haiku.rag/examples/a2a-server/haiku_rag_a2a/a2a/client.py

269 lines
8.6 KiB
Python

# pyright: reportMissingImports=false
import asyncio
import uuid
from typing import Any
import httpx
from rich.console import Console
from rich.markdown import Markdown
from rich.prompt import Prompt
try:
from fasta2a.client import A2AClient as FastA2AClient
from fasta2a.schema import Message, TextPart
except ImportError as e:
raise ImportError(
"A2A support requires the 'a2a' extra. "
"Install with: uv pip install 'haiku.rag[a2a]'"
) from e
class A2AClient:
"""Interactive A2A protocol client."""
def __init__(self, base_url: str = "http://localhost:8000"):
"""Initialize A2A client.
Args:
base_url: Base URL of the A2A server
"""
self.base_url = base_url.rstrip("/")
http_client = httpx.AsyncClient(timeout=60.0)
self._client = FastA2AClient(base_url=base_url, http_client=http_client)
async def close(self):
"""Close the HTTP client."""
await self._client.http_client.aclose()
async def get_agent_card(self) -> dict[str, Any]:
"""Fetch the agent card from the A2A server.
Returns:
Agent card dictionary with agent capabilities and metadata
"""
response = await self._client.http_client.get(
f"{self.base_url}/.well-known/agent-card.json"
)
response.raise_for_status()
return response.json()
async def send_message(
self,
text: str,
context_id: str | None = None,
skill_id: str | None = None,
) -> dict[str, Any]:
"""Send a message to the A2A agent and wait for completion.
Args:
text: Message text to send
context_id: Optional conversation context ID (creates new if None)
skill_id: Optional skill ID to use (defaults to document-qa)
Returns:
Completed task with response messages and artifacts
"""
if context_id is None:
context_id = str(uuid.uuid4())
message = Message(
kind="message",
role="user",
message_id=str(uuid.uuid4()),
parts=[TextPart(kind="text", text=text)],
)
metadata: dict[str, Any] = {"contextId": context_id}
if skill_id:
metadata["skillId"] = skill_id
response = await self._client.send_message(message, metadata=metadata)
if "error" in response:
return {"error": response["error"]}
result = response.get("result")
if not result:
return {"result": result}
# Result can be either Task or Message - check if it's a Task with an id
if result.get("kind") == "task":
task_id = result.get("id")
if task_id:
# Poll for task completion
return await self.wait_for_task(task_id)
# Return the message directly
return {"result": result}
async def wait_for_task(
self, task_id: str, max_wait: int = 120, poll_interval: float = 0.5
) -> dict[str, Any]:
"""Poll for task completion.
Args:
task_id: Task ID to poll for
max_wait: Maximum time to wait in seconds
poll_interval: Interval between polls in seconds
Returns:
Completed task result
"""
import time
start_time = time.time()
while time.time() - start_time < max_wait:
task_response = await self._client.get_task(task_id)
if "error" in task_response:
return {"error": task_response["error"]}
task = task_response.get("result")
if not task:
raise Exception("No task in response")
state = task.get("status", {}).get("state")
if state == "completed":
return {"result": task}
elif state == "failed":
raise Exception(f"Task failed: {task}")
await asyncio.sleep(poll_interval)
raise TimeoutError(f"Task {task_id} did not complete within {max_wait}s")
def print_agent_card(card: dict[str, Any], console: Console):
"""Pretty print the agent card using Rich."""
console.print()
console.print("[bold]Agent Card[/bold]")
console.rule()
console.print(f" [repr.attrib_name]name[/repr.attrib_name]: {card.get('name')}")
console.print(
f" [repr.attrib_name]description[/repr.attrib_name]: {card.get('description')}"
)
console.print(
f" [repr.attrib_name]version[/repr.attrib_name]: {card.get('version')}"
)
console.print(
f" [repr.attrib_name]protocol version[/repr.attrib_name]: {card.get('protocolVersion')}"
)
skills = card.get("skills", [])
console.print(f"\n[bold cyan]Skills ({len(skills)}):[/bold cyan]")
for skill in skills:
console.print(f"{skill.get('id')}: {skill.get('name')}")
console.print(f" [dim]{skill.get('description')}[/dim]")
examples = skill.get("examples", [])
if examples:
console.print(f" [dim]Examples: {', '.join(examples[:2])}[/dim]")
console.print()
def print_response(response: dict[str, Any], console: Console):
"""Pretty print the A2A response using Rich."""
if "error" in response:
console.print(f"[red]Error: {response['error']}[/red]")
return
result = response.get("result", {})
# Get messages from history and artifacts from completed task
history = result.get("history", [])
artifacts = result.get("artifacts", [])
# Print agent messages from history with markdown rendering
for msg in history:
if msg.get("role") == "agent":
for part in msg.get("parts", []):
if part.get("kind") == "text":
text = part.get("text", "")
# Render as markdown
console.print()
console.print("[bold green]Answer:[/bold green]")
console.print(Markdown(text))
# Print artifacts summary with details
if artifacts:
console.rule("[dim]Artifacts generated[/dim]")
summary_lines = []
for artifact in artifacts:
name = artifact.get("name", "")
parts = artifact.get("parts", [])
if name == "search_results" and parts:
data = parts[0].get("data", {})
query = data.get("query", "")
results = data.get("results", [])
summary_lines.append(f"🔍 search: '{query}' ({len(results)} results)")
elif name == "document" and parts:
part = parts[0]
if part.get("kind") == "text":
text = part.get("text", "")
length = len(text)
summary_lines.append(f"📄 document ({length} chars)")
elif name == "qa_result" and parts:
data = parts[0].get("data", {})
skill = data.get("skill", "unknown")
summary_lines.append(f"💬 {skill}")
if summary_lines:
console.print(f"[dim]{''.join(summary_lines)}[/dim]")
console.print()
async def run_interactive_client(url: str = "http://localhost:8000"):
"""Run the interactive A2A client.
Args:
url: Base URL of the A2A server
"""
console = Console()
client = A2AClient(url)
console.print("[bold]haiku.rag A2A interactive client[/bold]")
console.print()
# Fetch and display agent card
console.print("[dim]Fetching agent card...[/dim]")
try:
card = await client.get_agent_card()
print_agent_card(card, console)
except Exception as e:
console.print(f"[red]Error fetching agent card: {e}[/red]")
await client.close()
return
# Create a conversation context
context_id = str(uuid.uuid4())
console.print(f"[dim]context id: {context_id}[/dim]")
console.print("[dim]Type your questions (or 'quit' to exit)[/dim]\n")
try:
while True:
try:
question = Prompt.ask("[bold blue]Question[/bold blue]").strip()
if not question:
continue
if question.lower() in ("quit", "exit", "q"):
console.print("\n[dim]Goodbye![/dim]")
break
response = await client.send_message(question, context_id=context_id)
print_response(response, console)
except KeyboardInterrupt:
console.print("\n\n[dim]Exiting...[/dim]")
break
except Exception as e:
console.print(f"\n[red]Error: {e}[/red]\n")
finally:
await client.close()