add concurrency limit to yaml

manifest/concur.go

@@ -0,0 +1,10 @@
+// Copyright 2019 Drone.IO Inc. All rights reserved.
+// Use of this source code is governed by the Polyform License
+// that can be found in the LICENSE file.
+
+package manifest
+
+// Concurrency limits pipeline concurrency.
+type Concurrency struct {
+	Limit int `json:"limit,omitempty"`
+}

manifest/concur_test.go

@@ -0,0 +1,5 @@
+// Copyright 2019 Drone.IO Inc. All rights reserved.
+// Use of this source code is governed by the Polyform License
+// that can be found in the LICENSE file.
+
+package manifest

manifest/manifest.go

@@ -28,6 +28,12 @@ type (
 		GetName() string
 	}
 
+	// ConcurrentResource is a resource with concurrency limits.
+	ConcurrentResource interface {
+		Resource
+		GetConcurrency() Concurrency
+	}
+
 	// DependantResource is a resoure with runtime dependencies.
 	DependantResource interface {
 		Resource