fix: add missing agent_config.py — was untracked, causing extractor crash in cluster

services/shared/agent_config.py

@@ -0,0 +1,160 @@
+"""Agent configuration resolver with active-variant override and TTL cache.
+
+Resolves runtime configuration for AI agents from the database, preferring
+the active variant's values when one exists.  All three agent services
+(extractor, event classifier, thesis rewriter) share this module instead
+of duplicating resolution logic.
+
+Requirements: 4.3, 4.4, 9.1–9.5, 10.4–10.6
+Design: Config Resolution Module
+"""
+from __future__ import annotations
+
+import logging
+import time
+from dataclasses import dataclass
+
+import asyncpg
+
+logger = logging.getLogger(__name__)
+
+
+# ---------------------------------------------------------------------------
+# Resolved config dataclass
+# ---------------------------------------------------------------------------
+
+
+@dataclass(frozen=True, slots=True)
+class ResolvedAgentConfig:
+    """Runtime configuration resolved from DB agent + optional active variant."""
+
+    agent_id: str
+    variant_id: str | None
+    model_provider: str
+    model_name: str
+    system_prompt: str
+    user_prompt_template: str
+    prompt_version: str
+    temperature: float
+    max_tokens: int
+    context_window: int
+    input_token_limit: int
+    token_budget: int
+    timeout_seconds: int
+    max_retries: int
+
+
+# ---------------------------------------------------------------------------
+# SQL: resolve agent config, preferring active variant via COALESCE
+# ---------------------------------------------------------------------------
+
+_RESOLVE_SQL = """\
+SELECT a.id        AS agent_id,
+       v.id        AS variant_id,
+       COALESCE(v.model_provider,      a.model_provider)      AS model_provider,
+       COALESCE(v.model_name,          a.model_name)          AS model_name,
+       COALESCE(v.system_prompt,       a.system_prompt)       AS system_prompt,
+       COALESCE(v.user_prompt_template,a.user_prompt_template) AS user_prompt_template,
+       COALESCE(v.prompt_version,      a.prompt_version)      AS prompt_version,
+       COALESCE(v.temperature,         a.temperature)         AS temperature,
+       COALESCE(v.max_tokens,          a.max_tokens)          AS max_tokens,
+       COALESCE(v.context_window,      0)                     AS context_window,
+       COALESCE(v.input_token_limit,   0)                     AS input_token_limit,
+       COALESCE(v.token_budget,        0)                     AS token_budget,
+       COALESCE(v.timeout_seconds,     a.timeout_seconds)     AS timeout_seconds,
+       COALESCE(v.max_retries,         a.max_retries)         AS max_retries
+  FROM ai_agents a
+  LEFT JOIN agent_variants v
+         ON v.agent_id = a.id AND v.is_active = TRUE
+ WHERE a.slug = $1
+   AND a.active = TRUE
+"""
+
+
+# ---------------------------------------------------------------------------
+# Resolver with TTL-based in-memory cache
+# ---------------------------------------------------------------------------
+
+
+class AgentConfigResolver:
+    """Resolves agent configuration from DB with active variant override and TTL cache.
+
+    Usage::
+
+        resolver = AgentConfigResolver(pool, ttl_seconds=60)
+        config = await resolver.resolve("document-extractor")
+        if config is None:
+            # fall back to env-var OllamaConfig defaults
+            ...
+    """
+
+    def __init__(self, pool: asyncpg.Pool, ttl_seconds: int = 60) -> None:
+        self._pool = pool
+        self._ttl = ttl_seconds
+        self._cache: dict[str, tuple[float, ResolvedAgentConfig]] = {}
+
+    async def resolve(self, agent_slug: str) -> ResolvedAgentConfig | None:
+        """Resolve config for an agent slug, preferring active variant if present.
+
+        Returns ``None`` and logs a warning when the agent slug is not found
+        or the database query fails.  Callers should fall back to env-var
+        defaults in that case.
+        """
+        now = time.monotonic()
+
+        # Check cache
+        cached = self._cache.get(agent_slug)
+        if cached is not None:
+            ts, config = cached
+            if (now - ts) < self._ttl:
+                return config
+            # Expired — remove stale entry before re-querying
+            del self._cache[agent_slug]
+
+        # Query database
+        try:
+            row = await self._pool.fetchrow(_RESOLVE_SQL, agent_slug)
+        except Exception:
+            logger.warning(
+                "Failed to resolve agent config for %s from database",
+                agent_slug,
+                exc_info=True,
+            )
+            return None
+
+        if row is None:
+            logger.warning(
+                "No active agent found for slug %r",
+                agent_slug,
+            )
+            return None
+
+        config = ResolvedAgentConfig(
+            agent_id=str(row["agent_id"]),
+            variant_id=str(row["variant_id"]) if row["variant_id"] else None,
+            model_provider=row["model_provider"],
+            model_name=row["model_name"],
+            system_prompt=row["system_prompt"],
+            user_prompt_template=row["user_prompt_template"],
+            prompt_version=row["prompt_version"],
+            temperature=float(row["temperature"]),
+            max_tokens=int(row["max_tokens"]),
+            context_window=int(row["context_window"]),
+            input_token_limit=int(row["input_token_limit"]),
+            token_budget=int(row["token_budget"]),
+            timeout_seconds=int(row["timeout_seconds"]),
+            max_retries=int(row["max_retries"]),
+        )
+        self._cache[agent_slug] = (now, config)
+        return config
+
+    def invalidate(self, agent_slug: str | None = None) -> None:
+        """Drop cached entries.
+
+        If *agent_slug* is given, only that entry is removed.
+        If ``None``, the entire cache is cleared.
+        """
+        if agent_slug is None:
+            self._cache.clear()
+        else:
+            self._cache.pop(agent_slug, None)