My notes on "Greg Young - The Long Sad History of Microservices"

Greg Young - The Long Sad History of Microservices
From the "Build Stuff" event of April 2017.

Talk begins at 9:45.

Highlights of the talk:

27:00 Placing a network between modules simply to enforce programmer discipline 

29:05 There is other levels of isolation I can go to. I can run a docker container per service. That's the coolest stuff right? What that means is I can make it work on my machine so I send my machine to production. 

29:52 Now, one thing that's very useful is I don't necessarily want to make this decision up front. And I don't necessarily want to make the same decision in dev as in production. I may want in dev to have a different way that we run things, why? because bringing up 19 docker containers on your laptop is not very much fun. I may prefer to host everything inside a single process to make debugging and such a lot easier when I am running on dev in my laptop. Whereas in production we may go off to multiple nodes. 

34:16 If you have maintenance windows, why are you working towards getting rid of your maintenance windows? Is this a business drive or is this you just being like C.V. driven development? 

My notes:

Unfortunately his shrieky voice makes him sound like he is bitching about things, which in a sense he is, but it would help his cause to deliver his criticism in a more palatable tone. Also, in order to make his point about microservices being nothing new he seems to disregard statelessness.

Resources referenced in the talk:

https://en.wikipedia.org/wiki/Queueing_theory

https://en.wikipedia.org/wiki/π-calculus

https://en.wikipedia.org/wiki/Actor_model

Leslie Lamport - Time, Clocks, and the Ordering of Events in a Distributed System
(available on the interwebz)

C.A.R. Hoare - Communicating Sequential Processes
(available on the interwebz)

Dear recruiter...

If you are a recruiter wishing to contact me with regards to some job opportunity, please read this.

Migrating a project from java 8 to java 9

Now that Java 9 is out, I decided to migrate to it my pet project, which is around 120K lines of java.

The first step is to just start compiling and running against jdk9, without using any of its features yet.

This is an account of the surprisingly few issues that I encountered during this first step and how I resolved them.

Issue #1: Object.finalize() has been deprecated.

A Hacker's Tale (With a Human Side)

Screenshot of Borland Turbo Debugger found on the interwebz, possibly the same version that I was using back then.

This is a hacking story from my University years. It ends with a nice bit about human qualities. 

Grumpy Posts

Besides the delicate grumpiness which is gratuitously scattered throughout this blog like the golden rays of light in a gentle sunset, there exist a few blog posts which have been written with the express purpose of venting out some major grumpiness.

Here is a list of them:

On UML (oh, do not get me started)

The Wild, Wild Web

On JUnit's random order of test method execution

On UUIDs and GUIDs

On scripting languages

Why Oracle sucks

The GWX (Get Windows 10) KB3035583 trojan horse

"By using this site, you agree to the use of cookies."

(The list will be extended as more posts are added.)

Rich Hickey - Simple Made Easy

"Simple Made Easy" presentation by Rich Hickey from the InfoQ Software Development Conference, recorded at Strangeloop 2011

Watch the presentation here: https://www.infoq.com/presentations/Simple-Made-Easy 

(the slideshow plays alongside with the video.)

My notes on the presentation:

"Simplicity is prerequisite for reliability" - Edsger W. Dijkstra

Simple vs. Complex, Easy vs. Hard

What is wrong with UUIDs and GUIDs

Introduction

Universally Unique Identifiers (UUIDs) otherwise known as Globally Unique Identifiers (GUIDs) are 128-bit numbers that are often used to identify information. In its canonical representation, a UUID looks like this: 2205cf3e-139c-4abc-be2d-e29b692934b0.

The Wikipedia entry for Universally Unique Identifier (⬀) says that they are for practical purposes unique and that while the probability that a UUID will be duplicated is not zero, it is so close to zero as to be negligible. Wikipedia then does the math and shows that if 103 trillion UUIDs are generated, the chance of duplication among them is one in a billion.

Despite the infinitesimally small chances of receiving a duplicate UUID, there exist programmers out there who are afraid of this actually happening, and who will not hesitate to suspect duplicate UUIDs as being responsible for an observed malfunction rather than first look for a bug in their code. Clearly, these folks do not understand the meaning of infinitesimally small chance, so let me try to explain it:

Infinitessimally small chance means practically impossible to happen, and the practically part is only mentioned for scientific correctness: practically, you can disregard the word practically and consider it as simply impossible to happen.

Great. Now, let me tell you why I hate UUIDs.

6 videos from TechSummit Amsterdam 2017 (Jun 1st)

A couple of weeks ago some of us went to the TechSummit conference organized by LeaseWeb.  Here is a list of the talks that I attended, along with a short description for each.

The first presentation was “Shaving my head made me a better programmer” by Alex Qin, which was about what it is like to be a woman, and specifically a programmer, in the U.S. tech industry.  (And in the University before that.)  She talked about the inequality, the sexism, and the harassment.   She mentioned that she once gave a talk in a really big conference about accessibility in the U.S., and afterwards she was asked “How do I talk to women at bars?”  The head-shaving part refers to how changing her appearance resulted in being taken more seriously.  It was quite an interesting talk, though I suspect that in Amsterdam, she was to a large extent preaching to the choir.

 

My notes on the Fielding Dissertation (REST)

These are my notes on Roy T. Fielding's famous Ph.D. dissertation "Architectural Styles and the Design of Network-based Software Architecture"

What follows are excerpts from the dissertation, with my notes usually in parentheses.

Roy Thomas Fielding is: chief Scientist in some tech company; Chairman, Apache Software Foundation; Visiting Scholar, W3C @ MIT CS Lab; etc; Publications, Honors, Awards, Fellowships etc. Involved in the authoring of the Internet standards for the Hypertext Transfer Protocol (HTTP) and Uniform Resource Identifiers (URI).

Abstract:

"The World Wide Web has succeeded in large part because its software architecture has been designed to meet the needs of an Internet-scale distributed hypermedia system."

(He makes it sound as if it was designed this way on purpose.)

"In order to identify [...] aspects of the Web that needed improvement and avoid undesirable modifications, a model for the modern Web architecture was needed to guide its design, definition, and deployment."

(So, he admits the need to build a model after the fact.)

"An architectural style is a named, coordinated set of architectural constraints."

YouTube: Roy T. Fielding: Understanding the REST Style

A youtube videoclip titled "Roy T. Fielding: Understanding the REST Style"

Quote: "It's really an accessible piece of work.  It is not full of equations.  There is one equation.  The equation is there just to have an equation, by the way."

For my notes on REST, see other post: "My notes on the Fielding Dissertation (REST)"

https://blog.michael.gr/2017/06/my-notes-on-fielding-dissertation-rest.html