Trifecta offers a single-page web application (via Angular.js) with a REST service layer and web-socket support, which offers a comprehensive and powerful set of features for inspecting Kafka topic partitions and messages.
Table of Contents
To start the embedded web server, issue the following from the command line:
$ java -jar trifecta.jar --http-start
You'll see a few seconds of log messages, then a prompt indicating the web interface is ready for use.
Open your browser and navigate to http://localhost:8888
Additionally, Trifecta UI introduces a few new properties to the application configuration file (located in $HOME/.trifecta/config.properties). NOTE: The property values shown below are the default values.
# the embedded web server host/IP and port for client connections
trifecta.web.host = localhost
trifecta.web.port = 8888
# the interval (in seconds) that changes to consumer offsets will be pushed to web-socket clients
trifecta.web.push.interval.consumer = 15
# the interval (in seconds) that changes to topics (new messages) will be pushed to web-socket clients
trifecta.web.push.interval.topic = 15
# the number of actors to create for servicing requests
trifecta.web.actor.concurrency = 10
Trifecta UI supports decoding Avro-encoded messages and displaying them in JSON format. To associate an Avro schema to a
Kafka topic, place the schema file in a subdirectory with the same name as the topic. For example, if I wanted to
associate an Avro file named quotes.avsc to the Kafka topic shocktrade.quotes.avro, I'd setup the following
file structure:
$HOME/.trifecta/decoders/shocktrade.quotes.avro/quotes.avsc
The name of the actual schema file can be anything you'd like. Once the file has been placed in the appropriate location, restart Trifecta UI, and your messages will be displayed in JSON format.
Trifecta UI has powerful support for viewing Kafka messages, and when the messages are in either JSON or Avro format Trifecta displays them as human readable (read: pretty) JSON documents.
Trifecta UI also provides a way to execute queries against Avro-encoded topics using the Kafka Query Language (KQL). KQL is a SQL-like language with syntax as follows:
select <fields> from <topic> with <decoder>
[where <condition>]
[limit <count>]
Consider the following example:
select symbol, exchange, lastTrade, open, close, high, low
from "shocktrade.quotes.avro"
where lastTrade <= 1 and volume >= 1,000,000
limit 25
The above query retrieves the symbol, exchange, lastTrade, open, close, high and low fields from messages
within the Kafka topic shocktrade.quotes.avro (using the default decoder) filtering for only messages where the
lastTrade is less than or equal to 1, the volume is greater than or equal to 1,000,000, and limiting the
number of results to 25.
Now consider a similar example, except here we'll specify a custom decoder file (avro/quotes.avsc):
select symbol, exchange, lastTrade, open, close, high, low
from "shocktrade.quotes.avro" with "avro:file:avro/quotes.avsc"
where lastTrade <= 1 and volume >= 1,000,000
limit 25
