How To Implement Domain-Driven Design (DDD) in Go 

One thing which I like very much in your teaching style is that you 'speak' your thought process, even write comments sometimes to show what you are going to implement next. This enables this video to be viewed as a guiding excercise, one can pause it at the right time, execute the solution themselves and play again to see how you did it. Thank you.

I am just 1h into the video and I'm in awe at how good of a lecturer you are. One does not often find this quality in a person. Keep up the good work!

Better than a lot of courses and tutorials! This is super helpful who wants to learn design pattern with practical usecase! Thanks for the effort Percy!

This is the best video I've seen on DDD with go. Thankyou!

This was SO good, thank you! You have help put a bunch of design patterns together for me.

Thanks for sharing this. It literally elevates my unstanding and usage of Golang to another level. 😄

Amazing. This is exactly what i'm looking for. Greate video, super clear, thank you!

Thank you for making these tutorials!!

Thanks for this Mr.Percy

Thank you for this Great Content!!

You're amazing Percy, keep going!

great material, thanks a lot for your time!

Nice course, very helpful, thanks

Awesome, we need a FULL COURSE!

Awesome Percy, wow you are a wonderful lecturer!!! Great Content by the way... Enjoyed & Learned a Lot. Thank you

What amazing content, it was great to see all this working together in a more real example, great patterns too, it would be amazing if you could later bring more content about this, maybe implementing it in a Rest API, thank you very much!

Great materials Percy! 🙂

thanks a lot for such a wonderful video! a lot of useful information, right now we're going to improve our backend architecture (along with migration from Python to Go) and I'm looking for different approaches and experience and feel like you video might help us a lot to build a new architecture.

Wonderful. Thanks for the video. The issue I am facing is about cross-cutting concerns like logging and tracing. Not sure whether I am doing the right structuring or not with them. Bought the blue book. Let's see if it can help with those.

This was an amazing DDD tutorial. Just one funny thing was the spelling of peanuts as “peenuts” in your unit tests 😂.

Sir make a complete series on E-Commerce.

you saved my life

Thank you for the great video and lecture. It is really amazing, I have learned a lot from you. Anyway, do you mind also to share how to handle transactional is repository pattern and DDD perspective? Thanks again

Hello from Singapore!! Thanks for the video, it is very insightful. You mentioned in the video that this directory structure is not recommended for production use cases. Would be good if you could talk more about production.

Transaction Value Object be like: Am I a joke for you?

Such a great video, one thing I noticed is that you some times do "package _test" and "package " for the test files, is there a reason to add or omit the suffix _test ?

I watched the entire video and the next one but I'm curious on what's the semantic related on how do you integrate: - an websocket/http server for having api access to a Service: is there a term in that DDD? is the way we manage repository can fit the case? - workers that process data from external sources to be mutated/transformed into our aggregate struct: the DDD show how to manage your own data but what about externals? what about long term processes? - utilities that allow you to perform meta programming like reflection on a struct to output data: does DDD is ideal for libraries that does that type of work? I have so much questions - can we do a reference between two aggregates?: for example we could have entities (temperature, coordinates, etc..) linked to an aggregate (planet) which belong to another aggregate (system) which also belong to another aggregate (galaxy). Great video btw, very instructive!

i'm watching it and i wanna say thanks in advance: clear and simple. But i'm asking myself in Repository Pattern chapter (about 36:00 - 40:00) why checking if person or customers map exist when you get this aggregate by factory method that assure properly init of this entities?

@programmingpercy Aren't your customer and product domains creating separate connections to the same db ? (can be seen around 1:50:00)

Should the aggregate directory be in the domain directory？

What about generated code (like oapi-codegen)? Then my whole openapi spec is generated into one file. How one should deal with it?

shouldn't the products field in the aggregate.Customer struct just be []uuid instead of []*entity.Item?

i'm currently at the creating CustomerRepository and I see you don't use pointers when returning aggregate.Customer or accepting it as arguments, the struct could have a lot of data, like a lot of transactions and products, why didn't you use pointer here? How do you decide when or where to use pointers in go?

I'm a bit late to the party, but just finished the vid and had a question about the config pattern you used to hook up the repositories to the services. with that implementation, wouldn't you need to specify the repositories on EVERY implementation of a service? wouldn't it be better to call those configs in the init of a service to avoid having to change the config in every place that you use that service?

Hi, what if you need to update multiple orders of an user in a single transaction? the steps would be: begin tx, getUser, updateOrders, end tx but due to repositories we can't not start a lets say, postgres/mysql transaction. How can we do this in case we need a transaction through multiple repositores?

How do you handle cycle dependency when some services calling each other mutually?

why wouldn't you use a package for entities? and what would you do instead?

Do you have a repo with this code?

Cool explanation, how ever this is just crud, where will you add busines rules for instance, imagine there is a rule to not allow orders after 3pm or only allow to save only one beer by order I mean business rules not crud rules.. where will add those?

Peenuts.

do you live in paderborn or like all german houses look the same lol XD

interesting. At the very first start point, you exposed an idea about language use case to call same things differently with example by analogy as client to be also a drinker. By the facts, they are not the same thining of the same people as long as people doesn't react the same in different context. Ok, it is the same person id, but not the same idea of this person now. The bankster is looking for his money as a client, but the wine manufactor is looking at him as someone that will love his wine (the underground target is not the same, and because of that, depend of who is controlled the activity, the experience of the people will not be the same with a bankster and a wine manufactor). So, even if i do understand your point to teach domain driven design at the very first point, we can not delete that most of the time, people forget that they has been called differently because the target is very different and that is the power of a language to use the correct appelation depend of: "the context" (so, it is the school role to make student understand that crucial point that make a big difference between a dumb tool's guy society and an intelligent society). The context is the one than help to define the correct word to use to define a subject (it is lexicaly correct to understand this about language). Also, there is some "generic", that can embed all of them. For example, a client is a drinker or what ever that can paid for something, but all of them are humans (i think animals will not be accepted to drink or to paid for the drink too). It is all about to understand layer up to abstraction that exist due to context and motivated target. Let's said that this way we name things would also influence our own mind thinking the way we are thinking this topic about. And that is all about humans relationship and project orientation is. What i said is that... who is the boss ? Who is the one that should define the orientation of the project if not the owner of the project ? Is it the man that borrow the monnaie or is it the man that know to do the job and his the owner because of that ? Let me tell you an example that describe our low level society it is becoming right now because of genereic inplace of anything without conscience (because to not understand that point): More and more, now, in hospital, due to free international crazy market , people injured or seek are becoming: clients. And that is why they are not happy in this hospital who has no human skills as target at the very frst place. Peoople injured are no more happy due to the very low quality of treatment, and employed people are also not happy due to the treatment they have from the hospital that is becoming an other room for businessmen, instead to still be some valuable technicians, they become diplpomate personal, with lower and lower skills by the fact, with more an dmore pressure about time to treat a... client (or at least, a society of dumb that see only generic or there own business word to be the absolute priority, out of any cultural context, out of any politic context, out of any real life context and then, because of that, out of any valuable morality context). You can not make an adapter/wrapper between business and medecine or professional . Yeah... you can do it, but it is useless from the first start point to the end one.

may be also need mutex to read map? here's chat gpt's example package main import ( "sync" ) type SafeMap struct { sync.Mutex Map map[string]string } func main() { // create a new safe map safeMap := SafeMap{Map: make(map[string]string)} // use the map in multiple goroutines go safeMap.Write("key1", "value1") go safeMap.Write("key2", "value2") go safeMap.Read("key1") go safeMap.Read("key2") } func (sm *SafeMap) Write(key string, value string) { sm.Lock() defer sm.Unlock() sm.Map[key] = value } func (sm *SafeMap) Read(key string) string { sm.Lock() defer sm.Unlock() return sm.Map[key] }