Simple PowerShell module for Splunk with a connect and disconnect function. Module is based on the Splunk C# SDK which can be downloaded from http://dev.splunk.com/view/SP-CAAAEPK. To use, place this script and the SplunkSDK.dll from the SDK archive into a folder called "Splunk2" in your PSModulePath. PowerShell version 3 is required.

splunk2.psm1

#Requires -Version 3

# Import Splunk C# SDK types into module scope
Add-Type -Path "$PSScriptRoot\SplunkSDK.dll"

<#
.Synopsis
   Connects to a Splunk server
.DESCRIPTION
   This function connects to a Splunk server via the REST API and creates a service object called $SPLUNK_SERVICE.
   This object can be used to interact with Splunk directly, or is used by other functions in this module to
   share a persistent session. 
.EXAMPLE 
    Connect to a Splunk server and list all indexes greater than 100 MB in size
    Connect-Splunk -ComputerName splunk.company.com
    $idx = $SPLUNK_SERVICE.GetIndexes()
    $idx | Where-Object { $_.CurrentDBSizeMB -gt 100 } | Format-Table name, HomePathExpanded, CurrentDBSizeMB -AutoSize
#>
function Connect-Splunk
{
    [CmdletBinding()]
    [OutputType([Splunk.Service])]
    Param
    (
        # IP address or hostname of Splunk server
        [Parameter(Mandatory=$true,
                   ValueFromPipelineByPropertyName=$true,
                   Position=0)]
        [alias("Host","Server")]
        [string]
        $ComputerName,

        # (Optional) TCP port for Splunk REST endpoint (defaults to 8089)
        [int]
        $Port = 8089,

        # Credentials used to connect to the Splunk server. If not specified, you will be prompted to enter a username and password.
        [Parameter(Mandatory=$true)]
        [pscredential]
        $Credential
    )

    $svcArgs = New-Object Splunk.ServiceArgs
    $svcArgs.Host = $ComputerName
    $svcArgs.Port = $Port

    $splunk = New-Object Splunk.Service $svcArgs
    Write-Verbose ( "{0} Connecting to $ComputerName : $Port" -f ( (Get-Date).ToUniversalTime().ToString("u") ) )
    $global:SPLUNK_SERVICE = $splunk.Login( $Credential.UserName, $Credential.GetNetworkCredential().Password )
    Write-Output $SPLUNK_SERVICE
}

<#
.Synopsis
   Disconnects from a Splunk server
.DESCRIPTION
   This function disconnects from a Splunk server. If no parameters are specified, the session specified in the
   $SPLUNK_SERVICE object will be used.
.EXAMPLE
    Disconnect-Splunk -Service $SPLUNK_SERVICE
#>
function Disconnect-Splunk
{
    Param
    (
        # Splunk service object. If not specified, defaults to $SPLUNK_SERVICE. Can be passed via pipeline.
        [Parameter(ValueFromPipeline=$true,
                   Position=0)]
        [Splunk.Service]
        $Service = $SPLUNK_SERVICE
    )

    Write-Verbose ( "{0} Disconnecting from $( $Service.Host )" -f ( (Get-Date).ToUniversalTime().ToString("u") ) )
    $Service.Logout()
}