQueue that can run custom graders.
-These are separate processes that run compute-intensive assessments of
-learners’ work.
 
 ======
 Search
@@ -185,5 +119,5 @@ like order work flows and coupons.
 .. _Ruby: https://www.ruby-lang.org/en/
 .. _Sinatra: http://www.sinatrarb.com/
 .. _Celery: http://www.celeryproject.org/
-.. _RabbitMQ: http://www.rabbitmq.com/
+.. _Redis: https://redis.io/
 .. _Elasticsearch: https://www.elastic.co/