Backup files to AWS S3

gistfile1.txt

param(
    [Parameter(Mandatory = $True)]
    [string]$RootPath,
    [Parameter(Mandatory = $True)]
    [string]$BucketName,
    [Parameter(Mandatory = $True)]
    [string]$AccessKey,
    [Parameter(Mandatory = $True)]
    [string]$SecretKey,
    [switch]$RemoveRootPathFromS3Key
)

# Do not display errors, but add them to the $error collection.
$ErrorActionPreference = "SilentlyContinue"

# Display errors, but continue execution of the current cmdlet, script, function, or pipeline. This is the default.
# $ErrorActionPreference = "Continue"

function GetFileExtension {
    param (
        [Parameter(Mandatory = $True)]
        [string]$Path
    )
    [System.IO.Path]::GetExtension($Path)
}

<#
.SYNOPSIS
Set file extension
.DESCRIPTION
Set file extension, append or overwrite
.PARAMETER Path
File to operate with
#>
function SetFileExtension {
    param (
        [Parameter(Mandatory = $True)]
        [string]$Path,
        [Parameter(Mandatory = $True)]
        [string]$Extension
    )
    if (!$Extension.StartsWith('.')) {
        $Extension = ".$Extension"
    }
    if ($null -eq ([System.IO.Path]::GetExtension($Path))) {
        $Path + $Extension
    }
    else {
        [System.IO.Path]::Combine(
            [System.IO.Path]::GetDirectoryName($Path), 
            [System.IO.Path]::GetFileNameWithoutExtension($Path)) + $Extension
    }
}

function IsZipFile {
    param (
        [Parameter(Mandatory = $True)]
        [string]$Path
    )
    [System.IO.Path]::GetExtension($Path) -eq '.zip'
}

<#
.SYNOPSIS
Create the parameter key for Write-S3Object cmdlet.
.DESCRIPTION
A parameter key with slashes will create folders in S3 bucket
#>
function CreateS3Key {
    param(
        [Parameter(Mandatory = $True)]
        [string]$Path
    )
    [string]$key = [System.IO.Path]::GetDirectoryName($Path)
    if ($RemoveRootPathFromS3Key) { 
        $key = $key.Substring($RootPath.Length)
    }
    $key = $key.TrimStart('\').Replace('\', '/')
    $key = "$($env:computername)/$(if($key -ne '') {$key + '/'} else {''})$([System.IO.Path]::GetFileName($Path))"
    $key
}

function EnsureFileExtension {
    param (
        [Parameter(Mandatory = $True)]
        [string]$Path,
        [Parameter(Mandatory = $True)]
        [string]$Extension
    )
    if (!$Extension.StartsWith('.')) {
        $Extension = ".$Extension"
    }
    if ($null -eq ([System.IO.Path]::GetExtension($Path))) {        
        $Path + $Extension
    }
    else {
        [System.IO.Path]::Combine(
            [System.IO.Path]::GetDirectoryName($Path), 
            [System.IO.Path]::GetFileNameWithoutExtension($Path)) + $Extension
    }
}

function TestLastWriteTimeUtc {
    param(
        [Parameter(Mandatory = $True)]
        [string]$Path,
        [Parameter(Mandatory = $True)]
        [DateTime] $LastWriteTimeUtc
    )
    $Path = EnsureFileExtension $Path '.zip'
    $key = CreateS3Key -Path $Path
    $s3LastWriteTimeUtc = Get-S3ObjectTagSet -BucketName $BucketName -Key $key.TrimStart('/') | Where-Object { $_.Key -eq 'LastWriteTimeUtc' } | Select-Object -ExpandProperty Value
    if ($null -ne $s3LastWriteTimeUtc) {
        if ($s3LastWriteTimeUtc -eq $LastWriteTimeUtc.ToString()) {
            $true
            return
        }
    }
    $false
}

function UploadS3File {
    param (
        [Parameter(Mandatory = $True)]
        [string]$Path,
        [Parameter(Mandatory = $True)]
        [datetime]$LastWriteTimeUtc
    )
    $key = CreateS3Key -Path $Path
    "Uploading file $Path with key $key"
    Write-S3Object -BucketName $BucketName -File $Path -Key $key -TagSet @( @{ Key = 'LastWriteTimeUtc'; Value = $LastWriteTimeUtc.ToString() })    
}

function ZipFile {
    param (
        [Parameter(Mandatory = $True)]
        [string]$Path,
        [Parameter(Mandatory = $True)]
        [string]$TargetPath
    )
    "Compressing file $Path"
    Compress-Archive -Path $Path -DestinationPath $TargetPath -CompressionLevel Optimal
}

function DeleteFile {
    param(
        [Parameter(Mandatory = $True)]
        [string]$Path
    )
    "Deleting file $Path"
    Remove-Item -Path $Path
}

$files = Get-ChildItem $RootPath -Recurse -File -Exclude '*.s3.zip'

if ($files.Length -eq 0) {
    'there are no files that match the search pattern'
    exit
}

$profileName = [System.Guid]::NewGuid().ToString()
"Saving AWS profile"
Set-AWSCredential -AccessKey $AccessKey -SecretKey $SecretKey -StoreAs $profileName
"Setting AWS profile"
Set-AWSCredential -ProfileName $profileName

foreach ($file in $files) {
    if (IsZipFile $file) {
        if (TestLastWriteTimeUtc -Path $file.FullName -LastWriteTimeUtc $file.LastWriteTimeUtc) {
            "Identical LastWriteTimeUtc $LastWriteTimeUtc it's not necessary to upload file $($file.FullName)"
        }
        else {
            UploadS3File -Path $file.FullName -LastWriteTimeUtc $file.LastWriteTimeUtc
        }
    }
    else {
        $tempFile = (SetFileExtension $file.FullName -Extension "$(GetFileExtension $file.FullName).s3.zip")
        if (TestLastWriteTimeUtc -Path $tempFile -LastWriteTimeUtc $file.LastWriteTimeUtc) {
            "Identical LastWriteTimeUtc $LastWriteTimeUtc it's not necessary to upload file $($file.FullName)"
        }
        else {
            ZipFile -Path $file.FullName -TargetPath $tempFile
            UploadS3File -Path $tempFile -LastWriteTimeUtc $file.LastWriteTimeUtc
            DeleteFile -Path $tempFile
        }
    }
}

"Removing AWS profile"
Remove-AWSCredentialProfile -ProfileName $profileName -Force