cbf851ae1d
The 'summoning hermes…' phase blocked on gateway.ready, which ran MCP tool discovery inline. Any configured-but-unreachable MCP server burned its full connect-retry backoff (1+2+4s ≈ 7s) before the composer appeared — startup went from instant to ~7.5s of dead air for anyone with a down stdio/http server in mcp_servers. Move discovery into a background daemon thread so gateway.ready fires immediately; tools register into the shared registry as servers connect, and the agent isn't built until the first prompt. Measured spawn→ready: ~7500ms → ~115ms (dead twozero_td server in config). Also drop rich.console + prompt_toolkit off banner.py's import path (lazy-imported inside cprint/build_welcome_banner). tui_gateway.server imports banner only to reach the lightweight prefetch_update_check helper; the eager rich/pt imports added ~45ms before gateway.ready for no benefit. tui_gateway.server import: ~115ms → ~69ms.
79 lines
2.7 KiB
Python
79 lines
2.7 KiB
Python
"""Tests for tui_gateway.entry.wait_for_mcp_discovery (PR #35245).
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MCP tool discovery runs in a background daemon thread so a slow/dead server
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can't freeze ``gateway.ready``. The agent snapshots its tool list once at
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build time and never re-reads it, so ``_make_agent`` briefly joins the
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discovery thread before building — bounded, so a dead server can't re-introduce
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the startup hang, and a no-op once discovery has finished.
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"""
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import threading
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import time
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import tui_gateway.entry as entry
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def _restore_thread_slot(saved):
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entry._mcp_discovery_thread = saved
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def test_no_thread_is_noop():
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"""When no discovery thread was started (the common no-MCP case), the
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helper returns immediately and never blocks."""
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saved = entry._mcp_discovery_thread
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try:
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entry._mcp_discovery_thread = None
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start = time.monotonic()
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entry.wait_for_mcp_discovery(timeout=5.0)
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assert time.monotonic() - start < 0.1
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finally:
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_restore_thread_slot(saved)
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def test_already_finished_thread_is_noop():
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"""A thread that has already finished is not joined-on (dead thread)."""
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saved = entry._mcp_discovery_thread
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try:
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t = threading.Thread(target=lambda: None, daemon=True)
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t.start()
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t.join() # ensure it's finished
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entry._mcp_discovery_thread = t
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start = time.monotonic()
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entry.wait_for_mcp_discovery(timeout=5.0)
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assert time.monotonic() - start < 0.1
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finally:
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_restore_thread_slot(saved)
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def test_fast_thread_is_joined():
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"""A reachable-but-still-connecting (fast) server lands before the agent
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snapshots tools — the helper waits for it to finish."""
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saved = entry._mcp_discovery_thread
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try:
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t = threading.Thread(target=lambda: time.sleep(0.05), daemon=True)
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t.start()
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entry._mcp_discovery_thread = t
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entry.wait_for_mcp_discovery(timeout=1.0)
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assert not t.is_alive() # joined to completion
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finally:
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_restore_thread_slot(saved)
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def test_hung_thread_is_bounded_by_timeout():
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"""A slow/dead server must NOT re-introduce the startup hang — the join is
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bounded by the timeout and returns even though the thread is still alive."""
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saved = entry._mcp_discovery_thread
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stop = threading.Event()
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try:
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t = threading.Thread(target=stop.wait, daemon=True) # blocks until set
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t.start()
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entry._mcp_discovery_thread = t
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start = time.monotonic()
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entry.wait_for_mcp_discovery(timeout=0.3)
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elapsed = time.monotonic() - start
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assert 0.25 <= elapsed < 1.0 # bounded near the timeout, not forever
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assert t.is_alive() # thread still running; we did not block on it
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finally:
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stop.set()
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_restore_thread_slot(saved)
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