Use Traitlets for passing parameters to Build classes

.github/workflows/test.yml

@@ -43,6 +43,7 @@ jobs:
   # jobs or have "template" jobs, so we use `if` conditions on steps
   tests:
     runs-on: ubuntu-20.04
+    timeout-minutes: 10
     strategy:
       # keep running so we can see if tests with other k3s/k8s/helm versions pass
       fail-fast: false
@@ -278,6 +279,7 @@ jobs:
 
   test-local:
     runs-on: ubuntu-20.04
+    timeout-minutes: 5
     steps:
       - uses: actions/checkout@v3
 

binderhub/app.py

@@ -41,7 +41,7 @@
 from traitlets.config import Application
 
 from .base import AboutHandler, Custom404, VersionHandler
-from .build import Build
+from .build import Build, BuildExecutor
 from .builder import BuildHandler
 from .config import ConfigHandler
 from .events import EventLog
@@ -270,10 +270,11 @@ def _valid_badge_base_url(self, proposal):
 
     build_class = Type(
         Build,
+        klass=BuildExecutor,
         help="""
         The class used to build repo2docker images.
 
-        Must inherit from binderhub.build.Build
+        Must inherit from binderhub.build.BuildExecutor
         """,
         config=True,
     )
@@ -818,6 +819,7 @@ def initialize(self, *args, **kwargs):
                 "build_class": self.build_class,
                 "registry": registry,
                 "traitlets_config": self.config,
+                "traitlets_parent": self,
                 "google_analytics_code": self.google_analytics_code,
                 "google_analytics_domain": self.google_analytics_domain,
                 "about_message": self.about_message,