Documentation

[vardius]

If

1. You have some questions
2. You had a problem with setup
3. You had a problem with configuration
4. You don't know how to do something
5. Have ideas or propositions
6. Think something could be explained better/in more details

Let me know so I can update documentation, allowing other ppl get over same issues faster.
Please comment here about your suggestion what should/could be added/updated in the documentation. And I will try to explain or to do it as soon as possible.

[mar1n3r0]

Hello and thanks for the fantastic boilerplate. I am using it for a starter point for my own project and currently testing with minikube locally.
I will try to summarize my discoveries so far:

1. After the breaking changes with apiVersion with kubernetes 1.16 onwards some of the helm charts don't work for me since they were not updated according to the guidelines.
   See: https://kubernetes.io/blog/2019/07/18/api-deprecations-in-1-16/
   Example after running helm make-install originally:

helm install --name go-api-boilerplate --namespace go-api-boilerplate helm/app/
Error: validation failed: unable to recognize "": no matches for kind "Deployment" in version "extensions/v1beta1"
make: *** [Makefile:64: helm-install] Error 1

As you can see with the current script it's impossible to see which chart specifically failed. Do you observe the same behavior by any chance ?
2. Because of that I have heavily modified the helm scripts to actually get latest packages from helm hub rather than use the archives included in the repo.
3. Even some of the latest stable charts are not updated as of yet to 1.16 guidelines. Namely magic-namespace and heapster so far. Due to this I have disabled those for the time being
4. Since I am installing the charts one by one and not as one whole package like the original I am facing some unexpected issues. Mostly some kubernetes services names don't match nginx ingress definitions. For example: go-api-boilerplate.user, go-api-boilerplate.auth etc... I see them as microservice-user, microservice-auth in my services list.

As soon as I have some decent workaround for the hardcoded charts I can create a PR, meanwhile I would appreciate if you had some ideas how to make those dependencies more flexible instead of tgz packages in the repo.

[hmersin]

Hi,

Thank you for the great repo. I think it has a lot of potential but I think it has a steep learning curve.

I would like to ask for an architectural documents, one that shows the components and one for the data flow. Also some docs about AWS ECR would be nice. I was able to generate images, tag and upload them to ECR but couldn't make k8s pull the images from ECR, I am guessing due to some docker-secret thing.

Please keep up the great work

[vardius]

Hi @hmersin,

yes if your docker registry is private you need to add secret to your k8s so it can pull images
more info here: https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/

as to brief explanation for the architectural concepts I can list some key points

• external communication (client-api) -> http
• internal communication (between api's micro services) - grpc

the boilerplate comes with two micro services examples auth and user with grpc communication between them and ui service web that communicates with api via http

api allows to dispatch commands following cqrs pattern and exposes data to ui using view model, request flow would look as follow:

dispatch command request -> command handler -> aggregate root -> event store -> event handler

later on the data can be queried via api using desired persistence model

• commands are validated and handled with command handlers https://github.com/vardius/go-api-boilerplate/blob/master/cmd/user/internal/domain/user/commands.go
• single POST request handler for command dispatch https://github.com/vardius/go-api-boilerplate/blob/master/cmd/user/internal/interfaces/http/handlers/user.go#L22
• multiple GET handlers for view model https://github.com/vardius/go-api-boilerplate/blob/master/cmd/user/internal/interfaces/http/router.go#L63-L67
• multiple domains with aggregate roots per service https://github.com/vardius/go-api-boilerplate/blob/master/cmd/user/internal/domain/user/user.go
• event handers responsible for side effects https://github.com/vardius/go-api-boilerplate/tree/master/cmd/user/internal/application/eventhandler

Directory structure:

• https://github.com/vardius/go-api-boilerplate/tree/master/cmd/user/internal/application
  Package application is a layer responsible for driving the workflow of the application, matching the use cases at hand. These operatios are interface-independent and can be both synchronous or message-driven. This layer is well suited for spanning transactions, high-level logging and security. The application layer is thin in terms of domain logic it merely coordinates the domain layer objects to perform the actual work.
• https://github.com/vardius/go-api-boilerplate/tree/master/cmd/user/internal/domain
  Package domain is the heart layer of the software, and this is where the interesting stuff happens. The objects in this layer contain the data and the logic to manipulate that data, that is specific to the Domain itself and it’s independent of the business processes that trigger that logic, they are independent and completely unaware of the Application Layer. There is one package per aggregate and to each aggregate belongs entities, value objects, domain events, a repository interface and sometimes factories. The core of the business logic, such as determining whether a handling event should be registered. The structure and naming of aggregates, classes and methods in the domain layer should follow the ubiquitous language, and you should be able to explain to a domain expert how this part of the software works by drawing a few simple diagrams and using the actual class and method names of the source code.
• https://github.com/vardius/go-api-boilerplate/tree/master/cmd/user/internal/infrastructure
  Package infrastructure is a layer that holds everything that interacts with other systems - Secondary/Driven Adapters. Secondary adapters wrap around a tool and adapt its input/output to a port, which fits the application core needs and can simply be an interface or a complex set of interfaces and objects.
• https://github.com/vardius/go-api-boilerplate/tree/master/cmd/user/internal/interfaces
  Package interfaces is a layer that holds everything that other systems interacts with - Primary/Driving Adapters. Primary adapters wrap around a use case and adapt its input/output to a delivery mechanism, ie. HTTP/HTML, HTTP/JSON or CLI.

boilerplate setup should be easy enough to follow the flow, I hope its not as hard to understand as it might seem
if you have specific questions please ask, will try answering best to my abilities, hope this little explanation attempt helps a bit

[hmersin]

Thank you for the super fast response and the architectural explanation.

When I run make helm-install my pods start to fire up except the web one. I think if I putting the web section into the requirements.yaml will fix it.

Again thanks for the great work,

[vardius]

@hmersin ohh yea very possible that is missing
if you improve/fix anything pr is welcome

[luisliz]

Hello,
I'm trying to work with these locally but I don't understand how to do this, the only thing that I can successfully run are the docker-run BIN=. To develop would I use Helm or telepresence?

I'm also a bit confused about how a user is registered with email or is this not implemented?

p.s. Love the boilerplate, I hope to use it in a project if I can get the hang of it.

[vardius]

@luisliz let me answer about user registration first:
it is designed to work as a password-less signup meaning that every time you want to login/signup you basically just provide an email address and get an Email message with a link which includes auth token, so after clinking the button you get logged in automatically.

Ofc this is only a boilerplate and I did it this way because it seems kind of trendy nowadays to do so. If needed it shouldn't be hard to change/extend to a normal email/password login process. And yes it does work right now.

k8s setup comes with dev mailbox https://github.com/maildev/maildev which is preinstalled in the go-api-bilerplate namespace. So here we come to the first question how to run it locally.

To do so ideally you have some Kubernetes cluster, docker for desktop comes with k8s local coaster which works great.
https://www.docker.com/products/docker-desktop

after that you can simply follow readme file steps https://github.com/vardius/go-api-boilerplate#quick-start which will guide you how to deploy this boilerplate to you local k8s cluster.

as @hmersin mentioned earlier #15 (comment) there is one requirement missing for web service which I added here 86b2aac

once you get it to run you can enter dev mailbox via web ui

or just go to http://maildev.go-api-boilerplate.local if you have updated you /etc/hosts correctly

As to debugging/developing code locally the way I usually do it is have a develop version running on my cluster and then the service I am working on I simply run locally via go run cmd/user/main.go with env set to cluster so it does work on the same database. if you are using goland or vscode it is easy to run debugger but most of the time unnecessary, anyway you don't need telepresence.

If you want to override default env variables from config you can do it as follow MYSQL_HOST=mysql.go-api-boilerplate.local go run -race cmd/user/main.go

Let me know if you have further question or my explanation is not enough, I am happy to try and explain even further.

If you find it not working at the first time you might want to open api request in a new tab and make browser accept self signed certificate.

[luisliz]

Thank you very much!

[xtay315]

we should put commands into application layer , domain layer should know nothing about transaction and db

[vardius]

@xtay315 why commands ?

command are something you want system to do, and I believe they should be kept in the domain layer
commands are simply a DTOs and know nothing about transaction layer

I think we could move command handlers to application layer, but definitely not commands itself

[xtay315]

@xtay315 why commands ?

command are something you want system to do, and I believe they should be kept in the domain layer
commands are simply a DTOs and know nothing about transaction layer

I think we could move command handlers to application layer, but definitely not commands itself

commands are simply a DTOs, it is not a domain concept. when a command go into domain layer , you should translate it into domain concept (entity, vo, or agg). a command just the contract/interface/api of application facade.

[vardius]

Could you maybe do a simple PR ? Would be much easier for me to picture things in the head while reading the code

[beautyfree]

@vardius I interesting in pipeline of development. What is your development setup and how do you start and restart the service you are currently working on?