Emit a big deprecation warning on python 2.x at the end of the run

core/dbt/main.py

@@ -106,6 +106,8 @@ def main(args=None):
  logger.error(traceback.format_exc())
  exit_code = ExitCodes.UnhandledError
 
+ _python2_compatibility_message()
+
  sys.exit(exit_code)
 
 
@@ -175,6 +177,22 @@ def track_run(task):
  dbt.tracking.flush()
 
 
+_PYTHON_27_WARNING = '''
+Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade
+your Python as Python 2.7 won't be maintained after that date. A future version
+of dbt will drop support for Python 2.7.
+'''.strip()
+
+
+def _python2_compatibility_message():
+ if dbt.compat.WHICH_PYTHON != 2:
+ return
+
+ logger.critical(
+ dbt.ui.printer.red('DEPRECATION: ') + _PYTHON_27_WARNING
+ )
+
+
 def run_from_args(parsed):
  log_cache_events(getattr(parsed, 'log_cache_events', False))
  flags.set_from_args(parsed)