Private/New-TemplateResolver.ps1
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function New-TemplateResolver { <# .SYNOPSIS Resolve template location from path/url given on command lines .DESCRIPTION Returns an object that has methods for retrieving the template body and the size of the template file such that it can be checked for size limitations .PARAMETER TemplateLocation Location of the template. May be either - Path to local file - S3 URI (which is converted to HTTPS URI for the current region) Note that this only works if a default region is set in the shell and you don't try to point to a different region with -Region - HTTP(S) Uri .PARAMETER StackName Used if -UsePreviousTemplate is true .PARAMETER CredentialArguments Credential arguments passed to public function. .PARAMETER UsePreviousTemplate Setting of -UsePreviousTemplate if updating; else $false .OUTPUTS Custom Object. #> param ( [string]$TemplateLocation, [bool]$UsePreviousTemplate = $false, [string]$StackName, [hashtable]$CredentialArguments ) $resolver = New-Object PSObject -Property @{ Type = $null BucketName = $null Key = $null Path = $null Url = $null StackName = $null UsePreviousTemplate = $UsePreviousTemplate } | Add-Member -PassThru -Name ReadTemplate -MemberType ScriptMethod -Value { # Reads the template contents from either S3, previous tempalte or file system as approriate. if ($this.StackName -and $this.UsePreviousTemplate) { Get-CFNTemplate -StackName $this.StackName } elseif ($this.Path) { Get-Content -Raw -Path $this.Path } elseif ($this.BucketName -and $this.Key) { $tmpFile = "$([Guid]::NewGuid().ToString()).tmp" try { Read-S3Object -BucketName $this.BucketName -Key $this.Key -File $tmpFile | Out-Null Get-Content -Raw -Path $tmpFile } finally { Remove-Item -Path $tmpFile } } else { throw "Template location undefined" } } | Add-Member -PassThru -Name Length -MemberType ScriptMethod -Value { # Gets the file szie of the template if ($this.StackName) { # Template is always of acceptable size. 0 } elseif ($this.Path) { (Get-ItemProperty -Name Length -Path $this.Path).Length } elseif ($this.BucketName -and $this.Key) { (Get-S3Object -BucketName $this.BucketName -Key $this.Key).Size } else { throw "Template location undefined" } } $u = $null if ($StackName -and $UsePreviousTemplate) { # UsePreviousTemplate $resolver.StackName = $StackName $resolver.Type = 'UsePreviousTemplate' } elseif ([Uri]::TryCreate($TemplateLocation, 'Absolute', [ref]$u)) { switch ($u.Scheme) { 's3' { $r = Get-CurrentRegion -CredentialArguments $CredentialArguments # Convert to full URL if (-not $r) { throw "Cannot determine region. Please use Initialize-AWSDefaults or Set-DefaultAWSRegion" } $resolver.Url = [Uri]("https://s3-{0}.amazonaws.com/{1}{2}" -f $r, $u.Authority, $u.LocalPath) $resolver.BucketName = $u.Authority $resolver.Key = $u.LocalPath.TrimStart('/') $resolver.Type = 'Url' } 'file' { $resolver.Path = $TemplateLocation $resolver.Type = 'File' } { $_ -ieq 'http' -or $_ -ieq 'https' } { $resolver.Url = $u $resolver.BucketName = $u.Segments[1].Trim('/'); $resolver.Key = $u.Segments[2..($u.Segments.Length - 1)] -join '' $resolver.Type = 'Url' } default { throw "Unsupported URI: $($u.ToString())" } } } else { $resolver.Path = $TemplateLocation $resolver.Type = 'File' } $resolver } |