Uploading files to SFTP server using Powershell, WinSCP .NET Assembly, AWS SSM Parameter Store, SSH keys, and monitoring via AWS SNS notifications

WinSCP_Upload_SFTP.ps1

# Download and install .NET assembly at: https://winscp.net/eng/downloads.php#additional
# This process will send SNS notifications upload upload failure.
# Define connection parameters and globals
$server = '<127.0.0.1>'
$sftpUser = '<sftp_user>'
$ssmParam = '<sftp_password>'
$awsRegion = '<us-east-1>'
$snsTopic = '<sns_topic>'
$snsSubject = 'An error has occurred in production SFTP[IAM]'
$sftp_pass = (Get-SSMParameter -Region $awsRegion -Name $ssmParam -WithDecryption $true).Value

# This is the host key fingerprint of the server you're connecting to, NOT your private key.
$sshHostKeyFingerprint = '<ssh-rsa 2048 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx>'

# This is the location of your private key. Tidy up those key permissions (;
$sshPrivateKeyPath = "C:\location\to\key\file.ppk"

# Define the notification function
# The function takes the type of problem and the error contents as parameters in order to customize text and response procedure.
function notify($problem,$currErr){

if($problem -eq "delete"){
$message = @"
Greetings,

An error has occurred in the upload of the IAM reports to SFTP. Please see:

****
$currErr.Failures
****

Please investigate and escalate as neccessary.
"@}
elseif($problem -eq "upload"){
Write-Host $currErr

$message = @"
Greetings,

The follow error has occurred when attempting to upload data to the SFTP server in the IAM process.
****
$currErr
****

Please investigate and escalate as neccessary.
"@}

# Send SNS Notification with custom message contents.
Publish-SNSMessage -TopicArn $snsTopic -Message $message -Subject $snsSubject -Region $awsRegion
}

# Wrap SFTP in try block to catch exceptions in upload process
try
{
    # Load WinSCP .NET assembly
    Add-Type -Path "C:\sftp\WinSCPnet.dll"
    
    # Setup session options
    $sessionOptions = New-Object WinSCP.SessionOptions
    $sessionOptions.Protocol = [WinSCP.Protocol]::Sftp
    $sessionOptions.HostName = $server
    $sessionOptions.UserName = $sftp_user
    $sessionOptions.SshPrivateKeyPath = $sshPrivateKeyPath
    $sessionOptions.SshHostKeyFingerprint = $sshHostKeyFingerprint
    
    $session = New-Object WinSCP.Session
    
    try
    {
        # Connect and clear credentials from memory
        $session.Open($sessionOptions)
        $sessionOptions = $null

        # Define transfer options for upload process
        $transferOptions = New-Object WinSCP.TransferOptions
        $transferOptions.TransferMode = [WinSCP.TransferMode]::Binary

        # Upload file 1
        $transferResult = $session.PutFiles("C:\Export.csv", "/Export.csv", $False, $transferOptions)
        
        # Report on success
        foreach ($transfer in $transferResult.Transfers){Write-Host "Upload of $($transfer.FileName) succeeded"}
 
        # Throw on any error
        $transferResult.Check()

        # Upload file 2
        $transferResult = $session.PutFiles("C:\Export.json", "/Export.json", $False, $transferOptions)
        
        # Throw on any error
        $transferResult.Check()
 
        # Report on success
        foreach ($transfer in $transferResult.Transfers){Write-Host "Upload of $($transfer.FileName) succeeded"}
    }
    
    # Due diligence in cleanup saves many turtles
    finally{$session.Dispose()}
 
    exit 0
}
catch
{
    # Call notify function to send notifications via SNS
    notify -problem "upload" -currErr $_.Exception.Message
    exit 1
}