/// <summary>
/// Constructs the invoke delegate using Expressions
///
/// Serialize & Deserialize calls are only made when a serializer is provided.
/// Context is only passed when customer method has context parameter.
/// Lambda return type can be void.
///
/// (inStream, context, outStream) =>
/// {
/// var input = serializer.Deserialize(inStream);
/// var output = handler(input, context);
/// return serializer.Serialize(output);
/// }
///
/// </summary>
/// <param name="customerObject">Wrapped customer object.</param>
/// <param name="customerSerializerInstance">Instance of lambda input & output serializer.</param>
/// <returns>Action delegate pointing to customer's handler.</returns>
public Action <Stream, ILambdaContext, Stream> ConstructInvokeDelegate(object customerObject, object customerSerializerInstance, bool isPreJit)
{
var inStreamParameter = Expression.Parameter(Types.StreamType, "inStream");
var outStreamParameter = Expression.Parameter(Types.StreamType, "outStream");
var contextParameter = Expression.Parameter(typeof(ILambdaContext), "context");
_logger.LogDebug($"UCL : Constructing input expression");
var inputExpression = BuildInputExpressionOrNull(customerSerializerInstance, inStreamParameter, out var iLambdaContextType);
if (isPreJit)
{
_logger.LogInformation("PreJit: inputExpression");
UserCodeInit.InitDeserializationAssembly(inputExpression, inStreamParameter);
}
_logger.LogDebug($"UCL : Constructing context expression");
var contextExpression = BuildContextExpressionOrNull(iLambdaContextType, contextParameter);
_logger.LogDebug($"UCL : Constructing handler expression");
var handlerExpression = CreateHandlerCallExpression(customerObject, inputExpression, contextExpression);
_logger.LogDebug($"UCL : Constructing output expression");
var outputExpression = CreateOutputExpression(customerSerializerInstance, outStreamParameter, handlerExpression);
if (isPreJit)
{
_logger.LogInformation("PreJit: outputExpression");
UserCodeInit.InitSerializationAssembly(outputExpression, outStreamParameter, CustomerOutputType);
}
_logger.LogDebug($"UCL : Constructing final expression");
var finalExpression = Expression.Lambda <Action <Stream, ILambdaContext, Stream> >(outputExpression, inStreamParameter, contextParameter, outStreamParameter);
#if DEBUG
var finalExpressionDebugView = typeof(Expression)
.GetTypeInfo()
.GetProperty("DebugView", BindingFlags.Instance | BindingFlags.NonPublic)
.GetValue(finalExpression);
_logger.LogDebug($"UCL : Constructed final expression:\n'{finalExpressionDebugView}'");
#endif
_logger.LogDebug($"UCL : Compiling final expression");
return(finalExpression.Compile());
}
/// <summary>
/// Loads customer assembly, type, and method.
/// After this call returns without errors, it is possible to invoke
/// the customer method through the Invoke method.
/// </summary>
public void Init(Action <string> customerLoggingAction)
{
Assembly customerAssembly = null;
try
{
_logger.LogDebug($"UCL : Parsing handler string '{_handlerString}'");
_handler = new HandlerInfo(_handlerString);
// Set the logging action private field on the Amazon.Lambda.Core.LambdaLogger type which is part of the
// public Amazon.Lambda.Core package when it is loaded.
AppDomain.CurrentDomain.AssemblyLoad += (sender, args) =>
{
_logger.LogInformation($"UCL : Loaded assembly {args.LoadedAssembly.FullName} into default ALC.");
if (!_customerLoggerSetUpComplete && string.Equals(LambdaCoreAssemblyName, args.LoadedAssembly.GetName().Name, StringComparison.Ordinal))
{
_logger.LogDebug(
$"UCL : Load context loading '{LambdaCoreAssemblyName}', attempting to set {Types.LambdaLoggerTypeName}.{LambdaLoggingActionFieldName} to logging action.");
SetCustomerLoggerLogAction(args.LoadedAssembly, customerLoggingAction, _logger);
_customerLoggerSetUpComplete = true;
}
};
_logger.LogDebug($"UCL : Attempting to load assembly '{_handler.AssemblyName}'");
customerAssembly = AssemblyLoadContext.Default.LoadFromAssemblyName(_handler.AssemblyName);
}
catch (FileNotFoundException fex)
{
_logger.LogError(fex, "An error occured on UCL Init");
throw LambdaExceptions.ValidationException(Errors.UserCodeLoader.CouldNotFindHandlerAssembly, fex.FileName);
}
catch (LambdaValidationException validationException)
{
_logger.LogError(validationException, "An error occured on UCL Init");
throw;
}
catch (Exception exception)
{
_logger.LogError(exception, "An error occured on UCL Init");
throw LambdaExceptions.ValidationException(Errors.UserCodeLoader.UnableToLoadAssembly, _handler.AssemblyName);
}
_logger.LogDebug($"UCL : Attempting to load type '{_handler.TypeName}'");
var customerType = customerAssembly.GetType(_handler.TypeName);
if (customerType == null)
{
throw LambdaExceptions.ValidationException(Errors.UserCodeLoader.UnableToLoadType, _handler.TypeName, _handler.AssemblyName);
}
_logger.LogDebug($"UCL : Attempting to find method '{_handler.MethodName}' in type '{_handler.TypeName}'");
CustomerMethodInfo = FindCustomerMethod(customerType);
_logger.LogDebug($"UCL : Located method '{CustomerMethodInfo}'");
_logger.LogDebug($"UCL : Validating method '{CustomerMethodInfo}'");
UserCodeValidator.ValidateCustomerMethod(CustomerMethodInfo);
var customerObject = GetCustomerObject(customerType);
var customerSerializerInstance = GetSerializerObject(customerAssembly);
_logger.LogDebug($"UCL : Constructing invoke delegate");
var isPreJit = UserCodeInit.IsCallPreJit();
var builder = new InvokeDelegateBuilder(_logger, _handler, CustomerMethodInfo);
_invokeDelegate = builder.ConstructInvokeDelegate(customerObject, customerSerializerInstance, isPreJit);
if (isPreJit)
{
_logger.LogInformation("PreJit: PrepareDelegate");
RuntimeHelpers.PrepareDelegate(_invokeDelegate);
}
}