Friday, 22 June 2018

Migrating Redmine issues to VSTS work items with the REST API

Redmine is an open-source project management/issue tracking system. I wanted to copy issues out of Redmine and import them into a Visual Studio Team Services project.

Extracting issues can be done by using the "CSV" link at the bottom of the Issues list for a project in Redmine. This CSV file doesn't contain absolutely everything for each issue (eg. attachments and custom data from any plugins). Another alternative would be to query the database directly, but that wasn't necessary for my scenario.

To migrate the data to VSTS you can use a simple PowerShell script, making use of the VSTS REST API.

You'll need to create a Personal Access Token. Be aware that all items will be created under the account linked to this token - there's no way that I'm aware of that you can set the "CreatedBy" field to point to another user.

Notice in the script how we handle different fields for different work items types (eg. Product Backlog Items use the 'Description' field, whereas Bugs use 'Repro Steps'), and for optional fields (eg. not all Redmine issues had the 'Assignee' field set).

The full set of fields (and which work item types they apply to) is documented here. If you have more fields in Redmine that can be mapped to ones in VSTS then go ahead and add them.

Monday, 11 June 2018

Get programming in F#

I’m really interested in learning more about functional programming. It isn’t something I knew much about, but the benefits of reducing mutability (and shared state) promoted by functional languages and functional style are enticing.

To that end, I recently bought a copy of Isaac Abraham’s new book “Get programming in F#. A guide for .NET Developers”.

I have no background in functional languages at all, so I was looking for a “gentle” introduction to the F# language, without getting hung up on a lot of the functional terminology that seems to make learning this stuff a bit impenetrable for the newcomer. This book delivers.

The structure of the book is in 10 “units”, which in turn are broken down into separate “lessons” (each lesson is a separate chapter).

Here's my notes from each unit:

Unit 1 – F# and Visual Studio

  • Introduces using the Visual Studio IDE for F# development, and recommended extensions. Surprisingly for a book published in 2018, most of the book is based on using Visual Studio 2015. I can only presume this is an artifact of the time it takes to write a book. I understand the initial release of 2017 did have some tooling regressions for F# but I am under the impression those are now resolved, seeing at my time of writing the 7th update for 2017 has just been released, including specific enhancements for F#.
  • Throughout the book, comparisons are made to equivalent C# language constructs, and here too, the text is already a bit dated. An unfortunate downside of a printed book I guess.
  • One thing to note that is different from many other languages – the file order in F# projects is significant. You can’t reference something before the compiler has seen it, and the compiler processes files in project order.
  • The REPL is also a big part of F# development.

Unit 2 – Hello F#

  • The ‘let’ keyword is introduced. It’s more like C#’s const than var, seeing as F# defaults to things being immutable rather than mutable.
  • Scoping is based on whitespace indentation rather than curly braces.
  • Diving into how the F# compiler is much stricter because of the way the F# type system works, and how that can be a good thing.
  • A closer look at working with immutable data, and how you can opt in to mutable data when absolutely necessary, and how to handle state.
  • C# is statement based, whereas F# likes to be expression based.
  • The ‘unit’ type is introduced. It’s kind of like void, but is a way for expressions to always return a value (and means the use of those expressions is always consistent).

Unit 3 – Types and functions

  • Tuples, records
  • Composing functions, partial functions, pipelines,
  • How do you organise all these types and functions if you’re not using classes? Organising code through namespaces and modules

Unit 4 – Collections in F#

  • Looking at the F#-specific collection types – List, Array and Seq, the functions you can use with those collections. Immutable dictionaries, Map and Sets. Aggregation and fold.

Unit 5 – The pit of success with the F# type system

  • Conditional logic in F#, pattern matching
  • Discriminated unions

Unit 6 – Living on the .NET platform

  • How to use C# libraries from F#. Using Paket for NuGet package management
  • How to use F# libraries from C#

Unit 7 – Working with data

  • Introducing Type Providers. Specific use cases with JSON, SQL and CSV.

Unit 8 – Web programming

  • Asynchronous language support
  • Working with ASP.NET WebAPI 2
  • Suave – F#-focussed web library
  • Consuming HTTP data

Unit 9 – Unit testing

  • The role of unit testing in F# applications
  • Using common .NET unit testing libraries with F#
  • Property-based testing and FsCheck
  • Web testing

Unit 10 – Where next?

  • Further reading and resources to take your next steps.