Don't assume build isn't None in a docker build env (#6599)

* Don't assume build isn't None in a docker build env

This is kind of the same we hit with a local env
#6503

* Check for self.build

* Use context manager

Author: stsewd

readthedocs/doc_builder/environments.py

@@ -790,13 +790,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.client = None
         self.container = None
-        self.container_name = slugify(
-            'build-{build}-project-{project_id}-{project_name}'.format(
-                build=self.build.get('id'),
-                project_id=self.project.pk,
-                project_name=self.project.slug,
-            )[:DOCKER_HOSTNAME_MAX_LEN],
-        )
+        self.container_name = self.get_container_name()
 
         # Decide what Docker image to use, based on priorities:
         # Use the Docker image set by our feature flag: ``testing`` or,
@@ -908,6 +902,17 @@ def __exit__(self, exc_type, exc_value, tb):
 
         return super().__exit__(exc_type, exc_value, tb)
 
+    def get_container_name(self):
+        if self.build:
+            name = 'build-{build}-project-{project_id}-{project_name}'.format(
+                build=self.build.get('id'),
+                project_id=self.project.pk,
+                project_name=self.project.slug,
+            )
+        else:
+            name = f'sync-project-{self.project.pk}-{self.project.slug}'
+        return slugify(name[:DOCKER_HOSTNAME_MAX_LEN])
+
     def get_client(self):
         """Create Docker client connection."""
         try:
@@ -929,11 +934,13 @@ def get_client(self):
             # We don't raise an error here mentioning Docker, that is a
             # technical detail that the user can't resolve on their own.
             # Instead, give the user a generic failure
-            raise BuildEnvironmentError(
-                BuildEnvironmentError.GENERIC_WITH_BUILD_ID.format(
-                    build_id=self.build['id'],
-                ),
-            )
+            if self.build:
+                error = BuildEnvironmentError.GENERIC_WITH_BUILD_ID.format(
+                    build_id=self.build.get('id'),
+                )
+            else:
+                error = 'Failed to connect to Docker API client'
+            raise BuildEnvironmentError(error)
 
     def _get_binds(self):
         """

readthedocs/projects/tasks.py

@@ -262,9 +262,10 @@ def run(self, version_pk):  # pylint: disable=arguments-differ
                 environment=self.get_rtd_env_vars(),
             )
 
-            before_vcs.send(sender=self.version, environment=environment)
-            with self.project.repo_nonblockinglock(version=self.version):
-                self.sync_repo(environment)
+            with environment:
+                before_vcs.send(sender=self.version, environment=environment)
+                with self.project.repo_nonblockinglock(version=self.version):
+                    self.sync_repo(environment)
             return True
         except RepositoryError:
             # Do not log as ERROR handled exceptions