google--adk-python/contributing/workflow_samples/loop_self/README.md

ADK Workflow Loop Self Sample

Overview

This sample demonstrates how a node can repeatedly loop back to itself based on a specific route condition in ADK Workflows.

It takes a user-provided target number (between 0 and 10), and uses a guess_number function to randomly generate guesses. If the guess is incorrect, the function yields a specific route (guessed_wrong). The workflow is configured such that this route directs the execution right back to the guess_number node, creating a loop that continues until the correct number is guessed.

In ADK Workflows, you can create self-referential loops or iterative processes by routing a node's output back to itself.

Sample Inputs

• 5
• 0
• 10

Graph

                  [ START ]
                      |
                      v
              [ validate_input ]
                      |
                      v
             +->[ guess_number ]-----+
             |        |              |
             |        v              |
             +--"guessed_wrong"      v
                               (Loop ends when
                              guess is correct)

How To

1. From within your node (agent or function), yield a specific Event with a route name when you determine the node needs to be executed again:

   def guess_number(target_number: int):
     # ...
     if guess != target_number:
       yield Event(route='guessed_wrong')
   

2. In the Workflow edges definition, create a conditional edge where the source and target are the same node, using a routing map dict:

   (guess_number, {'guessed_wrong': guess_number})