Adding service definitions for Projections

Source/Runtime/Events.Processing/Projections.proto

@@ -0,0 +1,97 @@
+// Copyright (c) Dolittle. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+syntax = "proto3";
+
+import "Fundamentals/Artifacts/Artifact.proto";
+import "Fundamentals/Protobuf/Uuid.proto";
+import "Fundamentals/Protobuf/Failure.proto";
+import "Fundamentals/Services/ReverseCallContext.proto";
+import "Fundamentals/Services/Ping.proto";
+import "Runtime/Events.Processing/StreamEvent.proto";
+import "Runtime/Events.Processing/Processors.proto";
+
+package dolittle.runtime.events.processing;
+
+option csharp_namespace = "Dolittle.Runtime.Events.Processing.Contracts";
+
+enum ProjectEventKeySelectorType {
+    EVENT_SOURCE_ID = 0;
+    PARTITION_ID = 1;
+    PROPERTY = 2;
+}
+
+message ProjectionEventKeySelector {
+    ProjectEventKeySelectorType type = 1;
+    string expression = 2;
+}
+
+message ProjectionEventSelector {
+    artifacts.Artifact eventType = 1;
+    ProjectionEventKeySelector keySelector = 2;
+}
+
+message ProjectionRegistrationRequest {
+    services.ReverseCallArgumentsContext callContext = 1;
+    protobuf.Uuid scopeId = 2;
+    protobuf.Uuid projectionId = 3;
+    repeated ProjectionEventSelector events = 4;
+    string initialState = 5;
+}
+
+enum ProjectionNextStateType {
+    REPLACE = 0;
+    DELETE = 1;
+}
+
+message ProjectionNextState {
+    ProjectionNextStateType type = 1;
+    string value = 2;
+}
+
+message ProjectionResponse {
+    services.ReverseCallResponseContext callContext = 1;
+    ProjectionNextState nextState = 2;
+    ProcessorFailure failure = 3; // If not set/empty - no failure
+}
+
+message ProjectionClientToRuntimeMessage {
+    oneof Message {
+        ProjectionRegistrationRequest registrationRequest = 1;
+        ProjectionResponse handleResult = 2;
+        services.Pong pong = 3;
+    }
+}
+
+message ProjectionRegistrationResponse {
+    protobuf.Failure failure = 1;
+}
+
+enum ProjectionCurrentStateType {
+    CREATED_FROM_INITIAL_STATE = 0;
+    PERSISTED = 1;
+}
+
+message ProjectionCurrentState {
+    ProjectionCurrentStateType type = 1;
+    string state = 2;
+}
+
+message ProjectionRequest {
+    services.ReverseCallRequestContext callContext = 1;
+    ProjectionCurrentState currentState = 2;
+    StreamEvent event = 3;
+    RetryProcessingState retryProcessingState = 4;
+}
+
+message ProjectionRuntimeToClientMessage {
+    oneof Message {
+        ProjectionRegistrationResponse registrationResponse = 1;
+        ProjectionRequest handleRequest = 2;
+        services.Ping ping = 3;
+    }
+}
+
+service Projections {
+    rpc Connect(stream ProjectionClientToRuntimeMessage) returns(stream ProjectionRuntimeToClientMessage);
+}