Generic build script using Fake

Question

I have something like a generic build script for a group of projects. I am using Fake but my F# skills are pretty bad. Would you please take a look and point where I can improve it?

ORIGINAL

#I @"./bin/tools/FAKE/tools/"
#r @"./bin/tools/FAKE/tools/FakeLib.dll"
open System
open System.IO
open Fake
open Fake.Git
open Fake.FSharpFormatting
open Fake.AssemblyInfoFile
open Fake.ReleaseNotesHelper
type System.String with member x.contains (comp:System.StringComparison) str = x.IndexOf(str,comp) >= 0
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// BEGIN EDIT
let appName = getBuildParamOrDefault "appName" ""
let appType = getBuildParamOrDefault "appType" ""
let appSummary = getBuildParamOrDefault "appSummary" ""
let appDescription = getBuildParamOrDefault "appDescription" ""
let appAuthors = ["YourNameHere";]
// END EDIT
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
let buildDir = @"./bin/Release" @@ appName
let releaseNotes = @"./src/" @@ appName @@ @"RELEASE_NOTES.md"
let release = LoadReleaseNotes releaseNotes
let nuget = environVar "NUGET"
let nugetOutDir = "./bin/nuget" @@ appName
Target "Clean" (fun _ -> CleanDirs [buildDir; nugetOutDir;])
Target "RestorePackages" (fun _ ->
 let packagesDir = @"./src/packages"
 !! "./**/packages.config"
 |> Seq.iter (RestorePackage (fun p ->
 { p with
 ToolPath = nuget
 OutputPath = packagesDir }))
)
Target "Build" (fun _ ->
 let appProjectFile = match appType with
 | t when t = "msi" -> @"./src/" @@ appName + ".sln"
 | _ -> @"./src/" @@ appName @@ appName + ".csproj"
 !! appProjectFile
 |> MSBuildRelease buildDir "Build"
 |> Log "Build-Output: "
)
Target "CreateNuGet" (fun _ ->
 let packages = [appName, appType]
 for appName,appType in packages do
 let nugetOutArtifactsDir = nugetOutDir @@ "Artifacts"
 CleanDir nugetOutArtifactsDir
 // Exclude libraries which are part of the packages.config file only when nuget package is created.
 let nugetPackagesFile = "./src/" @@ appName @@ "packages.config"
 let nugetDependenciesFlat =
 match fileExists nugetPackagesFile with
 | t when t = true -> getDependencies nugetPackagesFile |> List.unzip |> fun(A,B) -> A
 | _ -> ["CodeContracts"]
 let excludePaths (pathsToExclude : string list) (path: string) = pathsToExclude |> List.exists (path.contains StringComparison.OrdinalIgnoreCase)|> not
 let exclude = excludePaths (nugetDependenciesFlat @ ["CodeContracts"])
 // Copy the build artifacts to the nuget pick dir
 match appType with
 | t when t = "web" -> CopyDir nugetOutArtifactsDir (buildDir @@ "_PublishedWebsites" @@ appName) allFiles
 | t when t = "nuget" -> CopyDir nugetOutDir buildDir exclude
 | _ -> CopyDir nugetOutArtifactsDir buildDir allFiles
 // Copy the deployment files if any to the nuget pick dir.
 let depl = @".\src\" @@ appName @@ @".\deployment\"
 if TestDir depl then XCopy depl nugetOutDir
 let nuspecFile = appName + ".nuspec"
 let nugetAccessKey =
 match appType with
 | t when t = "nuget" -> getBuildParamOrDefault "nugetkey" ""
 | _ -> ""
 let nugetDoPublish = nugetAccessKey.Equals "" |> not
 let nugetPublishUrl = getBuildParamOrDefault "nugetserver" "https://nuget.org"
 // Create/Publish the nuget package
 NuGet (fun app ->
 {app with
 NoPackageAnalysis = true
 Authors = appAuthors
 Project = appName
 Description = appDescription
 Version = release.NugetVersion
 Summary = appSummary
 ReleaseNotes = release.Notes |> toLines
 AccessKey = nugetAccessKey
 Publish = nugetDoPublish
 PublishUrl = nugetPublishUrl
 ToolPath = nuget
 OutputPath = nugetOutDir
 WorkingDir = nugetOutDir
 }) nuspecFile
)
"Clean"
 ==> "RestorePackages"
 ==> "Build"
 ==> "CreateNuGet"
RunParameterTargetOrDefault "target" "Build"

IMPROVED

#I @"./bin/tools/FAKE/tools/"
#r @"./bin/tools/FAKE/tools/FakeLib.dll"
open System
open System.IO
open Fake
open Fake.Git
open Fake.FSharpFormatting
open Fake.AssemblyInfoFile
open Fake.ReleaseNotesHelper
type System.String with member x.contains (comp:System.StringComparison) str = x.IndexOf(str,comp) >= 0
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// BEGIN EDIT
let appName = getBuildParamOrDefault "appName" ""
let appType = getBuildParamOrDefault "appType" ""
let appSummary = getBuildParamOrDefault "appSummary" ""
let appDescription = getBuildParamOrDefault "appDescription" ""
let appAuthors = ["YourNameHere";]
// END EDIT
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
let buildDir = @"./bin/Release" @@ appName
let releaseNotes = @"./src/" @@ appName @@ @"RELEASE_NOTES.md"
let release = LoadReleaseNotes releaseNotes
let nuget = environVar "NUGET"
let nugetOutDir = "./bin/nuget" @@ appName
Target "Clean" (fun _ -> CleanDirs [buildDir; nugetOutDir;])
Target "RestorePackages" (fun _ ->
 let packagesDir = @"./src/packages"
 !! "./**/packages.config"
 |> Seq.iter (RestorePackage (fun p ->
 { p with
 ToolPath = nuget
 OutputPath = packagesDir }))
)
Target "Build" (fun _ ->
 let appProjectFile = match appType with
 | "msi" -> @"./src/" @@ appName + ".sln"
 | _ -> @"./src/" @@ appName @@ appName + ".csproj"
 !! appProjectFile
 |> MSBuildRelease buildDir "Build"
 |> Log "Build-Output: "
)
Target "CreateNuGet" (fun _ ->
 let packages = [appName, appType]
 for appName,appType in packages do
 let nugetOutArtifactsDir = nugetOutDir @@ "Artifacts"
 CleanDir nugetOutArtifactsDir
 // Exclude libraries which are part of the packages.config file only when nuget package is created.
 let nugetPackagesFile = "./src/" @@ appName @@ "packages.config"
 let nugetDependenciesFlat =
 match fileExists nugetPackagesFile with
 | true -> getDependencies nugetPackagesFile |> List.unzip |> fst
 | _ -> []
 let excludePaths (pathsToExclude : string list) (path: string) = pathsToExclude |> List.exists (path.contains StringComparison.OrdinalIgnoreCase) |> not
 let exclude = excludePaths ("CodeContracts" :: nugetDependenciesFlat)
 // Copy the build artifacts to the nuget pick dir
 match appType with
 | "web" -> CopyDir nugetOutArtifactsDir (buildDir @@ "_PublishedWebsites" @@ appName) allFiles
 | "nuget" -> CopyDir nugetOutDir buildDir exclude
 | _ -> CopyDir nugetOutArtifactsDir buildDir allFiles
 // Copy the deployment files if any to the nuget pick dir.
 let depl = @".\src\" @@ appName @@ @".\deployment\"
 if TestDir depl then XCopy depl nugetOutDir
 let nuspecFile = appName + ".nuspec"
 let nugetAccessKey =
 match appType with
 | "nuget" -> getBuildParamOrDefault "nugetkey" ""
 | _ -> ""
 let nugetDoPublish = nugetAccessKey.Equals "" |> not
 let nugetPublishUrl = getBuildParamOrDefault "nugetserver" "https://nuget.org"
 // Create/Publish the nuget package
 NuGet (fun app ->
 {app with
 NoPackageAnalysis = true
 Authors = appAuthors
 Project = appName
 Description = appDescription
 Version = release.NugetVersion
 Summary = appSummary
 ReleaseNotes = release.Notes |> toLines
 AccessKey = nugetAccessKey
 Publish = nugetDoPublish
 PublishUrl = nugetPublishUrl
 ToolPath = nuget
 OutputPath = nugetOutDir
 WorkingDir = nugetOutDir
 }) nuspecFile
)
"Clean"
 ==> "RestorePackages"
 ==> "Build"
 ==> "CreateNuGet"
RunParameterTargetOrDefault "target" "Build"

Answer 1

All of the match expressions can be simplified. For example,

match fileExists nugetPackagesFile with
| t when t = true -> ...
| _ -> ...

Can be

match fileExists nugetPackagesFile with
| true -> ...
| _ -> ...

Similarly,

 match appType with
 | t when t = "web" -> ...
 | t when t = "nuget" -> ...
 | _ -> ...

Can be

 match appType with
 | "web" -> ...
 | "nuget" -> ...
 | _ -> ...

In the first example above, fun(A,B) -> A can be written as fst.

---

It looks like nugetDependenciesFlat is only used by exclude, where you're already appending "CodeContracts". So you can change the second match in nugetDependenciesFlat from _ -> ["CodeContracts"] to _ -> [].

While you're at it, change nugetDependenciesFlat @ ["CodeContracts"] to "CodeContracts" :: nugetDependenciesFlat. The reason being, prepending an element to a list is a constant-time operation, while appending will take time proportional to to the length of nugetDependenciesFlat. It won't make a noticeable difference since I assume nugetDependenciesFlat will be very short, but it's a good practice to get into.

• mynkow: Thank you. I did not know about this. Would you please help me with the fst?
• mjolka: @mynkow Sure, so instead of getDependencies nugetPackagesFile |> List.unzip |> fun(A,B) -> A you can write getDependencies nugetPackagesFile |> List.unzip |> fst. Documentation is here.
• mynkow: Got it. Is there something for the second element?
• mjolka: @mynkow Yep, it's called snd.
• mynkow: you rock. If you go to "// Exclude libraries which are part of the..." The idea there is to have "CodeContracts" directory excluded always and if packages.config exists to exclude files described there. I do not like this piece of code especially "| _ -> ["CodeContracts"]" just to make the compile happy. Any ideas how to make it better?