Add flag to main.py. Reinstantiate after flags (#4416) (#4419)

Co-authored-by: Jeremy Cohen <jeremy@dbtlabs.com>

core/dbt/events/functions.py

@@ -23,8 +23,9 @@
 from collections import deque
 
 
-# create the global event history buffer with a max size of 100k records
+# create the global event history buffer with the default max size (10k)
 # python 3.7 doesn't support type hints on globals, but mypy requires them. hence the ignore.
+# TODO the flags module has not yet been resolved when this is created
 global EVENT_HISTORY
 EVENT_HISTORY = deque(maxlen=flags.EVENT_BUFFER_SIZE) # type: ignore
 
@@ -49,6 +50,10 @@
 
 
 def setup_event_logger(log_path, level_override=None):
+ # flags have been resolved, and log_path is known
+ global EVENT_HISTORY
+ EVENT_HISTORY = deque(maxlen=flags.EVENT_BUFFER_SIZE) # type: ignore
+
  make_log_dir_if_missing(log_path)
  this.format_json = flags.LOG_FORMAT == 'json'
  # USE_COLORS can be None if the app just started and the cli flags

core/dbt/main.py

@@ -1076,6 +1076,14 @@ def parse_args(args, cls=DBTArgumentParser):
  '''
  )
 
+ p.add_argument(
+ '--event-buffer-size',
+ dest='event_buffer_size',
+ help='''
+ Sets the max number of events to buffer in EVENT_HISTORY
+ '''
+ )
+
  subs = p.add_subparsers(title="Available sub-commands")
 
  base_subparser = _build_base_subparser()