casserver.py: Add buildstream capabilities service

Part of #915

1 files changed, 17 insertions, 0 deletions

diff --git a/src/buildstream/_cas/casserver.py b/src/buildstream/_cas/casserver.py
index 203b2f021..774548216 100644
--- a/src/buildstream/_cas/casserver.py
+++ b/src/buildstream/_cas/casserver.py
@@ -88,6 +88,13 @@ def create_server(repo, *, enable_push,
     artifact_pb2_grpc.add_ArtifactServiceServicer_to_server(
         _ArtifactServicer(cas, artifactdir), server)
 
+    # Create up reference storage and artifact capabilities
+    artifact_capabilities = buildstream_pb2.ArtifactCapabilities(
+        allow_updates=enable_push)
+    buildstream_pb2_grpc.add_CapabilitiesServicer_to_server(
+        _BuildStreamCapabilitiesServicer(artifact_capabilities),
+        server)
+
     return server
 
 
@@ -501,6 +508,16 @@ class _ArtifactServicer(artifact_pb2_grpc.ArtifactServiceServicer):
                           "Artifact {} specified but not found".format(name))
 
 
+class _BuildStreamCapabilitiesServicer(buildstream_pb2_grpc.CapabilitiesServicer):
+    def __init__(self, artifact_capabilities):
+        self.artifact_capabilities = artifact_capabilities
+
+    def GetCapabilities(self, request, context):
+        response = buildstream_pb2.ServerCapabilities()
+        response.artifact_capabilities.CopyFrom(self.artifact_capabilities)
+        return response
+
+
 def _digest_from_download_resource_name(resource_name):
     parts = resource_name.split('/')