FAKE 5 - Custom Modules

Requirements to modules

You can use any NuGet packages which are compatible with netcoreapp20, for example all packages targeting netstandard20 or lower.

Declaring module dependencies

Reference paket group

Create a new file paket.dependencies and add the following content

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// [ FAKE GROUP ]
group NetcoreBuild
    source https://api.nuget.org/v3/index.json

    nuget Fake.Core.Target prerelease

Now you can directly use open Fake.Core and use the Target module.

For example create a new file build.fsx with

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// Use this for IDE support. Not required by FAKE 5. Change "build.fsx" to the name of your script.
#load ".fake/build.fsx/intellisense.fsx"

open Fake.Core

Target.create "MyBuild" (fun _ ->
    printfn "message from MyBuild target"
)

Target.runOrDefault "MyBuild"

and execute fake run build.fsx. This works for all FAKE 5 modules, just add other nuget Fake.Other.Module prerelease files to the paket.dependencies file.

Please read introduction about Paket for more information about the paket.dependencies file.

NOTE
This works because by default FAKE 5 searches for a group annotated with the // [ FAKE GROUP ] comment.

Declaring FAKE 5 dependencies within the script

To be more independent from paket infrastructure (stand-alone-scripts and similar situations) there is a way to specify dependencies from within the script itself.

INFO
We use the new syntax specified in FST-1027. However, to be fully compatible with existing tooling and infrastructure make sure to add `//` at the end of the `#r` string. See for details.

Reference a paket group

To reference a FAKE group explicitely you can put the following at the top of your build script

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#r "paket: groupref netcorebuild //"
#load "./.fake/build.fsx/intellisense.fsx"

This header will reference the paket.dependencies file and the netcorebuild group within.

The last line #load is not required by FAKE 5, however this way the file can still be edited in editors (after restoring packages initially). Fake will write an intellisense.fsx file for you importing all required references.

INFO
Note that in this scenario the // [ FAKE GROUP ] comment mentioned above is not required.

Inline dependencies

To write your build dependencies in-line you can put the following at the top of your build.fsx script

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#r "paket:
nuget Fake.Core.Target prerelease //"
#load "./.fake/build.fsx/intellisense.fsx"

This has the advantage that your build-script is now "standalone" and no separate paket.dependencies is required. Fake will generate a build.fsx.lock file with the "locked" dependencies to have reproducable script runs. If you need to update your dependencies just delete the build.fsx.lock file and run fake again.

Using module dependencies

You use the modules as documented in their corresponding help section.

But usually it's:

  • open Fake.<Namespace> for example open Fake.Core
  • Using the features
val printfn : format:Printf.TextWriterFormat<'T> -> 'T