raise occupied exception before creating workflow (#4126)

skyvern/exceptions.py

@@ -777,8 +777,8 @@ class LLMCallerNotFoundError(SkyvernException):
 
 
 class BrowserSessionAlreadyOccupiedError(SkyvernHTTPException):
-    def __init__(self, browser_session_id: str) -> None:
-        super().__init__(f"Browser session {browser_session_id} is already occupied")
+    def __init__(self, browser_session_id: str, runnable_id: str) -> None:
+        super().__init__(f"Browser session {browser_session_id} is already occupied by {runnable_id}")
 
 
 class BrowserSessionNotRenewable(SkyvernException):

skyvern/forge/sdk/workflow/service.py

@@ -21,6 +21,7 @@ from skyvern.constants import GET_DOWNLOADED_FILES_TIMEOUT, SAVE_DOWNLOADED_FILE
 from skyvern.exceptions import (
     BlockNotFound,
     BrowserProfileNotFound,
+    BrowserSessionAlreadyOccupiedError,
     BrowserSessionNotFound,
     CannotUpdateWorkflowDueToCodeCache,
     FailedToSendWebhook,
@@ -404,6 +405,27 @@ class WorkflowService:
             workflow_request.proxy_location = workflow.proxy_location
         if workflow_request.webhook_callback_url is None and workflow.webhook_callback_url is not None:
             workflow_request.webhook_callback_url = workflow.webhook_callback_url
+
+        if workflow_request.browser_session_id:
+            persistent_browser_session = await app.DATABASE.get_persistent_browser_session(
+                workflow_request.browser_session_id, organization.organization_id
+            )
+            if persistent_browser_session is None:
+                LOG.warning(
+                    "Failed to create workflow run, browser sesssion not found",
+                    browser_session_id=workflow_request.browser_session_id,
+                )
+                raise BrowserSessionNotFound(workflow_request.browser_session_id)
+
+            if persistent_browser_session.runnable_id:
+                LOG.warning(
+                    "Failed to create workflow run, browser session is already occupied",
+                    browser_session_id=workflow_request.browser_session_id,
+                )
+                raise BrowserSessionAlreadyOccupiedError(
+                    workflow_request.browser_session_id, persistent_browser_session.runnable_id
+                )
+
         # Create the workflow run and set skyvern context
         workflow_run = await self.create_workflow_run(
             workflow_request=workflow_request,