_context.py: Replace is_fork_allowed() with prepare_fork()

2 files changed, 10 insertions, 13 deletions

diff --git a/src/buildstream/_context.py b/src/buildstream/_context.py
index 7ff993166..879555089 100644
--- a/src/buildstream/_context.py
+++ b/src/buildstream/_context.py
@@ -526,19 +526,16 @@ class Context():
                                       log_level=log_level)
         return self._cascache
 
-    # is_fork_allowed():
+    # prepare_fork():
     #
-    # Return whether fork without exec is allowed. This is a safeguard against
+    # Prepare this process for fork without exec. This is a safeguard against
     # fork issues with multiple threads and gRPC connections.
     #
-    def is_fork_allowed(self):
-        # Do not allow fork if there are background threads.
-        if not utils._is_single_threaded():
-            return False
-
-        # Do not allow fork if there are open gRPC channels.
+    def prepare_fork(self):
+        # gRPC channels must be closed before fork.
         for cache in [self._cascache, self._artifactcache, self._sourcecache]:
-            if cache and cache.has_open_grpc_channels():
-                return False
+            if cache:
+                cache.close_grpc_channels()
 
-        return True
+        # Do not allow fork if there are background threads.
+        return utils._is_single_threaded()
diff --git a/src/buildstream/_scheduler/scheduler.py b/src/buildstream/_scheduler/scheduler.py
index 08db1a1e9..d3faa2a8e 100644
--- a/src/buildstream/_scheduler/scheduler.py
+++ b/src/buildstream/_scheduler/scheduler.py
@@ -406,8 +406,8 @@ class Scheduler():
             # If that happens, do another round.
             process_queues = any(q.dequeue_ready() for q in self.queues)
 
-        # Check whether fork is allowed before starting jobs
-        if not self.context.is_fork_allowed():
+        # Make sure fork is allowed before starting jobs
+        if not self.context.prepare_fork():
             message = Message(MessageType.BUG, "Fork is not allowed", detail="Background threads are active")
             self._notify(Notification(NotificationType.MESSAGE, message=message))
             self.terminate_jobs()