ADK state example

This example demonstrates how to manage and update session state within an ADK application. It showcases two primary methods for state modification:

1. Using output_key in an LlmAgent to automatically save the agent's final text response to a specified state key.
2. Manually constructing state_delta within EventActions for more complex state updates, including those with user: and temp: prefixes.

Requirements

• Python 3.10+
• A Google API key set as an environment variable (GOOGLE_API_KEY)

Steps for running this example in the shell

1. Install dependencies:

python -m venv .venv

# macOS/Linux:
source .venv/bin/activate

# Windows Command Prompt:
.venv\Scripts\activate.bat

# Windows PowerShell:
.venv\Scripts\Activate.ps1

pip install -r requirements.txt

2. Export your API key as an environment variable:

export GOOGLE_API_KEY="sk-..." # Windows cmd: set GOOGLE_API_KEY="sk-..." # Windows PowerShell: $env:GOOGLE_API_KEY="sk-..."

3. Run the script:

python state_example.py

Output

The script will execute two scenarios:

• Greeting Agent: An LlmAgent with output_key configured will generate a greeting, and its response will be automatically saved to the session state.
• Manual State Update: Explicit EventActions will be used to update task_status, user:login_count, and user:last_login_ts in the session state.

The script will print the initial and updated states of the sessions, demonstrating how state changes are recorded and persisted.

Example output (simplified):

--- Running GreetingAgent (output_key) Example ---
Initial state: {'user:login_count': 0, 'task_status': 'idle'}
Agent responded with: "Hello there! How can I help you today?"
State after agent run: last_greeting = "Hello there! How can I help you today?"

--- Running Manual State Update (EventActions) Example ---
Initial state: {'user:login_count': 0, 'task_status': 'idle'}
`append_event` called with explicit state delta.
State after event: task_status='active', user:login_count=1, user:last_login_ts=<timestamp>
As expected, temp state was not persisted: 'temp:validation_needed' not found.