https://www.dc0d.com/ Recent content on sketches Hugo -- gohugo.io en-us © Copyright Notice | Kaveh Shahbazian Fri, 07 Jan 2022 15:27:59 +0100 https://www.dc0d.com/about/ Sun, 09 Feb 2020 18:00:00 +0100 https://www.dc0d.com/about/ My name is Kaveh Shahbazian. I enjoy programming. These are some sketches for software development. https://www.dc0d.com/post/2022/disposable-ideas/ Fri, 07 Jan 2022 15:27:59 +0100 https://www.dc0d.com/post/2022/disposable-ideas/ Key Takeaways Here a style of thinking - and some questions - about software development is put forward. It is a personal practice in note-taking and communicating thoughts. The first step in software development is to run the application, not design or write the code. It was like this, since before Smalltalk. The code is just a representation of the running application. There are two major decisions to make in software development, deciding what to keep, deciding what things to leave out. https://www.dc0d.com/post/2021/code-is-a-liability-and-must-be-disposable/ Mon, 22 Nov 2021 21:00:00 +0100 https://www.dc0d.com/post/2021/code-is-a-liability-and-must-be-disposable/ All the reduction in revenue comes from the code. All the lost opportunities and overdue time-to-market come from the code. The code causes long lead times. All the bugs come from the code. And for developers all the beautiful weekends, that you could be spent with your kids and your family, but weren’t so, come from the code. Code is a liability, not an asset. The functionality of it could be an asset, assuming you’re building something that someone is willing to pay for it. https://www.dc0d.com/microlog/2021/testing_without_mocks/ Sat, 10 Apr 2021 23:06:23 +0200 https://www.dc0d.com/microlog/2021/testing_without_mocks/ Blog post: Testing Without Mocks: A Pattern Language YouTube series: Testing lessons&livestreams of James Shore https://www.dc0d.com/microlog/2021/mocks_arent_stubs/ Thu, 25 Mar 2021 09:09:09 +0200 https://www.dc0d.com/microlog/2021/mocks_arent_stubs/ Mocks are not Stubs - Martin Fowler In this article I’ve explained a pair of differences: state or behavior verification / classic or mockist TDD. If it’s an easy collaboration then the choice is simple. If I’m a classic TDDer I don’t use a mock, stub or any kind of double. I use a real object and state verification. If I’m a mockist TDDer I use a mock and behavior verification. https://www.dc0d.com/post/2021/reliable-messaging-without-distributed-transactions/ Fri, 05 Mar 2021 22:09:21 +0100 https://www.dc0d.com/post/2021/reliable-messaging-without-distributed-transactions/ In a Microservice Architecture, some services update an entity. A service that updates an entity, might need to send an event to a down-stream service, to inform it about the update. The problem is, these two actions - updating a database and sending a message to a queue - can not be guaranteed to be completed transactionally. What if updating the database fails, but a message be sent to the queue? https://www.dc0d.com/slides/2020/the-role-of-the-code/ Sat, 05 Dec 2020 07:06:00 +0100 https://www.dc0d.com/slides/2020/the-role-of-the-code/ The role of the code in our organizations Or why no one likes the code? (The Source Code) (WIP - Twitter - Email) What is code? It executes all the steps and the details of the business. What is code? It executes all the steps and the details of the business automatically, thousands of times, every day. Code is your business rules and policies, validations, workflows. https://www.dc0d.com/microlog/2020/latencies/ Sun, 29 Nov 2020 07:08:52 +0100 https://www.dc0d.com/microlog/2020/latencies/ Source: ... and here's hoping that I've fixed all the typos people have pointed out to me from that earlier tweet: pic.twitter.com/3R1reNadXp — Udi Dahan (@UdiDahan) September 9, 2020 https://www.dc0d.com/microlog/2020/tdd_and_the_half_life_of_the_line_of_code/ Sun, 15 Nov 2020 20:50:57 +0100 https://www.dc0d.com/microlog/2020/tdd_and_the_half_life_of_the_line_of_code/ So there’s a variable that I didn’t know existed at that time, which is really important for the trade-off about when automated testing is valuable. It is the half-life of the line of code. If you’re in exploration mode and you’re just trying to figure out what a program might do, and most of your experiments are going to be failures and be deleted in a matter of hours or perhaps days, then most of the benefits of TDD don’t kick in, and it slows down the experimentation—a latency between “I wonder” and “I see”. https://www.dc0d.com/microlog/2020/idempotent_transactional_service/ Wed, 02 Sep 2020 21:18:09 +0200 https://www.dc0d.com/microlog/2020/idempotent_transactional_service/ This is draft for a blog post - some day. It is based on a talk by Udi Dahan: Reliable Messaging Without Distributed Transactions. https://www.dc0d.com/microlog/2020/what_would_be_an_example_of_lsp_violation/ Thu, 27 Aug 2020 21:21:23 +0200 https://www.dc0d.com/microlog/2020/what_would_be_an_example_of_lsp_violation/ An example of violation of Liskov Substitution Principle (LSP) If Square inherits from Rectangle, the problem starts when the intention is to change the width. We expect the height of a rectangle remains the same. But that’s not the behavior of a Square. It is a behavioral violation of LSP. To fix it: Make Rectangle immutable or, Break the inheritance chain https://www.dc0d.com/microlog/2020/where_to_start/ Thu, 27 Aug 2020 21:21:22 +0200 https://www.dc0d.com/microlog/2020/where_to_start/ Stop thinking in terms of language constructs - if statements, calls, etc - and start thinking in terms of concepts. Decide what to keep and what to leave out. A class should have one clear responsibility. Everything other than that should be left out - and delegated to collaborators. These two together, is a good zero point in programming. Don’t fall below zero. https://www.dc0d.com/microlog/2020/isnt_devops_enough/ Thu, 27 Aug 2020 21:21:21 +0200 https://www.dc0d.com/microlog/2020/isnt_devops_enough/ If you have not adopted a culture of learning and have not moved away from a culture of knowing then it doesn’t matter what practices you have adopted; DevOps, Lean, blah, blah. https://www.dc0d.com/microlog/2020/how_to_change_code/ Thu, 06 Aug 2020 20:19:19 +0200 https://www.dc0d.com/microlog/2020/how_to_change_code/ Wow! Reality was easier to change than code.. — Josemy Duarte (@JosemyD) August 6, 2020 humorous (pun intended - at so many levels) https://www.dc0d.com/microlog/2020/how_to_bring_change/ Sat, 11 Jul 2020 21:54:04 +0200 https://www.dc0d.com/microlog/2020/how_to_bring_change/ You cannot "force... change" if people are not enthusiastic. You're just beating yourself over the head with a rock if you try. Go find something more gratifying to do. https://t.co/VyaEy50lpW — Allen Holub (@allenholub) July 9, 2020 https://www.dc0d.com/microlog/2020/how_does_our_language_shape_the_way_we_think/ Sat, 11 Jul 2020 21:33:48 +0200 https://www.dc0d.com/microlog/2020/how_does_our_language_shape_the_way_we_think/ Follow me to Pormpuraaw, a small Aboriginal community on the western edge of Cape York, in northern Australia. I came here because of the way the locals, the Kuuk Thaayorre, talk about space. Instead of words like “right,” “left,” “forward,” and “back,” which, as commonly used in English, define space relative to an observer, the Kuuk Thaayorre, like many other Aboriginal groups, use cardinal-direction terms — north, south, east, and west — to define space. https://www.dc0d.com/microlog/2020/what_are_some_problems_that_can_show_up_while_using_localized_mutation/ Sat, 11 Jul 2020 18:12:48 +0200 https://www.dc0d.com/microlog/2020/what_are_some_problems_that_can_show_up_while_using_localized_mutation/ (pure as in Haskell) It is said that employing pure state, makes reasoning about the code harder. Aside from this point, what is the advantage of pure state, over some other approaches to make state mutation safe? (From a developer’s experience point of view, in “real world” - in this context, decided by “majority” - projects) (Other approaches like borrowing in Rust, capabilities in Pony and uniquness typing in Clean - they are very different and shouldn’t be placed together, from a language-design point of view; but in this context, we are looking at developer’s experience point of view, while writing code and applying different practices) https://www.dc0d.com/microlog/2020/how_to_make_writing_the_code_faster/ Sat, 11 Jul 2020 18:03:22 +0200 https://www.dc0d.com/microlog/2020/how_to_make_writing_the_code_faster/ Saying Software Development is just writing code, is like saying a carpenter’s job is just hammering nails. Let’s assume the design just falls out of thin air, into our hands, magically - like a sofa taking shape, on its own, while we just hammering the wood, without any need for calculations, measuring, angles, choosing the material, “blah, blah, blah” - pun intended. We might write or edit the code once a week. https://www.dc0d.com/microlog/2020/ports-and-adapters/ Fri, 05 Jun 2020 06:25:27 +0200 https://www.dc0d.com/microlog/2020/ports-and-adapters/ Ports on driver side, are implemented inside the application. Ports on driven side are implemented inside the infrastructure (outside the application). Application here can be seen as usecases, which cover the core vocabulary - two inner layers of the onion. Ports and Adapters is an architecture also known as Hexagonal Architecture. Ports & Adapters - image found on Google https://www.dc0d.com/microlog/2020/oop-and-fp/ Sun, 31 May 2020 01:38:54 +0200 https://www.dc0d.com/microlog/2020/oop-and-fp/ Let’s assume that we can question everything that is assumed to be a fact (or ask stupid questions - your take). OOP was about message passing Apparently, the language that is most close to the original idea of OOP, is … Erlang! According to Alan Kay (mentioned this on different occassions). Closures & Functional Programming Here we are cheating a bit, just to communicate better. We can blame things after. https://www.dc0d.com/microlog/2020/if_i_were_to_begin_from_the_start/ Sun, 24 May 2020 23:56:19 +0200 https://www.dc0d.com/microlog/2020/if_i_were_to_begin_from_the_start/ Triggered by this question on Quora. I would start with trying to understand What is Software Development? Wasted big time to “tech it”. Different programming languages, different technologies, different databases, “Everybody should use Haskell”, “Everybody should use NoSql”, “MamboJamboScript, is going to take over the world”, and so on and so forth. Imagine you join a new team. There is no shared language (human language), no intent-revealing test suites providing feedback, no big picture of how your team is actually interacting with the whole organization and nobody knows about that specific code base because (say) Mark is on vacation. https://www.dc0d.com/microlog/2020/jez_humble_agile_nad_accelerate/ Sun, 24 May 2020 21:37:21 +0200 https://www.dc0d.com/microlog/2020/jez_humble_agile_nad_accelerate/ If you’re an expert in Agile, you might not find anything particularly new, but what you will get is a very strong sense of validation, that actually, here’s a scientific approach demonstrating that the stuff you’ve been talking about, how it works and why it works and how it connects to everything else in this space. A conversation with Jez Humble on Accelerate: the new book explaining the data and science behind DevOps https://www.dc0d.com/microlog/2020/when_should_we_use_mocks/ Sun, 24 May 2020 00:33:23 +0200 https://www.dc0d.com/microlog/2020/when_should_we_use_mocks/ Mock across architecturally significant boundaries, but not within those boundaries. Uncle Bob When to Mock? https://www.dc0d.com/microlog/2020/how_to_get_the_erlang_version/ Sun, 24 May 2020 00:17:36 +0200 https://www.dc0d.com/microlog/2020/how_to_get_the_erlang_version/ 1 $ erl -eval 'erlang:display(erlang:system_info(otp_release)), halt().' -noshell https://www.dc0d.com/microlog/2020/how_to_resize_image_from_command_line_on_mac/ Sun, 24 May 2020 00:15:39 +0200 https://www.dc0d.com/microlog/2020/how_to_resize_image_from_command_line_on_mac/ 1 $ sips -Z 512 image.png https://www.dc0d.com/microlog/2020/how_to_have_at_it/ Sun, 24 May 2020 00:13:01 +0200 https://www.dc0d.com/microlog/2020/how_to_have_at_it/ The trick is to fix the problem you have, rather than the problem you want. Bram Cohen https://www.dc0d.com/microlog/2020/how_gee_paw_hill_works/ Sat, 23 May 2020 23:56:20 +0200 https://www.dc0d.com/microlog/2020/how_gee_paw_hill_works/ Tweet thread: How I Work: (Just Programming Mix) When I'm programming, I am centered broadly on the cyclical application of small textual changes, each one producing value I then harvest to identify, enable, or energize the next. — GeePaw Hill (@GeePawHill) November 23, 2019 Unrolled thread: When I’m programming, I am centered broadly on the cyclical application of small textual changes, each one producing value I then harvest to identify, enable, or energize the next. https://www.dc0d.com/microlog/2020/how_to_avoid_declining_into_irrelevance/ Sat, 23 May 2020 23:49:05 +0200 https://www.dc0d.com/microlog/2020/how_to_avoid_declining_into_irrelevance/ Losing your focus on value is the beginning of the end. A long slow but inevitable decline into irrelevance. — Allen Holub (@allenholub) May 22, 2020 https://www.dc0d.com/microlog/2020/is_there_a_better_story_for_test_coverage_in_go/ Sat, 23 May 2020 20:19:15 +0200 https://www.dc0d.com/microlog/2020/is_there_a_better_story_for_test_coverage_in_go/ So far, using Go Modules, it is possible to: 1 2 $ go test -count=1 -coverprofile=./cover/profile.out -covermode=atomic -coverpkg ./... $ go tool cover -html=./cover/profile.out -o ./cover/coverage.html Still, stuff are missing - maybe a story for another time. https://www.dc0d.com/microlog/2020/first/ Sat, 23 May 2020 04:08:36 +0200 https://www.dc0d.com/microlog/2020/first/ Micrologs usually contain snippets of interesting stuff from difference sources. It is just like a normal post - in Markdown. Keep dates when transferring any old note/snippet/doclet. Title should be a question. Follow AGQ style - when applicable. https://www.dc0d.com/post/2020/dialogue-ii/ Sat, 07 Mar 2020 04:58:23 +0100 https://www.dc0d.com/post/2020/dialogue-ii/ This is a work-in-progress - and will be so for some time. It is picturing how one could think about Software Development - one of many possible ways. Tradeoffs are made - the main goal here was/is to communicate. Niklas: Something feels broken about all that code we have. Edmond: Maybe. But aren’t you making money? Niklas: We do. But doing anything new is hard, changing or fixing stuff is hard, everything feels so slow, so ineffective. https://www.dc0d.com/post/2020/first/ Sun, 09 Feb 2020 19:00:00 +0100 https://www.dc0d.com/post/2020/first/ I have stopped blogging at some point (for the third time). And many things happened during the last year, I decided to relocate to another country, experienced a multi-culture life & work atmosphere and tackled the ups and downs. Maybe I write about that experience someday. And start blogging again. I do not know yet. Squares A and B have the same color.