Handle builder creation race condition with an exception

Author: Julien-Ben

scripts/release/build_images.py

@@ -43,6 +43,7 @@ def ecr_login_boto3(region: str, account_id: str):
 def ensure_buildx_builder(builder_name: str = DEFAULT_BUILDER_NAME) -> str:
  """
  Ensures a Docker Buildx builder exists for multi-platform builds.
+ This function is safe for concurrent execution across multiple processes.
 
  :param builder_name: Name for the buildx builder
  :return: The builder name that was created or reused
@@ -66,6 +67,13 @@ def ensure_buildx_builder(builder_name: str = DEFAULT_BUILDER_NAME) -> str:
  )
  logger.info(f"Created new buildx builder: {builder_name}")
  except DockerException as e:
+ # Check if this is a race condition (another process created the builder)
+ if hasattr(e, 'stderr') and 'existing instance for' in str(e.stderr):
+ logger.info(f"Builder '{builder_name}' was created by another process – using it.")
+ docker.buildx.use(builder_name)
+ return builder_name
+ 
+ # Otherwise, it's a real error
  logger.error(f"Failed to create buildx builder: {e}")
  raise