Running targets in "FAKE - F# Make"

Listing targets

Before running any specific target it is useful to know all the targets that are available in a build script. FAKE can list all the avaiable targets including the dependencies by running the following command:

Fake.exe YourBuildScript -lt

The option -lt stands for "list targets". It is an abbreviation of the option --listTargets.

Running specific targets

FAKE has a special param "target" which can be used to run specific targets in a build. We assume the following build script:

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// include Fake libs
#I @"tools\FAKE"
#r "FakeLib.dll"
open Fake 

// *** Define Targets ***
Target "Clean" (fun () -> 
	trace " --- Cleaning stuff --- "
)

Target "Build" (fun () -> 
	trace " --- Building the app --- "
)

Target "Deploy" (fun () -> 
	trace " --- Deploying app --- "
)

// *** Define Dependencies ***
"Clean"
  ==> "Build"
  ==> "Deploy"

// *** Start Build ***
RunTargetOrDefault "Deploy"

Now we have the following options:

Fake.exe "target=Build" --> starts the Build target and runs the dependency Clean
Fake.exe Build --> starts the Build target and runs the dependency Clean
Fake.exe Build --single-target --> starts only the Build target and runs no dependencies
Fake.exe Build -st --> starts only the Build target and runs no dependencies
Fake.exe --> starts the Deploy target (and runs the dependencies Clean and Build)

Final targets

Final targets can be used for TearDown functionality. These targets will be executed even if the build fails but have to be activated via ActivateFinalTarget().

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FinalTarget "CloseSomePrograms" (fun _ ->
	// close stuff and release resources
)

// Activate FinalTarget somewhere during build
ActivateFinalTarget "CloseSomePrograms"

Build failure targets

Build failure targets can be used to execute tasks after a build failure. These targets will be executed only after a build failure but have to be activated via ActivateBuildFailureTarget().

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BuildFailureTarget "ReportErrorViaMail" (fun _ ->
	// send mail about the failure
)

// Activate BuildFailureTarget somewhere during build
ActivateBuildFailureTarget "ReportErrorViaMail"

Visualising target dependencies

FAKE can output the graph of target dependencies in the DOT format, which can then be rendered to a PNG-file by Graphviz.

Specifying the command line option --dotGraph (short version: -dg) makes FAKE write the dependency graph to the standard output instead of building anything. This option only works when the build script contains a call like this:

1:	`RunTargetOrDefault "Default"`

Example

Say, the build script build.fsx defines the target dependencies as follows:

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// The rest of the script is omitted...

"BuildJs"
  ==> "WebPackage" <=> "AdminPackage" <=> "WebApiPackage"
  ==> "MainAppPackage"

The following command saves the target dependency graph in the graph.png file (PowerShell syntax):

1:	`FAKE.exe build.fsx -dg \| & 'C:/Program Files (x86)/Graphviz2.38/bin/dot.exe' -Tpng -o ./graph.png`

resulting in an image like this:

graph