Build: use gvisor for projects using build.tools (#9114)

Closes #9103

Author: stsewd

readthedocs/doc_builder/director.py

@@ -107,12 +107,14 @@ def create_vcs_environment(self):
         )
 
     def create_build_environment(self):
+        use_gvisor = self.data.config.using_build_tools and self.data.config.build.jobs
         self.build_environment = self.data.environment_class(
             project=self.data.project,
             version=self.data.version,
             config=self.data.config,
             build=self.data.build,
             environment=self.get_build_env_vars(),
+            use_gvisor=use_gvisor,
         )
 
     def setup_environment(self):

readthedocs/doc_builder/environments.py

@@ -554,13 +554,16 @@ class DockerBuildEnvironment(BuildEnvironment):
     container_time_limit = DOCKER_LIMITS.get('time')
 
     def __init__(self, *args, **kwargs):
-        container_image = kwargs.pop('container_image', None)
-
+        container_image = kwargs.pop("container_image", None)
+        self.use_gvisor = kwargs.pop("use_gvisor", False)
         super().__init__(*args, **kwargs)
         self.client = None
         self.container = None
         self.container_name = self.get_container_name()
 
+        if self.project.has_feature(Feature.DOCKER_GVISOR_RUNTIME):
+            self.use_gvisor = True
+
         # Decide what Docker image to use, based on priorities:
         # Use the Docker image set by our feature flag: ``testing`` or,
         if self.project.has_feature(Feature.USE_TESTING_BUILD_IMAGE):
@@ -790,11 +793,7 @@ def create_container(self):
         """Create docker container."""
         client = self.get_client()
         try:
-            docker_runtime = self.project.get_feature_value(
-                Feature.DOCKER_GVISOR_RUNTIME,
-                positive="runsc",
-                negative=None,
-            )
+            docker_runtime = "runsc" if self.use_gvisor else None
             log.info(
                 'Creating Docker container.',
                 container_image=self.container_image,