feat(config): add GRAPH_BACKEND + NEO4J_* + LLM_PROVIDER config vars

backend/app/config.py

@@ -33,9 +33,20 @@ class Config:
     LLM_BASE_URL = os.environ.get('LLM_BASE_URL', 'https://api.openai.com/v1')
     LLM_MODEL_NAME = os.environ.get('LLM_MODEL_NAME', 'gpt-4o-mini')
     
-    # Zep settings
+    # Graph backend: "zep" (default, cloud) o "graphiti" (Neo4j local)
+    GRAPH_BACKEND = os.environ.get('GRAPH_BACKEND', 'zep')
+
+    # Zep Cloud
     ZEP_API_KEY = os.environ.get('ZEP_API_KEY')
 
+    # Graphiti + Neo4j
+    NEO4J_URI = os.environ.get('NEO4J_URI', 'bolt://localhost:7687')
+    NEO4J_USER = os.environ.get('NEO4J_USER', 'neo4j')
+    NEO4J_PASSWORD = os.environ.get('NEO4J_PASSWORD')
+
+    # LLM provider ("" = OpenAI-compatible per defecte, "gemini" = Google AI Studio)
+    LLM_PROVIDER = os.environ.get('LLM_PROVIDER', '')
+
     # File upload settings
     MAX_CONTENT_LENGTH = 50 * 1024 * 1024  # 50MB
     UPLOAD_FOLDER = os.path.join(os.path.dirname(__file__), '../uploads')
@@ -64,13 +75,25 @@ class Config:
     REPORT_AGENT_MAX_REFLECTION_ROUNDS = int(os.environ.get('REPORT_AGENT_MAX_REFLECTION_ROUNDS', '2'))
     REPORT_AGENT_TEMPERATURE = float(os.environ.get('REPORT_AGENT_TEMPERATURE', '0.5'))
     
+    @classmethod
+    def get_graph_config_errors(cls) -> list:
+        errors = []
+        if cls.GRAPH_BACKEND == 'zep':
+            if not cls.ZEP_API_KEY:
+                errors.append("ZEP_API_KEY is not configured (required when GRAPH_BACKEND=zep)")
+        elif cls.GRAPH_BACKEND == 'graphiti':
+            if not cls.NEO4J_PASSWORD:
+                errors.append("NEO4J_PASSWORD is not configured (required when GRAPH_BACKEND=graphiti)")
+        else:
+            errors.append(f"Unknown GRAPH_BACKEND value: '{cls.GRAPH_BACKEND}'. Use 'zep' or 'graphiti'.")
+        return errors
+
     @classmethod
     def validate(cls):
         """Validate required configuration"""
         errors = []
         if not cls.LLM_API_KEY:
             errors.append("LLM_API_KEY is not configured")
-        if not cls.ZEP_API_KEY:
-            errors.append("ZEP_API_KEY is not configured")
+        errors.extend(cls.get_graph_config_errors())
         return errors
 

backend/tests/test_graph_factory.py

@@ -11,3 +11,40 @@ def test_graph_backend_has_required_methods():
     ]
     for method in required:
         assert hasattr(GraphBackend, method), f"GraphBackend missing: {method}"
+
+
+def test_config_graph_backend_default():
+    import os
+    os.environ.pop("GRAPH_BACKEND", None)
+    import importlib
+    import backend.app.config as cfg_mod
+    importlib.reload(cfg_mod)
+    assert cfg_mod.Config.GRAPH_BACKEND == "zep"
+
+
+def test_config_zep_errors_when_key_missing():
+    import backend.app.config as cfg_mod
+    orig_backend = cfg_mod.Config.GRAPH_BACKEND
+    orig_key = cfg_mod.Config.ZEP_API_KEY
+    try:
+        cfg_mod.Config.GRAPH_BACKEND = "zep"
+        cfg_mod.Config.ZEP_API_KEY = None
+        errors = cfg_mod.Config.get_graph_config_errors()
+        assert any("ZEP_API_KEY" in e for e in errors)
+    finally:
+        cfg_mod.Config.GRAPH_BACKEND = orig_backend
+        cfg_mod.Config.ZEP_API_KEY = orig_key
+
+
+def test_config_graphiti_errors_when_missing():
+    import backend.app.config as cfg_mod
+    orig_backend = cfg_mod.Config.GRAPH_BACKEND
+    orig_pw = cfg_mod.Config.NEO4J_PASSWORD
+    try:
+        cfg_mod.Config.GRAPH_BACKEND = "graphiti"
+        cfg_mod.Config.NEO4J_PASSWORD = None
+        errors = cfg_mod.Config.get_graph_config_errors()
+        assert len(errors) >= 1
+    finally:
+        cfg_mod.Config.GRAPH_BACKEND = orig_backend
+        cfg_mod.Config.NEO4J_PASSWORD = orig_pw