/// <summary>
/// Constructs a query/signal method map for a workflow type.
/// </summary>
/// <param name="workflowType">The workflow type.</param>
/// <returns>The <see cref="WorkflowMethodMap"/>.</returns>
public static WorkflowMethodMap Create(Type workflowType)
{
Covenant.Requires <ArgumentNullException>(workflowType != null, nameof(workflowType));
Covenant.Requires <ArgumentException>(!workflowType.IsInterface, nameof(workflowType));
var map = new WorkflowMethodMap();
foreach (var @interface in workflowType.GetInterfaces())
{
foreach (var method in @interface.GetMethods(BindingFlags.Public | BindingFlags.Instance))
{
// Signal methods are tagged by [SignalMethod].
var signalMethodAttribute = method.GetCustomAttribute <SignalMethodAttribute>();
if (signalMethodAttribute != null)
{
map.nameToSignalMethod[signalMethodAttribute.Name] = method;
continue;
}
// Query methods are tagged by [QueryMethod].
var queryMethodAttribute = method.GetCustomAttribute <QueryMethodAttribute>();
if (queryMethodAttribute != null)
{
map.nameToQueryMethod[queryMethodAttribute.Name] = method;
continue;
}
}
}
return(map);
}
/// <summary>
/// Registers a workflow implementation.
/// </summary>
/// <param name="client">The associated client.</param>
/// <param name="workflowType">The workflow implementation type.</param>
/// <param name="workflowTypeName">The name used to identify the implementation.</param>
/// <returns><c>true</c> if the workflow was already registered.</returns>
/// <exception cref="InvalidOperationException">Thrown if a different workflow class has already been registered for <paramref name="workflowTypeName"/>.</exception>
internal static bool Register(CadenceClient client, Type workflowType, string workflowTypeName)
{
Covenant.Requires <ArgumentNullException>(client != null);
CadenceHelper.ValidateWorkflowImplementation(workflowType);
// We need to register each workflow method defined for the workflow.
var methodMap = WorkflowMethodMap.Create(workflowType);
foreach (var method in workflowType.GetMethods())
{
var workflowMethodAttribute = method.GetCustomAttribute <WorkflowMethodAttribute>();
if (workflowMethodAttribute == null)
{
continue;
}
workflowTypeName = GetWorkflowTypeKey(client, workflowTypeName, method);
lock (syncLock)
{
if (nameToRegistration.TryGetValue(workflowTypeName, out var existingRegistration))
{
if (!object.ReferenceEquals(existingRegistration.WorkflowType, workflowType))
{
throw new InvalidOperationException($"Conflicting workflow interface registration: Workflow interface [{workflowType.FullName}] is already registered for workflow type name [{workflowTypeName}].");
}
return(true);
}
else
{
nameToRegistration[workflowTypeName] =
new WorkflowRegistration()
{
WorkflowType = workflowType,
WorkflowMethod = method,
MethodMap = methodMap
};
}
}
}
return(false);
}
/// <summary>
/// Constructs a query/signal method map for a workflow type.
/// </summary>
/// <param name="workflowType">The workflow interface.</param>
/// <returns>The <see cref="WorkflowMethodMap"/>.</returns>
public static WorkflowMethodMap Create(Type workflowType)
{
Covenant.Requires <ArgumentNullException>(workflowType != null);
// $todo(jeff.lill):
//
// The code below doesn't not verify that query/signal names are unique
// but also doesn't barf. It will send requets to the last method
// encountered with the same name, which is pretty reasonable.
//
// In a perfect world, we'd detect this and throw an exception.
var map = new WorkflowMethodMap();
foreach (var method in workflowType.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
{
// Signal methods are tagged by [SignalHandler], accept a single byte array parameter,
// and returns [Task].
var signalHandlerAttribute = method.GetCustomAttribute <SignalMethodAttribute>();
if (signalHandlerAttribute != null)
{
if (method.ReturnType != typeof(Task))
{
Log.LogWarn($"Workflow [{workflowType.FullName}.{method.Name}()] signal handler is invalid because it doesn't return [void]. It will be ignored.");
continue;
}
var parameters = method.GetParameters();
if (parameters.Length != 1 || parameters[0].ParameterType != typeof(byte[]))
{
Log.LogWarn($"Workflow [{workflowType.FullName}.{method.Name}()] signal handler is invalid because it doesn't accept a single byte array parameter. It will be ignored.");
continue;
}
map.nameToSignalMethod[signalHandlerAttribute.Name] = method;
continue;
}
// Query methods are tagged by [QueryHandler], accept a single byte array parameter,
// and returns [Task<byte[]>].
var queryHandlerAttribute = method.GetCustomAttribute <QueryMethodAttribute>();
if (queryHandlerAttribute != null)
{
if (method.ReturnType != typeof(Task <byte[]>))
{
Log.LogWarn($"Workflow [{workflowType.FullName}.{method.Name}()] query handler is invalid because it doesn't return a byte array. It will be ignored.");
continue;
}
var parameters = method.GetParameters();
if (parameters.Length != 1 || parameters[0].ParameterType != typeof(byte[]))
{
Log.LogWarn($"Workflow [{workflowType.FullName}.{method.Name}()] query handler is invalid because it doesn't accept a single byte array parameter. It will be ignored.");
continue;
}
map.nameToQueryMethod[queryHandlerAttribute.Name] = method;
continue;
}
}
return(map);
}
/// <summary>
/// Registers a workflow implementation.
/// </summary>
/// <param name="client">The associated client.</param>
/// <param name="workflowType">The workflow implementation type.</param>
/// <param name="workflowTypeName">The name used to identify the implementation.</param>
/// <param name="domain">Specifies the target domain.</param>
/// <exception cref="InvalidOperationException">Thrown if a different workflow class has already been registered for <paramref name="workflowTypeName"/>.</exception>
internal static async Task RegisterAsync(CadenceClient client, Type workflowType, string workflowTypeName, string domain)
{
Covenant.Requires<ArgumentNullException>(client != null, nameof(client));
Covenant.Requires<ArgumentNullException>(!string.IsNullOrEmpty(domain), nameof(domain));
CadenceHelper.ValidateWorkflowImplementation(workflowType);
var methodMap = WorkflowMethodMap.Create(workflowType);
// We need to register each workflow method that implements a workflow interface method
// with the same signature that that was tagged by [WorkflowMethod].
//
// First, we'll create a dictionary that maps method signatures from any inherited
// interfaces that are tagged by [WorkflowMethod] to the attribute.
var methodSignatureToAttribute = new Dictionary<string, WorkflowMethodAttribute>();
foreach (var interfaceType in workflowType.GetInterfaces())
{
foreach (var method in interfaceType.GetMethods(BindingFlags.Public | BindingFlags.Instance))
{
var workflowMethodAttribute = method.GetCustomAttribute<WorkflowMethodAttribute>();
if (workflowMethodAttribute == null)
{
continue;
}
var signature = method.ToString();
if (methodSignatureToAttribute.ContainsKey(signature))
{
throw new NotSupportedException($"Workflow type [{workflowType.FullName}] cannot implement the [{signature}] method from two different interfaces.");
}
methodSignatureToAttribute.Add(signature, workflowMethodAttribute);
}
}
// Next, we need to register the workflow methods that implement the
// workflow interface.
foreach (var method in workflowType.GetMethods())
{
if (!methodSignatureToAttribute.TryGetValue(method.ToString(), out var workflowMethodAttribute))
{
continue;
}
var workflowTypeKey = GetWorkflowTypeKey(client, workflowTypeName, workflowMethodAttribute);
lock (syncLock)
{
if (nameToRegistration.TryGetValue(workflowTypeName, out var existingRegistration))
{
if (!object.ReferenceEquals(existingRegistration.WorkflowType, workflowType))
{
throw new InvalidOperationException($"Conflicting workflow interface registration: Workflow interface [{workflowType.FullName}] is already registered for workflow type name [{workflowTypeName}].");
}
}
else
{
nameToRegistration[workflowTypeKey] =
new WorkflowRegistration()
{
WorkflowType = workflowType,
WorkflowMethod = method,
WorkflowMethodParameterTypes = method.GetParameterTypes(),
MethodMap = methodMap
};
}
}
var reply = (WorkflowRegisterReply)await client.CallProxyAsync(
new WorkflowRegisterRequest()
{
Name = GetWorkflowTypeNameFromKey(workflowTypeKey),
Domain = client.ResolveDomain(domain)
});
// $hack(jefflill):
//
// We're going to ignore any errors here to handle:
//
// https://github.com/nforgeio/neonKUBE/issues/668
// reply.ThrowOnError();
}
}
