Kafka Streams Interactive Queries and gRPC

Kafka Streams Interactive Queries and gRPC

#kafka #grpc #developer

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Kafka Streams Interactive Queries and gRPC
Roberta  Ward

Roberta Ward

1595344320

Wondering how to upgrade your skills in the pandemic? Here's a simple way you can do it.

Corona Virus Pandemic has brought the world to a standstill.

Countries are on a major lockdown. Schools, colleges, theatres, gym, clubs, and all other public places are shut down, the country’s economy is suffering, human health is on stake, people are losing their jobs and nobody knows how worse it can get.

Since most of the places are on lockdown, and you are working from home or have enough time to nourish your skills, then you should use this time wisely! We always complain that we want some ‘time’ to learn and upgrade our knowledge but don’t get it due to our ‘busy schedules’. So, now is the time to make a ‘list of skills’ and learn and upgrade your skills at home!

And for the technology-loving people like us, Knoldus Techhub has already helped us a lot in doing it in a short span of time!

If you are still not aware of it, don’t worry as Georgia Byng has well said,

“No time is better than the present”

– Georgia Byng, a British children’s writer, illustrator, actress and film producer.

No matter if you are a developer (be it front-end or back-end) or a data scientisttester, or a DevOps person, or, a learner who has a keen interest in technology, Knoldus Techhub has brought it all for you under one common roof.

From technologies like Scala, spark, elastic-search to angular, go, machine learning, it has a total of 20 technologies with some recently added ones i.e. DAML, test automation, snowflake, and ionic.

How to upgrade your skills?

Every technology in Tech-hub has n number of templates. Once you click on any specific technology you’ll be able to see all the templates of that technology. Since these templates are downloadable, you need to provide your email to get the template downloadable link in your mail.

These templates helps you learn the practical implementation of a topic with so much of ease. Using these templates you can learn and kick-start your development in no time.

Apart from your learning, there are some out of the box templates, that can help provide the solution to your business problem that has all the basic dependencies/ implementations already plugged in. Tech hub names these templates as xlr8rs (pronounced as accelerators).

xlr8rs make your development real fast by just adding your core business logic to the template.

If you are looking for a template that’s not available, you can also request a template may be for learning or requesting for a solution to your business problem and tech-hub will connect with you to provide you the solution. Isn’t this helpful 🙂

Confused with which technology to start with?

To keep you updated, the Knoldus tech hub provides you with the information on the most trending technology and the most downloaded templates at present. This you’ll be informed and learn the one that’s most trending.

Since we believe:

“There’s always a scope of improvement“

If you still feel like it isn’t helping you in learning and development, you can provide your feedback in the feedback section in the bottom right corner of the website.

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akshay L

akshay L

1572344038

Kafka Spark Streaming | Kafka Tutorial

In this kafka spark streaming tutorial you will learn what is apache kafka, architecture of apache kafka & how to setup a kafka cluster, what is spark & it’s features, components of spark and hands on demo on integrating spark streaming with apache kafka and integrating spark flume with apache kafka.

# Kafka Spark Streaming #Kafka Tutorial #Kafka Training #Kafka Course #Intellipaat

Kafka Streams Interactive Queries and gRPC

Kafka Streams Interactive Queries and gRPC

#kafka #grpc #developer

Ahebwe  Oscar

Ahebwe Oscar

1620185280

How model queries work in Django

How model queries work in Django

Welcome to my blog, hey everyone in this article we are going to be working with queries in Django so for any web app that you build your going to want to write a query so you can retrieve information from your database so in this article I’ll be showing you all the different ways that you can write queries and it should cover about 90% of the cases that you’ll have when you’re writing your code the other 10% depend on your specific use case you may have to get more complicated but for the most part what I cover in this article should be able to help you so let’s start with the model that I have I’ve already created it.

**Read More : **How to make Chatbot in Python.

Read More : Django Admin Full Customization step by step

let’s just get into this diagram that I made so in here:

django queries aboutDescribe each parameter in Django querset

we’re making a simple query for the myModel table so we want to pull out all the information in the database so we have this variable which is gonna hold a return value and we have our myModel models so this is simply the myModel model name so whatever you named your model just make sure you specify that and we’re gonna access the objects attribute once we get that object’s attribute we can simply use the all method and this will return all the information in the database so we’re gonna start with all and then we will go into getting single items filtering that data and go to our command prompt.

Here and we’ll actually start making our queries from here to do this let’s just go ahead and run** Python manage.py shell** and I am in my project file so make sure you’re in there when you start and what this does is it gives us an interactive shell to actually start working with our data so this is a lot like the Python shell but because we did manage.py it allows us to do things a Django way and actually query our database now open up the command prompt and let’s go ahead and start making our first queries.

#django #django model queries #django orm #django queries #django query #model django query #model query #query with django

Stateful Joins with the Kafka Streams Processor API

My team, Expedia Group™ Commerce Data, needed to join events coming in on two (and more in the future) Kafka topics to provide a realtime stream view of our bookings. This is a pretty standard requirement, but our team was not very experienced with Kafka Streams, and we had a few wrinkles that made going with an “out of the box” Kafka Streams join less attractive than dropping down to the Processor API.

What we needed, in a nutshell, was to:

  • Join two or more events,
  • Repartition one event to extract the proper join key,
  • Report on unjoined events,
  • Possibly purge orphaned events to a dead letter topic,
  • Configurable no set join window (for expiration of unjoined events),
  • Oh, and with Kafka Streams newbies at the helm.

Processor API vs DSL

There are two approaches to writing a Kafka Streams application:

Developers prefer the DSL for most situations because it simplifies some common use cases and lets you accomplish a lot with very little code. But you sacrifice some control when using the DSL. There’s a certain amount of magic going on under the covers that’s hidden by the KStream and KTable abstractions. And the out-of-the-box joins available between these abstractions may not fit all use cases.

The most common way I see the DSL characterized is as “expressive,” which just means “hides lots of stuff from you.” Sometimes explicit is better. And for some (like me), the “raw” Processor API just seems to fit my brain better than the DSL abstractions.

Don’t fear the Processor API

Most documentation I found around Kafka Streams leans towards using the DSL (Confluent docs state “it is recommended for most users”), but the Processor API has a much simpler interface than the DSL in many respects. You still build a stream topology, but you only use Source nodes (to read from Kafka topics), Sink nodes (to write to Kafka topics), and Processor nodes (to do stuff to Kafka events flowing through your topology). Plus the DSL is built on top of the Processor API, so if it’s good enough for the DSL, it should be good enough for our humble project (in fact, as a Confluent engineer says, “the DSL compiles down to the Processor API”).

Processor nodes have to implementProcessor, which has a process method you override which takes the key and the value of the event that is traversing your Kafka Streams topology. Processors also have access to aProcessorContext object which contains useful information on the current event being processed (like what topic & partition it was consumed from) and a forward method that is used to send the event to a downstream node in your topology.

To illustrate the difference, here’s a comparison of doing a repartition on a stream in the DSL and the Processor API.

#kafka-streams #kafka #streaming #data-science