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DevOpsDash/app/mcp_client.py
Henrik Jess Nielsen 86c44799a6
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fix: MCP client SSE transport — add correct Accept headers and SSE response parsing
FastMCP 2.0 streamable HTTP requires Accept: application/json, text/event-stream
and can return text/event-stream responses with data: {...} SSE lines.
2026-05-09 17:00:52 +02:00

139 lines
4.3 KiB
Python

"""MCP proxy client — calls DevOpsMCP's worklog/standup tools over HTTP MCP protocol.
FastMCP 2.0 uses streamable HTTP transport (MCP spec §6.3.3):
- POST to /mcp with Accept: application/json, text/event-stream
- Server may respond with JSON or SSE stream (text/event-stream)
- SSE responses have `data: {...}` lines containing JSON-RPC messages
"""
from __future__ import annotations
import json
import os
from typing import Any, Dict, Optional
import httpx
MCP_URL = os.environ.get("DEVOPS_MCP_URL", "http://localhost:8000")
_MCP_ENDPOINT = f"{MCP_URL}/mcp"
_HEADERS = {
"Content-Type": "application/json",
"Accept": "application/json, text/event-stream",
}
def _parse_sse_data(text: str) -> Dict[str, Any]:
"""Extract JSON-RPC result from SSE stream data lines."""
for line in text.splitlines():
line = line.strip()
if line.startswith("data:"):
chunk = line[5:].strip()
if not chunk or chunk == "[DONE]":
continue
try:
msg = json.loads(chunk)
if "result" in msg or "error" in msg:
return msg
except json.JSONDecodeError:
continue
return {}
def _extract_result(data: Dict[str, Any]) -> Dict[str, Any]:
"""Extract tool result content from JSON-RPC response."""
if "error" in data:
raise RuntimeError(f"MCP error: {data['error']}")
result = data.get("result", {})
content = result.get("content", [])
if content and isinstance(content[0], dict):
text = content[0].get("text", "{}")
try:
return json.loads(text)
except json.JSONDecodeError:
return {"raw": text}
return result
async def _call_tool(tool_name: str, arguments: Dict[str, Any]) -> Dict[str, Any]:
"""Call a DevOpsMCP tool via MCP JSON-RPC 2.0 streamable HTTP transport."""
payload = {
"jsonrpc": "2.0",
"method": "tools/call",
"params": {"name": tool_name, "arguments": arguments},
"id": 1,
}
async with httpx.AsyncClient(timeout=60.0) as client:
resp = await client.post(_MCP_ENDPOINT, json=payload, headers=_HEADERS)
resp.raise_for_status()
content_type = resp.headers.get("content-type", "")
if "text/event-stream" in content_type:
data = _parse_sse_data(resp.text)
else:
data = resp.json()
return _extract_result(data)
async def get_worklog(
context: str = "egmont",
days: int = 7,
group_by: str = "repo",
since_date: Optional[str] = None,
until_date: Optional[str] = None,
) -> Dict[str, Any]:
args: Dict[str, Any] = {"context": context, "days": days, "group_by": group_by}
if since_date:
args["since_date"] = since_date
if until_date:
args["until_date"] = until_date
return await _call_tool("worklog", args)
async def get_standup(days: int = 2, context: str = "egmont") -> Dict[str, Any]:
return await _call_tool("generate_standup", {"days": days, "context": context})
async def list_knowledge(category: Optional[str] = None, tag: Optional[str] = None) -> Dict[str, Any]:
args: Dict[str, Any] = {}
if category:
args["category"] = category
if tag:
args["tag"] = tag
return await _call_tool("list_knowledge", args)
async def get_knowledge(storage_filename: str) -> Dict[str, Any]:
return await _call_tool("get_knowledge", {"storage_filename": storage_filename, "include_metadata": False})
async def list_howtos() -> Dict[str, Any]:
return await _call_tool("list_howtos", {})
async def get_howto(filename: str) -> Dict[str, Any]:
return await _call_tool("get_howto_content", {"filename": filename})
async def list_agents(domain: Optional[str] = None) -> Dict[str, Any]:
args: Dict[str, Any] = {}
if domain:
args["domain"] = domain
return await _call_tool("get_agent", args)
async def get_agent(name: str) -> Dict[str, Any]:
return await _call_tool("get_agent", {"name": name})
async def list_skills(domain: Optional[str] = None) -> Dict[str, Any]:
args: Dict[str, Any] = {}
if domain:
args["domain"] = domain
return await _call_tool("get_skill", args)
async def get_skill(name: str) -> Dict[str, Any]:
return await _call_tool("get_skill", {"name": name})