About a year ago, I realised something else I was also missing in these documentation options: All these diagrams, they tell us what are the building blocks of the application, which blocks interact with each other and how they are related, but they don’t tell us what they do, nor how and when they interact with each other. They’re key to the architecture. It would try to be a pure function and leave details like saving the post somewhere to other modules. You are left with a description of modules that take data of form A and return data of form A’. IBM and Red Hat — the next chapter of open innovation. The full article is provided "as is" in a PDF file. Deleting a user will trigger an event that will delete the users’ posts; Creating a post will trigger the event that will lead to both subscribing the author to the posts’ subjects and increasing the authors rating; Deleting a post, from whatever use case, triggers an event that will result in decreasing that authors’ rating. and it only concern the domain part. A software architecture document is a high-level map. I think the C4 Model is a great way to document applications architecture, it is great to understand the architecture of the application to a certain level, but I still find it insufficient, although it took me some time to put my finger in what is missing. If this application had a Microservices Architecture, these two components would be the microservices. The handbook, tentatively entitled Documenting Software Architectures, will be published in early 2002 by Addison Wesley Longman as part of the SEI Series on Software Engineering. This tells us that our application deletes posts as a result of either a direct command from a user or when a post author has been deleted. Architecture must be documented in a good amount of detail and should be presented in … Software architecture has increasingly become important for the I made this decision because, we may want to trigger the command manually too. Furthermore, maybe more important than the diagrams themselves is the ability to use these dependencies analysis to stop a build in the case of a break in our predefined dependency rules. Specially important is that the two components (User and Blog, in mid-blue colour) are decoupled. Now, we zoom into our application, the blue square in the diagram above which maps to the dashed square in the diagram below. I find it specially important that all the options under consideration be written down with their pros and cons, as to spark discussion and a clear decision. You can find the configuration used to generate them in the repository root. Good to know we are facing the same issue. These services are relevant because, for example, they trigger an event or are used directly by another component. In this new series, learn why and Basic Idea is to keep business logic isolated from the Input/Output and external libraries This is important because the application map should make visible the connections between components as well as what they mean and any followup side effects, and for this we need to expose the services that wiring to other components and their names (which should express what they do). No human will understand such a map generated for a mid-to-large sized system. The Application and Domain namespaces represent layers, and each component is a vertical slice of the application, as explained by Uncle Bob, Simon Brown and others. Documenting Software Architectures, Second Edition, provides the most complete and current guidance, independent of language or notation, on how to capture an architecture in a … Core.Component.Application.Listener.WhateverListener.class Personally I prefer source-trackable documentation formats, but have historically steered away from generated documentation because it seems to lack readability or go out of date. An example of good usage of an UML class diagram is to document design patterns: This is fine, this is actually great! The Application Map is aimed at being truly a map of the application, defining its “cities” (Components), its “local roads” (use cases), “highways” (events), etc. Within this category of diagram, I find it useful to have 3 different types of diagram, to assert about different dependency types. Note, in the diagram below, how the modules in the same layer (nodes with the same colour) are all unaware of each other, at least directly. Documenting software architecture, Part 3, Develop the architecture overview. CCP – The Common Closure Principle – Classes that change together are packaged together Tilak Mitra. Maybe we just need an application map per command. domain.handlers.subdomain.MySubdomainEventHandler.class. In the User component, we can see that when a post is created, its author is automatically subscribed to that post subjects (tags). They don’t quite help us see what is wrong in our application codebase, in regards to promiscuous code relations and poor structure, which impacts modularity and encapsulation, essential to any engineering product; They don’t help us understand our codebase as a whole, what the application cog wheels can do and how they interact with each other. So we need a tool… which does not exist… yet! Documenting Software Architectures, Second Edition, provides the most complete and current guidance, independent of language or notation, on how to capture an architecture in a commonly understandable form. Software architecture has increasingly become important for the development of complex real-time systems. The idea is to use 4 different granularity (or zoom) levels for documenting software architecture: 1. If you want to explore this subject more, I recommend heading to the Joel Parker Henderson github repository about ADRs. Regards to autogeneration, there is a great PlantUML plugin for Archimate: https://github.com/ebbypeter/Archimate-PlantUML. The SEI Series in Software Engineering represents is a collaborative undertaking of the Carnegie Mellon Software Engineering Institute (SEI) and Addison-Wesley to develop and publish books on software engineering and related topics. Core.Component.Application.Command. 1, What software architecture is, and why it's important to document Now, I have some trouble with events in my architecture, to the point I started to restrict/limit them until I find a solution. it. Enter your email address to follow this blog and receive notifications of new posts by email. Documenting Software Architectures: Views and Beyond; Applying UML and Patterns: An Introduction to Object-Oriented Analysis and Design and Iterative Development; Written by. I also feel there is too much information in that Application Map, making it very difficult to read, but I think the CLI application to generate the map could use filters to only put in the map the events or commands we want to visualize. Furthermore, applying the same decoupling requirements to the other non domain wise modules, we can guarantee that we can easily replace any module. However, to document a whole application architecture using UML we need to use several types of diagrams. Noté /5. Change ). If you can model your problem as a sequence of data transformations a lot of the complexities mentioned above are going away. They must issue command, which is then processed by the command handler (where reside the business), which add another level of indirection…. This article is very helpful to understand Hexagonal architecture as well, but still I am not able to make it link with my requirement. It was the difficulty to understand what code was being executed as a result of events that made me come up with the Application Map idea. So I came up with an idea for a new documentation diagram, which I call an Application Map, that can replace the C4 Model Component diagram. There are three limitations I see in these diagrams: I have found two categories of diagrams that can help us with that. Sometimes, if there is some, it’s out-of-date, inap-propriate and basically not very useful. However when we need to explain to someone else (new developer, product owner, investor, …) how the application works, we need something more… we need documentation. The heart of the book is an introduction to the most relevant architectural views, grouped into three major families (which we call viewtypes ) along with practical guidance about how to write them down. Components can be mapped to DDD bounded contexts and/or Microservices, which means they must be completely decoupled, physically and temporally, from other components. By listener I mean a class whose public methods are all independently triggered by only one type of event, they focus on the event. The best is to use it as the starting point for the discussion, as an RFC (Request For Comments), which is an idea/proposal that we submit to the other members of the team/department requesting their input/opinion/approval. The advantage of generated documentation is that we can generate it every time we need it, so basically removes tge issue of getting outdated. Yes I must admit that I could improve the packaging to a more feature/component based style. This can help us clarify our code, and our idea of the application behaviour. Learn More. Any technical or non-technical person can clearly visualise what happens when any of the use cases of the application is triggered. The “User” component can create and delete users, while the “Blog” component can create and delete posts, and create comments to a post. So, it will be composed by one single box for the whole application, and it will be surrounded by other boxes that refer to the external systems and users the application interacts with. We learn how to code and we build some cool applications, and then we learn about architecture and how to make the application maintainable for several years…. 2. We always need to understand the tools, and use no more and no less than what we need. In this new series, learn why and how you should document software architecture. It has little detail but its main goal is to describe the context in which the application is. So, while an ORM is a module of the application, it is not a component because it only deals with technical concerns. The component diagram shows us the components inside one container. In the image below, we can see that deleting a post (“DeletePost”) will trigger the deletePost() method in the PostService, which is also triggered by a listener listening to the event that notifies that a user has been deleted. The readability is indeed a problem, but there are ways of making it more readable, ie using filters to generate only what we are interested on. Yes, i do, but there must always be some way of detecting what types of code we have. “Application Map” is something truly important in this profession, as developers come and go but knowledge must stay. development of complex real-time systems. Where do you place your event handler in your code ? series of posts about Software Architecture, https://java-design-patterns.com/patterns/strategy, Architectural Blueprints—The “4+1” View Model of Software Architecture, https://docs.google.com/document/d/1Xe5erulKsdaha3uwU6tNWsAWxjQK-Rcrr_iJeOCXuSQ/edit?usp=sharing, Joel Parker Henderson github repository about ADRs, https://github.com/hgraca/explicit-architecture-php, Java Annotated Monthly – September 2019 | IntelliJ IDEA Blog, Documenting Software Architecture – Trần Ngọc Minh Notes, Documenting Software Architecture — @herbertograca – ianwattsblog, Documenting Software Architecture – Notes de Francis, Dew Drop – August 23, 2019 (#3016) | Morning Dew, http://www.codingthearchitecture.com/2015/03/08/package_by_component_and_architecturally_aligned_testing.html, https://github.com/ebbypeter/Archimate-PlantUML, http://www.idesign.net/Training/Architect-Master-Class, Documenting Software Architecture – Ameer Academy, Lean Architecture by James Coplien and Gertrud Bjornvig, Patterns of Enterprise Application Architecture by Martin Fowler, Patterns Principles and Practices of Domain-Driven Design by Scott Millett and Nick Tune, The mythical man-month by Frederick P. Brooks, DDD, Hexagonal, Onion, Clean, CQRS, … How I put it all together, Microservices architecture: What the gurus say about it, Teams: building, managing, leading, performing, DDD Europe 2017: The 3 talks I most enjoyed, Dare to be Good Enough—You'll be Happier for it. Sometime, I send events from my command handler. In this context, each component is a module of the application, not restricted to domain wise modules (ie. In my experience, on our line of work, all type of documentation gets outdated. Date archived: November 8, 2016 | First published: June 27, 2008. With this type of diagram, or more accurately with the tool to test dependencies, we can easily detect such cases and prevent them from reaching production. Following the services, we list all the event listeners in each component, even if they are not actually used, which is handy because then we can detect it and either fix whatever needs to be fixed or remove the unused code. Architecture documentation (also known as software architecture description) is a special type of design document. A Template for Documenting Software and Firmware Architectures Version 1.3, 15-Mar-00 Michael A. Ogush, Derek Coleman, Dorothea Beringer Hewlett-Packard Product Generation Solutions mike_ogush@hp.com derek_coleman@hp.com dorothea_beringer@hp.com Abstract This paper defines a template for producing architectural documentation. Do you consider using Archimate as a graphic notation for your application map? Ideally, the namespaces/folder structure should communicate that on its own. You can, and maybe should, create yours as well, one that makes sense to you and your team. In Juval’s class, it’s applied at the Service/Component level. It reminds me this post by simon brown http://www.codingthearchitecture.com/2015/03/08/package_by_component_and_architecturally_aligned_testing.html. This content is no longer being updated or maintained. The use of a consistent, color-coded taxonomy is also a very helpful take-away from Juval’s course. To solve the second problem, we need to be able to selectively generate only part of the diagram. ( Log Out /  Furthermore, if we try to use one single class diagram to express the whole application we are asking for trouble. A component can be, for example, “Billing” containing all its use cases and Domain logic. Date archived: May 15, 2019 This will make it effortless to create such a diagram, remove the need for maintaining it, and make it virtually immediate to create it. That’s why I have the “OpenOrderCommand”, and it can be triggered manually or by an event handler. The Layer dependency diagram analyses the dependencies between layers, but within a layer there are still dependencies that must not occur. ( Log Out /  An event subscriber is similar to an event listener, except that its public methods are triggered by different events, they focus on a composite task, an example of a subscriber can be a class listening to different framework events in order to control when to start, commit or rollback the Request transaction. The previous diagrams don’t tell us what use cases we have in the application, nor what events are triggered by what use cases, nor what are the consequences of those events. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. How do you mitigate the cost of generation? http://www.idesign.net/Training/Architect-Master-Class. Next, in each component, we list any relevant services. In order to achieve that, the first step is to list what happens in a component when a specific capability is triggered. You'll Noté /5. introduces software architecture and the importance of documentation. This first article in the series and same with output – response call back to Client service, File store and Database, Input from all these apis will be first converted to Intermediate object -> then this IO will be processed by actual application -> Response will be put as JSON, File or Database. They are specially important because they intend to tell others, and our future selves, why the architecture is what it is. Do you think it can apply to any codebase written in different styles? It won’t be up to date, it won’t be trusted, and it won’t be used. The intention is really to use it to start a discussion, brainstorm, make the best decision possible, and use the proposal document itself as the decision log entry (ADR). But then the question remains, how do we document a full application?! The difference between modules and components is that a module is any modular piece of the application, while a component is a domain wise module of the application. I may have done a bad design decision which do not facilitate source code navigation : event handlers are not allowed to have business code. The fact that the ADR is written before hand, doesn’t mean that it is immutable, it must be updated/improved as the discussion unfolds. Core.Component.Domain.Entity.AnEntity.class. However, the application map you show, is for a very small system and it’s already unusable. Documenting Software Architectures in an Agile World July 2003 • Technical Note Paul C. Clements, James Ivers, Reed Little, Robert Nord, Judith A. Stafford. You have the right idea that we need to document the dynamic behavior of the system and it would be nice to have a tool that automatically generates this. Some time ago I started creating it, and I got to the point where only the component internal flow is missing, but it lists all the commands, services, listeners, subscribers and events. Lisez « Documenting Software Architectures Views and Beyond » de Paul Clements disponible chez Rakuten Kobo. I found it very helpful to have these different approaches cataloged together for easy reference. Since this report is a snapshot of current work, the material described here may change before the handbook is published. To start, there are a few artefacts that we need to know: I have seen a few templates for creating ADRs, and I saw nice things in several of them, so I created my own template. Software Architecture in Practice Second Edition Bass.book Page i Thursday, March 20, 2003 7:21 PM Third Edition . Core.Component.Application.Event.WhateverEvent.class A central precept of the book is that documenting an architecture entails two essential steps: (1) documenting the set of relevant views of that architecture, and then completing the picture by (2) documenting information that transcends any single view. The most fine grained diagram, aimed at describing the code structure inside a component. Level 4: Code diagram Three complementary views lay the foundation. Very nice article! The solution is fairly simple and it’s already mentioned in the article: It’s an artefact that will take a lot of effort and time to get done and also to simply keep it up to date; We will still end up having a big diagram with a lot of lines on it, which is not the most readable. The contents of this post might make more sense if you read the previous posts in this series. large-scale software development project. Software architecture has become a widely accepted conceptual basis for the development of nontrivial software in all application areas and by organizations of all sizes. You will learn about the five On the other hand, a “Billing” module is a component because it deals with domain concerns. It also documents the major technologies used and how the containers communicate. They contain the why behind the the diagrams that describe the architecture. Events are great in these cases, but I noticed the business intents of the command handler is less explicit. It is also concise and readable, and because it’s small, it’s also fast to create. how you should document software architecture. The idea is to use 4 different granularity (or zoom) levels for documenting software architecture: This is the highest granularity diagram. For me, the most important thing for a template is that it’s simple, and it has some documentation in it to help fill it in and even to help make pragmatical and unbiased decisions. ( Log Out /  I think they all should be separate, and it should be clear what they are used for. The Class dependency diagram is useful to analyse the dependencies between the different types of class we have in our codebase, specially if they are in the same layer. I use SharedCore to name my business Shared Kernel namespace, and Domain.Core to name my business domain core interactions (the most inner layer of the architecture, that has no dependencies except the SharedCore. A component is a domain wise module, a module that contains both Application and Domain layers. Most likely one would opt for something like queues or channels to give other functions an opportunity to react to a new post without having to explicitly model events and building up use cases as a data flow were functions participate – independently. Although they are pretty good for the other diagrams. In this series, learn why and how you should document software architecture. Yes, what you say totally resonates with me. And because of that, the document won’t need to change much either. Documenting Software Architectures, Second Edition, provides the most complete and current guidance, independent of language or notation, on how to capture an architecture in a commonly understandable form. At this point, we have all the components and their capabilities in the map. The same goes for events that would just be put on a queue by the source. Also, when I see the size of your application map, it looks way to big and unreadable. We hold that documenting software architecture is primarily about documenting the relevant views, and then augmenting this information with relevant information that applies across views. Do note, however, that I added the colours myself as to make it easier to read in this blog post. But, when used in a big application, this diagram will still have problems common to the previously mentioned diagrams: To solve the first problem, we need to be able to generate the diagram from the code, on-demand. เอกสารของ Architecture ในแต่ละโครงการจะเปลี่ยนไป . Documenting Software Architectures การนำเอกสารไปใช้ (ประโยชน์) 1. The C4 model was introduced by Simon Brown, and it’s the best idea about software architecture documentation that I’ve come across so far. The 4+1 Architectural view model was created by Philippe Kruchten and published, back in 1995, in his paper titled “Architectural Blueprints—The “4+1” View Model of Software Architecture“. For that we need to either know the application very well from the user perspective, or the codebase from the developer perspective. static.content.url=http://www.ibm.com/developerworks/js/artrating/, ArticleTitle=Documenting software architecture, Part 1: What software architecture is, and why it's important to document it. I have a similar architecture (decoupled, hexagonal, clean etc.) | Change ), You are commenting using your Google account. 6 Documenting a Software Architecture 6.1 Introduction Architecture documentation is often a thorny issue in IT projects. email, sms, …). So, we can and should use UML, but for the situations it should be used: to describe patterns, small portions of an application in detail, or high granularity views of the application with low detail (not using class diagrams). We will also list the event subscribers in each component, for exactly the same reasons as we list the listeners. But what documentation options do we have that can express the whole application building blocks and how it works?! It provides handy semantic which looks suitably for the things you draw on your map, but it’s standardized, more or less common, and for my opinion more readable than just color elements. I don’t think its possible to use those tools to have an auto generated application map. All the business logic related to a subdomain would be in the same package and it may help to understand everything the subdomain is doing and when. Documenting Software Architectures Software architecture has become a widely accepted conceptual basis for the development of nontrivial software in all application areas and by organizations of all sizes. This report compares the Software Engineering Institute's Views and Beyond approach for documenting software architectures with the documentation philosophy embodied in agile software-development methods. billing, users, …) but also including purely functional modules (ie. This post is part of The Software Architecture Chronicles, a series of posts about Software Architecture. As i see it, you are going in the right direction by grouping them into packages, but i go even further. – you need to provide an activity diagram for all use cases in your system. Online Examination System (OES) Version: 1.0 Software Architecture Document Date: 08/04/2016 Confidential , 2016 Page 4 of 58 6.1.7 Lecturer creates a new MCQ 36 6.1.8 Lecturer creates a new essay question 37 6.1.9 Lecturer generates a MCQ paper using the MCQs that are already saved in the database. Now we have the information about the flow within a component, but we are still lacking the information about cross component flow, so lets add the events being triggered and listened to: With all this information in our map, we can navigate it. domain.commandhandlers.subdomain.MySubdomainCommandHandler.class Yes, I feel exactly the same pain as you. I’ll quickly explain the main idea in my own words, although using his own example diagrams. It’s important to note that the 4+1 architectural view-model does not mandate that we use all mentioned diagrams, and not even all the views. However, the example below is not so useful… It’s very big, so it gets confusing and difficult to follow. domain.eventhandlers.subdomain.MySubdomainEventHandler.class, domain.handlers.subdomain.MySubdomainCommandHandler.class However, it still doesn’t tell us how all these capabilities relate to each other, for example “what happens as a consequence of a user creating a blog post?”. They are specially important because they intend to tell others, and our future selves, why the architecture is what it is. The Architecture Decision Records (ADR) are actually not really about documenting the current, or future, state of an application architecture, but instead the reasons that led to it. So, the tool used to generate these diagrams should also be usable as a testing tool and included in our CI pipeline, just like unit tests are, preventing unwanted dependencies to reach production, which maintains and enforces modularity, which in turn helps reach high changeability rate and therefore high velocity of feature development. It will quickly lose value if it’s too detailed (comprehensive). For example by providing the name of the use case that we want to analyse, which would result in only generating the sections of the diagram that somehow are related to the given use case. Highly recommend taking Juval Lowy’s Architect’s Master Class, it teaches how to correctly decompose a system based on volatility and how to document it. If we have a monolithic application with fully decoupled components, it will be fairly easy (code wise) to transform it into a Microservice Architecture. The application map looks very interesting, and specifically for events and events handler. I see elements of this in the color-codings of the Application Map. I’ll second the recommendation of Juval Lowy’s Architect’s Master Class: It is less readable, you don’t know exactly what the handler is doing, because when you see `bus.emit(new SomethingHappened()), you have to search for all the event handlers handling this event to know exactly what the command is doing. Given the rapid evolution of technology, some content, steps, or It’s common for there to be little or no documentation covering the architec-ture in many projects. To know more about it, you can read Simon Brown’s own explanations about it here and here, or even watch him talk about it here. It would also not make sense for an event to depend on a service. However, the treatment of architecture to date has largely concentrated on its design and, to a lesser extent, its validation.