What is Event Driven Architecture? (EDA

What is Event Driven Architecture? (EDA - part 1)

День тому

Introduction video to Event Driven Architecture (aka Message Driven Architecture or PubSub).
With this video I start the series of videos regarding Event Driven Architecture, also known as Message Driven Architecture or Publish/Subscribe (PubSub) in the most generic concepts. We start covering the concepts, looking into the pros and cons and some examples of how this architecture works. In the next videos in the series I will be covering also additional concepts that relate to microservices and some additional software architecture patterns associated to EDA. At the end of the video you will get a clear idea of what is Event Driven Architecture.
This video can also be seen as a follow up to my Software Architecture Introduction Series, as the examples are built from there ( • Getting the Basics - S... ).
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🔖 Resources:
- Presentation: The many meanings of Event Driven Architecture: • The Many Meanings of E...
- Best Practices (Heroku via Dev.to): dev.to/heroku/best-practices-...
- Free whitepaper on EDA from Axon: lp.axoniq.io/whitepaper-event...
- Software Architecture Patterns: www.oreilly.com/library/view/...
- Risk Driven Architecture (incentivized): amzn.to/3a8wdQC
- Microservices Patterns (incentivized): amzn.to/3e5C7Ds
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🤓 If you are preparing for a technical interview, don't miss my playlist: devstory.page.link/technical-...
📚 I have also prepared FREE study guides available here (no subscription needed): devstory.page.link/study-guides
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Remember you can reach me here:
- #️⃣ Twitter: / cv13lm4
-⌨️ Github: github.com/cvielma
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In A Dev' Story I explain Software Development related topics from my point of view. I'll be explaining different topics in "Chapters" according to the stage of the story I think they belong. Hope is as entertaining for you as it's fun for me to create these videos
Thanks again for watching! Feel free to like, comment, share and subscribe, it means a lot to me and helps the channel grow.
#Microservices #SoftwareArchitecture #EventDrivenArchitecture

КОМЕНТАРІ: 134

@javier.alvarez764 2 роки тому

Event driven architecture Event - something that happened - immutable or can't be changed. - can be communicated or implemented through event notification. Command - request, or order, expects a response - can be communicated or implemented through message. Event Driven architecture - also referred to as publisher-subscriber model. Three Components 1. Producer 2. Broker 3. Consumer Producer -> Broker -> Consumer - a producer creates events that are redirected by a broker into the right consumer. - consumers will react to this event and execute things they need to execute. Benefits - decoupling (not dependent to other services) - dependency inversion - scalability Traditional architecture Service1 -> Service Event driven architecture Service1 -> Event -> Service2 - in an event driven architecture, service1 doesn't need to know about service2 vice versa. - they communicate through events: producing and consuming events. Events Persistence - using a broker. ex kafka - previously you need service1 and service2 to be both online and pass data, but having a broker enables events to be persisted. in other words brokers can be used a temporary storage if there is a situation that the consumer is down, once the consumer is online again the data can be send to the consumer again. traditional architecture Service1 -> Service2 Service1 -> Broker (havings events) -> Service2 When to use 1. Scalability is more important than performance. 2. Data replication/Parallel Processing - you need the same information in multiple systems. - if you multiple services (subscribers) that needs to be process or executed at the same time.

@bachle4148 Місяць тому

What a useful sumary for us! Thanks a lot

@SuperPradeep21 Рік тому

Its the first video I have ever seen that showed pros and cons of Event Driven Architecture. This is perfect example that one size doesn't fit all. Awesome content and thank you so much.

@ADevStory Рік тому

Thank you! Glad it was so useful!

@MrYass24 2 роки тому

Yes I prefer to differentiate between the event and command notions, since events are simply a notification that can trigger something else asynchronously while a command can be rejected and the commander must receive the rejection code and the cause of his rejection

@pramilaveluri1180 2 роки тому

I really liked the way you have organized the content and made it very crisp and clear for anybody to have a high level knowledge or those who want to recap just before interviews. A very useful series.

@ADevStory 2 роки тому

Glad it helped! Thanks for the feedback! :)

@yerson557 2 роки тому

I arrived to learn about software architecture and I find more than just that. Thanks! Cristhian. It's kind of difficult for me to understand some concepts but I don't care, I just want to learn even if the learning curve is very steep.

@ADevStory 2 роки тому

Glad you are enjoying the channel! If there's any specific topic you might be interested in or anything I can do to make it more digestible let me know :)

@vinodcs80 2 роки тому

action packed 10 min, very nice explanation characteristics of EDA and when to use and not use

@ADevStory 2 роки тому

Glad you liked it!

@zparragi 7 місяців тому

I've just seen all the 3 videos of this series. Thanks a lot.

@ADevStory 7 місяців тому

You're very welcome!

@kirtimanmishra8097 Рік тому

These videos are the best videos for starters. Also good for experienced folks. Thanks for the amazing content.

@ADevStory Рік тому

Thank you! Glad you found it useful!

@amirtv106 Рік тому

Definitely most easy to understand and best presented series on system design

@ADevStory Рік тому

Oh thank you!

@NomeshDeSilva 3 роки тому

Hey, thanks man for the awesome series..love you ❤

@gabriellebeduya2063 3 роки тому

I'm planning to take CS in college and your videos are really inspiring me to become a Software Architect thanks a lot!! Can't wait to see more of your vids!!!

@ADevStory 3 роки тому

Glad they have been inspiring :)

@gabriellebeduya2063 3 роки тому

@@ADevStory can you do a series too about being a Cloud Engineer/Architect?

@ADevStory 3 роки тому

@@gabriellebeduya2063 it's a bit farther away for me, but maybe in the future I can do one :) thanks for recommending it.

@ismaelperezmesa524 Рік тому

Thank you for sharing your knowledge in such an amazing way. I would like to suggest you put all these concepts into practice, implementing it in some language you prefer. I think that would be great.

@ADevStory Рік тому

Thank you for the suggestion! I'm trying to focus more on concepts but maybe in the future I can include some code too 🙂

@tylergaugler6294 3 роки тому

Great content - enjoying the series so far!

@ADevStory 3 роки тому

Glad to hear that! :)

@mikelsilva6220 2 роки тому

Thanks. Awesome explanation

@Jashobantac 2 роки тому

Loved the illustrations. Subscribed immediately

@ADevStory 2 роки тому

Thanks :)

@herodotogates3072 Рік тому

You deserve a way more visibility, great content!

@ADevStory Рік тому

Thank you for the kind words! I won't be sad if you can help me share it with more people 😜

@JohnDoe-xi6df 2 роки тому

Perfectly explained! Thanks :)

@ADevStory 2 роки тому

Anytime!

@trini8042 Рік тому

I dont know much of CS and this helped me a lot! Taking Azure Dev Associate certification

@ADevStory Рік тому

Amazing! Good luck in your certification!

@lugojenkins Рік тому

Very nice video - thanks for giving me a good understanding!

@ADevStory Рік тому

Thanks! Glad it was useful!

@starkarabil9260 7 місяців тому

thanks for this video series. What would be nice to see is that if you could explain different architecture Patterns and go for a sample project and select a pattern with explaining reason and implement the architecture with technology and create at the end a very simple product. Let's say a web application built through cloud and could also be implemented by watchers by watching your video. Then another example another pattern implementation. With those key samples, the one who has interest in learning software architecture can build his/her understanding and build his/her own knowledge about software architecture and implementation of it.

@ADevStory 7 місяців тому

Thank you! Glad you enjoyed it! I've been thinking about it, but also would like to keep the videos short. I can try to come up with an idea.

@ray811030 2 роки тому

Thanks for your great sharing. Since i'm very junior and i'm preparing system design for interview, I'm just wondering what doest event-driven play a role in system design or there are two totally difference concepts

@MrDangrove 2 роки тому

Brilliant video, great explanation

@ADevStory 2 роки тому

Thanks! Glad you enjoyed it!

@shirish2005 Рік тому

Nice explanation

@sezif3157 2 роки тому

bro this info is awesome! , THANKS!

@ADevStory 2 роки тому

Thank you for watching! If you'd like a specific topic don't miss the poll in the community section!

@TheFxGuy100 Рік тому

This is great, thank you so much

@ADevStory Рік тому

Glad it was useful!

@salahuddin3938 3 роки тому

very well sir

@lahwfsk167 2 роки тому

very very nice tutos, Big thx for the effort !!

@ADevStory 2 роки тому

Thanks!

@felipecaetano15 Місяць тому

Great video, thanks a lot! I just wish audio was a little bit clearer. Since I'm not a native english speaker I had trouble understanding some parts. I tend to dislike videos with background music for the name reason. Bus still amazing. Moving on to the next parts!

@ADevStory Місяць тому

Oh I try also to have subtitles in other languages and fix the close captioning to help in that sense, but I'll take the feedback also for new videos. Thanks!

@vinayborikar9988 2 роки тому

Nice easy to understand explanation

@ADevStory 2 роки тому

Thank you! Glad you liked it!

@breakunknown Рік тому

great content, thanks

@ADevStory Рік тому

Thanks! Glad you liked it!

@nikhilgoyal007 Рік тому

very helpful!! thanks!!

@ADevStory Рік тому

Glad you liked it!

@salamesalehpour 2 місяці тому

very very usefull

@ADevStory 2 місяці тому

Glad you liked it!

@petersteel7735 21 день тому

Very nice! Thank you for the video! One recommendation, invest in a microphone to increase sound quality. My ears are bleeding 😂

@ADevStory 20 днів тому

Yeah newer videos sound better. Sorry about that!

@MyHussnain 2 місяці тому

Thank you for the explanation it was really comprehensive! My question is, can a response to an event (order) can also be an event (order/event)?

@ADevStory 2 місяці тому

Yes it can. But keep in mind that if you are expecting a response it would be a request-response model .

@imsathyasekar Рік тому

This was a great video.. thanks!! One question- you mention that there isn't a single point of failure with EDA. But isn't the broker in your diagram a single point of failure? If that goes down, the rest of the system is also impacted right? The services themselves are up and running but with no events, they will not be processing anything.

@ADevStory Рік тому

Hi! Sorry for taking long to get back to you. This is a good question! Thanks for asking. So in summary, in any distributed system you face the issue of any component being able to fail (technically in non-distributed systems too, but it would make the whole system fail). There are things that can make the whole systems fail, think for example: the network and electricity. If those go down, so does your system. But network or electricity are typically not considered a single point of failure. There are mechanisms that allow to make it more reliable, even when they can fail (redundancy, partitioning, batteries, etc). Same thing happens with the broker. A message broker is typically a system that is very efficient and reliable to handle _just_ message passing. It typically is a distributed system with multiple nodes, replication, and reliability considerations that make it highly available. Of course it can happen that it goes down and take all the communication between services too, but typically this risk is highly mitigated. I found this article from Ciaran O'Donnell that might help clarify it a bit more: ciaranodonnell.dev/posts/message-broker-as-spof/ There's also the Fundamentals of Software Architecture book that has a chapter on EDA where it explains it (amzn.to/3HSKYXC *) Please let me know if it isn't clear :) And again, thanks for watching! * Disclaimer, I _may_ receive some payment from Amazon if you go through this link and buy the book at no additional cost to you.

@mysocial Рік тому

Good job dude

@ADevStory Рік тому

Thanks!

@u2ubevipin 2 роки тому

In your profile image, Character D and S are swapped. :) Thanks for the video, it was quite helpful.

@ADevStory 2 роки тому

Glad you liked it and it's great you noticed 😁 the idea is to be the acronym for A Dev' Story 😁

@toxicitysocks 5 місяців тому

In the example where a response comes back to the user after confirming payment, how would you route that response back to the user? Are there any options beyond polling from the frontend or using a web socket (which makes your server stateful)?

@ADevStory 5 місяців тому

Not much else. So basically there are two ways from the client: pull (polling) or have a open connection to receive the message (websockets, SSE, http2 type connections and the like). You can have ways to notify the client via an intermediate service. Even having a websockets might be fine if you are able to restablish the connection in case of failures.

@toxicitysocks 5 місяців тому

@@ADevStory makes sense, thanks for the reply!

@ADevStory 5 місяців тому

Any time!

@alexmagnitov7324 Рік тому

@ComputerWhisperer, why may I choose Event-Driven Architecture instead of Layered Architecture, which both scalable and, as I see, Layered Architecture provides even better performance?

@ADevStory Рік тому

Depending on the use cases sometimes event driven can be more scalable and have better throughput. For example, in bidding systems, online multiplayer games or even Twitter or feed-like systems. The type and amount of data is better processed in an event driven model there. There are some other cases that are less intuitive at first like web servers based on Netty or NodeJs where an async / event driven model takes advantage of the very slow processing of input/output of a connection. Hope it's s bit clearer if it's not I can explain more. Just as a final thought: layered and event driven are not opposed. You can have layered AND event driven systems (for example, web frameworks).

@arvinto9149 3 роки тому

For a request that expects a response in an event-driven architecture, how would you send back the response? What are the common ways to do this?

@ADevStory 3 роки тому

You can send the response as another event that the first service expects / is subscribe to

@iliriandahri2674 2 роки тому

xyc c c c c, , y a ys foon te ny

@koeber99 Рік тому

When you say broker, do you mean just a queue (i.e. kafka)? Are there other types of brokers? Maybe a cache?

@ADevStory Рік тому

Basically a broker is a system that is able to pass events (Kafka being an example). It's not only a queue as a broker can have different ways to do so (topics too for example) but it does follow the publish subscribe pattern. Here's a definition: solace.com/what-is-an-event-broker/. Hope is clearer :)

@koeber99 Рік тому

@@ADevStory thanks!!

@sug_madic7683 3 роки тому

For me its hard to understand these things but one day i will reach to this

@ADevStory 3 роки тому

What is unclear? Anything I can do to help explaining it better?

@DogChowde 2 роки тому

really good. feel better than Martin Fowler's!

@ADevStory 2 роки тому

Thank you very much! But incomparable Martin Fowler is a legend and this video just takes a small part of what he he has talked about EDA. Thank you though! :) Hope you continue enjoying the series

@chessmaster856 4 місяці тому

Some implementation rs required. Architects deem to be complacent about not going full length, conveniently avoiding some details

@philipvangompel994 2 роки тому

If I understand your video correctly, EDA uses events while API's use commands. How does using API's fit in this EDA story? It is something completely different, or can both be combined? (If so, are there brokers able to both: 1) receive events, queue them, make them available to other services, and 2) maintain an inventory of "API locations" and call the respective API and redirect the response back to the original requester.)

@ADevStory 2 роки тому

So there are different things here. 1) API is Application Programming Interface. It's basically a contract for your app. So Events can be part of the API. 2) I think you meant rest/rpc apis which most are synchronous / command like executions. And that's the main difference with EDA. You can implement some type of EDA via wev by using technology like websockets. In a local machine tou can also implement EDA by having something like NodeJs' Event Loop, it having a process periodically check if there are events for it to process. The main takeaway here is that in EDA the communication is asynchronous and the coupling is low, so it is indifferent to the underlying technology (can ve Kafka, http, a process, etc). The "calling application" doesn't know anything about the application that will end up executing the task. And the executing application processes it whenever it receives the event. Hope is clearer :)

@deepshakumarroy4663 2 роки тому

Can u explain the performance drawback on choosing event driven architecture

@ADevStory 2 роки тому

Great question! The answer could be really long and become more of a discussion but will try to be concise. When you use distributed systems there's always a hit in performance compared to doing the same job in a single machine. Same happens for example in a machine with single thread/single process vs multiple processes. There's an overhead of: having to deploy more resources, greater latency in network communication (vs in memory) and serialization/deserialization among other things. Of course distributed systems can help improve a system's overall performance in other ways: having load balancing and parallelizing tasks, as well as other capabilities like (potentially) better maintainability, and more robustness. But if you could have a big machine that never goes down and it's able to parallelize jobs, it will more certainly be more performant than a distributed system. Add to that that in event driven architectures you need a message/event broker system in the middle between every system. So any communication between a Service A and a Service B has to go to an intermediate Service C which is a broker. As fast as the broker can be it adds some overhead and it will take a hit on performance. There are things to handle like: how to make sure events are not written/read twice? what happens if the broker goes down? and many of these decisions add to the overall performance. Is this something important? Should you discard EDA completely or use it always? It depends a lot on the context. It could be that scalability is more important in your system than performance for example in which case EDA tends to be a good option, or it could be the other way: maybe your system just need to respond within a very tight bound of ms and you're actually not planning to scale much. So at the end it depends a lot on the needs of your project.

@larssonsoder4824 2 роки тому

Could you help me explain more about 2 points in details: the benefits of "loosely coupling" and "dependency inversion" (some examples in real life about the difficulties if we don't use EDA and how EDA solves in these examples) when we use EDA? For example (Service A Service B C D directly) vs (Service A message broker Service B C D): - If I use a message broker, Service A won't have to care what Service B (or C D) is, Service A just needs to send an event, and Service B, C, D just need to receive, but I still have to configure the message broker so that it can be aware of the services if we have to change the endpoints. - If the customers ask for requirement changes (input or output changes), there will be a high chance that all services related to the functionality (service A, B, C, D in this example) will have to change - If one service is down (because of failure or deployment time), the others still can be online, but the overall functionality won't work properly, because one service requires all other services to work in order to achieve the goal These are the questions that I've been having a headache for a long time... Could you help me clarify and suggest me some best resources related to this field (microservices, distributed system, event-driven architecture, DDD). I wish you the best Christian.

@MrBa143 Рік тому

1. You only have to configure the message broker yes, after that you can just plug services into that broker, and as long as all services correctly implements the Events (as in a contract) they are ready to go 2. You always have to change software if you get new requirements, loose coupling doesnt change that, but it can make it easier. You can take down Service A and substitute it with a new service without changing anything else in your overall system / architechture, as long as the new service has properly implemented the required Events (contracts) 3. Correct, if all your use cases needs all services to be online, then your system wont work. But in best case scenario, some use cases will still work, despite one service being down. It is at this point you might load balance and have multiple instances of the same service running, to counteract system failures due to just one service instance going down. Rememeber, EDA coupled with microservices makes your system insanely scalable and resiliant.

@abhishekrathod4267 Рік тому

What is eventConsumerBufferSize? There is a use of this in circuitbreaker design pattern but it is not clear what this does

@ADevStory Рік тому

Where did you get that from? Is it a specific config?

@yuriastoria1477 9 місяців тому

does it EDA have the similarity concept with mesh architecture ?

@ADevStory 9 місяців тому

What do you mean by mesh architecture? Do you mean service mesh?

@ezzou2889 Рік тому

I have a question about the single point of failure part, Doesn’t the broker then become the single point of failure ? If it’s down then no event can be sent or received ? If so, how can we say that this approach solve the problem of having a single point of failure ?

@ADevStory Рік тому

Hi! Sorry for taking so long to reply, this is a good question, I already answered it in another comment but UKposts doesn't allow me to link it, so I copy here the same answer :D So in summary, in any distributed system you face the issue of any component being able to fail (technically in non-distributed systems too, but it would make the whole system fail). There are things that can make the whole systems fail, think for example: the network and electricity. If those go down, so does your system. But network or electricity are typically not considered a single point of failure. There are mechanisms that allow to make it more reliable, even when they can fail (redundancy, partitioning, batteries, etc). Same thing happens with the broker. A message broker is typically a system that is very efficient and reliable to handle just message passing. It typically is a distributed system with multiple nodes, replication, and reliability considerations that make it highly available. Of course it can happen that it goes down and take all the communication between services too, but typically this risk is highly mitigated. I found this article from Ciaran O'Donnell that might help clarify it a bit more: ciaranodonnell.dev/posts/message-broker-as-spof/ There's also the Fundamentals of Software Architecture book that has a chapter on EDA where it explains it (amzn.to/3HSKYXC *) Please let me know if it isn't clear :) And again, thanks for watching! * Disclaimer, I may receive some payment from Amazon if you go through this link and buy the book at no additional cost to you.

@aryadiadi6888 2 роки тому

@A Dev' Story, what's the solution, if a producer like web needs a response ?

@ADevStory 2 роки тому

It depends. If you are waiting for a response typically event driven architecture is not the best approach. EDA works best for asynchronous communication (when you don't expect an answer). In the case of waiting for an answer you are looking for synchronous communication or request/reply patterns. Of course you can implement it also with EDA but you have to deal with more complexity. So in the case of web requiring an answer my suggestion would be not to use EDA or change the behavior on the web to be async.

@suzhiyam-org469 2 роки тому

and what is the full form of BE on layered architecture that u had drawn?

@ADevStory 2 роки тому

What do you mean?

@nagag9166 2 роки тому

Is there a git link to check sample projects on these architectures please ?

@ADevStory 2 роки тому

I haven't created it but if it's helpful I can look for some time to do it 😁

@hassaanahmadawan1076 2 роки тому

İs event driven also know as event centered ?

@ADevStory 2 роки тому

I've never heard of event centered. What do you mean by that?

@javier.alvarez764 2 роки тому

Can you do a video about message driven architecture? It's use case?

@ADevStory 2 роки тому

Event driven and message driven are very similar. I can think of doing a video but won't be soon due to time limitations 😅 what doubts did you have?

@suzhiyam-org469 2 роки тому

I like this video and its good but on some places your explanation is very fast and its hard to understand. Kindly slow down the explanation way which will help us to understand clearly. Thanks for this video.

@ADevStory 2 роки тому

Thanks for the feedback! Will try to do in future videos!

@johnmorsley 2 роки тому

Cracking content, but please drop the background music!

@ADevStory 2 роки тому

Glad you liked the content. Why didn't you like the background music? 😅

@johnmorsley 2 роки тому

@@ADevStory, all background music is distracting! 😢

@ADevStory 2 роки тому

Oh sad to hear that. I found out actually the opposite. If you want to try, my first videos (algorithms) didn't have any and it was harder to focus I'd say (same for other videos online). I can try lowering a bit more the background music though so it's less distracting. Or maybe having some parts of the video without it. Do you think that'll help?

@munjal55555 2 роки тому

consistency part is little not clear , as when you want to have something like happens before relationship , you might want to use chain of events. and now your system it consistent.

@ADevStory 2 роки тому

If I get the question right, I meant eventually consistent. So when you do a transaction or request/reply all systems are seeing the same information after the operation was executed. With event driven a system sends an event and the other system will read it at one point in the future. If multiple systems are reading the event they may do so at different times

@Andy-si1pl 6 місяців тому

This sounds like the Observer/Observable pattern

@ADevStory 5 місяців тому

It's related. I mean partially as you implement observer/observable pattern with an event driven architecture. But you also implement other patterns like event sourcing with it.

@ingoleashish 3 роки тому

link for next part of event driven architecture

@ADevStory 3 роки тому

It hasn't been released yet but soon :)

@ChrisAthanas 2 роки тому

Consider a microphone, the room reverb is bad

@ADevStory 2 роки тому

Thanks for the feedback! I'm using one but probably will need a different one. 😓

@Zero-ym9qi Рік тому

The meaning of your logo ?

@ADevStory Рік тому

Just a QWERTY keyboard with the keys inverted (ADS instead of ASD)

@codelucky 2 роки тому

Good video but too low volume.

@ADevStory 2 роки тому

Thanks . It improved in the next one in the series

@PedroAntonioAngaritaRojas 2 роки тому

the volume is very low, you can hardly hear it!

@ADevStory 2 роки тому

Sad to hear that. Will try to improve next time

@BugTrampler 2 роки тому

Hey, your audio is way to quiet - i had to turn my speakers all the way up to 100% to hear your voice. Please consider turning the master volume up next time while mastering your videos (its easier to turn the volume down a little rather then having to turn the speakers up to 100% and having to adjust volume for all other running applications)

@ADevStory 2 роки тому

Thanks! May I ask you on which device are you listening it? Some people have reported it but I've tested in many devices (android phones, tv and desktop) and everything seems to fine. In my latest videos I've been increasing a bit more the volume just in case

@syedmubariz3106 10 місяців тому

he is looking like andrew TECH (tate)

@subaruhassufferredenough7892 2 роки тому

If you are like me and followed the playlist from the beginning, you might get confused about Layered architecture and how did event driven architecture come into the picture. Here is a link that I found helpful: www.ibm.com/cloud/blog/four-architecture-choices-for-application-development

@ADevStory 2 роки тому

Oh this is a great article. Thanks for sharing! Sorry it was a bit confusing. It's actually 2 series of videos and are related but not continuos though. But the article you shared connects them nicely!