Files
webui/api/streaming.py
Nathan Esquenazi 241357595d refactor: extract resolve_model_provider helper, fix cross-provider routing
Replace duplicated inline provider resolution in routes.py and streaming.py
with a shared resolve_model_provider() helper in config.py.

Improvements over original:
- If model ID has a prefix matching any known direct-API provider
  (not just the config provider), strip it and route correctly.
  This handles edge cases like localStorage restoring a model from
  a different provider group.
- Single source of truth for the resolution logic.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-01 22:56:34 -07:00

222 lines
9.8 KiB
Python

"""
Hermes Web UI -- SSE streaming engine and agent thread runner.
Includes Sprint 10 cancel support via CANCEL_FLAGS.
"""
import json
import os
import queue
import threading
import time
import traceback
from pathlib import Path
from api.config import (
STREAMS, STREAMS_LOCK, CANCEL_FLAGS, CLI_TOOLSETS,
_get_session_agent_lock, _set_thread_env, _clear_thread_env,
resolve_model_provider,
)
# Lazy import to avoid circular deps -- hermes-agent is on sys.path via api/config.py
try:
from run_agent import AIAgent
except ImportError:
AIAgent = None
from api.models import get_session, title_from
from api.workspace import set_last_workspace
def _sse(handler, event, data):
"""Write one SSE event to the response stream."""
payload = f"event: {event}\ndata: {json.dumps(data, ensure_ascii=False)}\n\n"
handler.wfile.write(payload.encode('utf-8'))
handler.wfile.flush()
def _run_agent_streaming(session_id, msg_text, model, workspace, stream_id, attachments=None):
"""Run agent in background thread, writing SSE events to STREAMS[stream_id]."""
q = STREAMS.get(stream_id)
if q is None:
return
# Sprint 10: create a cancel event for this stream
cancel_event = threading.Event()
with STREAMS_LOCK:
CANCEL_FLAGS[stream_id] = cancel_event
def put(event, data):
# If cancelled, drop all further events except the cancel event itself
if cancel_event.is_set() and event not in ('cancel', 'error'):
return
try:
q.put_nowait((event, data))
except Exception:
pass
try:
s = get_session(session_id)
s.workspace = str(Path(workspace).expanduser().resolve())
s.model = model
_agent_lock = _get_session_agent_lock(session_id)
# TD1: set thread-local env context so concurrent sessions don't clobber globals
# Check for pre-flight cancel (user cancelled before agent even started)
if cancel_event.is_set():
put('cancel', {'message': 'Cancelled before start'})
return
_set_thread_env(
TERMINAL_CWD=str(s.workspace),
HERMES_EXEC_ASK='1',
HERMES_SESSION_KEY=session_id,
)
# Still set process-level env as fallback for tools that bypass thread-local
with _agent_lock:
old_cwd = os.environ.get('TERMINAL_CWD')
old_exec_ask = os.environ.get('HERMES_EXEC_ASK')
old_session_key = os.environ.get('HERMES_SESSION_KEY')
os.environ['TERMINAL_CWD'] = str(s.workspace)
os.environ['HERMES_EXEC_ASK'] = '1'
os.environ['HERMES_SESSION_KEY'] = session_id
try:
def on_token(text):
if text is None:
return # end-of-stream sentinel
put('token', {'text': text})
def on_tool(name, preview, args):
args_snap = {}
if isinstance(args, dict):
for k, v in list(args.items())[:4]:
s2 = str(v); args_snap[k] = s2[:120]+('...' if len(s2)>120 else '')
put('tool', {'name': name, 'preview': preview, 'args': args_snap})
# also check for pending approval and surface it immediately
from tools.approval import has_pending as _has_pending, _pending, _lock
if _has_pending(session_id):
with _lock:
p = dict(_pending.get(session_id, {}))
if p:
put('approval', p)
if AIAgent is None:
raise ImportError("AIAgent not available -- check that hermes-agent is on sys.path")
resolved_model, resolved_provider = resolve_model_provider(model)
agent = AIAgent(
model=resolved_model,
provider=resolved_provider,
platform='cli',
quiet_mode=True,
enabled_toolsets=CLI_TOOLSETS,
session_id=session_id,
stream_delta_callback=on_token,
tool_progress_callback=on_tool,
)
# Prepend workspace context so the agent always knows which directory
# to use for file operations, regardless of session age or AGENTS.md defaults.
workspace_ctx = f"[Workspace: {s.workspace}]\n"
workspace_system_msg = (
f"Active workspace at session start: {s.workspace}\n"
"Every user message is prefixed with [Workspace: /absolute/path] indicating the "
"workspace the user has selected in the web UI at the time they sent that message. "
"This tag is the single authoritative source of the active workspace and updates "
"with every message. It overrides any prior workspace mentioned in this system "
"prompt, memory, or conversation history. Always use the value from the most recent "
"[Workspace: ...] tag as your default working directory for ALL file operations: "
"write_file, read_file, search_files, terminal workdir, and patch. "
"Never fall back to a hardcoded path when this tag is present."
)
result = agent.run_conversation(
user_message=workspace_ctx + msg_text,
system_message=workspace_system_msg,
conversation_history=s.messages,
task_id=session_id,
persist_user_message=msg_text,
)
s.messages = result.get('messages') or s.messages
s.title = title_from(s.messages, s.title)
# Extract tool call metadata grouped by assistant message index
# Each tool call gets assistant_msg_idx so the client can render
# cards inline with the assistant bubble that triggered them.
tool_calls = []
pending_names = {} # tool_call_id -> name
pending_asst_idx = {} # tool_call_id -> index in s.messages
for msg_idx, m in enumerate(s.messages):
if m.get('role') == 'assistant':
c = m.get('content', '')
if isinstance(c, list):
for p in c:
if isinstance(p, dict) and p.get('type') == 'tool_use':
tid = p.get('id', '')
pending_names[tid] = p.get('name', 'tool')
pending_asst_idx[tid] = msg_idx
elif m.get('role') == 'tool':
tid = m.get('tool_call_id') or m.get('tool_use_id', '')
name = pending_names.get(tid, 'tool')
asst_idx = pending_asst_idx.get(tid, -1)
raw = str(m.get('content', ''))
try:
import json as _j2
rd = _j2.loads(raw)
snippet = str(rd.get('output') or rd.get('result') or rd.get('error') or raw)[:200]
except Exception:
snippet = raw[:200]
tool_calls.append({
'name': name, 'snippet': snippet, 'tid': tid,
'assistant_msg_idx': asst_idx,
})
s.tool_calls = tool_calls
# Tag the matching user message with attachment filenames for display on reload
# Only tag a user message whose content relates to this turn's text
# (msg_text is the full message including the [Attached files: ...] suffix)
if attachments:
for m in reversed(s.messages):
if m.get('role') == 'user':
content = str(m.get('content', ''))
# Match if content is part of the sent message or vice-versa
base_text = msg_text.split('\n\n[Attached files:')[0].strip()
if base_text[:60] in content or content[:60] in msg_text:
m['attachments'] = attachments
break
s.save()
put('done', {'session': s.compact() | {'messages': s.messages, 'tool_calls': tool_calls}})
finally:
if old_cwd is None: os.environ.pop('TERMINAL_CWD', None)
else: os.environ['TERMINAL_CWD'] = old_cwd
if old_exec_ask is None: os.environ.pop('HERMES_EXEC_ASK', None)
else: os.environ['HERMES_EXEC_ASK'] = old_exec_ask
if old_session_key is None: os.environ.pop('HERMES_SESSION_KEY', None)
else: os.environ['HERMES_SESSION_KEY'] = old_session_key
except Exception as e:
put('error', {'message': str(e), 'trace': traceback.format_exc()})
finally:
_clear_thread_env() # TD1: always clear thread-local context
with STREAMS_LOCK:
STREAMS.pop(stream_id, None)
CANCEL_FLAGS.pop(stream_id, None)
# ============================================================
# SECTION: HTTP Request Handler
# do_GET: read-only API endpoints + SSE stream + static HTML
# do_POST: mutating endpoints (session CRUD, chat, upload, approval)
# Routing is a flat if/elif chain. See ARCHITECTURE.md section 4.1.
# ============================================================
def cancel_stream(stream_id: str) -> bool:
"""Signal an in-flight stream to cancel. Returns True if the stream existed."""
with STREAMS_LOCK:
if stream_id not in STREAMS:
return False
flag = CANCEL_FLAGS.get(stream_id)
if flag:
flag.set()
# Put a cancel sentinel into the queue so the SSE handler wakes up
q = STREAMS.get(stream_id)
if q:
try:
q.put_nowait(('cancel', {'message': 'Cancelled by user'}))
except Exception:
pass
return True