Trim of the cherry-picked #104566 so it clears the salvage bar and covers #86241: - The config getter matches entries the way every sibling per-provider knob does (`_entries_for_route`, route identity only) instead of a second provider-name axis; returns "" like `get_custom_provider_extra_headers` returns {}. - `merge_opencode_session_headers` becomes `merge_session_affinity_headers` at both call sites (main `build_api_kwargs`, auxiliary `_build_call_kwargs`); the alias line is gone. Both sources merge (an OpenCode target that also declares a header gets both). - Tests cut from six to two invariants: configured header carries one value per conversation on chat_completions, anthropic_messages and auxiliary kwargs (different for another session, caller-pinned wins); unconfigured → no header on any path. - Docs: `configuring-models.md` per-provider options, `providers.md` entry key list, `cli-config.yaml.example` — the key is opt-in, default off, so DEFAULT_CONFIG is unchanged. Why: a session-aware proxy classifies a request with no session id whose last message is a tool_result as a NEW conversation and re-sends the whole history upstream (cache_write ≈ cache_read). Hermes already derives a rotation-stable conversation key for OpenCode; naming the header per provider lets any proxy receive it without shipping an identifier by default. Co-authored-by: 0xAlyDev <agentai891@gmail.com>
113 lines
4.6 KiB
Python
113 lines
4.6 KiB
Python
"""Conversation-affinity request headers for session-aware relays and proxies.
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Two sources, one merge point:
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* ``x-opencode-session`` — OpenCode (opencode.ai Zen/Go relay) pins requests that share this
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value to the same upstream backend, which keeps its prompt cache warm across the turns of one
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conversation. Always sent to OpenCode targets.
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* ``providers.<name>.session_affinity_header`` — an opt-in header NAME on a custom provider entry
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(default off). Session-aware proxies fronting a stateful backend (LiteLLM's ``x-litellm-session-id``,
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self-hosted Claude/OpenAI gateways) otherwise classify an agent-loop request whose last message is
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a ``tool_result`` as a new conversation and replay the whole history upstream (#86241, #104449).
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The value only has to be opaque and consistent per conversation, so it is derived the same way as
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the other affinity hints Hermes already sends (OpenRouter's sticky ``session_id``, xAI's
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``x-grok-conv-id``): the host-declared routing scope first (a host that names its own conversation,
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#96811), then the ambient conversation ROOT (stable across compaction rotation and delegate trees),
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then the physical session id — normalized through ``_cache_scope_from_session_id`` so cron fires of
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one job share a scope. Auxiliary calls (compression, titles, vision, MoA) have no session handle and
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resolve the ambient value, so they stay on the conversation's backend too (#70820).
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Every request — main turn on any transport, auxiliary calls — goes through
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:func:`merge_session_affinity_headers` so the headers cannot drift per code path.
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"""
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from __future__ import annotations
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from typing import Any, Optional
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OPENCODE_SESSION_HEADER = "x-opencode-session"
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def is_opencode_target(provider: Optional[str], base_url: Optional[str]) -> bool:
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"""True when *provider* or *base_url* addresses the OpenCode relay.
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Matches the built-in opencode-zen/go providers, custom
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``opencode-<family>-*`` providers, and any base_url hosted on opencode.ai.
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"""
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try:
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from hermes_cli.models import opencode_provider_family
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if opencode_provider_family(provider) is not None:
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return True
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except Exception:
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pass
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try:
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from agent.anthropic_endpoints import _is_opencode_endpoint
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return _is_opencode_endpoint(str(base_url or ""))
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except Exception:
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return False
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def resolve_affinity_key(session_id: Optional[str] = None) -> str:
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"""Return the normalized rotation-stable conversation affinity key ("" when unknown)."""
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try:
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from agent.portal_tags import get_affinity_scope, get_conversation_context
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from agent.transports.codex import _cache_scope_from_session_id
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return _cache_scope_from_session_id(get_affinity_scope() or get_conversation_context() or session_id)
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except Exception:
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return str(session_id or "")
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def opencode_session_headers(
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provider: Optional[str],
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base_url: Optional[str],
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session_id: Optional[str] = None,
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) -> dict[str, str]:
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"""Return ``{"x-opencode-session": <key>}`` for OpenCode targets, else ``{}``."""
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if not is_opencode_target(provider, base_url):
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return {}
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key = resolve_affinity_key(session_id)
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return {OPENCODE_SESSION_HEADER: key} if key else {}
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def custom_provider_session_affinity_headers(
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base_url: Optional[str],
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session_id: Optional[str] = None,
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) -> dict[str, str]:
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"""Return ``{<session_affinity_header>: <key>}`` when the route's provider entry declares one, else ``{}``."""
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try:
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from hermes_cli.config import get_custom_provider_session_affinity_header
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header = get_custom_provider_session_affinity_header(str(base_url or ""))
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except Exception:
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return {}
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if not header:
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return {}
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key = resolve_affinity_key(session_id)
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return {header: key} if key else {}
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def merge_session_affinity_headers(
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kwargs: dict[str, Any],
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provider: Optional[str],
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base_url: Optional[str],
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session_id: Optional[str] = None,
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) -> dict[str, Any]:
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"""Merge the affinity header(s) into ``kwargs["extra_headers"]`` (in place).
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Existing per-request headers win, so a caller-pinned value is preserved.
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Targets with neither source configured are left untouched.
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"""
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headers = opencode_session_headers(provider, base_url, session_id)
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headers.update(custom_provider_session_affinity_headers(base_url, session_id))
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if headers:
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existing = kwargs.get("extra_headers")
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merged = dict(existing) if isinstance(existing, dict) else {}
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for key, value in headers.items():
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merged.setdefault(key, value)
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kwargs["extra_headers"] = merged
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return kwargs
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