Go to material on sagas

The one about estimates

Other: "How long will this take?"
You: "I don't know"
Other: "It's just a button like the other"
You: "I know it looks like the other button but there's a whole different list of things to consider"
Other: "But I need costs to prioritise"
You: "I understand, and I wish I could help you. You know I won't lower quality and you don't want scope being reduced... in that case time is an open variable."
Other: "Not again with the triangle thing. You've done that a thousand times, that's jour profession".

(pause for drama)

You: "Ok. Let's play this game. I've already told you about scope-quality-time, right?"
Other: "Yes"
You: "Ok, John/Jane/MrSmith... do you have kids?"
Other: "Uuuh. Yes. How is that related?"

You: "Ok, let's imagine I asked how long will it take you to bath, feed and put to sleep tonight. I need to know so we can skype with Australia".
Other: "Uuuh... well, If we have to skype I can have my significant other to do it"

You: "Don't be a chicken. Give me the time when the kid will be bathed, belly-full and wonderfuly asleep"

Other: "9pm"

You: "exactly 9pm?"
Other: "9-ish"

You: "and bathroom is cleaned, kitchen is all cleaned up too, right? No traces of food on the wall or ceiling, right?"

Other: "Ok, maybe 9.30"

You: "9 or 9.30. You mentioned you start your routines at 7.30 so you just admitted to a 30% potential deviation."
Other: "err..."

You: "But you do this everyday. Ok, forget about tonight. Let me ask you something different. What time will your kid be at kindergarten tomorrow?"
Other: "8.30 sharp"

You: "not 8.35?"
Other: "No, 8.30 or they have shut the door"

You: "And the kid was perfectly dressed and ate everything you prepared for breakfast, right?"
Other: "Well, not always."

You: "No traces of food on the wall or ceiling, right? Bed is made and there's no breakfast utensils laying around."
Other: "We have to make it to the 8.30 deadline"

You: "But you do this every day. It's you field of expertise. Daily repetition, same tools, same team, same risks, ..."
Other: "yeahs, but kids... entropy."

You: "Daily repetition, same tools, same team, same risks, ... I don't deal with any of those simplifications. Plus I also get entropy, arguably smaller than the entropy generated by kids or toddlers, but entropy nonetheless."
Other: "Ok, but how long will this take?"



Special thanks to Roger Segura and Yorgo Saslis, their parenthood inspired this story. 
DISCLAIMER: None of them are The Other in the story, they just happened to tell personal experiences that helped building the script.

This work is licensed under a Creative Commons Attribution 4.0 International License.

jCrete 2016

Many harvested content, videos and other materials are available at: https://github.com/JCrete/jcrete2016

My current go-to material on micro-Services

#kudos Graham Lea

CQRS Recipes (by @tjaskula)

Been trying to grasp my head around the DDD+CQRS+ES+CS+... concepts and finally found this step by step presentation:

CQRS recipes or how to cook your architecture from Tomasz Jaskuła

Enjoy! PS: kudos tjaskula

JCrete 2014

This post is, sort of, a reply to Geertjan’s post about JCrete (https://blogs.oracle.com/geertjan/entry/jcrete_2014).

Geertjan describes a group of trees and paths and a river and (purposely or not) lacks to mention he’s describing a forest. It’s great to have people with Geertjan’s reach to present and support this way of organising conferences, but I’d like to give my two cents on the subject.

Before continuing, let me say what Geertjan didn’t: "JCrete is a conference that uses Open Space Technology (http://en.wikipedia.org/wiki/Open_Space_Technology)”. A description like that is usually simplified as “FOO is an Open Space”. Hmm! We got rid of ’technology' and ‘conference’. 

I’m still surprised to see the amount of people still unfamiliar with OpenSpace Technolgy, but that’s probably because we’ve been using a lot in Barcelona (more on that later), therefore I'm the weird one. As Dmitry said during the wrap-up, this format should be used all around and I completely agree to that. 

But! I think wide adoption of Open Space Technology is still not possible, or that it should happen slowly.

Open Spaces don’t scale well. Even in JCrete things changed comparing 2012 edition and 2014. There were twice as many attendees and I’d say the number of people familiar with Open Space Technology is and how to *use it* remained the same (thus decreasing the %).

While preparing the main room on Sunday evening, some of the un-organizers and I went for a round gathering of chairs. That mutated the day after into a semi-circle around the screen the following days. Ok, we need to see code, it’s true. But then I noticed all rooms ended up in a similar layout. We are still too wired for the sit-and-listen conference format and unlearning this takes time.

In Agile Barcelona there’s been an open space every 6 months for the last few years. That led to some other communities (AngularJS, Java Hispano, Bcn Dev Con,…) to adopt it. The results are usually the same: people unfamiliar with the format, even when it’s explained (including 4 principles and law) still don’t grok it. 

Open Space Technology is easy to explain but hard to use.

I think one of the reasons why people get so surprised in JCrete is because it’s an Open Space, not a Conference. What I’m trying to say here is that when a conference was publicised as a using Open Space Technology, attendees should only hear the ‘Open Space’ part. Actually, it might be a good thing to just use the two terms separately: Conference vs Open Space. These are not exclusive terms though. It’s possible to have the two mixed up: plain-old-cfp-talks-in-slots during the morning and open spaces during the afternoon (see for instance ALE 2014 program http://ale2014.alenetwork.eu/ale14-program/ ).

But I agree with Geertjan on that (1) morning open space followed by (2) at-the-beach, spontaneous sessions in the afternoon followed by (3) wonderful share-all food is plain genius. 

PS: I was really surprised to see talks popup out of nowhere and happen on the so-called 'room 5' (see first picture of  Geertjan’s post) as that is actually the ultimate ‘Open Space’.

Baggage Collector Kata

I recently worked with a team trying to get them to grok some habits around testing. One of the most challenging tasks was to make them learn to unlearn.

They know a lot about their business and so they know all exceptions to all the rules. This leads to overcomplexifying any solution. That leads to paralysis by analysis in some cases too. Since the problem we were using to practice testing was getting in the way again and again (due to corner cases) I decided we would ignore the problem and do a kata instead.

Since I also wanted them to do a kata similar enough to what they were trying to solve I just made one up on the spot and made it so that some problems in the kata were close enough to the actual problem. 

DISCLAIMER: I know this intro is extremely vague. Just cut to the chase.

Baggage Collector Kata

Imagine you work at a baggage handling service of a regional airport in 1987. You spend your day taking bags that fall through a slide into a pile of baggage, from the pile to (a) the Hangars, (b) the baggage claim Hall or (c) Lost and Found.

Write the code so that a baggage is sent to the appropriate location:

 - a baggage has a label with a FROM and TO

 - a baggage whose FROM matches the current airport goes to the HANGARS

 - a baggage whose TO matches the current airport goes to the HALL

(Hidden rule)

 - all others go to LOST and FOUND

NOTE: The hidden rule was left out on purpose. I expected the team to notice there's cases not covered by the original set of rules and to (1) go ask the business expert (me) about what to do and (2) get a test for those cases.

Moving on to the future

While they were coding, I decided time was a variable to consider so I made it so each year would actually happen in 10 minutes. Meaning I added extra rules every 10 minutes.

Time goes by and the airport is being successful. Management is preparing some changes in order to make the airport an international hub.

Your team is merged with the Hangar's team. You now must:

 - send baggages to appropriate HANGAR depending on the TO indicated on the label. That is, you no longer send baggages to HANGAR but you send them to HANGAR-8 or HANGAR-4, etc...

Also, you may start receiving bags that are on transit!

 - a bag's label may now have several hops on the itinerary. Send bags to HALL if bag is on the last hop or send them to the appropriate hangar if current airport is on the itinerary. 

 -if the current airport is not on the itinerary, just move the bag to LOST and FOUND.

The Golden Years

The plan seems to be working and your airport is now an international airport! Kudos!

Here's some more considerations:

 - if a bag FROM your airport will go abroad, you must send it to X-Ray and then to the appropriate Hangar

 - a bag arriving (our airport is final destination) from a country abroad (original airport) then the bag must go to CUSTOMS and then to the HALL.

NOTE: At this point you can let your imagination flow and add all kinds of rules. For example:

 - merge your team with lost-and-found teams so that if you receive a baggage you can re-route (even if you are not on the itinerary), just do it.

 - make the hangar-to-flight mapping change during time. If a flight has a very early checkin, make it's baggage to the hangar even thought the plane is still not there or even if there's another plane there.

 - remove all bags belonging to JACINTO RAMIREZ (a known drug dealer on Interpol's Most Wanted List)

Head fake

I used the kata as a way to get the team to get used to a set of simple rules changing very quickly. You can only go refactor crazy if your basic functionality is granted.

The original problem was simple and easy enough to reason about so as to dig deep into the possible corner cases it presented. We got into the exception handling quick enough. The message I was trying to pass on was: a simple problem is easy to reason but will surely have unspecified corner cases get your business expert in hand, find those cases quickly. Before you start coding your cathedral, step back and think of a good set of possible inputs and the expected outputs. If you find cases you can't answer to, get back to the business expert.

Also, your business will change soon enough and probably on a direction different than what you expected. Don't try to anticipate the future and keep you design simple and uncoupled so that it accepts change easily.