We plan to use Vert.x framework for setting up our microservice, but at the same time we need to embed a third party application inside our microservice. This third-party application is multi-threaded, and thus I am not sure if this can be safely embedded inside our Vert.x based microservice. Can someone suggest reliable ways to proceed on this.
PS: I am very new to Vert.x so pardon me for my ignorance of it's internals, but I do understand Vert.x doesn't recommend multi-threading and goes with the Verticles based approach.
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So we have decided to use NestJS to build our web-app with, and we have this ongoing argument about whether we should use a Microservice or a Standalone app to implement our queue-interactions module with.
A bit of background - we use Amazon SQS as our queue provider, and we use the
bbc/sqs-consumer package for handling the connection.
Now one approach is to use a microservice, in a similar fashion to what is done here: https://github.com/algoan/nestjs-components/tree/master/packages/google-pubsub-microservice
I believe the implications are pretty clear, and it seems as if the NestJS documentation really pushes you towards microservices here, if only because all the biult-in implementations are for queues/pubSub services (rabbitMQ, kafka, redis...).
On the other hand, you can choose to use a standalone app, which I feel is basically a microservice but without controllers.
Since we opted for using a 3rd party package to handle the actual transport and all the technical details, this feels in a way more appropriate. We don't actually need to send the messages from the messageHandler to some controller and then process it, if we can process it directly from the messageHandler, no controllers included.
Personally, it seems to me that if we don't want to go into details with the transport implementation (i.e. use sqs-consumer package for it) then the microservice approach, while works perfectly, is an overkill. A standalone app feels like it would give us the benefits of separating the "main" and the "queues" processes, while maintaining simplicity of implementation as much as possible.
Conversely, using a Microservice feels more natural to others. The way to think about it is that it doesn't matter whether we choose to implement transport ourselves or use some package, the semantic meaning is the same in the way that we have some messages coming into our app from outside, thus using a custom transport Microservice really is the most appropriate solution.
What do you guys think about it?
Would you use the Microservice or the standalone approach?
And in general, when would you choose Microservice over a Standalone app and vice-versa?
In theory I understand how Microservices work and why they can be helpful in various cases but I still don´t get how it works in practice.
Let´s say there´s an online shop based on a CMS as a monolith application.
And there´s now the need to run the online shop in a MIcroservices architecture.
How would this Microservices architecture differ technically from the current, monolith, architecture?
For example, I pick out the productsearch.php. If i want to scale this function, normally I had to set up a new server and copy the whole CMS ressources folder to it for loadbalancing.
And with Microservices, productsearch.php would be a single Microservice I guess, and I would have to just copy this php file to scale without the need to copy other ressources?
I have tried to explain it using this diagram of a fictitious CMS. With micro services architecture, we can independently scale each micro service. Each micro service may be developed by a different team, they may be even developed using different technology. But we great flexibility comes great maintenance overhead, I believe it is worth it as most of it can be automated.
Put simply, each module in a molithic application is a potential candidate for microservice. Howerver, microservices can be more granular than a traditional module.
This provides a good job at explaining how to decompose your monolithic application. http://microservices.io/patterns/decomposition/decompose-by-business-capability.html
Technically and conceptually, a microservice is independent of other services (where in a monolith you'd have modules with inter-dependencies).
Technically, a microservice built on modern microservices platforms (such as Node.JS, Spring Boot or .NetCore) will be more easily able to take advantages of containerization systems (such as Docker), perhaps supported by service registry and configuration management technologies (such as Kubernetes, ZooKeeper, Eureka and so on).
The advantage of containerization is that it'll be easier to scale-out (add more containers). Going further, the whole microservice / containerization concepts, and related technologies, also help enable things like CI/CD.
I spent the last couple of days figuring out what development stack to use for the interactive student platform I'm planning to build.
I figured out that the MEAN stack may suit the job very well. However, I face a dilemma whether to use Node.js as backend technology for the application:
Reasons to consider Node
The backend will mainly consist of realtime components. E.g. collaboration tools, notifications, etc.
These components will handle this data concurrently
It will scale better than a conventional server-side programming language such as PHP
Exposing the data with REST for e.g. a mobile applications will be a breeze
Having one data format (JSON) in the front- and backend will speed up development.
Doubts
Some components require computation. Although not that complex, it may slow down the application.
Although the application is mostly a single page application, the application will (in a later stage have some features that Node seems not typically suited for. E.g. a payment workflow.
I already made the switch from a previous approach, so this time I want to be sure to choose the right approach. Will Node.js be the right choice for this application, or will a, for example, PHP backend with Laravel suit the job better as the application matures?
I think there's a whole range of possibilities you're not considering, for example it's a perfectly valid approach to use Node for some of the back-end (e.g. connections to third parties, managing the UI, handling concurrent users) while delegating some of the back-end to other components that are more suited (e.g. components that require heavy computation).
That said, I don't see anything you describe in your 'doubts' as being particularly non-nodish. The computation stuff you say will be lightweight, but my recommendation there is to treat it like any other async task, then if you decide later that it is a problem (e.g. slows down the app) it's pretty trivial to extract that out into either a separate Node process (therefore not blocking your main app's event loop) or use a component built in your language of choice (Java, .NET, C, Perl, whatever) as described above.
I don't understand why you suggest a workflow isn't something Node is suited for. I've seen and built a number of them in Node and other frameworks, it's no less suited for it than any other framework, and better than some.
I want to be clear: I am asking about the case where I am not using any concurrency in my own implementation. I just want to know if the framework within which my backend will be invoked (ie google app engine) itself imposes thread-safety requirements on the code running on it.
Thank you!
P.S. as a related but separate question, is there any guidance on how to do multithreading in our own backend code (which then obviously needs to be appropriately thread-safe). Specifically, can we use java's standard executor services / thread pools, or there is some google-approved API? Thanks.
So google app engine or any other platform won't ensure thread safety for you because all the critical sections which your concurrency control techniques are trying to make thread safe are defined by the developer (you) and there is no way for the OS to know when reads and writes should occur. For the JVM, the two main concurrency libraries which are heavily used are the Guava libraries (made by google! ;-) ) and the Akka framework.
Both are great libraries, I've used both and have had a pleasure from their learning curves. I would also recommend looking into the Play Framework, they support the akka framework, and building reactive web apps is their main focus. If you're interested in learning some cool aspects of production frameworks, I would highly recommend learning and implementing Dropwizard (Google app engine doesn't support it, but the take aways you get from it definitely outweigh that con).
Please let me know if you have any questions!
I am developing a project and In this project I need calling multiple concurent web services ( least 5 webservice) asynchrously.
For that , whcih framework can be used Vertx , node , or Play
thanks
In play there is too much working out of the box. Node js will be nice if you can lose some time for writing your own tools.
All of these frameworks can be used.
Disclaimer: I work on the Play framework.
Given Play's Scala heritage, even if you're using Java, we provide Promises so that you can reason the flow of making async calls without suffering from what is known as "callback-hell". You may want to consider using promises for Node also... I believe they are available. I think Vert.x may offer something there too. I'm unsure but I don't believe Node and vert.x provide promises out of the box.
You may find this page useful: http://www.playframework.com/documentation/2.2.x/ScalaWS
Play documentation is not so good. If you are thinking to implement in scala play can be good option, but for java you may not find it so great as few things are not supported in Java (Eg to write a body parser of your own you need to use scala)
Nodejs can be a good choice however, in nodejs utilizing all the cpu cores is hard. There is a framework jxcore which claims to have a solution for this, but, I have not used it.
Vert.X IMO can be a good framework, it makes good use of all cpu cores, provides N event loops. Optionally, you can use worker thread pool if you really need to do cpu intensive operation and be responsive.
You can use vertx with RxJava module ( https://github.com/vert-x/mod-rxvertx ). You can combine your async results in anyway you want. rxvertx module supports wrappers for EventBus, HttpServer, HttpClient, NetServer, NetClient and Timer.