Add pull-artifact-files configuration option for remote execution

This decides whether to fetch the file blobs of remote execution built
artifacts.

Part of #1043

2 files changed, 21 insertions, 3 deletions

diff --git a/src/buildstream/_context.py b/src/buildstream/_context.py
index 52e4c3db9..2bdf5b0b4 100644
--- a/src/buildstream/_context.py
+++ b/src/buildstream/_context.py
@@ -129,6 +129,9 @@ class Context():
         # Whether or not to attempt to pull build trees globally
         self.pull_buildtrees = None
 
+        # Whether to pull the files of an artifact when doing remote execution
+        self.pull_artifact_files = None
+
         # Whether or not to cache build trees on artifact creation
         self.cache_buildtrees = None
 
@@ -258,6 +261,19 @@ class Context():
         # Load source cache config
         self.source_cache_specs = SourceCache.specs_from_config_node(defaults)
 
+        # Load remote execution config getting pull-artifact-files from it
+        remote_execution = _yaml.node_get(defaults, dict, 'remote-execution', default_value=None)
+        if remote_execution:
+            self.pull_artifact_files = _yaml.node_get(
+                remote_execution, bool, 'pull-artifact-files', default_value=True)
+            # This stops it being used in the remote service set up
+            _yaml.node_del(remote_execution, 'pull-artifact-files', safe=True)
+            # Don't pass the remote execution settings if that was the only option
+            if _yaml.node_keys(remote_execution) == []:
+                _yaml.node_del(defaults, 'remote-execution')
+        else:
+            self.pull_artifact_files = True
+
         self.remote_execution_specs = SandboxRemote.specs_from_config_node(defaults)
 
         # Load pull build trees configuration
diff --git a/src/buildstream/_stream.py b/src/buildstream/_stream.py
index 9a400933c..705e0a5d3 100644
--- a/src/buildstream/_stream.py
+++ b/src/buildstream/_stream.py
@@ -273,9 +273,11 @@ class Stream():
             # Require artifact files only for target elements and their runtime dependencies.
             self._context.set_artifact_files_optional()
 
-            scope = Scope.ALL if build_all else Scope.RUN
-            for element in self.targets:
-                element._set_artifact_files_required(scope=scope)
+            # fetch blobs of targets if options set
+            if self._context.pull_artifact_files:
+                scope = Scope.ALL if build_all else Scope.RUN
+                for element in self.targets:
+                    element._set_artifact_files_required(scope=scope)
 
         # Now construct the queues
         #