public InMemoryCommandBus(InMemoryCommandBusConfiguration?configuration = null,
IScopeFactory?scopeFactory = null)
{
if (scopeFactory != null)
{
_scope = scopeFactory.CreateScope();
}
_logger =
_scope?.Resolve <ILoggerFactory>()?.CreateLogger <InMemoryCommandBus>()
??
new LoggerFactory(new[] { new DebugLoggerProvider() }).CreateLogger <InMemoryCommandBus>();
_config = configuration ?? InMemoryCommandBusConfiguration.Default;
}
internal InMemoryCommandBus(InMemoryCommandBusConfiguration configuration = null,
IScopeFactory scopeFactory = null)
{
if (scopeFactory != null)
{
_scope = scopeFactory.CreateScope();
}
_logger =
_scope?.Resolve <ILoggerFactory>()?.CreateLogger <InMemoryCommandBus>()
??
new LoggerFactory().CreateLogger <InMemoryCommandBus>();
_config = configuration ?? InMemoryCommandBusConfiguration.Default;
}
/// <summary>
/// Dispatch command and context to all handlers.
/// </summary>
/// <param name="command">Command to dispatch.</param>
/// <param name="context">Context associated to command</param>
public async Task <Result> DispatchAsync(ICommand command, ICommandContext context = null)
{
var commandTypeName = command.GetType().FullName;
_logger.LogInformation($"InMemoryCommandBus : Beginning of dispatching a command of type {commandTypeName}");
var commandTasks = new List <Task <Result> >();
_config = _config ?? InMemoryCommandBusConfiguration.Default;
var ifClause = _config.IfClauses.FirstOrDefault(i => i.Key == command.GetType()).Value;
if (ifClause?.Invoke(command) == false)
{
_logger.LogInformation($"InMemoryCommandBus : If condition for command type {commandTypeName} has returned false.");
return(Result.Ok());
}
var handlers = TryGetHandlerFromIoCContainer(command);
if (!handlers.Any())
{
_logger.LogInformation($"InMemoryCommandBus : Handler for command type {commandTypeName} not found in Ioc container, trying to get it from CoreDispatcher.");
handlers = TryGetHandlersInstancesFromCoreDispatcher(command);
}
if (!handlers.Any())
{
_logger.LogInformation($"InMemoryCommandBus : Handler for command type {commandTypeName} not found in CoreDispatcher, trying to instantiate if by reflection.");
handlers = TryGetHandlersInstancesByReflection(command);
}
if (!handlers.Any())
{
_logger.LogWarning($"InMemoryCommandBus : No handlers for command type {commandTypeName} were found.");
_config.OnNoHandlerFounds?.Invoke(command, context);
return(Result.Fail($"No handlers for command type {commandTypeName} were found."));
}
bool manyHandlersAndShouldWait = false;
if (handlers.Skip(1).Any())
{
if (!_config.CommandAllowMultipleHandlers.Any(t => new TypeEqualityComparer().Equals(t.CommandType, command.GetType())))
{
return(Result.Fail($"the command of type {commandTypeName} have multiple handlers within the same process. " +
"If this is expected, you should update your configuration to allow multiple handlers for this specific command type, altough this is not recommended."));
}
else
{
manyHandlersAndShouldWait
= _config.CommandAllowMultipleHandlers.FirstOrDefault(t => new TypeEqualityComparer().Equals(t.CommandType, command.GetType()))?.ShouldWait ?? false;
}
}
var cmdHandlers = handlers.ToList();
if (cmdHandlers.Count > 1)
{
cmdHandlers = cmdHandlers.OrderByDescending(h => h.GetType().GetCustomAttribute <HandlerPriorityAttribute>()?.Priority ?? 0).ToList();
}
foreach (var handler in cmdHandlers)
{
_logger.LogInformation($"InMemoryCommandBus : Invocation of handler of type {handlers.GetType().FullName}");
var handlerType = handler.GetType();
var method = handlerType.GetMethods()
.First(m => m.Name == nameof(ICommandHandler <ICommand> .HandleAsync));
try
{
if (manyHandlersAndShouldWait)
{
var result = await((Task <Result>)method.Invoke(handler, new object[] { command, context })).ConfigureAwait(false);
commandTasks.Add(Task.FromResult(result));
}
else
{
var t = (Task <Result>)method.Invoke(handler, new object[] { command, context });
commandTasks.Add(t);
}
}
catch (Exception e)
{
_logger.LogErrorMultilines($"InMemoryCommandBus.DispatchAsync() : Exception when trying to dispatch command {commandTypeName} to handler {handler.GetType().FullName}",
e.ToString());
if (handlerType.IsDefined(typeof(CriticalHandlerAttribute)))
{
Result r = Result.Fail($"Critical handler {handlerType.FullName} has failed, so next ones will not be called");
commandTasks.Add(Task.FromResult(r));
break;
}
}
}
if (!manyHandlersAndShouldWait)
{
await Task.WhenAll(commandTasks).ConfigureAwait(false);
}
if (commandTasks.Count == 1)
{
return(commandTasks[0].Result);
}
return(Result.Ok().Combine(commandTasks.Select(t => t.Result).ToArray()));
}
