Java MSMQ Interop on Windows
Comments Posted on Friday, February 8th, 2008. |
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Sagas and Unit Testing – Business Process Verification Made EasyPosted in Autonomous Services | Business Rules | EDA | ESB | NServiceBus | Pub/Sub | SOA | Testing | Workflow
Sagas have always been designed with unit testing in mind. By keeping them disconnected from any communications or persistence technology, it was my belief that it should be fairly easy to use mock objects to test them. I’ve heard back from projects using nServiceBus this way that they were pleased with their ability to test them, and thought all was well. Not so. The other day I sat down to implement and test a non-trivial business process, and the testing was far from easy. Now as developers go, I’m not great, or an expert on unit testing or TDD, but I’m above average. It should not have been this hard. And I tried doing it with Rhino.Mocks, TypeMock, and finally Moq. It seemed like I was in a no-mans-land, between trying to do state-based testing, and setting expectations on the messages being sent (as well as correct values in those messages), nothing flowed. Until I finally stopped trying to figure out how to test, and focused on what needed to be tested. I mean, it’s not like I was trying to build a generic mocking framework like Daniel. Here’s an example business process, or actually, part of one, and then we’ll see how that can be tested. By the way, there will be a post coming soon which describes how we go about analysing a system, coming up with these message types, and how these sagas come into being, so stay tuned. Either that, or just come to my tutorial at QCon. On with the process:
And here’s the test: public class OrderSagaTests { private OrderSaga orderSaga = null; private string timeoutAddress; private Saga Saga; [SetUp] public void Setup() { timeoutAddress = "timeout"; Saga = Saga.Test(out orderSaga, timeoutAddress); } [Test] public void OrderProcessingShouldCompleteAfterOneAuthorizationAndOneTimeout() { Guid externalOrderId = Guid.NewGuid(); Guid customerId = Guid.NewGuid(); string clientAddress = "client"; CreateOrderMessage createOrderMsg = new CreateOrderMessage(); createOrderMsg.OrderId = externalOrderId; createOrderMsg.CustomerId = customerId; createOrderMsg.Products = new List<Guid>(new Guid[] { Guid.NewGuid() }); createOrderMsg.Amounts = new List<float>(new float[] { 10.0F }); createOrderMsg.Completed = true; TimeoutMessage timeoutMessage = null; Saga.WhenReceivesMessageFrom(clientAddress) .ExpectSend<AuthorizeOrderRequestMessage>( delegate(AuthorizeOrderRequestMessage m) { return m.SagaId == orderSaga.Id; }) .ExpectSend<AuthorizeOrderRequestMessage>( delegate(AuthorizeOrderRequestMessage m) { return m.SagaId == orderSaga.Id; }) .ExpectSendToDestination<OrderStatusUpdatedMessage>( delegate(string destination, OrderStatusUpdatedMessage m) { return m.OrderId == externalOrderId && destination == clientAddress; }) .ExpectSendToDestination<TimeoutMessage>( delegate(string destination, TimeoutMessage m) { timeoutMessage = m; return m.SagaId == orderSaga.Id && destination == timeoutAddress; }) .When(delegate { orderSaga.Handle(createOrderMsg); }); Assert.IsFalse(orderSaga.Completed); AuthorizeOrderResponseMessage response = new AuthorizeOrderResponseMessage(); response.ManagerId = Guid.NewGuid(); response.Authorized = true; response.SagaId = orderSaga.Id; Saga.ExpectSendToDestination<OrderStatusUpdatedMessage>( delegate(string destination, OrderStatusUpdatedMessage m) { return (destination == clientAddress && m.OrderId == externalOrderId && m.Status == OrderStatus.Authorized1); }) .When(delegate { orderSaga.Handle(response); }); Assert.IsFalse(orderSaga.Completed); Saga.ExpectSendToDestination<OrderStatusUpdatedMessage>( delegate(string destination, OrderStatusUpdatedMessage m) { return (destination == clientAddress && m.OrderId == externalOrderId && m.Status == OrderStatus.Accepted); }) .ExpectPublish<OrderAcceptedMessage>( delegate(OrderAcceptedMessage m) { return (m.CustomerId == customerId); }) .When(delegate { orderSaga.Timeout(timeoutMessage.State); }); Assert.IsTrue(orderSaga.Completed); } } You might notice that this style is a bit similar to the fluent testing found in Rhino Mocks. That’s not coincidence. It actually makes use of Rhino Mocks internally. The thing that I discovered was that in order to test these sagas, you don’t need to actually see a mocking framework. All you should have to do is express how messages get sent, and under what criteria those messages are valid. If you’re wondering what the OrderSaga looks like, you can find the code right here. It’s not a complete business process implementation, but its enough to understand how one would look like: using System; using System.Collections.Generic; using ExternalOrderMessages; using NServiceBus.Saga; using NServiceBus; using InternalOrderMessages; namespace ProcessingLogic { [Serializable] public class OrderSaga : ISaga<CreateOrderMessage>, ISaga<AuthorizeOrderResponseMessage>, ISaga<CancelOrderMessage> { #region config info [NonSerialized] private IBus bus; public IBus Bus { set { this.bus = value; } } [NonSerialized] private Reminder reminder; public Reminder Reminder { set { this.reminder = value; } } #endregion private Guid id; private bool completed; public string clientAddress; public Guid externalOrderId; public int numberOfPendingAuthorizations = 2; public List<CreateOrderMessage> orderItems = new List<CreateOrderMessage>(); public void Handle(CreateOrderMessage message) { this.clientAddress = this.bus.SourceOfMessageBeingHandled; this.externalOrderId = message.OrderId; this.orderItems.Add(message); if (message.Completed) { for (int i = 0; i < this.numberOfPendingAuthorizations; i++) { AuthorizeOrderRequestMessage req = new AuthorizeOrderRequestMessage(); req.SagaId = this.id; req.OrderData = orderItems; this.bus.Send(req); } } this.SendUpdate(OrderStatus.Recieved); this.reminder.ExpireIn(message.ProvideBy - DateTime.Now, this, null); } public void Timeout(object state) { if (this.numberOfPendingAuthorizations <= 1) this.Complete(); } public Guid Id { get { return id; } set { id = value; } } public bool Completed { get { return completed; } } public void Handle(AuthorizeOrderResponseMessage message) { if (message.Authorized) { this.numberOfPendingAuthorizations--; if (this.numberOfPendingAuthorizations == 1) this.SendUpdate(OrderStatus.Authorized1); else { this.SendUpdate(OrderStatus.Authorized2); this.Complete(); } } else { this.SendUpdate(OrderStatus.Rejected); this.Complete(); } } public void Handle(CancelOrderMessage message) { } private void SendUpdate(OrderStatus status) { OrderStatusUpdatedMessage update = new OrderStatusUpdatedMessage(); update.OrderId = this.externalOrderId; update.Status = status; this.bus.Send(this.clientAddress, update); } private void Complete() { this.completed = true; this.SendUpdate(OrderStatus.Accepted); OrderAcceptedMessage accepted = new OrderAcceptedMessage(); accepted.Products = new List<Guid>(this.orderItems.Count); accepted.Amounts = new List<float>(this.orderItems.Count); this.orderItems.ForEach(delegate(CreateOrderMessage m) { accepted.Products.AddRange(m.Products); accepted.Amounts.AddRange(m.Amounts); accepted.CustomerId = m.CustomerId; }); this.bus.Publish(accepted); } } } All this code is online in the subversion repository under /Samples/Saga. Questions, comments, and general thoughts are always appreciated.
Differentiated UX – my a$$As if there wasn’t enough stuff for developers to deal with. After the grand release of WPF, and the industry’s collective shrug and back to business, Microsoft stirs the pot again. I’ve read Brian’s authoritative description, even done some of the examples he’s outlined, and let me tell you, tech won’t help. Again. I don’t know about differentiation, but empowerment is important. Make the system work for the user. What an idea. Let the user specify minimal inventory levels for products, and rules for replenishing. Give them a dashboard where they can see the status – what’s back ordered, orders expected to be authorized in the next relevant time interval, recent supplier timeliness, etc. If you’re thinking that this ties in to Event Driven Architecture, you’re right. Let the user subscribe to business events that interest them, pop up a messenger-like notification when they occur. Let the user click on the data in there, and have the rest of the UI synchronize around that. Purchasing has struck a new deal with a supplier? Let me know. Click. Products they supply open in one view. Suppliers providing the same or similar products open in another. Contact info in another. Replenishment times in another. Everything synchronized. Everything in real time. Let them seamlessly work connected and disconnected. You do that with regular boring winforms, and they’ll kiss the ground you walk on. Differentiated user experience? Shrug.
[Podcast] Message Priority – You Aren’t Gonna Need ItIn this podcast we’ll be discussing the issues around supporting different kinds of service-level agreements in an SOA, and how using message prioritization helps and hurts. We’ll also be looking at alternative solutions more distributed in nature,which make use of specific deployment and configuration schemes that result in a more robust system. Symon asks:
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nServiceBus Going GlobalPosted in NServiceBus
Things have been really busy with nServiceBus. I mean crazy-busy. The number of people emailing me that they want to use nServiceBus on their projects instead of (other technology) is beginning to grow beyond my capacity to answer them all. Companies buying training are popping up quicker then ever. I’ve just finished training a team of Indian developers tasked with developing a security system for an American company, and now I’m flying to Australia to do two weeks of in-depth training over there. There are Software-as-a-Service Startups doing nServiceBus-Web integration in Ireland and getting amazing performance. There are manufacturing-ish companies in France using the grid-like capabilities of nServiceBus to support various batch sizes, service-level agreements, and rush jobs. Rails projects in the US are beginning to look at nServiceBus on top of ActiveMQ for their back-ends. It’s looking like this isn’t going to stay a one-man operation much longer.
Distributed Architecture on ARCast.TV Rapid ResponseA while ago, me and Ron Jacobs (virtually) got together and did a couple “rapid responses” to questions on the MSDN architecture forums, and I just noticed that they’re online. The really great thing is that there are transcripts! For your convenience, I’ve included them here. By the way, if you’re looking for more Q&A style info, check out the Ask Udi podcast. If you have a pressing question and need a shorter turn around time than the month or so it usually takes me for the podcast, send me an email to OnlineConsultation@UdiDahan.com. Number 1
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Durable Messaging Is Not EnoughI’ve been sitting on this post for a while, waiting, before outlining all the kinds of problems durable messaging doesn’t solve, I wanted to have a solution handy. Harry Pierson begins to outline the goodness that durable messaging brings to SOA, and in a later post on idempotence describes in general terms how it ties back into durable messaging and transaction – in essence describing a saga. Let’s do this in story form. Since you’re concerned that maybe your shipping company’s servers may be down for some kind of planned (or unplanned) maintenance just as you’re trying to fulfill orders, you use a durable messaging solution there. What happens is that messages get written to disk on your end, and later the messaging tries to transfer the messages until it succeeds. So what’s wrong with that? Well, let’s say that the shipping company’s servers went up in smoke (true story – broken down air conditioners + poor ventilation, you get the picture). Those servers aren’t going to be coming back online any second now. So, you have all these order messages buffering on your disk. Taking into account all the data, meta-data, XML, SOAP, encryption and everything, we may get up to 1MB per message. And now’s holiday season and your company’s selling hand over fist, hundreds of orders per second from all over the world. So that means we’re eating up 100MB of disk per second, that’s 6GB a minute, and in under an hour of our shipping company’s servers going down – so do ours. Durable messaging – yay? We don’t want to lose those orders, right? In short, durable messaging is an important part of the solution, but it’s not the whole solution. [Continued next time…] If you’re impatient and just want the solution, yes, nServiceBus give you all the tools you need.
Israel Grid Technologies Association Presentation on NServiceBusI know that I’ve been alluding to the grid-like capabilities that are gained when working with nServiceBus, and I’ll be giving a presentation on that next week. Here’s the info:
As usual, I’ll be putting up the slides and example code after the presentation.
[Presentation files] Asynchronous Systems Architecture for the WebWe had a great turnout yesterday at the Web Developer Community (not user group <grin/>). I passed on the presentation files and code samples to Noam but figured that the rest of my readers might enjoy them as well. The (pdf) presentation is here: Asynchronous Systems Architecture for the Web The code sample is here: Asynchronous User Management Code Sample In the sample, you can see the use of sagas to manage the user registration process; store user email and hashed password, send a confirmation “email”, when the user clicks the “link”, the web server will take the saga id found in the url, and send a message with that id. This will cause the saga to complete and the user to be written to the “database”. Since I didn’t have an email component on my laptop, and I’m guessing you don’t either, the saga just writes the url to the console. Copy and paste it from there into the browser, and you’re good to go. A Word on TimeoutExceptionsOne other thing that I want to call to your attention. When stepping-through the code in the debugger, you’re liable to spend more time than the Transaction Coordinator likes, which will cause it to rollback and try the message again. This is supposed to happen and occurs by design. When you’re actually working with a database in a high performance environment, there will be cases where one transaction locks a page of a table and may cause other transactions to either timeout or be chosen as victims and just tossed. The behavior that best handles this scenario is just to retry the transaction. However, you don’t have to write ugly code that checks for the specific error codes of each specific database for your code to work properly. The infrastructure will automatically do that for you – just let the exception happen. No need to write any try-catch code. The sample is built on the newly released version of nServiceBus (1.6.1) but already contains all the binaries so you don’t have to set anything up yourself. What’s coming for nServiceBusWe’re working towards a 2.0 release in the June-July timeframe which, beyond having the necessary documentation, web site, samples and everything any self-respecting open-source project has, is going to have some amazing grid-style features that will make all the message-priority & dynamic-routing stuff look “so last year”. Stay tuned.
Israel Web User Group Presentation: Asynchronous Systems Architecture for the WebPosted in Presentations
This Sunday, at 17:00 in the Microsoft Offices in Raanana I’ll be presenting at the grand re-opening of the web user group. Looking forward to seeing you there. Title: Asynchronous Systems Architecture for the Web Abstract: The main lesson learned from the big sites – EBay, Amazon, etc over the past year has been to step away from the database and do more work in memory. The scalability benefits of asynchronous communication have become better known but many developers are still struggling with taking traditionally synchronous processes like user authentication and making them asynchronous. In this presentation, developers will be shown, step-by-step the patterns, frameworks, and code needed to implement all user management processes for a web site. We’ll be dealing with scalability, web farms, long-running workflows, as well as the security implications of our decisions.
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Bryan Wheeler, Director Platform Development at msnbc.com
“Udi Dahan is the real deal. We brought him on site to give our development staff the 5-day “Advanced Distributed System Design” training. The course profoundly changed our understanding and approach to SOA and distributed systems. Consider some of the evidence: 1. Months later, developers still make allusions to concepts learned in the course nearly every day 2. One of our developers went home and made her husband (a developer at another company) sign up for the course at a subsequent date/venue 3. Based on what we learned, we’ve made constant improvements to our architecture that have helped us to adapt to our ever changing business domain at scale and speed If you have the opportunity to receive the training, you will make a substantial paradigm shift. If I were to do the whole thing over again, I’d start the week by playing the clip from the Matrix where Morpheus offers Neo the choice between the red and blue pills. Once you make the intellectual leap, you’ll never look at distributed systems the same way. Beyond the training, we were able to spend some time with Udi discussing issues unique to our business domain. Because Udi is a rare combination of a big picture thinker and a low level doer, he can quickly hone in on various issues and quickly make good (if not startling) recommendations to help solve tough technical issues.” November 11, 2010 Sam Gentile, Independent WCF & SOA Expert “Udi, one of the great minds in this area. A man I respect immensely.” Ian Robinson, Principal Consultant at ThoughtWorks "Your blog and articles have been enormously useful in shaping, testing and refining my own approach to delivering on SOA initiatives over the last few years. Over and against a certain 3-layer-application-architecture-blown-out-to- distributed-proportions school of SOA, your writing, steers a far more valuable course." Shy Cohen, Senior Program Manager at Microsoft “Udi is a world renowned software architect and speaker. I met Udi at a conference that we were both speaking at, and immediately recognized his keen insight and razor-sharp intellect. Our shared passion for SOA and the advancement of its practice launched a discussion that lasted into the small hours of the night. It was evident through that discussion that Udi is one of the most knowledgeable people in the SOA space. It was also clear why – Udi does not settle for mediocrity, and seeks to fully understand (or define) the logic and principles behind things. Humble yet uncompromising, Udi is a pleasure to interact with.” Glenn Block, Senior Program Manager - WCF at Microsoft “I have known Udi for many years having attended his workshops and having several personal interactions including working with him when we were building our Composite Application Guidance in patterns & practices. What impresses me about Udi is his deep insight into how to address business problems through sound architecture. Backed by many years of building mission critical real world distributed systems it is no wonder that Udi is the best at what he does. When customers have deep issues with their system design, I point them Udi's way.” Karl Wannenmacher, Senior Lead Expert at Frequentis AG “I have been following Udi’s blog and podcasts since 2007. I’m convinced that he is one of the most knowledgeable and experienced people in the field of SOA, EDA and large scale systems. Udi helped Frequentis to design a major subsystem of a large mission critical system with a nationwide deployment based on NServiceBus. It was impressive to see how he took the initial architecture and turned it upside down leading to a very flexible and scalable yet simple system without knowing the details of the business domain. I highly recommend consulting with Udi when it comes to large scale mission critical systems in any domain.” Simon Segal, Independent Consultant “Udi is one of the outstanding software development minds in the world today, his vast insights into Service Oriented Architectures and Smart Clients in particular are indeed a rare commodity. Udi is also an exceptional teacher and can help lead teams to fall into the pit of success. I would recommend Udi to anyone considering some Architecural guidance and support in their next project.” Ohad Israeli, Chief Architect at Hewlett-Packard, Indigo Division “When you need a man to do the job Udi is your man! No matter if you are facing near deadline deadlock or at the early stages of your development, if you have a problem Udi is the one who will probably be able to solve it, with his large experience at the industry and his widely horizons of thinking , he is always full of just in place great architectural ideas. I am honored to have Udi as a colleague and a friend (plus having his cell phone on my speed dial).” Ward Bell, VP Product Development at IdeaBlade “Everyone will tell you how smart and knowledgable Udi is ... and they are oh-so-right. Let me add that Udi is a smart LISTENER. He's always calibrating what he has to offer with your needs and your experience ... looking for the fit. He has strongly held views ... and the ability to temper them with the nuances of the situation. I trust Udi to tell me what I need to hear, even if I don't want to hear it, ... in a way that I can hear it. That's a rare skill to go along with his command and intelligence.” Eli Brin, Program Manager at RISCO Group “We hired Udi as a SOA specialist for a large scale project. The development is outsourced to India. SOA is a buzzword used almost for anything today. We wanted to understand what SOA really is, and what is the meaning and practice to develop a SOA based system. We identified Udi as the one that can put some sense and order in our minds. We started with a private customized SOA training for the entire team in Israel. After that I had several focused sessions regarding our architecture and design. I will summarize it simply (as he is the software simplist): We are very happy to have Udi in our project. It has a great benefit. We feel good and assured with the knowledge and practice he brings. He doesn’t talk over our heads. We assimilated nServicebus as the ESB of the project. I highly recommend you to bring Udi into your project.” Catherine Hole, Senior Project Manager at the Norwegian Health Network “My colleagues and I have spent five interesting days with Udi - diving into the many aspects of SOA. Udi has shown impressive abilities of understanding organizational challenges, and has brought the business perspective into our way of looking at services. He has an excellent understanding of the many layers from business at the top to the technical infrstructure at the bottom. He is a great listener, and manages to simplify challenges in a way that is understandable both for developers and CEOs, and all the specialists in between.” Yoel Arnon, MSMQ Expert “Udi has a unique, in depth understanding of service oriented architecture and how it should be used in the real world, combined with excellent presentation skills. I think Udi should be a premier choice for a consultant or architect of distributed systems.” Vadim Mesonzhnik, Development Project Lead at Polycom “When we were faced with a task of creating a high performance server for a video-tele conferencing domain we decided to opt for a stateless cluster with SQL server approach. In order to confirm our decision we invited Udi. After carefully listening for 2 hours he said: "With your kind of high availability and performance requirements you don’t want to go with stateless architecture." One simple sentence saved us from implementing a wrong product and finding that out after years of development. No matter whether our former decisions were confirmed or altered, it gave us great confidence to move forward relying on the experience, industry best-practices and time-proven techniques that Udi shared with us. It was a distinct pleasure and a unique opportunity to learn from someone who is among the best at what he does.” Jack Van Hoof, Enterprise Integration Architect at Dutch Railways “Udi is a respected visionary on SOA and EDA, whose opinion I most of the time (if not always) highly agree with. The nice thing about Udi is that he is able to explain architectural concepts in terms of practical code-level examples.” Neil Robbins, Applications Architect at Brit Insurance “Having followed Udi's blog and other writings for a number of years I attended Udi's two day course on 'Loosely Coupled Messaging with NServiceBus' at SkillsMatter, London. I would strongly recommend this course to anyone with an interest in how to develop IT systems which provide immediate and future fitness for purpose. An influential and innovative thought leader and practitioner in his field, Udi demonstrates and shares a phenomenally in depth knowledge that proves his position as one of the premier experts in his field globally. The course has enhanced my knowledge and skills in ways that I am able to immediately apply to provide benefits to my employer. Additionally though I will be able to build upon what I learned in my 2 days with Udi and have no doubt that it will only enhance my future career. I cannot recommend Udi, and his courses, highly enough.” Nick Malik, Enterprise Architect at Microsoft Corporation “You are an excellent speaker and trainer, Udi, and I've had the fortunate experience of having attended one of your presentations. I believe that you are a knowledgable and intelligent man.” Sean Farmar, Chief Technical Architect at Candidate Manager Ltd “Udi has provided us with guidance in system architecture and supports our implementation of NServiceBus in our core business application. He accompanied us in all stages of our development cycle and helped us put vision into real life distributed scalable software. He brought fresh thinking, great in depth of understanding software, and ongoing support that proved as valuable and cost effective. Udi has the unique ability to analyze the business problem and come up with a simple and elegant solution for the code and the business alike. With Udi's attention to details, and knowledge we avoided pit falls that would cost us dearly.” Børge Hansen, Architect Advisor at Microsoft “Udi delivered a 5 hour long workshop on SOA for aspiring architects in Norway. While keeping everyone awake and excited Udi gave us some great insights and really delivered on making complex software challenges simple. Truly the software simplist.” Motty Cohen, SW Manager at KorenTec Technologies “I know Udi very well from our mutual work at KorenTec. During the analysis and design of a complex, distributed C4I system - where the basic concepts of NServiceBus start to emerge - I gained a lot of "Udi's hours" so I can surely say that he is a professional, skilled architect with fresh ideas and unique perspective for solving complex architecture challenges. His ideas, concepts and parts of the artifacts are the basis of several state-of-the-art C4I systems that I was involved in their architecture design.” Aaron Jensen, VP of Engineering at Eleutian Technology “Awesome. Just awesome. We’d been meaning to delve into messaging at Eleutian after multiple discussions with and blog posts from Greg Young and Udi Dahan in the past. We weren’t entirely sure where to start, how to start, what tools to use, how to use them, etc. Being able to sit in a room with Udi for an entire week while he described exactly how, why and what he does to tackle a massive enterprise system was invaluable to say the least. We now have a much better direction and, more importantly, have the confidence we need to start introducing these powerful concepts into production at Eleutian.” Gad Rosenthal, Department Manager at Retalix “A thinking person. Brought fresh and valuable ideas that helped us in architecting our product. When recommending a solution he supports it with evidence and detail so you can successfully act based on it. Udi's support "comes on all levels" - As the solution architect through to the detailed class design. Trustworthy!” Chris Bilson, Developer at Russell Investment Group “I had the pleasure of attending a workshop Udi led at the Seattle ALT.NET conference in February 2009. I have been reading Udi's articles and listening to his podcasts for a long time and have always looked to him as a source of advice on software architecture. When I actually met him and talked to him I was even more impressed. Not only is Udi an extremely likable person, he's got that rare gift of being able to explain complex concepts and ideas in a way that is easy to understand. All the attendees of the workshop greatly appreciate the time he spent with us and the amazing insights into service oriented architecture he shared with us.” Alexey Shestialtynov, Senior .Net Developer at Candidate Manager “I met Udi at Candidate Manager where he was brought in part-time as a consultant to help the company make its flagship product more scalable. For me, even after 30 years in software development, working with Udi was a great learning experience. I simply love his fresh ideas and architecture insights. As we all know it is not enough to be armed with best tools and technologies to be successful in software - there is still human factor involved. When, as it happens, the project got in trouble, management asked Udi to step into a leadership role and bring it back on track. This he did in the span of a month. I can only wish that things had been done this way from the very beginning. I look forward to working with Udi again in the future.” Christopher Bennage, President at Blue Spire Consulting, Inc. “My company was hired to be the primary development team for a large scale and highly distributed application. Since these are not necessarily everyday requirements, we wanted to bring in some additional expertise. We chose Udi because of his blogging, podcasting, and speaking. We asked him to to review our architectural strategy as well as the overall viability of project. I was very impressed, as Udi demonstrated a broad understanding of the sorts of problems we would face. His advice was honest and unbiased and very pragmatic. Whenever I questioned him on particular points, he was able to backup his opinion with real life examples. I was also impressed with his clarity and precision. He was very careful to untangle the meaning of words that might be overloaded or otherwise confusing. While Udi's hourly rate may not be the cheapest, the ROI is undoubtedly a deal. I would highly recommend consulting with Udi.” Robert Lewkovich, Product / Development Manager at Eggs Overnight “Udi's advice and consulting were a huge time saver for the project I'm responsible for. The $ spent were well worth it and provided me with a more complete understanding of nServiceBus and most importantly in helping make the correct architectural decisions earlier thereby reducing later, and more expensive, rework.” Ray Houston, Director of Development at TOPAZ Technologies “Udi's SOA class made me smart - it was awesome. The class was very well put together. The materials were clear and concise and Udi did a fantastic job presenting it. It was a good mixture of lecture, coding, and question and answer. I fully expected that I would be taking notes like crazy, but it was so well laid out that the only thing I wrote down the entire course was what I wanted for lunch. Udi provided us with all the lecture materials and everyone has access to all of the samples which are in the nServiceBus trunk. Now I know why Udi is the "Software Simplist." I was amazed to find that all the code and solutions were indeed very simple. The patterns that Udi presented keep things simple by isolating complexity so that it doesn't creep into your day to day code. The domain code looks the same if it's running in a single process or if it's running in 100 processes.” Ian Cooper, Team Lead at Beazley “Udi is one of the leaders in the .Net development community, one of the truly smart guys who do not just get best architectural practice well enough to educate others but drives innovation. Udi consistently challenges my thinking in ways that make me better at what I do.” Liron Levy, Team Leader at Rafael “I've met Udi when I worked as a team leader in Rafael. One of the most senior managers there knew Udi because he was doing superb architecture job in another Rafael project and he recommended bringing him on board to help the project I was leading. Udi brought with him fresh solutions and invaluable deep architecture insights. He is an authority on SOA (service oriented architecture) and this was a tremendous help in our project. On the personal level - Udi is a great communicator and can persuade even the most difficult audiences (I was part of such an audience myself..) by bringing sound explanations that draw on his extensive knowledge in the software business. Working with Udi was a great learning experience for me, and I'll be happy to work with him again in the future.” Adam Dymitruk, Director of IT at Apara Systems “I met Udi for the first time at DevTeach in Montreal back in early 2007. While Udi is usually involved in SOA subjects, his knowledge spans all of a software development company's concerns. I would not hesitate to recommend Udi for any company that needs excellent leadership, mentoring, problem solving, application of patterns, implementation of methodologies and straight out solution development. There are very few people in the world that are as dedicated to their craft as Udi is to his. At ALT.NET Seattle, Udi explained many core ideas about SOA. The team that I brought with me found his workshop and other talks the highlight of the event and provided the most value to us and our organization. I am thrilled to have the opportunity to recommend him.” Eytan Michaeli, CTO Korentec “Udi was responsible for a major project in the company, and as a chief architect designed a complex multi server C4I system with many innovations and excellent performance.” Carl Kenne, .Net Consultant at Dotway AB “Udi's session "DDD in Enterprise apps" was truly an eye opener. Udi has a great ability to explain complex enterprise designs in a very comprehensive and inspiring way. I've seen several sessions on both DDD and SOA in the past, but Udi puts it in a completly new perspective and makes us understand what it's all really about. If you ever have a chance to see any of Udi's sessions in the future, take it!” Avi Nehama, R&D Project Manager at Retalix “Not only that Udi is a briliant software architecture consultant, he also has remarkable abilities to present complex ideas in a simple and concise manner, and... always with a smile. Udi is indeed a top-league professional!” Ben Scheirman, Lead Developer at CenterPoint Energy “Udi is one of those rare people who not only deeply understands SOA and domain driven design, but also eloquently conveys that in an easy to grasp way. He is patient, polite, and easy to talk to. I'm extremely glad I came to his workshop on SOA.” Scott C. Reynolds, Director of Software Engineering at CBLPath “Udi is consistently advancing the state of thought in software architecture, service orientation, and domain modeling. His mastery of the technologies and techniques is second to none, but he pairs that with a singular ability to listen and communicate effectively with all parties, technical and non, to help people arrive at context-appropriate solutions. Every time I have worked with Udi, or attended a talk of his, or just had a conversation with him I have come away from it enriched with new understanding about the ideas discussed.” Evgeny-Hen Osipow, Head of R&D at PCLine “Udi has helped PCLine on projects by implementing architectural blueprints demonstrating the value of simple design and code.” Rhys Campbell, Owner at Artemis West “For many years I have been following the works of Udi. His explanation of often complex design and architectural concepts are so cleanly broken down that even the most junior of architects can begin to understand these concepts. These concepts however tend to typify the "real world" problems we face daily so even the most experienced software expert will find himself in an "Aha!" moment when following Udi teachings. It was a pleasure to finally meet Udi in Seattle Alt.Net OpenSpaces 2008, where I was pleasantly surprised at how down-to-earth and approachable he was. His depth and breadth of software knowledge also became apparent when discussion with his peers quickly dove deep in to the problems we current face. If given the opportunity to work with or recommend Udi I would quickly take that chance. When I think .Net Architecture, I think Udi.” Sverre Hundeide, Senior Consultant at Objectware “Udi had been hired to present the third LEAP master class in Oslo. He is an well known international expert on enterprise software architecture and design, and is the author of the open source messaging framework nServiceBus. The entire class was based on discussion and interaction with the audience, and the only Power Point slide used was the one showing the agenda. He started out with sketching a naive traditional n-tier application (big ball of mud), and based on suggestions from the audience we explored different solutions which might improve the solution. Whatever suggestions we threw at him, he always had a thoroughly considered answer describing pros and cons with the suggested solution. He obviously has a lot of experience with real world enterprise SOA applications.” Raphaël Wouters, Owner/Managing Partner at Medinternals “I attended Udi's excellent course 'Advanced Distributed System Design with SOA and DDD' at Skillsmatter. Few people can truly claim such a high skill and expertise level, present it using a pragmatic, concrete no-nonsense approach and still stay reachable.” Nimrod Peleg, Lab Engineer at Technion IIT “One of the best programmers and software engineer I've ever met, creative, knows how to design and implemet, very collaborative and finally - the applications he designed implemeted work for many years without any problems!” Jose Manuel Beas “When I attended Udi's SOA Workshop, then it suddenly changed my view of what Service Oriented Architectures were all about. Udi explained complex concepts very clearly and created a very productive discussion environment where all the attendees could learn a lot. I strongly recommend hiring Udi.” Daniel Jin, Senior Lead Developer at PJM Interconnection “Udi is one of the top SOA guru in the .NET space. He is always eager to help others by sharing his knowledge and experiences. His blog articles often offer deep insights and is a invaluable resource. I highly recommend him.” Pasi Taive, Chief Architect at Tieto “I attended both of Udi's "UI Composition Key to SOA Success" and "DDD in Enterprise Apps" sessions and they were exceptionally good. I will definitely participate in his sessions again. Udi is a great presenter and has the ability to explain complex issues in a manner that everyone understands.” Eran Sagi, Software Architect at HP “So far, I heard about Service Oriented architecture all over. Everyone mentions it – the big buzz word. But, when I actually asked someone for what does it really mean, no one managed to give me a complete satisfied answer. Finally in his excellent course “Advanced Distributed Systems”, I got the answers I was looking for. Udi went over the different motivations (principles) of Services Oriented, explained them well one by one, and showed how each one could be technically addressed using NService bus. In his course, Udi also explain the way of thinking when coming to design a Service Oriented system. What are the questions you need to ask yourself in order to shape your system, place the logic in the right places for best Service Oriented system. I would recommend this course for any architect or developer who deals with distributed system, but not only. In my work we do not have a real distributed system, but one PC which host both the UI application and the different services inside, all communicating via WCF. I found that many of the architecture principles and motivations of SOA apply for our system as well. Enough that you have SW partitioned into components and most of the principles becomes relevant to you as well. Bottom line – an excellent course recommended to any SW Architect, or any developer dealing with distributed system.” Consult with Udi
Guest Authored Books
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