Silence messages from Source cache interrogation

Source interrogation usually involves calling out to host tools
to quickly check if a given ref exists. This has however regressed
over time when running `bst build --track`.

This patch adds a new context manager to silence the messages,
and silences messages while calling `Source.get_consistency()`

Fixes #280

1 files changed, 13 insertions, 0 deletions

diff --git a/buildstream/_context.py b/buildstream/_context.py
index 332b2c020..3f5a4d62f 100644
--- a/buildstream/_context.py
+++ b/buildstream/_context.py
@@ -343,6 +343,19 @@ class Context():
         self._message_handler(message, context=self)
         return
 
+    # _silence()
+    #
+    # A context manager to silence messages, this behaves in
+    # the same way as the `silent_nested` argument of the
+    # Context._timed_activity() context manager: especially
+    # important messages will not be silenced.
+    #
+    @contextmanager
+    def _silence(self):
+        self._push_message_depth(True)
+        yield
+        self._pop_message_depth()
+
     # _timed_activity()
     #
     # Context manager for performing timed activities and logging those