PowerShellでAWS Lambdaを試してみた

Install-Module -Name AWSLambdaPSCore -Scope CurrentUser

Install-Module -Name AWSPowerShell.NetCore -Scope CurrentUser

PS C:\> Get-AWSPowerShellLambdaTemplate

Template Description
-------- -----------
Basic Bare bones script
CloudFormationCustomResource PowerShell handler base for use with CloudFormation custom resource events
CodeCommitTrigger Script to process AWS CodeCommit Triggers
DetectLabels Use Amazon Rekognition service to tag image files in S3 with detected labels.
KinesisStreamProcessor Script to be process a Kinesis Stream
S3Event Script to process S3 events
SNSSubscription Script to be subscribed to an SNS Topic
SQSQueueProcessor Script to be subscribed to an SQS Queue

cd [任意のディレクトリ]
New-AWSPowerShellLambda -ScriptName HelloPowerShellLambda -Template Basic

$message = $LambdaInput.Message
Write-Output ("Hello {0}!(on PowerShell Core {1})" -f $message, ($PSVersionTable.PSVersion.ToString()))

cd .\HelloPowerShellLambda
Publish-AWSPowerShellLambda -ScriptPath .\HelloPowerShellLambda.ps1 -Name HelloPowerShellLambda -Region ap-northeast-1 -Profile MyProfile

{
  "Message": "Lambda"
}

New-AWSPowerShellLambdaPackage -ScriptPath .\HelloPowerShellLambda.ps1 -OutputPackage .\Package.zip

// HelloPowerShellLambda.dll
using Amazon.Lambda.PowerShellHost;

namespace HelloPowerShellLambda.Bootstrap
{
    public class Bootstrap : PowerShellFunctionHost
    {
        public Bootstrap() : base("HelloPowerShellLambda.ps1")
        {
        }
    }
}

// PowerShellFunctionHostクラス
// https://github.com/aws/aws-lambda-dotnet/blob/master/Libraries/src/Amazon.Lambda.PowerShellHost/PowerShellFunctionHost.cs
// より一部抜粋
namespace Amazon.Lambda.PowerShellHost
{
    ///
    /// Base class for Lambda functions hosting PowerShell Core runtime
    ///
    public abstract class PowerShellFunctionHost
    {
        ///
        /// Creates an instances of the class. As part of creation it will initiate the PowerShell Core runtime and load any required PowerShell modules.
        ///
        protected PowerShellFunctionHost()
        {
            // This will only be true for local testing.
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                var state = InitialSessionState.CreateDefault();
                state.ExecutionPolicy = Microsoft.PowerShell.ExecutionPolicy.Unrestricted;
                this._ps = PowerShell.Create(state);
            }
            else
            {
                this._ps = PowerShell.Create();
            }

            this.SetupStreamHandlers();
            this.LoadModules();

            // Can be true if there was an exception importing modules packaged with the function.
            if (this._lastException != null)
            {
                Console.WriteLine(this._constructorLoggingBuffer.ToString());
                throw this._lastException;
            }

            this.PowerShellFunctionName = Environment.GetEnvironmentVariable(POWERSHELL_FUNCTION_ENV);
            if (!string.IsNullOrEmpty(this.PowerShellFunctionName))
            {
                this._constructorLoggingBuffer.AppendLine($"Configured to call function {this.PowerShellFunctionName} from the PowerShell script.");
            }
        }

        ///
        /// Creates an instances of the class. As part of creation it will initiated the PowerShell Core runtime and load any required PowerShell modules.
        /// The PowerShell script that will run as part of every Lambda invocation
        ///
        protected PowerShellFunctionHost(string powerShellScriptFileName)
            : this()
        {
            this._powerShellScriptFileName = powerShellScriptFileName;
        }

        ///
        /// AWS Lambda function handler that will execute the PowerShell script with the PowerShell Core runtime initiated during the construction of the class.
        ///
        public Stream ExecuteFunction(Stream inputStream, ILambdaContext context)
        {
            this._lastException = null;

            if (this._runFirstTimeInitialization)
            {
                this._logger = context.Logger;

                if (this._constructorLoggingBuffer?.Length > 0)
                {
                    context.Logger.Log(this._constructorLoggingBuffer.ToString());
                    this._constructorLoggingBuffer = null;
                }

                this._runFirstTimeInitialization = false;
            }

            string inputString;
            using (var reader = new StreamReader(inputStream))
            {
                inputString = reader.ReadToEnd();
            }

            var result = this.BeginInvoke(inputString, context);
            this.WaitPowerShellExecution(result);

            if (this._lastException != null || this._ps.InvocationStateInfo.State == PSInvocationState.Failed)
            {
                var exception = this._exceptionManager.DetermineExceptionToThrow(this._lastException ?? this._ps.InvocationStateInfo.Reason);
                throw exception;
            }

            return new MemoryStream(Encoding.UTF8.GetBytes(this.GetExecutionOutput()));
        }
    }
}