Support passing a policy file to the proxy on startup.

proxy/common/config_manager.py

@@ -0,0 +1,63 @@
+"""Common Configurations for the Proxy Server."""
+
+import os
+import threading
+
+from invariant.analyzer import Policy
+
+
+class ProxyConfig:
+    """Common configurations for the Proxy Server."""
+
+    def __init__(self):
+        print("hello in init of ProxyConfig")
+        self.policies = self._load_policies()
+
+    def _load_policies(self) -> str:
+        """
+        Loads and validates policies from the file specified in POLICIES_FILE_PATH.
+        Returns the policy file content as a string if valid; otherwise, raises an error.
+        """
+        print("hello in load_policies")
+        policies_file = os.getenv("POLICIES_FILE_PATH", "")
+
+        if not policies_file:
+            print("Warning: POLICIES_FILE_PATH is not set. Using empty policies.")
+            return ""
+
+        try:
+            with open(policies_file, "r", encoding="utf-8") as f:
+                policy_file_content = f.read()
+            _ = Policy.from_string(policy_file_content)
+            return policy_file_content
+
+        except (FileNotFoundError, PermissionError, OSError) as e:
+            raise ValueError(
+                f"Error: Unable to read policies file ({policies_file}): {e}"
+            ) from e
+
+        except Exception as e:
+            raise ValueError(f"Invalid policy content in {policies_file}: {e}") from e
+
+    def __repr__(self) -> str:
+        return f"ProxyConfig(policies={repr(self.policies)})"
+
+
+class ProxyConfigManager:
+    """Manager for Proxy Configuration."""
+
+    _config_instance = None
+    _lock = threading.Lock()
+
+    @classmethod
+    def get_config(cls):
+        """Initializes and returns the proxy configuration using double-checked locking."""
+        local_config = cls._config_instance
+
+        if local_config is None:
+            with cls._lock:
+                local_config = cls._config_instance
+                if local_config is None:
+                    local_config = ProxyConfig()
+                    cls._config_instance = local_config
+        return local_config

proxy/requirements.txt

@@ -1,5 +1,6 @@
 fastapi==0.115.7
 httpx==0.28.1
+invariant-ai>=0.2.1
 invariant-sdk>=0.0.10
 starlette-compress==1.4.0
 uvicorn==0.34.0

proxy/routes/anthropic.py

@@ -4,6 +4,7 @@ import json
 from typing import Any, Optional
 
 import httpx
+from common.config_manager import ProxyConfig, ProxyConfigManager
 from fastapi import APIRouter, Depends, Header, HTTPException, Request, Response
 from starlette.responses import StreamingResponse
 from utils.constants import CLIENT_TIMEOUT, IGNORED_HEADERS
@@ -43,6 +44,7 @@ def validate_headers(x_api_key: str = Header(None)):
 async def anthropic_v1_messages_proxy(
     request: Request,
     dataset_name: str = None,
+    config: ProxyConfig = Depends(ProxyConfigManager.get_config),  # pylint: disable=unused-argument
 ):
     """Proxy calls to the Anthropic APIs"""
     headers = {

proxy/routes/open_ai.py

@@ -4,6 +4,7 @@ import json
 from typing import Any, Optional
 
 import httpx
+from common.config_manager import ProxyConfig, ProxyConfigManager
 from fastapi import APIRouter, Depends, Header, HTTPException, Request, Response
 from fastapi.responses import StreamingResponse
 from utils.constants import CLIENT_TIMEOUT, IGNORED_HEADERS
@@ -33,9 +34,9 @@ def validate_headers(authorization: str = Header(None)):
 async def openai_chat_completions_proxy(
     request: Request,
     dataset_name: str = None,
+    config: ProxyConfig = Depends(ProxyConfigManager.get_config),  # pylint: disable=unused-argument
 ) -> Response:
     """Proxy calls to the OpenAI APIs"""
-
     headers = {
         k: v for k, v in request.headers.items() if k.lower() not in IGNORED_HEADERS
     }

proxy/run.sh

@@ -1,8 +1,16 @@
 #!/bin/bash
 
-# if DEV_MODE is true, then run the app with auto-reload
+# Validate configuration
+python validate_config.py
+
+# Check exit code of validation script
+if [ $? -ne 0 ]; then
+    echo "Configuration validation failed. Exiting."
+    exit 1
+fi
+
 if [ "$DEV_MODE" = "true" ]; then
     uvicorn serve:app --host 0.0.0.0 --port 8000 --reload
 else
     uvicorn serve:app --host 0.0.0.0 --port 8000
-fi
+fi

proxy/serve.py

@@ -19,7 +19,7 @@ router = fastapi.APIRouter(prefix="/api/v1")
 @router.get("/proxy/health", tags=["health_check"], include_in_schema=False)
 async def get_proxy_info():
     """Health check"""
-    return {"message": "Hello v1/proxy"}
+    return {"message": "Hello from Invariant v1/proxy"}
 
 
 router.include_router(open_ai_proxy, prefix="/proxy", tags=["open_ai_proxy"])
@@ -28,6 +28,6 @@ router.include_router(anthropic_proxy, prefix="/proxy", tags=["anthropic_proxy"]
 
 app.include_router(router)
 
-# Serve the API
+
 if __name__ == "__main__":
     uvicorn.run(app, host="0.0.0.0", port=8000)

proxy/validate_config.py

@@ -0,0 +1,13 @@
+"""Validates the ProxyConfigManager configuration."""
+
+import sys
+
+from common.config_manager import ProxyConfigManager
+
+try:
+    _ = ProxyConfigManager.get_config()
+    print("ProxyConfig validated successfully.")
+    sys.exit(0)
+except Exception as e:
+    print(f"Error loading ProxyConfig error: {e}")
+    sys.exit(1)