Category Archives: software

The Goal: A process of ongoing improvement – Quick review

Score

⏰⏰⏰⏰⏰ / 5

Cover

Visualizza immagine di origine

Quick review

I read this book because it is listed inside the bibliography of The Phoenix Project and this was a good reason to go for it.

The book is written as a novel and explains the Theory of Constraints inside the process of growth of the main character, Alex Rogo. He’s in charge of a manufacturing plant in serious trouble and he has 90 days to increase performance to save the plant from failure.

The title of this book represents the main question that Alex ask himself to understand what actions he must undertake to solve the task assigned to him. This is the first of many questions that the author uses to drive the improvement and the change of Alex.

The author opens the reader’s mind by revealing us a new way to think about performance and what are the really important things to do to achieve The Goal. He does that with a socratic approach and a progressive discolsure of concepts guided by events that happens in the plant.

If you’re searching for a book that teaches how to think in an effective way and how to organize complex activites inside a plant this is the book for you. Don’t wait to buy it, do it now!

Buy

Amazon – http://amzn.eu/d/68yxMo9

CQRS by Example – Simple ASP.Net CORE implementation

In this blog post we’re going to explore a simple ASP.Net Core CQRS WebApi project. The code for this tutorial exposes a demonstrative API to manage a blog.

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CQRS by example – Introduction

I’m doing some R&D for a future project at work and I’m currently exploring some architectural prototypes. In the last few weeks I explored the CQRS pattern.

CQRS thanks to the separation of the read/query services from the action/command services enables us to do many things.

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ALM DOs & DON’Ts – Definition of done

We all have been in this kind of situation: someone in the team states that a feature is done but in reality there is that little thing to figure out and the coding is completed the day after. Why is that? Because every person has a different definition of done inside his mind.
How can we protect a team from this? Simple! With a Definition of Done.

definition-of-done.png

A good definition of done explicits what activities has to be done before declaring that our coding activites are over.
For example:

  • All unit tests are green
  • Coding style and conventions are respected
  • UI respects the specs validated by the Customer.

Every team and every project will create a different definition of done. The very important thing is that you and your team discuss such a definition to remove wrong expectaions about the status of work in progress.

How to release a hotfix with pull-request inside VSTS in 3 steps

We all know the situation: the customer finds a critical bug in the latest release and he wants us to release a new version of our application with a fix. How do we handle this situation without breaking our team policies? How to release a specific fix to avoid regression problems?

First we need to fix that bug with the classical approach of feature-branches. We create a branch, fix the bug, create a pull-request and the team approves. These activities are set at the highest priority because a customer is in trouble and we must help.

Now we are in a situation where we have a specific commit that solves a specific problem with only the necessary lines of code modified.

commit-with-fix.png

Our target is to ship that specific commit that fixes that specific bug with a standard pull-request, without all the other work done in the development branch since the latest release. So we write down (in our clipboard for example) the id of the commit.

shaid

What can we do now to release?

1. New branch

We create a new branch.

git checkout -b my-hotifx

Now we fetch the latest updates from the remote repo.

git fetch origin

Then we set our branch my-hotfix to point to the latest commit of the remote release branch.

git reset --hard origin/release

branch-release.png

2. Cherry-pick

Now we cherry-pick the specific commit we want to apply to the release branch without commiting (–no-commit option). We choose the no-commit option to carefully inspect what is going on in our files. It’s here where we use the commit id we saved early.

git cherry-pick <commit-hash> --no-commit

We verify that everything is fine (where fine depends on your specific project). Now we can commit and push to VSTS.

git add .
git commit -m "Hotfix"
git push origin mybranch:mybranch

final-situation-1

3. Open pull-request

Our branch is now on the remote repo and we can open the pull-request with VSTS.

pull-request.png

From here the team can approve the PR and fire up our automated release process that activates our automated test and if everything is fine we deploy safely.

TL; DR

With this blog post we explored the critical situation to release a hotfix without breaking the rules or taking shortcuts to avoid our release pipeline. As engineers we must maintain a cold approach even in hot situation and rely on our best practices. Human errors are always possible in particular when we’re stressed and a customer is making our phones hot.

ALM DOs and DON’Ts – Unit test

A unit test is a runnable piece of code that verifies that another piece of code (called production code) does what it is supposed to do.

A unit test has many characteristics and one of the most important is that a single unit test must verify one and only one thing.
If a unit test specifies more than one behavior things became harder to mantain. One a tests fail it has to be easy to understand what is going wrong and which section of our production code is behaving badly.

unit-test-one-thing.png

As a best practice we make each test independent to all the others: any given behaviour should be specified in one and only one test. Otherwise if you later change that behaviour, you’ll have to change multiple tests.

 

Mastering database migrations scripts with VSTS

During the lifecycle of our applications it’s very likely that to support new functionalities we need to modify the structure of our database. In this particular post I mean a relational database.

When we deal with a database in a production environment we can’t simply drop an existing database and create a new one with the latest version of the schema.

The database is unlike application code in as much as it contains state, in terms of table-based data,  that needs to be preserved after an upgrade.

drop-create

This is why when dealing with database changes we need to talk about migration scripts.

Migration Scripts

A migration script is a set of SQL commands that changes the database schema or updates data to evolve the database from the version n-1 to the version whitout loss of data.

Migration scripts are typically collected in a dedicated folder in our repository, named sequentially.

The migration scripts must be executed in the specific order to be able to build the n-th version of our database.

The first migration script

The first script in our collection is responsible to create the first version of our db starting from an empty database.

The following is an example of a simple first migration script that we can name 00000001.sql. The example is for a simple database with one schema named Ordering and one table called Customers in the Ordering schema.

CREATE SCHEMA Ordering
GO
CREATE TABLE Ordering.Customers(
    Id INT PRIMARY KEY,
    CompanyName NVARCHAR(100) NOT NULL
)
GO

Create the first migration script from an existing database

If we work on a solution with an existing complex database we need a tool to create our first migration script. Tools are capable of tracking dependencies and relations inside the db schema to calculate a single script that evolves our db to the desired state. There are many tools on the market. In this example we’ll use Red-Gate SQL Compare. With this tool we select our existing db as the source (IC6.ParrishShoes) and our target to sync. As we explained before we need an empty database so we compare our db to that and we obtain our first script.

The script calculated by SQL Compare engine is the following.

/*
Run this script on:

        ..EmptyTarget    -  This database will be modified

to synchronize it with:

        ..IC6.ParrishShoes

You are recommended to back up your database before running this script

Script created by SQL Compare version 13.4.0.6563 from Red Gate Software Ltd at 03/08/2018 23:20:53

*/
SET NUMERIC_ROUNDABORT OFF
GO
SET ANSI_PADDING, ANSI_WARNINGS, CONCAT_NULL_YIELDS_NULL, ARITHABORT, QUOTED_IDENTIFIER, ANSI_NULLS ON
GO
SET XACT_ABORT ON
GO
SET TRANSACTION ISOLATION LEVEL Serializable
GO
BEGIN TRANSACTION
GO
IF @@ERROR  0 SET NOEXEC ON
GO
PRINT N'Creating schemas'
GO
CREATE SCHEMA [Ordering]
AUTHORIZATION [dbo]
GO
IF @@ERROR  0 SET NOEXEC ON
GO
PRINT N'Creating [Ordering].[Customers]'
GO
CREATE TABLE [Ordering].[Customers]
(
[Id] [int] NOT NULL,
[CompanyName] [nvarchar] (100) COLLATE Latin1_General_CI_AS NOT NULL
)
GO
IF @@ERROR  0 SET NOEXEC ON
GO
PRINT N'Creating primary key [PK__Customer__3214EC072CF93715] on [Ordering].[Customers]'
GO
ALTER TABLE [Ordering].[Customers] ADD CONSTRAINT [PK__Customer__3214EC072CF93715] PRIMARY KEY CLUSTERED  ([Id])
GO
IF @@ERROR  0 SET NOEXEC ON
GO
COMMIT TRANSACTION
GO
IF @@ERROR  0 SET NOEXEC ON
GO
-- This statement writes to the SQL Server Log so SQL Monitor can show this deployment.
IF HAS_PERMS_BY_NAME(N'sys.xp_logevent', N'OBJECT', N'EXECUTE') = 1
BEGIN
    DECLARE @databaseName AS nvarchar(2048), @eventMessage AS nvarchar(2048)
    SET @databaseName = REPLACE(REPLACE(DB_NAME(), N'\', N'\\'), N'"', N'\"')
    SET @eventMessage = N'Redgate SQL Compare: { "deployment": { "description": "Redgate SQL Compare deployed to ' + @databaseName + N'", "database": "' + @databaseName + N'" }}'
    EXECUTE sys.xp_logevent 55000, @eventMessage
END
GO
DECLARE @Success AS BIT
SET @Success = 1
SET NOEXEC OFF
IF (@Success = 1) PRINT 'The database update succeeded'
ELSE BEGIN
	IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION
	PRINT 'The database update failed'
END
GO

Compile a database

If we run the previous script and we get zero errors we can say that we can compile our database. The same concept apply when we can execute a collection of migration scripts in the correct order without errors.

Being able to compile a database it’s a huge benefit because it enables us to create a database on demand by simply executing a list of script to get the desired version on which we can develop, run test, deploy to a new customer etc. We can also start to do some automation for our database tasks.

Automation with VSTS – Checking our migration scripts

An important part of having a collection of db migrations scripts is that we have to frequently check that this chain of scripts is valid.

We can invest in automation to do that and with VSTS is very simple to get started.

In the following example we create a build process that executes all the migrations scripts in our repository to a target database to check if everything can be completed without errors.

We go to the Build section of VSTS and create a new Build process from an empty process.

We browse in the marketplace the DbUp extension (free!).

DbUp is a .NET library that helps you to deploy changes to SQL Server databases. It tracks which SQL scripts have been run already, and runs the change scripts that are needed to get your database up to date.

2018-08-03_23-40-20

After the installation process of DbUb we can refresh our list of available task and add the DbUp Migration task. With this task we can execute scripts included in a folder of our repository to a target database. The configuration of the connection string is done with VSTS Build variables in the dedicated tab. We configure the script folder path and the Single Transaction strategy, too. This way all the scripts are executed in one single transaction and if we get an error everything will be rolled-back.

2018-08-04_00-06-31

2018-08-04_00-16-49.png

When we complete the configuration of the task we click Save And Queue.

The build process will start and if we’re a bit lucky everything will succeed.

2018-08-04_00-24-07.png

We can see that DbUp applied correctly the scripts by browing the db with SQL Mangament.

  • First 2018-08-04_00-07-34
  • After 2018-08-04_00-12-42

TL; DR

With this tutorial we’ve learned the basics of migrations scripts, how to create them with a tool and how to check if our collection of scripts is valid with automation implemented with VSTS and DbUp.

This is just the start

When we have such powerful tools we can start to think about automated processes that test our chain of scripts in many ways. We can do an “incremental” approach like the example above triggered at every change in the scripts folder. We can schedule a build process that every day at noon will execute all the migration scripts versus a temporary brand new database.

What will you do with this super powers? Let me know in the comments below!

Reference

VSTS DbUp Marketplace – https://marketplace.visualstudio.com/items?itemName=johanclasson.UpdateDatabaseWithDbUp

Red-Gate SQL Compare – https://www.red-gate.com/products/sql-development/sql-compare/index

Power is nothing without control

You can’t control (leave alone improve) what you can’t see – Me

Power is nothing without control – Pirelli

Why a dashboard?

When we drive our car we have everything under control: speed, revs, oil and water temperatures and fuel level. We need a dashboard in our car because we have to know our current speed to respect speed limits, to know how much petrol we have in our fuel-tank to decide if we can go to work without a trip to the gas station etc. All this data to do the simple job of driving! This is necessary because we need to take informed decisions.

white motorcycle cluster gauge

Photo by Mikes Photos on Pexels.com

What does it mean for our daily activities in a software department? We need our dashboard, too! How can we do our job of deliveing (not only writing!) a working software with the lowest bug count as possibile, quickly, on a budget and coordinating with other people? It’s a huge task compared to drive a car alone and yet many of us rely on instinct and guts to make decisions for an entire software team.

A dashboard for the software Engineer

Which indicators and gauges do we need as software engineers? I think there are a few things we Always need to know about our team.

  1. Team Cycle time: how much time/days does a unit of work take to go from started to completed? And with completed we mean delivered to the customer.
  2. Team Lead time: how much time/days dows a unit of work take to go from a created to completed?
  3. How fast are we going? How many story points we deliver every fixed amount of time? (sprint, week… name your favorite).
  4. Bug count. How many known defects (bugs) have we? Is the count increasing or decreasing?

Here we can see a dashboard created with Microsoft VSTS where the team can get an immediate report of the situation.

2018-08-03_13-46-49.png

Create a dashboard

Every team is different and needs specific/custom dashboard. To create a dashboard with Microsoft VSTS we can go to

https://THE_DOMAIN/THE_PROJECT/_dashboards/

and then we expand the dashboard list with the arrow button (1) and click New Dashboard (2).

2018-08-03_14-02-31.pngWe give our dashboard a name and hit Create.

2018-08-03_14-09-48.pngWe can add widgets picking from the right-side list, search or browse the Marketplace to add something extra to our VSTS.

2018-08-03_14-11-55.png

When we’ve finished to create our dashboard we click “Done editing”.

TL; DR

A dashboard is a must have to control or improve our team and our process. It enables us to understand our current indicators and shows if a new way to work improves or worsen the situation. With a dashboard we can take informed decisions about many arugments: current velocity of the team, quality of the software, lead time and so on. We’ve seen how to create and configure a dashboard with Microsoft VSTS.

Reference

Microsoft VSTS Docs: https://docs.microsoft.com/en-us/vsts/report/dashboards/?view=vsts

Import from JIRA to VSTS in 5 steps

In previous posts I documented some features of VSTS and a few scenarios of Application Lifecycle Management.

If you like VSTS it’s likely that you want to move your existing project from your current platform to VSTS. I’m currently planning a migration from JIRA to VSTS at work and here I am to share my findings.

This blog post has been inspired by the work of the ALM DevOps Rangers.

We’re going to build a simple tool to migrate and map Jira issues into VSTS items.

The source code is available on GitHub. Continue reading