Zeppelin - pass variable from Spark to Markdown to generate dynamic narrative text

Question

Is it possible to pass a variable from Spark interpreter (pyspark or sql) to Markdown? The requirement is to display a nicely formatted text (i.e. Markdown) such as "20 events occurred between 2017-01-01 and 2017-01-08" where the 20, 2017-01-01 and 2017-01-08 are dynamically populated based on output from other paragraphs.

Answer 1

Posting this for benefit of other users, this is what I have been able to find:

• Markdown paragraphs can only contain static text.
• But it is possible to achieve a dynamic formatted text output with the Angular interpreter instead.

(First paragraph)

%spark
// create data frame
val eventLogDF = ... 
// register temp table for SQL access
eventLogDF.registerTempTable( "eventlog" )

val query = sql( "select max(Date), min(Date), count(*) from eventlog" ).take(1)(0)
val maxDate = query(0).toString()
val minDate = query(1).toString()
val evCount = query(2).toString()

// bind variables which can be accessed from angular interpreter 
z.angularBind( "maxDate", maxDate )
z.angularBind( "minDate", minDate )
z.angularBind( "evCount", evCount ) 

(Second paragaph)

%angular

<div>There were <b>{{evCount}} events</b> between <b>{{minDate}}</b> and <b>{{maxDate}}</b>.</div>