Background

I decided to write this PowerShell build script as a gentle introduction to PS. It builds this Go application, which is an internal tool I decided to open source, and not the focus of this review.

This script is used primarily for packaging artifacts for release.

My approach

The script below gets, vets and builds a small Go application and then invokes a separate command-line tool to add Windows rsrc metadata such as version strings and icons.

Since the version number is mandatory for the packaging process, I validated it using param() rules rather than if statements. It validates against a regex for semver.

I then execute every packing step, check for its return status, and present a graceful message in addition to the error output by the build step.

The packager relies on having rcedit-x64.exe available in the PATH. I originally allowed specifying a path to the executable as a command-line flag, but it seemed to make the code messier for nothing, so I just removed it. The tool is primarily for myself.

Example

Invocation

powershell.exe -ExecutionPolicy Unrestricted .build.ps1 -version 1.1.0

Output

Packing bittray version 1.1.0

Cleaning old build products.

go get...

go vet...

go build...

Validating artifact...

Applying rsrc metadata...

Compressing archive (bittray-1.1.0.zip)...

SHA1 hash of bittray-1.1.0.zip:

cd283afd10f613919bb4dc694bce3c1f9bd23483

CertUtil: -hashfile command completed successfully.

Done!

Concerns

1. Does the code follow PS idioms?


2. Is there a more elegant way to check for the success of commands and bail than repeating if (!$?) all the time?


3. To wit, is the single trap appropriate?


4. Is the code adequately defensive? Overly defensive?


5. I cannot sign my script as I don't have a code signing certificate. Is my invocation correct and safe?


6. Is there a shorter invocation available without altering the system-side Execution Policy?


7. Because of the validator on -version, you need to provide a valid version to be able to run just -clean. Any way around that (like providing some order of precedence of param()s, or short-cutting)? I really like those top-level validators, and would prefer to keep them in favor of if statements, if possible.

Code

param(

    [string]

    [Parameter(Mandatory = $True)]

    [ValidateNotNullorEmpty()]

    [ValidatePattern('^([0-9]|[1-9][0-9]*).([0-9]|[1-9][0-9]*).([0-9]|[1-9][0-9]*)(?:-([0-9A-Za-z-]+(?:.[0-9A-Za-z-]+)*))?(?:+[0-9A-Za-z-]+)?$')]

    $version,



    [switch]

    $clean

)



function Clean-Artifacts

{

    Write-Host "Cleaning old build products."

    Remove-Item * -Include bittray.exe, bittray-*.zip

    if (!$?)

    {

        Write-Host -BackgroundColor red -ForegroundColor white "Failed to remove existing artifacts; see above."

        exit 1

    }

}



if ($clean -eq $True)

{

    Clean-Artifacts

    exit 0

}



if ((Get-Command "rcedit-x64.exe" -ErrorAction SilentlyContinue) -eq $null)

{

    Write-Host -ForegroundColor red "Unable to find rcedit-x64.exe in your PATH."

    exit 1

}



Write-Host "Packing bittray version $version" -ForegroundColor green



Clean-Artifacts



Write-Host "go get..."

go get



Write-Host "go vet..."

go vet ./...

if (!$?)

{

    Write-Host -BackgroundColor red -ForegroundColor white "'go vet' failed; see above."

    exit 1

}



Write-Host "go build..."

go build -ldflags -H=windowsgui bittray.go

if (!$?)

{

    Write-Host -BackgroundColor red -ForegroundColor white "'go build' failed; see above."

    exit 1

}



Write-Host "Validating artifact..."

if ( [System.IO.File]::Exists("bittray.exe"))

{

    Write-Host "Applying rsrc metadata..."

    trap

    {

        "Error adding resource metadata: $_"

    }



    rcedit-x64.exe --set-icon .bitbucket.ico "bittray.exe"

    rcedit-x64.exe "bittray.exe" --set-version-string "ProductName" "Bittray"

    rcedit-x64.exe "bittray.exe" --set-version-string "ProductVersion" "$version"

}

else

{

    Write-Host -BackgroundColor red -ForegroundColor white "'go build' claims to have succeeded, but there is no artifact?"

    exit 1

}



$package = "bittray-$version.zip"

Write-Host "Compressing archive ($package)..."

Compress-Archive -Path .bittray.exe -CompressionLevel Optimal -DestinationPath $package

if (!$?)

{

    Write-Host -BackgroundColor red -ForegroundColor white "Failed to create zip package."

    exit 1

}



certUtil -hashfile "$package" sha1

if (!$?)

{

    Write-Host -BackgroundColor red -ForegroundColor white "Failed to generate SHA1 integrity checksum."

    exit 1

}

else

{

    Write-Host -BackgroundColor green -ForegroundColor white "Done!"

}