Files
ss-tools/backend/src/services/llm_provider.py
2026-05-20 23:54:53 +03:00

307 lines
12 KiB
Python

# #region llm_provider [C:3] [TYPE Module] [SEMANTICS sqlalchemy, llm, provider, encryption, config]
# @BRIEF Service for managing LLM provider configurations with encrypted API keys.
# @LAYER: Domain
# @RELATION DEPENDS_ON -> [LLMProvider]
# @RELATION DEPENDS_ON -> [EncryptionManager]
# @RELATION DEPENDS_ON -> [LLMProviderConfig]
import os
from typing import TYPE_CHECKING
from cryptography.exceptions import InvalidTag
from cryptography.fernet import Fernet
from sqlalchemy.orm import Session
from ..core.logger import belief_scope, logger
from ..models.llm import LLMProvider
if TYPE_CHECKING:
from ..plugins.llm_analysis.models import LLMProviderConfig
MASKED_API_KEY_PLACEHOLDER = "********"
# #region mask_api_key [C:2] [TYPE Function]
# @BRIEF Mask an API key for safe display, showing first 4 and last 4 characters.
# @PRE: api_key is a plaintext string or None.
# @POST: Returns "****" for very short keys; "{first 2}...{last 2}" for <=8 chars;
# "{first 4}...{last 4}" for longer keys; "" for None/empty.
def mask_api_key(api_key: str | None) -> str:
if not api_key:
return ""
if len(api_key) <= 4:
return "****"
if len(api_key) <= 8:
return f"{api_key[:2]}...{api_key[-2:]}"
return f"{api_key[:4]}...{api_key[-4:]}"
# #endregion mask_api_key
# #region is_masked_or_placeholder [C:2] [TYPE Function]
# @BRIEF Predicate: True when api_key is None, empty, "********", or contains "...".
# @PRE: api_key can be None.
# @POST: Returns True only for non-real-key values.
def is_masked_or_placeholder(api_key: str | None) -> bool:
if not api_key:
return True
return api_key == MASKED_API_KEY_PLACEHOLDER or "..." in api_key
# #endregion is_masked_or_placeholder
# #region _require_fernet_key [C:5] [TYPE Function]
# @BRIEF Load and validate the Fernet key used for secret encryption.
# @PRE: ENCRYPTION_KEY environment variable must be set to a valid Fernet key.
# @POST: Returns validated key bytes ready for Fernet initialization.
# @RELATION DEPENDS_ON -> [backend.src.core.logger:Function]
# @SIDE_EFFECT: Emits belief-state logs for missing or invalid encryption configuration.
# @DATA_CONTRACT: Input[ENCRYPTION_KEY:str] -> Output[bytes]
# @INVARIANT: Encryption initialization never falls back to a hardcoded secret.
def _require_fernet_key() -> bytes:
with belief_scope("_require_fernet_key"):
raw_key = os.getenv("ENCRYPTION_KEY", "").strip()
if not raw_key:
logger.explore(
"Missing ENCRYPTION_KEY blocks EncryptionManager initialization"
)
raise RuntimeError("ENCRYPTION_KEY must be set")
key = raw_key.encode()
try:
Fernet(key)
except Exception as exc:
logger.explore(
"Invalid ENCRYPTION_KEY blocks EncryptionManager initialization"
)
raise RuntimeError("ENCRYPTION_KEY must be a valid Fernet key") from exc
logger.reflect("Validated ENCRYPTION_KEY for EncryptionManager initialization")
return key
# #endregion _require_fernet_key
# #region EncryptionManager [C:5] [TYPE Class]
# @BRIEF Handles encryption and decryption of sensitive data like API keys.
# @RELATION CALLS -> [_require_fernet_key]
# @PRE: ENCRYPTION_KEY is configured with a valid Fernet key before instantiation.
# @POST: Manager exposes reversible encrypt/decrypt operations for persisted secrets.
# @SIDE_EFFECT: Initializes Fernet cryptography state from process environment.
# @DATA_CONTRACT: Input[str] -> Output[str]
# @INVARIANT: Uses only a validated secret key from environment.
#
# @TEST_CONTRACT: EncryptionManagerModel ->
# {
# required_fields: {},
# invariants: [
# "encrypted data can be decrypted back to the original string"
# ]
# }
# @TEST_FIXTURE: basic_encryption_cycle -> {"data": "my_secret_key"}
# @TEST_EDGE: decrypt_invalid_data -> raises Exception
# @TEST_EDGE: empty_string_encryption -> {"data": ""}
# @TEST_INVARIANT: symmetric_encryption -> verifies: [basic_encryption_cycle, empty_string_encryption]
class EncryptionManager:
# region EncryptionManager_init [TYPE Function]
# @PURPOSE: Initialize the encryption manager with a Fernet key.
# @PRE: ENCRYPTION_KEY env var must be set to a valid Fernet key.
# @POST: Fernet instance ready for encryption/decryption.
def __init__(self):
self.key = _require_fernet_key()
self.fernet = Fernet(self.key)
# endregion EncryptionManager_init
# region encrypt [TYPE Function]
# @PURPOSE: Encrypt a plaintext string.
# @PRE: data must be a non-empty string.
# @POST: Returns encrypted string.
def encrypt(self, data: str) -> str:
with belief_scope("encrypt"):
return self.fernet.encrypt(data.encode()).decode()
# endregion encrypt
# region decrypt [TYPE Function]
# @PURPOSE: Decrypt an encrypted string.
# @PRE: encrypted_data must be a valid Fernet-encrypted string.
# @POST: Returns original plaintext string.
def decrypt(self, encrypted_data: str) -> str:
with belief_scope("decrypt"):
return self.fernet.decrypt(encrypted_data.encode()).decode()
# endregion decrypt
# #endregion EncryptionManager
# #region LLMProviderService [C:3] [TYPE Class]
# @BRIEF Service to manage LLM provider lifecycle.
# @RELATION DEPENDS_ON -> [LLMProvider]
# @RELATION DEPENDS_ON -> [EncryptionManager]
# @RELATION DEPENDS_ON -> [LLMProviderConfig]
class LLMProviderService:
# region LLMProviderService_init [TYPE Function]
# @PURPOSE: Initialize the service with database session.
# @PRE: db must be a valid SQLAlchemy Session.
# @POST: Service ready for provider operations.
# @RELATION: [DEPENDS_ON] ->[EncryptionManager]
def __init__(self, db: Session):
self.db = db
self.encryption = EncryptionManager()
# endregion LLMProviderService_init
# region get_all_providers [TYPE Function]
# @PURPOSE: Returns all configured LLM providers.
# @PRE: Database connection must be active.
# @POST: Returns list of all LLMProvider records.
# @RELATION: [DEPENDS_ON] ->[LLMProvider]
def get_all_providers(self) -> list[LLMProvider]:
with belief_scope("get_all_providers"):
return self.db.query(LLMProvider).all()
# endregion get_all_providers
# region get_provider [TYPE Function]
# @PURPOSE: Returns a single LLM provider by ID.
# @PRE: provider_id must be a valid string.
# @POST: Returns LLMProvider or None if not found.
# @RELATION: [DEPENDS_ON] ->[LLMProvider]
def get_provider(self, provider_id: str) -> LLMProvider | None:
with belief_scope("get_provider"):
return (
self.db.query(LLMProvider).filter(LLMProvider.id == provider_id).first()
)
# endregion get_provider
# region create_provider [TYPE Function]
# @PURPOSE: Creates a new LLM provider with encrypted API key.
# @PRE: config must contain valid provider configuration.
# @POST: New provider created and persisted to database.
# @RELATION: [DEPENDS_ON] ->[LLMProviderConfig]
# @RELATION: [DEPENDS_ON] ->[LLMProvider]
# @RELATION: [CALLS] ->[encrypt]
def create_provider(self, config: "LLMProviderConfig") -> LLMProvider:
with belief_scope("create_provider"):
encrypted_key = self.encryption.encrypt(config.api_key)
db_provider = LLMProvider(
provider_type=config.provider_type.value,
name=config.name,
base_url=config.base_url,
api_key=encrypted_key,
default_model=config.default_model,
is_active=config.is_active,
is_multimodal=config.is_multimodal,
)
self.db.add(db_provider)
self.db.commit()
self.db.refresh(db_provider)
return db_provider
# endregion create_provider
# region update_provider [TYPE Function]
# @PURPOSE: Updates an existing LLM provider.
# @PRE: provider_id must exist, config must be valid.
# @POST: Provider updated and persisted to database.
# @RELATION: [DEPENDS_ON] ->[LLMProviderConfig]
# @RELATION: [DEPENDS_ON] ->[LLMProvider]
# @RELATION: [CALLS] ->[encrypt]
def update_provider(
self, provider_id: str, config: "LLMProviderConfig"
) -> LLMProvider | None:
with belief_scope("update_provider"):
db_provider = self.get_provider(provider_id)
if not db_provider:
return None
db_provider.provider_type = config.provider_type.value
db_provider.name = config.name
db_provider.base_url = config.base_url
# Ignore masked/placeholder values; they are display-only and must not overwrite secrets.
if not is_masked_or_placeholder(config.api_key):
db_provider.api_key = self.encryption.encrypt(config.api_key)
db_provider.default_model = config.default_model
db_provider.is_active = config.is_active
db_provider.is_multimodal = config.is_multimodal
self.db.commit()
self.db.refresh(db_provider)
return db_provider
# endregion update_provider
# region delete_provider [TYPE Function]
# @PURPOSE: Deletes an LLM provider.
# @PRE: provider_id must exist.
# @POST: Provider removed from database.
# @RELATION: [DEPENDS_ON] ->[LLMProvider]
def delete_provider(self, provider_id: str) -> bool:
with belief_scope("delete_provider"):
db_provider = self.get_provider(provider_id)
if not db_provider:
return False
self.db.delete(db_provider)
self.db.commit()
return True
# endregion delete_provider
# region get_decrypted_api_key [TYPE Function]
# @PURPOSE: Returns the decrypted API key for a provider.
# @PRE: provider_id must exist with valid encrypted key.
# @POST: Returns decrypted API key or None on failure.
# @RELATION: [DEPENDS_ON] ->[LLMProvider]
# @RELATION: [CALLS] ->[decrypt]
def get_decrypted_api_key(self, provider_id: str) -> str | None:
with belief_scope("get_decrypted_api_key"):
db_provider = self.get_provider(provider_id)
if not db_provider:
logger.warning(
f"[get_decrypted_api_key] Provider {provider_id} not found in database"
)
return None
logger.info(f"[get_decrypted_api_key] Provider found: {db_provider.id}")
logger.info(
f"[get_decrypted_api_key] Encrypted API key length: {len(db_provider.api_key) if db_provider.api_key else 0}"
)
try:
decrypted_key = self.encryption.decrypt(db_provider.api_key)
logger.info(
f"[get_decrypted_api_key] Decryption successful, key length: {len(decrypted_key) if decrypted_key else 0}"
)
return decrypted_key
except InvalidTag as e:
logger.error(
f"[get_decrypted_api_key] Integrity check failed (InvalidTag): {e!s}. "
"The encrypted API key may be corrupted or the ENCRYPTION_KEY has changed."
)
return None
except ValueError as e:
logger.error(
f"[get_decrypted_api_key] Decryption format error (ValueError): {e!s}. "
"The encrypted data may not be valid Fernet ciphertext."
)
return None
except Exception as e:
logger.error(
f"[get_decrypted_api_key] Decryption failed with unexpected error "
f"({type(e).__name__}): {e!s}"
)
return None
# endregion get_decrypted_api_key
# #endregion LLMProviderService
# #endregion llm_provider