writetimetable

Write timetable to event stream

Since R2022b

This function requires Streaming Data Framework for MATLAB^® Production Server™.

Syntax

writetimetable(stream,tt)

writetimetable(ks,tt,MissingTopic=action)

Description

writetimetable(stream,tt) writes the timetable tt to the end of the event stream stream.

writetimetable converts rows of a timetable into events in an event stream, where:

• The column names in the timetable become variable names in the event body.

• The values in each event row become the values of those variables.

• The row timestamp becomes the event timestamp.

You can append data to a stream but cannot modify data that is already written to a stream.

writetimetable(ks,tt,MissingTopic=action) specifies whether to create a topic when writing a timetable to an event stream hosted by Kafka^® or fail the write operation when the topic is missing. If the Kafka cluster that you are writing to is configured to auto-create topics, specifying action has no effect.

Examples

Write Timetable to Event Stream

Load air quality data and weather measurements into a timetable.

load indoors

Create an InMemoryStream object to connect to an event stream hosted by MATLAB.

i = inMemoryStream;

Write the timetable to the event stream.

writetimetable(i,indoors)

Preview the data in the event stream.

preview(i)

ans =

  8×2 timetable

           Time            Humidity    AirQuality
    ___________________    ________    __________

    2015-11-15 00:00:24       36           80    
    2015-11-15 01:13:35       36           80    
    2015-11-15 02:26:47       37           79    
    2015-11-15 03:39:59       37           82    
    2015-11-15 04:53:11       36           80    
    2015-11-15 06:06:23       36           80    
    2015-11-15 07:19:35       36           80    
    2015-11-15 08:32:47       37           80    

Write Timetable to Stream Hosted by Kafka

Load air quality data and weather measurements into a timetable.

load indoors

Assume that you have a Kafka host running at network address kafka.host.com:9092. Create a KafkaStream object that processes 10 stream events at a time.

ks = kafkaStream("kafka.host.com",9092,"IndoorTemp",Rows=10);

Create the IndoorTemp topic and write the timetable to it.

writetimetable(ks,indoors)

Read the first 10 events from the stream.

tt1 = readtimetable(ks)

tt1 =

  10×3 timetable

         timestamp          Humidity    AirQuality    key
    ____________________    ________    __________    ___

    15-Nov-2015 00:00:24       36           80        "" 
    15-Nov-2015 01:13:35       36           80        "" 
    15-Nov-2015 02:26:47       37           79        "" 
    15-Nov-2015 03:39:59       37           82        "" 
    15-Nov-2015 04:53:11       36           80        "" 
    15-Nov-2015 06:06:23       36           80        "" 
    15-Nov-2015 07:19:35       36           80        "" 
    15-Nov-2015 08:32:47       37           80        "" 
    15-Nov-2015 09:45:59       37           79        "" 
    15-Nov-2015 10:59:11       36           80        "" 

Read the next 10 events from the stream.

tt2 = readtimetable(ks)

tt2 =

  10×3 timetable

         timestamp          Humidity    AirQuality    key
    ____________________    ________    __________    ___

    16-Nov-2015 00:24:22       36           81        "" 
    16-Nov-2015 01:37:34       37           80        "" 
    16-Nov-2015 02:50:46       36           79        "" 
    16-Nov-2015 04:03:58       37           80        "" 
    16-Nov-2015 05:17:09       37           81        "" 
    16-Nov-2015 06:30:21       36           79        "" 
    16-Nov-2015 07:43:33       37           79        "" 
    16-Nov-2015 08:56:45       37           79        "" 
    16-Nov-2015 10:09:57       37           85        "" 
    16-Nov-2015 11:23:09       37           80        ""  

Input Arguments

stream — Object connected to event stream

KafkaStream object | InMemoryStream object | TestStream object

Object connected to an event stream, specified as a KafkaStream, InMemoryStream, or TestStream object.

tt — Input timetable

timetable

Input timetable.

ks — Object connected to Kafka stream topic

KafkaStream object

Object connected to a Kafka stream topic, specified as a KafkaStream object.

action — Action to take if topic does not exist

"create" (default) | "fail"

Action to take if the topic to write the timetable to does not exist, specified as one of the following values:

• "create" — Creates new topic, if you have the required permissions on the Kafka host.

• "fail" — Does not create a new topic and the write operation fails.

Data Types: char | string

Version History

Introduced in R2022b