YarnDsc

0.1.0-alpha

YarnDsc.psm1

# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License.

using namespace System.Collections.Generic

# Assert once that Yarn is already installed on the system.
Assert-Yarn

#region DSCResources
[DSCResource()]
class YarnInstall
{
    # DSCResource requires a key. Do not set.
    [DscProperty(Key)]
    [string]$SID

    [DscProperty()]
    [string]$Arguments

    [DscProperty()]
    [string]$PackageDirectory

    [DscProperty(NotConfigurable)]
    [string[]]$Dependencies

    [YarnInstall] Get()
    {
        if (-not([string]::IsNullOrEmpty($this.PackageDirectory)))
        {
            if (Test-Path -Path $this.PackageDirectory -PathType Container)
            {
                Set-Location -Path $this.PackageDirectory
            }
            else
            {
                throw "$($this.PackageDirectory) does not point to a valid directory."
            }
        }

        $currentState = [YarnInstall]::new()
        $currentState.Dependencies = Invoke-YarnInfo -Arguments '--name-only --json' | ConvertFrom-Json
        $currentState.Arguments = $this.Arguments
        $currentState.PackageDirectory = $this.PackageDirectory
        return $currentState;
    }

    [bool] Test()
    {
        # Yarn install is inherently idempotent as it will also resolve package dependencies. Set to $false
        return $false
    }

    [void] Set()
    {
        $currentState = $this.Get()
        Invoke-YarnInstall -Arguments $currentState.Arguments
    }
}

#endregion DSCResources

#region Functions
function Assert-Yarn
{
    # Refresh session $path value before invoking 'npm'
    $env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User")
    try
    {
        Invoke-Yarn -Command 'help'
        return
    }
    catch
    {
        throw "Yarn is not installed"
    }
}

function Invoke-YarnInfo
{
    param(
        [Parameter()]
        [string]$Arguments       
    )

    $command = [List[string]]::new()
    $command.Add("info")
    $command.Add($Arguments)
    return Invoke-Yarn -Command $command
}

function Invoke-YarnInstall
{
    param (
        [Parameter()]
        [string]$Arguments
    )

    $command = [List[string]]::new()
    $command.Add("install")
    $command.Add($Arguments)
    return Invoke-Yarn -Command $command
}

function Invoke-Yarn
{
    param (
        [Parameter(Mandatory = $true)]
        [string]$Command
    )

    return Invoke-Expression -Command "yarn $Command"
}

#endregion Functions