Looker CA API with Google ADK Streaming

This skill provides guidance for integrating the Looker Conversational Analytics (CA) API with the Google Agent Development Kit (ADK) to build sophisticated, streaming data agents.

Overview

By combining the CA API's natural language-to-query capabilities with ADK's orchestration and streaming features, you can create applications that:

• Stream Real-time Responses: Provide immediate feedback as the CA API processes and generates data.
• Orchestrate Multi-step Workflows: Chain data fetching with analysis, visualization, or external tool calls.
• Implement Conditional Logic: Use run_when predicates to execute sub-agents only when specific data conditions are met.
• Normalize Session State: Share data between agents using ADK's session.state.

1. Prerequisites

• Looker Instance: Configured with the CA API enabled and appropriate IAM roles.
• Google ADK: Installed (pip install google-adk).
• GCP Project: Vertex AI and Gemini Data Analytics APIs enabled.
• Environment Variables: LOOKERSDKBASEURL, LOOKERSDKCLIENTID, LOOKERSDKCLIENTSECRET, GCPPROJECTID, GCP_LOCATION.

2. Implementation Pattern: CA Query Agent

The ConversationalAnalyticsQueryAgent bridges the CA API with ADK's streaming interface.

from google.adk.agents import BaseAgent, InvocationContext
from google.cloud import geminidataanalytics_v1beta as geminidataanalytics

class ConversationalAnalyticsQueryAgent(BaseAgent):
    def run(self, input_text: str, context: InvocationContext):
        # 1. Initialize CA API Client
        client = geminidataanalytics.DataChatServiceClient()
        
        # 2. Build Chat Request (Inline or Stateful)
        request = geminidataanalytics.ChatRequest(
            parent=f"projects/{PROJECT_ID}/locations/{LOCATION}",
            messages=[geminidataanalytics.Message(
                user_message=geminidataanalytics.UserMessage(text=input_text)
            )],
            inline_context=self._build_inline_context()
        )

        # 3. Stream from CA API and Bridge to ADK
        stream = client.chat(request=request)
        for response in stream:
            # Extract text/data from response
            text_part = response.message.text
            if text_part:
                context.stream(text_part) # Stream to ADK output
            
            # Store data in session state for downstream agents
            if response.data_result:
                context.session.state["temp:data_result"] = response.data_result

3. Implementation Pattern: Root Orchestration

The RootAgent manages the deterministic execution flow and conditional sub-agents.

from google.adk.agents import RootAgent

# Define Optional Sub-Agents
sub_agents = [
    OptionalSubAgentSpec(
        agent=visualization_agent,
        run_when=lambda state: "temp:data_result" in state, # Predicate
        description="Generates charts if data is available"
    )
]

# Build Root Agent
root_agent = RootAgent(
    primary_agent=ca_query_agent,
    optional_sub_agents=sub_agents
)

4. Key Orchestration Patterns

Deterministic CA-First

1. Primary Agent: Always executes the CA Query Agent first.
2. Session State: The primary agent populates temp:dataresult or temp:summarydata.
3. Conditional Sub-agents: Executed sequentially based on run_when predicates.

Real-time Sanitization

During streaming, ensure the output is compatible with the target interface:

• Image Conversion: Convert inline bytes from CA API into Markdown image URIs.
• Text Cleaning: Strip unnecessary code blocks or formatting from partial streams.

5. Best Practices

• Resilient Flows: Ensure the RootAgent continues even if an optional sub-agent fails.
• Predicate Precision: Keep run_when logic simple and focused on state keys.
• Context Management: Use inline_context for testing and ConversationReference for stateful multi-turn chats.
• Normalization: Standardize the structure of data stored in session.state to make sub-agents reusable across different data sources.

6. Troubleshooting

• Streaming Interruption: Check if intermediate proxies or gateways support long-lived HTTP/2 streams.
• State Mismatch: Verify that the keys used in run_when match exactly what is set by the primary agent.
• Permission Errors: Ensure the service account has both roles/geminidataanalytics.user and Looker access_data permissions.