Refactor: message handlers take 'is_silenced'

Remove the need to pass the Context object to message handlers, by
passing what is usually requested from the context instead.

This paves the way to sharing less information with some child jobs -
they won't need the whole context object, just the messenger.

1 files changed, 13 insertions, 8 deletions

diff --git a/src/buildstream/_messenger.py b/src/buildstream/_messenger.py
index 6dcb649d7..069ca124a 100644
--- a/src/buildstream/_messenger.py
+++ b/src/buildstream/_messenger.py
@@ -42,8 +42,13 @@ class Messenger():
     # Sets the handler for any status messages propagated through
     # the context.
     #
-    # The message handler should have the same signature as
-    # the message() method
+    # The handler should have the signature:
+    #
+    #   def handler(
+    #      message: _message.Message,  # The message to send.
+    #      is_silenced: bool,          # Whether messages are currently being silenced.
+    #   ) -> None
+    #
     def set_message_handler(self, handler):
         self._message_handler = handler
 
@@ -66,7 +71,7 @@ class Messenger():
     # Args:
     #    message: A Message object
     #
-    def message(self, message, context):
+    def message(self, message):
 
         # Tag message only once
         if message.depth is None:
@@ -80,7 +85,7 @@ class Messenger():
         # to the frontend)
         assert self._message_handler
 
-        self._message_handler(message, context=context)
+        self._message_handler(message, is_silenced=self.silent_messages())
 
     # silence()
     #
@@ -109,7 +114,7 @@ class Messenger():
     #    silent_nested (bool): If specified, nested messages will be silenced
     #
     @contextmanager
-    def timed_activity(self, activity_name, context, *, unique_id=None, detail=None, silent_nested=False):
+    def timed_activity(self, activity_name, *, unique_id=None, detail=None, silent_nested=False):
 
         starttime = datetime.datetime.now()
         stopped_time = None
@@ -128,7 +133,7 @@ class Messenger():
             try:
                 # Push activity depth for status messages
                 message = Message(unique_id, MessageType.START, activity_name, detail=detail)
-                self.message(message, context)
+                self.message(message)
                 self._push_message_depth(silent_nested)
                 yield
 
@@ -138,13 +143,13 @@ class Messenger():
                 elapsed = datetime.datetime.now() - starttime
                 message = Message(unique_id, MessageType.FAIL, activity_name, elapsed=elapsed)
                 self._pop_message_depth()
-                self.message(message, context)
+                self.message(message)
                 raise
 
             elapsed = datetime.datetime.now() - starttime
             message = Message(unique_id, MessageType.SUCCESS, activity_name, elapsed=elapsed)
             self._pop_message_depth()
-            self.message(message, context)
+            self.message(message)
 
     # recorded_messages()
     #