Improve logging for standalone mode (#1768)

src/sdk/pynni/nni/common.py

@@ -68,6 +68,27 @@ def init_logger(logger_file_path, log_level_name='info'):
 
     sys.stdout = _LoggerFileWrapper(logger_file)
 
+def init_standalone_logger():
+    """
+    Initialize root logger for standalone mode.
+    This will set NNI's log level to INFO and print its log to stdout.
+    """
+    fmt = '[%(asctime)s] %(levelname)s (%(name)s) %(message)s'
+    formatter = logging.Formatter(fmt, _time_format)
+    handler = logging.StreamHandler(sys.stdout)
+    handler.setFormatter(formatter)
+    nni_logger = logging.getLogger('nni')
+    nni_logger.addHandler(handler)
+    nni_logger.setLevel(logging.INFO)
+    nni_logger.propagate = False
+
+    # Following line does not affect NNI loggers, but without this user's logger won't be able to
+    # print log even it's level is set to INFO, so we do it for user's convenience.
+    # If this causes any issue in future, remove it and use `logging.info` instead of
+    # `logging.getLogger('xxx')` in all examples.
+    logging.basicConfig()
+
+
 _multi_thread = False
 _multi_phase = False
 

src/sdk/pynni/nni/platform/standalone.py

@@ -22,14 +22,26 @@
 import logging
 import json_tricks
 
+from ..common import init_standalone_logger
 
-# print INFO log to stdout
-logging.basicConfig()
-logging.getLogger('nni').setLevel(logging.INFO)
+__all__ = [
+    'get_next_parameter',
+    'get_experiment_id',
+    'get_trial_id',
+    'get_sequence_id',
+    'send_metric',
+]
+
+init_standalone_logger()
+_logger = logging.getLogger('nni')
 
 
 def get_next_parameter():
-    pass
+    _logger.warning('Requesting parameter without NNI framework, returning empty dict')
+    return {
+        'parameter_id': None,
+        'parameters': {}
+    }
 
 def get_experiment_id():
     pass
@@ -43,6 +55,8 @@ def get_sequence_id():
 def send_metric(string):
     metric = json_tricks.loads(string)
     if metric['type'] == 'FINAL':
-        print('Final result:', metric['value'])
+        _logger.info('Final result: %s', metric['value'])
     elif metric['type'] == 'PERIODICAL':
-        print('Intermediate result:', metric['value'])
+        _logger.info('Intermediate result: %s  (Index %s)', metric['value'], metric['sequence'])
+    else:
+        _logger.error('Unexpected metric: %s', string)

src/sdk/pynni/nni/trial.py

@@ -126,9 +126,10 @@ def report_intermediate_result(metric):
         serializable object.
     """
     global _intermediate_seq
-    assert _params is not None, 'nni.get_next_parameter() needs to be called before report_intermediate_result'
+    assert _params or trial_env_vars.NNI_PLATFORM is None, \
+        'nni.get_next_parameter() needs to be called before report_intermediate_result'
     metric = json_tricks.dumps({
-        'parameter_id': _params['parameter_id'],
+        'parameter_id': _params['parameter_id'] if _params else None,
         'trial_job_id': trial_env_vars.NNI_TRIAL_JOB_ID,
         'type': 'PERIODICAL',
         'sequence': _intermediate_seq,
@@ -147,9 +148,10 @@ def report_final_result(metric):
     metric:
         serializable object.
     """
-    assert _params is not None, 'nni.get_next_parameter() needs to be called before report_final_result'
+    assert _params or trial_env_vars.NNI_PLATFORM is None, \
+        'nni.get_next_parameter() needs to be called before report_final_result'
     metric = json_tricks.dumps({
-        'parameter_id': _params['parameter_id'],
+        'parameter_id': _params['parameter_id'] if _params else None,
         'trial_job_id': trial_env_vars.NNI_TRIAL_JOB_ID,
         'type': 'FINAL',
         'sequence': 0,