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Henri Bergius, a.k.a. Bergie, is a former Viking based in the Nordic country of Finland. When he is not exploring Georgia’s cave cities or running with the bulls in Pamplona, Bergie works on web services built on top of the Midgard toolkit. His company, Nemein, provides web and mobile solutions for several major companies in Finland and abroad. He has been actively working on integrating standards like RDFa into the system and traveling the world advocating interoperation between open-source CMS’s. Much of his latest work involves building web services in CoffeeScript and doing data integration with the NoFlo flow-based programming toolkit. Henri is a DZone MVB and is not an employee of DZone and has posted 31 posts at DZone. You can read more from them at their website. View Full User Profile

Business Analytics with CouchDB and NoFlo

05.21.2012
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The purpose of business analytics is to find data from the company's information systems that can be used to support decision making. What customers buy most? What do they do before a buying decision? What are the signs that a customer may be leaving?

For the last month we've been working in Salzburg to build such a system, the Intelligent Project Controlling Tool needed for running large collaborative research projects like IKS. Since the design we went with can be reused for other business analytics needs, I wanted to write a bit about it.

But first, here is how our system looks like:

Proggis displaying IKS project plan

Where does the data come from?

There are many ways to gather business data. Often the information systems already contain the data needed. But it may also be hidden in a jungle of spreadsheets. Or maybe some data is simply not available, and has to be filled in manually.

Handling all these cases in one system is a tricky question. To solve it, we went with a two-layered strategy:

  • All data used for analytics is stored as Linked Data in a CouchDB system
  • NoFlo workflows are used for gathering data from the diverse sources and convert it to the format needed

In IKS's case, much of the data was available in a series of spreadsheets. With these, we built the necessary workflows for first converting the spreadsheets into XML with Apache Tika, and then extracting the information from them in a sensible subset of JSON-LD.

Because IKS is a collaborative project, information needs to be gathered from a diverse group of partner organizations. Some of them have systems that provide the needed APIs (like Basecamp, which we use), and we can just periodically import the data. But with many we decided on a simple data interchange approach: spreadsheets handled over email.

In this approach, user files a data request into the system. This gets picked up by NoFlo, which sends an email with the appropriate spreadsheet template to the partner. Then it starts waiting for a reply. When a reply arrives, it extracts the data from the attached spreadsheet and imports it to the system.

Our NoFlo processes are mostly initiated by the CouchDB change notification API. We keep them running persistently using forever Node, so whenever some operation needs to be run it happens nearly immediately.

Ensuring data consistency

With any automation, and especially with the email-based data interchange, things can go wrong. Because of this we tag all data that we receive with its origin, whether it was some automated operation or an imported spreadsheet. These origins are called execution documents. Users can browse all completed workflow executions and see what data came in from them. These can then be either accepted or rejected.

This way if some partner accidentally sends faulty data, or something else breaks, the incorrect information received can be easily removed. CouchDB's versioning capabilities help here.

Analyzing the data

CouchDB is built on top of the concept of map/reduce. Here you can modify and combine the data in lots of different ways using simple JavaScript functions. In our case we elected to write all our CouchDB code in CoffeeScript for simplicity. For example, here is the reduce function in CoffeeScript that counts totals of time planned, time used, and time left per task or partner in a project:

(keys, values, rereduce) ->
    roundNumber = (rnum, rlength) ->
        Math.round(parseFloat(rnum) * Math.pow(10, rlength)) / Math.pow(10, rlength)
    data =
        planned: 0.0
        spent: 0.0
        left: 0.0

    if rereduce
        for reducedData in values
            data.planned += reducedData.planned
            data.spent += reducedData.spent
        data.left = data.planned - data.spent
        return data

    for doc in values
        if doc['@type'] is 'effortallocation'
            data.planned += roundNumber doc.value, 1
        if doc['@type'] is 'effort'
            data.spent += roundNumber doc.value, 1
    data.left = roundNumber data.planned - data.spent, 1
    return data

If you figure out a new way to look at the data you have, simply write the needed map and reduce functions and save them into the database. CouchDB will then run them against existing data and produce numbers.

Data visualizations

Numbers are good, but to really see the information buried in them you need some visualizations. For this we decided to follow the CouchApp idea where the user interface code is stored in the database together with the data itself. This way no application servers are needed, and you can take the whole system with you just by replicating the database. Think of the possibility of doing some analysis on your company while flying to a meeting!

The visuals are in our case provided by JavaScript InfoVis Toolkit, a nice, MIT-licensed interactive graph library.

CouchDB views handle the number crunching, then CouchDB list functions process the numbers into the format needed for visualization. This leaves only a minimal amount of work for the client side.

For consistency our application has been built with CoffeeApp, so all the database and user interface code is in CoffeeScript.

In a nutshell

Any business analytics system dealing with moderate amounts of data can be built following this approach.

Simple architecture for a business analytics system

This way you have a business analytics environment that is easy to extend with more data when it becomes available. New analysis can be done by writing reasonably simple map/reduce functions, and CouchDB's replication capabilities allow you to take the system and data with you.

Using JSON-LD for the data storage makes a lot of sense, as this way the relations between different pieces of information are easy to handle. And using URIs for data identifiers means you can easily mash up information coming from different sources together.

The two-layered approach of using NoFlo for data imports, and CouchDB for analysis also allows for clean separation of concerns. In our case, I did the workflow part of things, and Szaby built the visualizations.

Published at DZone with permission of Henri Bergius, author and DZone MVB. (source)

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)

Comments

Herry Johnson replied on Tue, 2012/06/12 - 3:11pm

In a conversation the question arose whether it could be a case of throwing a runtime exception for anything other than a bug. The tutorial on oracle site says "These Usually Indicate programming bugs" leading to think that can be used in situations in which there is no bug.
Anyone have a practical example of a runtime exception when there is no bug?
Thanks.

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