Merge Node | Vellum | Documentation

vellum.workflows.nodes.MergeNode

Used to merge the control flow of multiple nodes into a single node. This node exists primarily for backwards compatibility with Vellum’s Merge Node functionality.

For most cases, you should extend from BaseNode.Trigger directly instead of using MergeNode. Read more on Triggers

Attributes

This node doesn’t have any specific attributes as it’s a simple control flow node.

Outputs

This node passes through any outputs from its parent nodes without modification.

1	from vellum.workflows.nodes import BaseNode
2
3	class QuickNode(BaseNode):
4	class Outputs(BaseNode.Outputs):
5	prefix = "Hello"
6
7	class SlowNode(BaseNode):
8	class Outputs(BaseNode.Outputs):
9	suffix: str
10	def run(self) -> Outputs:
11	time.sleep(5)
12	return self.Outputs(suffix="World")
13
14	class MergeNode(BaseNode):
15	prefix = QuickNode.Outputs.prefix
16	suffix = SlowNode.Outputs.suffix
17	class Outputs(BaseNode.Outputs):
18	message: str
19	class Trigger(BaseNode.Trigger):
20	merge_strategy = MergeStrategy.AWAIT_ALL
21	def run(self) -> Outputs:
22	return self.Outputs(message=f"{self.prefix} {self.suffix}")

1	from vellum.workflows.nodes import BaseNode
2
3	class QuickNode(BaseNode):
4	class Outputs(BaseNode.Outputs):
5	prefix = "Hello"
6
7	class SlowNode(BaseNode):
8	class Outputs(BaseNode.Outputs):
9	suffix: str
10	def run(self) -> Outputs:
11	time.sleep(5)
12	return self.Outputs(suffix="World")
13
14	class MergeNode(BaseNode):
15	prefix = QuickNode.Outputs.prefix
16	suffix = SlowNode.Outputs.suffix
17	class Outputs(BaseNode.Outputs):
18	message: str
19	class Trigger(BaseNode.Trigger):
20	merge_strategy = MergeStrategy.AWAIT_ALL
21	def run(self) -> Outputs:
22	return self.Outputs(message=f"{self.prefix} {self.suffix}")