We are 3 teams:
Website front-end (React)
Website back-end (Node.js)
Native app (React Native, Node.js)
We want to share logic (e.g. Validations).
As of now I found articles on 3 ways to do so:
A NPM Package we will create for our own needs
A micro-service with endpoints who carry relevant logic
Serverless functions who carry relevant logic
Any other real-life, production suggestions?
Any other real-life, production suggestions?
Kind of - in no specific order:
You could specify the rules in a language/technology agnostic way, and then have your app load them at runtime (or be compiled in during build). The rules could then exist as a config file, or even be fetched from a remote location (a variation on your options 2 & 3).
Of course, designing a language agnostic rules engine / approach is non-trivial, and depends on what you need the rules to do (how complex, etc). You might find a pre-built open source solution that does that.
I have seen people try this, but the projects never succeeded (for unrelated reasons). One team specified the rules in an Excel sheet.
But there are trade-offs:
Performance hit - how to take language agnostic rules and be able to execute them? This will probably take some translation. Native code is almost always going to be faster and more efficient.
Higher development effort.
Added complexity - harder to debug (even if you compensate by developing more mechanisms to assist you do that - which is more development effort).
Regarding Your Options
For what it's worth, code / design-time sharing is an obvious approach, which I guess is sufficiently covered by NPM. I don't know enough about React and Node to know if they have any better ways of doing that. Normally if I have logic I want to share I'll use a component which is purpose built (lean as possible, minimal dependencies, intended to be re-used across multiple projects), and ingested in (C# / .Net) at compile/design time.
As an alternative to NPM you could look at dependency injection. This would allow you to do things like update the logic even after the app was deployed, as long as it can access where ever a newer set of rules are. So it's a bit like your option 1 (NPM, code level loading) but at runtime, and just once, and your options 2 & 3 - fetched remotely at runtime - the difference being that you're ingesting the logic not firing off questions and receiving answers (less chatty).
Service base rules are good in that they are totally separated, but the obvious trade-offs are availability and performance at runtime.
I don't see a difference in your options 2 & 3 from the stand-point of creating, managing and sharing logic. The only material impact is on whomever implements and supports that service system.
Related
I am creating a new project that will run in Azure Web App on the new ASP.NET 5. We are not planning to run it on linux or anything like that, at least now. So the question is, should I try to keep both frameworks if possible just in case or I should prefer one of them. There are e.g. much less dependencies that I can use with dnxcore50 which is not so nice. So the main question is: are there any benefits of using dnxcore50 if running in Azure Web App, like: performance, stability, etc. over dnx451.
I have to start that I'm still the beginner in ASP.NET 5 (like the most other), so I didn't posted my answer before and you should ignore my reputation, because it's come from another subjects, which I know better.
I think that everybody, who switch to ASP.NET 5, ask the same question whether it does make sense to keep both framework in his projects. I try to post below my personal thoughts about the subject.
My personal choice is my short recommendation to you: keep both framework till you find some really important reason to drop one from there.
ASP.NET 5 is still not final. The strategy is not full fixed and it can be changed in a short time later. Just some examples. Previous beta versions have supported "Helios" as an option for hosting ASP.NET 5 applications on IIS. The option was dropped later (see the statement). Even the name dnxcore50 is renamed now to dotnet5.4 at least in all internal Microsoft components (see the announcement). One can suppose that some other things could be changed in the future. Thus I think that putting all your eggs in one basket would be too dangerous now: keeping of both frameworks could reduce the risk.
The next thing, which I found, was the following. dnxcore50 (dotnet5.4 or CoreFX or .NET Core foundational libraries) don't support many features supported by .Net Framework. One important example for me was missing XSD Schema validation (see here and here). I use XML only in combination with XSD Schema validation. I prefer JSON in the most other cases. Kipping of both frameworks in your project could helps you to locate the parts of your code, which could be not yet implemented in CoreFX. It could helps you to move the code in separate component or to change the implementation.
About the performance. One should distinguish potentiality of both frameworks from the current implementation. In general CoreFX was redesigned and decomposed. Many parts of one mscorlib was separated or removed (remoting, AppDomains and so on). It means that the performance of CoreFX should be better. Theoretically the factored API can provide better performance. Moreover one can more easy improve one parts of CoreFX and publish new version with improved performance. More modules instead of having one monolith gives us the new way for improvement of the performance and for fixing the bugs. On the other side replacing of dependencies to new version could be origin of new compatibility problems and thus it increases the risk and could decrease the stability. By keeping of both frameworks we can test whether the new problem exist in alternative framework. It allows us to suppose that the last changes of dependencies and not the last changes of our main code is the origin of new problems.
I can continue with pros and cons of the usage of every framework, but nodoby like to read long text and all my arguments forward me to the same practical decision: keeping by default of both frameworks in my projects as soon as I would find out a real requirement to drop one from the frameworks.
No major advantages really so far.
This might change in the future and why I'm planning to target both (CoreCLR and .NET 4.6). A lot of investment is being spent in CoreCLR but also on Docker and Service Fabric.
Just my 2 cents.
Here is the scenario.
We are developing a product where we have a base product and regional variations for the product. We have all the common code checked into the main trunk while we have created 2 branches (branch_us, branch_uk) for the variations off of the main trunk. There is common code that is constantly being checked into the main trunk and the code that is being checked into branch_uk,branch_us is dependent on the code that is checked into the main trunk. This is being done because we expect more regions to added in future releases and as a result we want to have max reuse as well as thin regional variations layer.
Based on the current strategy, the developer will have to develop locally and then manually check-in the common files into main_trunk and regional variations into branch_uk & branch_us. Then everytime code is checked into the main_trunk, we will have to perform a merge from main_trunk->branch_uk & main_trunk->branch_us before we can perform a build for branch_uk & branch_uk (two separate deployments) because of dependency of new code in branch_uk/us branch to the new common code in main_trunk. This model seems extremely painful to think about and unproductive.
I'm by no means an expert on TFS. Here is what I am seeking opinion on:
Is there a way TFS can dynamically pull changes into branch_uk/branch_us from the main_trunk without doing a manual merge after every check-in (in the main_trunk)?
Do you guys have any other recommendations on the code management process that might be more effective/productive than the current one?
Any thoughts and feedback will be much appreciated!
This seems like a weird architecture to me, but of course I'm coming at it from a position of almost total ignorance, so there might be a compelling reason to approach it that way.
That being said: It sounds to me like you don't have a single application with two regional variations, you have two separate applications that share a common ancestor. The short answer to your question is "No". A slightly longer answer is "No, but you could write code to automate it."
A more thoughtful question-answer is "Are you sure centralized version control is the right tool for the job?" It might be more intuitive to use Git for this. What you have are, in effect, a base repository and two forks of that repository. Developers can work against whatever fork makes sense, and if something represents a change that should apply to all localizations, open a pull request to have the change merged into the base repository. This would require more discipline on the part of the developers, since they would have to ensure that their commits are isolated such that they can open a pull request that contains just commits that apply to the core platform. Git has powerful but difficult history-rewriting tools that can assist. Or, of course, they could just switch back and forth between working on the core platform, then pulling changes from the core platform back up to the separate repositories. This puts you back to where you started, but Git merges are very fast and shouldn't be a big issue.
Either way, thinking of the localizations are a single application is your mistake.
A non-source control answer might involve changing the application's architecture so that all localizations run off of the same codebase, but with locale-specific functionality expressed in a combination of configuration flags and runtime-discoverable MEF plugins, or making a "core" application platform that runs as an isolated service, and separately developed locale-specific services that express only deviations from the core application platform.
I'm currently starting a new project where we are hoping to develop a new system using reusable components and services.
We currently have 30+ systems that all have common elements, but at the moment we develop each system in isolation so it feels like we are often duplicating code and then of course we have 30+ separate code bases to maintain and support.
What we would like to do is create a generic platform using shared components to enable quick development of new collections, reusing code and reusing automated tests and reduce the code base that needs to be maintained.
Our thoughts so far are that we would have a common code base for specific modules for example User Management and Secure System Access, these modules could consist of their own generic web module, API and Context. This would create a generic package of code.
We could then deploy these different components/packages to build up a new system to save coding the same modules over and over again, so if the new system needed to manage users, you could get the User Management package and boom it does what you need. However, because we have 30+ systems we will deploy the components multiple times for each collection. Also we appreciate that some of the systems will need unique functionality so there would be the potential to add extensions to the generic modules for system specific needs OR to choose not to use one of the generic modules and create a new one, but use the rest of the generic components.
For example if we have 4 generic components that make up the system A, B, C and D. These could be deployed to create the following system set ups:
System 1 - A, B, C and D (Happy with all generic components)
System 2 - Aa, B, C and D (extended component A to include specific functionality)
System 3 - A, E, C and F (Can't reuse components B and D so create specific ones, but still reuse components A and C)
This is throwing up a few issues for me as I need to be able to test this platform and each system to ensure it works and this is the first time I've come across having to test a set up like this.
I've done some reading around Mircroservices and how to test them, but these often approach the problem for just 1 system using microservices where we are looking at multiple systems with different configurations.
My thoughts so far lead me to believe that for the generic components that will be utilised by the different collections I can create automated tests at the base code level and then those tests will confirm the generic functionality and therefore it will not be necessary to retest these functions again for each component, other than perhaps a manual sense check after deployment. Then at each system level additional automated tests can be added to check the specific functionality that may be created.
Ideally what I'd like would be to have some sort of testing platform set up so that if a change is made to a core component such as User Management it would be possible to trigger all the auto tests at the core level and then all of the specific system tests for all systems that will share the component to ensure that any changes don't affect core functionality or create a knock on effect to the specific systems. Then a quick manual check would be required. I'm keen to try and remove a massive manual test overhead checking 30+ systems each time a shared component is changed.
We work in an agile way and for our current projects we have a strong continuous integration process set up, so when a developer checks in some code (Visual Studio) this triggers a CI build (TeamCity / Octopus) that will run all of the unit tests, provided that all these tests pass, this then triggers an Integration build that will run my QA Automated tests which are a mixture of tests run at an API level and Web tests using SpecFlow and PhantomJS or Selenium Webdriver. We would like to keep this sort of framework in place to keep the quick feedback loops.
It all sounds great in theory, but where I'm struggling is trying to put something into practice and create a sound testing strategy to cover this kind of system set up.
So really what I'm hoping is that there is someone out there who has encountered something similar in the past and has thoughts on the best way to tackle this and has proven that they work.
I'm keen to get a better understanding of how I could set up a testing platform / rig to aid the continuous integration for all systems considering that each system could potentially look different, yet have shared code.
Any thoughts or links to blogs / whitepapers etc. that you think might help would be much appreciated!!
Your approach is quite good, and since soon I'll have to face the same issues like you - I can give you my ideas so far. I'm pretty sure that to
create a sound testing strategy to cover this kind of system set up
can't be squeezed-in in one post. So the big picture looks like this (to me) - you're in the middle of the Enterprise application integration process, the fundamental basis to be test covered will be the Data migration. Maybe you need to consider the concept of Service-oriented architecture
generic platform using shared components
since it'll enable you to provide application functionality as services to other applications. Here indirect benefit will be that SOA involves dramatically simplified testing. Services are autonomous, stateless, with fully documented interfaces, and separate from the cross-cutting concerns of the implementation. There are a lot of resources like this E2E testing or efficiently testing SOA.
Background:
I'm thinking about web application organisation. I will separate front (web site for browser) from back (API): 2 apps, 2 repository, 2 hosting. Front will call API for almost everything.
So, if I have two separate domain services with my API (example: learning context and booking context) with no direct link between them, should I build 2 API (with 2 repository, 2 build process, etc.) ? Is it a good practice to build n APIs for n needs or one "big" API ? I'm speaking about a substantial web app with trafic.
(I hope this question will not be closed as not constructive... I think it's a real question for a concrete case, sorry if not. This question and some other about architecture were not closed so there is hope for mine)
It all depends on the application you are working on, its business needs, priorities you have and so on. Generally you have several options:
Stay with one monolithic application
Stay with one monolithic application but decouple domain model across separate modules/bundles/libraries
Create distributed architecture (like Service Oriented Architecture (SOA) or Event Driven Architecture (EDA))
One monolithic application
It's the easiest and the cheapest way to develop application on its beginning stage. You don't have to worry about complex architecture, complex deployment and development process. It also works better if there are no many developers around.
Once the application is growing up, this model begins to be problematic. You can't deploy modules separately, the app is more exposed to anti-patterns, spaghetti code/design (especially when a lot people working on it). QA process takes more and more time, which may make it unusable on CI basis. Introducing approaches like Continuous Integration/Delivery/Deployment is also much much harder.
Within this approach you have one repo/build process for all your APIs,
One monolithic application but decouple domain model
Within this approach you still have one big platform, but you connect logically separate modules on 3rd party basis. For example you may extract one module and create a library from it.
Thanks to that you are able to introduce separate processes (QA, dev) for different libraries but you still have to deploy whole application at once. It also helps you avoid anti-patterns, but it may be hard to keep backward compatibility across libraries within the application lifespan.
Regarding your question, in this way you have separate API, dev process and repository for each "type of actions" as long as you move its domain logic to separate library.
Distributed architecture (SOA / EDA)
SOA has a lot profits. You can introduce completely different processes for each service: dev, QA, deploying. You can deploy just one service at once. You also can use different technologies for different purposes. QA process gets more reliable as it involves smaller projects. You can version communication (API) between services which makes them even more independent. Moreover you have better ability to scale horizontally.
On the other hand complexity of the high level architecture grows. You have much more different components you have to take care: authentication / authorisation between services, security, service discovering, distributed transactions etc. If your application is data driven (separate frontend which use APIs for consuming data) and particular services don't need to communicate to each other - it may be not as much complicate (but such assumption is IMO quite risky, sooner or letter you will need to communicate them).
In that approach you have separate API, with separate repositories and separate processes for each "type of actions" (which I understand ss separate domain model / services).
As I wrote on the beginning the way you choose depends on the application and its needs. Anyway, back to your original question, my suggestion is to keep APIs as separate as you can. Even if you have one monolithic application you should be able to version APIs separately and keep their domain logic separate. Separating repositories and/or processes depends on the approach you choose (eg. among these I mentioned before).
If I missed your point, please describe in more detailed way what answer do you expect.
Best!
I have been having this debate with a friend where i have a library (its python but I didn't include that as a tag as the question is applicable to any language) that has a few dependencies. The debate is whether to provide a default environment in the initialization or force the user of the code to explicitly set one.
My opinion is to force the user as its explicit and will avoid confusion and make it clear what they are pointing to.
My friend this is safer and more convenient to default to an environment and let the user override if he wants to.
Thoughts ? Are there any good references or examples / patterns in popular libraries that support either of our arguments? also, any popular blogs or articles that discuss this API design point?
I don't have any references, but here are my thoughts as a potential user of said library.
I think it's good to have a default configuration available to allow developers to quickly evaluate the library. I don't want to have to go through a bunch of configuration just to see if the library will do what I need. Once I'm happy that the library will do what i need it to do, then I'm happy to configure it the way I want.
A good example is Microsoft's ASP.Net MVC framework. When you create a new MVC project it hooks in a default authentication and membership provider, which allows the developer to very quickly get a functioning application up and running. It is also easy to configure different providers to be used if the default one's don't meet the requirements of the application in question.
As a slightly different example, Atlassian Confluence is wiki software which supports many different back-end databases. Atlassian could have chosen to have no default DB configuration, but instead Confluence ships with a default, simple, file-based database to allow users to evaluate the software. For production installations you can then hook up to Oracle, SQL Server, mySQL or whatever else you like.
There may be instances where a default configuratino for a library doesn't really make sense, but I think that would be a special case, rather than a general rule.
It depends. If you can provide sensible defaults, you might want to do that: it will make life easer on the occasional user of the library as they can set only the relevant settings, as opposed to the whole environment (with possibly settings the implications of which they don't fully understand (yet)). You are correct, that in situations it is possible this leads to frustration and confusion as the defaulted settings might cause unexpected behavior (unexpected by the (inexperienced) user) -- you have to weigh the reduced frustration of convenience against the price of not-understood defaults to make the choice for each of these possible-to-default settings, which choice might affect the choice for other, related settings as well
On the other hand, if there is no sensible default (e.g. DB credentials, remote address), you should require the user to provide those settings.
The key in both cases is to provide enough information in the documentation of the library and in the error messages (either for missing settings or conflicting ones) that the user can figure out what those settings actually mean/control without having to read through the source code of the library. This part is hard because 1) it is usally tedious from the point of view of the library developer (so it is often skimped) and 2) the documentation has to be written from the mindset of a newbie to the library, which is often different from the library developer's mindset -- the latter knows the implicit connections/implications, the former has to be told about those in an understandable way.
Although not exactly identical in terms of problem domain, this strikes me as the Convention over Configuration argument.
There has been quite a lot momentum behind CoC in recent years, and in my mind, it makes a whole lot of sense. As long as flexibility is not lost, you have everything to gain. Lower friction development is what we are all after, and if I've got to configure every aspect of your API in order to get it working, I'm less inclined to use it over another API of equal functionality.
I happen to like Hanselman's podcasts, so if you want a little light listening, check out this podcast.
I think your question needs some clarification. For starters, I don't think a library should have any runtime configuration. In terms of dependencies, library dependencies should be handled in a manner appropriate to the environment they are being written for. In python, those dependencies should be in the setup.py file (under requirements), and ultimately that file should meet the requirements of whatever service you plan on making it available on (i.e. pypi for python).
For applications, it is completely okay to require runtime configuration, but you should try to have sensible defaults. If your application depends on libraries, that dependency should be handled in the same way a library dependency would be handled, even though that information may be redundant in the context of an installer (if needed). For the most part first-run scripts and their ilk should be apart of the installer/rpm.
For Web Frameworks, it is typical that your app would carry configuration with it, and likely that it would need to be installed in a different way than traditional applications. Here, about the only thing you can do is try to follow the conventions of whatever framework you are writing in.