add lock to serialize workflow script regeneration (#4487)

skyvern/forge/sdk/cache/base.py

@@ -1,11 +1,49 @@
 from abc import ABC, abstractmethod
 from datetime import timedelta
-from typing import Any, Union
+from types import TracebackType
+from typing import Any, Protocol, Self, Union, runtime_checkable
 
 CACHE_EXPIRE_TIME = timedelta(weeks=4)
 MAX_CACHE_ITEM = 1000
 
 
+@runtime_checkable
+class AsyncLock(Protocol):
+    """Protocol for async context manager locks (compatible with redis.asyncio.lock.Lock and NoopLock)."""
+
+    async def __aenter__(self) -> Self: ...
+
+    async def __aexit__(
+        self,
+        exc_type: type[BaseException] | None,
+        exc_val: BaseException | None,
+        exc_tb: TracebackType | None,
+    ) -> None: ...
+
+
+class NoopLock:
+    """
+    A no-op lock implementation for use when distributed locking is not available.
+    Acts as an async context manager that does nothing - suitable for OSS/local deployments.
+    """
+
+    def __init__(self, lock_name: str, blocking_timeout: int = 5, timeout: int = 10) -> None:
+        self.lock_name = lock_name
+        self.blocking_timeout = blocking_timeout
+        self.timeout = timeout
+
+    async def __aenter__(self) -> "NoopLock":
+        return self
+
+    async def __aexit__(
+        self,
+        exc_type: type[BaseException] | None,
+        exc_val: BaseException | None,
+        exc_tb: TracebackType | None,
+    ) -> None:
+        pass
+
+
 class BaseCache(ABC):
     @abstractmethod
     async def set(self, key: str, value: Any, ex: Union[int, timedelta, None] = CACHE_EXPIRE_TIME) -> None:
@@ -14,3 +52,11 @@ class BaseCache(ABC):
     @abstractmethod
     async def get(self, key: str) -> Any:
         pass
+
+    def get_lock(self, lock_name: str, blocking_timeout: int = 5, timeout: int = 10) -> AsyncLock:
+        """
+        Get a distributed lock for the given name.
+        Default implementation returns a no-op lock for OSS deployments.
+        Cloud implementations should override this to use Redis locks.
+        """
+        return NoopLock(lock_name, blocking_timeout, timeout)