fleet-memory/memory/entity_resolver.py
2025-10-30 12:53:12 +01:00

373 lines
12 KiB
Python

"""
Entity extraction and resolution for memory system.
Uses spaCy for entity extraction and implements resolution logic
to disambiguate entities across memory units.
"""
import spacy
from typing import List, Dict, Optional, Set
from difflib import SequenceMatcher
# Load spaCy model (singleton)
_nlp = None
def get_nlp():
"""Get or load spaCy model."""
global _nlp
if _nlp is None:
_nlp = spacy.load("en_core_web_sm")
return _nlp
def extract_entities(text: str) -> List[Dict[str, any]]:
"""
Extract entities from text using spaCy.
Args:
text: Input text
Returns:
List of entities with text, type, and span info
"""
nlp = get_nlp()
doc = nlp(text)
entities = []
for ent in doc.ents:
# Filter to important entity types
if ent.label_ in ['PERSON', 'ORG', 'GPE', 'LOC', 'PRODUCT', 'EVENT']:
entities.append({
'text': ent.text,
'type': ent.label_,
'start': ent.start_char,
'end': ent.end_char,
})
return entities
class EntityResolver:
"""
Resolves entities to canonical IDs with disambiguation.
"""
def __init__(self, db_conn):
"""
Initialize entity resolver.
Args:
db_conn: psycopg2 database connection
"""
self.conn = db_conn
def resolve_entity(
self,
agent_id: str,
entity_text: str,
entity_type: str,
context: str,
nearby_entities: List[Dict],
unit_event_date,
) -> str:
"""
Resolve an entity to a canonical entity ID.
Args:
agent_id: Agent ID (entities are scoped to agents)
entity_text: Entity text ("Alice", "Google", etc.)
entity_type: Entity type (PERSON, ORG, etc.)
context: Context where entity appears
nearby_entities: Other entities in the same unit
unit_event_date: When this unit was created
Returns:
Entity ID (creates new entity if needed)
"""
cursor = self.conn.cursor()
try:
# Find candidate entities with same type and similar name
cursor.execute(
"""
SELECT id, canonical_name, metadata, last_seen
FROM entities
WHERE agent_id = %s
AND entity_type = %s
AND (
canonical_name ILIKE %s
OR canonical_name ILIKE %s
OR %s ILIKE canonical_name || '%%'
)
ORDER BY mention_count DESC
""",
(agent_id, entity_type, entity_text, f"%{entity_text}%", entity_text)
)
candidates = cursor.fetchall()
if not candidates:
# New entity - create it
return self._create_entity(
cursor, agent_id, entity_text, entity_type, unit_event_date
)
# Score candidates based on:
# 1. Name similarity
# 2. Context overlap (TODO: could use embeddings)
# 3. Co-occurring entities
# 4. Temporal proximity
best_candidate = None
best_score = 0.0
best_name_similarity = 0.0
nearby_entity_set = {e['text'].lower() for e in nearby_entities if e['text'] != entity_text}
for candidate_id, canonical_name, metadata, last_seen in candidates:
score = 0.0
# 1. Name similarity (0-1)
name_similarity = SequenceMatcher(
None,
entity_text.lower(),
canonical_name.lower()
).ratio()
score += name_similarity * 0.5
# 2. Co-occurring entities (0-0.5)
# Get entities that co-occurred with this candidate before
# Use the materialized co-occurrence cache for fast lookup
cursor.execute(
"""
SELECT e.canonical_name, ec.cooccurrence_count
FROM entity_cooccurrences ec
JOIN entities e ON (
CASE
WHEN ec.entity_id_1 = %s THEN ec.entity_id_2
WHEN ec.entity_id_2 = %s THEN ec.entity_id_1
END = e.id
)
WHERE ec.entity_id_1 = %s OR ec.entity_id_2 = %s
""",
(candidate_id, candidate_id, candidate_id, candidate_id)
)
co_entities = {row[0].lower() for row in cursor.fetchall()}
# Check overlap with nearby entities
overlap = len(nearby_entity_set & co_entities)
if nearby_entity_set:
co_entity_score = overlap / len(nearby_entity_set)
score += co_entity_score * 0.3
# 3. Temporal proximity (0-0.2)
if last_seen:
days_diff = abs((unit_event_date - last_seen).total_seconds() / 86400)
if days_diff < 7: # Within a week
temporal_score = max(0, 1.0 - (days_diff / 7))
score += temporal_score * 0.2
if score > best_score:
best_score = score
best_candidate = candidate_id
best_name_similarity = name_similarity
# Threshold for considering it the same entity
# For PERSON entities with exact name match, use lower threshold
threshold = 0.4 if entity_type == 'PERSON' and best_name_similarity >= 0.95 else 0.6
if best_score > threshold:
# Update entity
cursor.execute(
"""
UPDATE entities
SET mention_count = mention_count + 1,
last_seen = %s
WHERE id = %s
""",
(unit_event_date, best_candidate)
)
return best_candidate
else:
# Not confident - create new entity
return self._create_entity(
cursor, agent_id, entity_text, entity_type, unit_event_date
)
finally:
cursor.close()
def _create_entity(
self,
cursor,
agent_id: str,
entity_text: str,
entity_type: str,
event_date,
) -> str:
"""
Create a new entity.
Args:
cursor: Database cursor
agent_id: Agent ID
entity_text: Entity text
entity_type: Entity type
event_date: When first seen
Returns:
Entity ID
"""
cursor.execute(
"""
INSERT INTO entities (agent_id, canonical_name, entity_type, first_seen, last_seen, mention_count)
VALUES (%s, %s, %s, %s, %s, 1)
RETURNING id
""",
(agent_id, entity_text, entity_type, event_date, event_date)
)
entity_id = cursor.fetchone()[0]
return entity_id
def link_unit_to_entity(self, unit_id: str, entity_id: str):
"""
Link a memory unit to an entity.
Also updates co-occurrence cache with other entities in the same unit.
Args:
unit_id: Memory unit ID
entity_id: Entity ID
"""
cursor = self.conn.cursor()
try:
# Insert unit-entity link
cursor.execute(
"""
INSERT INTO unit_entities (unit_id, entity_id)
VALUES (%s, %s)
ON CONFLICT DO NOTHING
""",
(unit_id, entity_id)
)
# Update co-occurrence cache: find other entities in this unit
cursor.execute(
"""
SELECT entity_id
FROM unit_entities
WHERE unit_id = %s AND entity_id != %s
""",
(unit_id, entity_id)
)
other_entities = [row[0] for row in cursor.fetchall()]
# Update co-occurrences for each pair
for other_entity_id in other_entities:
self._update_cooccurrence(cursor, entity_id, other_entity_id)
finally:
cursor.close()
def _update_cooccurrence(self, cursor, entity_id_1: str, entity_id_2: str):
"""
Update the co-occurrence cache for two entities.
Uses CHECK constraint ordering (entity_id_1 < entity_id_2) to avoid duplicates.
Args:
cursor: Database cursor
entity_id_1: First entity ID
entity_id_2: Second entity ID
"""
# Ensure consistent ordering (smaller UUID first)
if entity_id_1 > entity_id_2:
entity_id_1, entity_id_2 = entity_id_2, entity_id_1
cursor.execute(
"""
INSERT INTO entity_cooccurrences (entity_id_1, entity_id_2, cooccurrence_count, last_cooccurred)
VALUES (%s, %s, 1, NOW())
ON CONFLICT (entity_id_1, entity_id_2)
DO UPDATE SET
cooccurrence_count = entity_cooccurrences.cooccurrence_count + 1,
last_cooccurred = NOW()
""",
(entity_id_1, entity_id_2)
)
def get_units_by_entity(self, entity_id: str, limit: int = 100) -> List[str]:
"""
Get all units that mention an entity.
Args:
entity_id: Entity ID
limit: Max results
Returns:
List of unit IDs
"""
cursor = self.conn.cursor()
try:
cursor.execute(
"""
SELECT unit_id
FROM unit_entities
WHERE entity_id = %s
ORDER BY unit_id
LIMIT %s
""",
(entity_id, limit)
)
return [row[0] for row in cursor.fetchall()]
finally:
cursor.close()
def get_entity_by_text(
self,
agent_id: str,
entity_text: str,
entity_type: Optional[str] = None
) -> Optional[str]:
"""
Find an entity by text (for query resolution).
Args:
agent_id: Agent ID
entity_text: Entity text to search for
entity_type: Optional entity type filter
Returns:
Entity ID if found, None otherwise
"""
cursor = self.conn.cursor()
try:
if entity_type:
cursor.execute(
"""
SELECT id FROM entities
WHERE agent_id = %s
AND entity_type = %s
AND canonical_name ILIKE %s
ORDER BY mention_count DESC
LIMIT 1
""",
(agent_id, entity_type, entity_text)
)
else:
cursor.execute(
"""
SELECT id FROM entities
WHERE agent_id = %s
AND canonical_name ILIKE %s
ORDER BY mention_count DESC
LIMIT 1
""",
(agent_id, entity_text)
)
row = cursor.fetchone()
return row[0] if row else None
finally:
cursor.close()