Moved archived_tag definition + pep8

trains/backend_interface/task/task.py

@@ -26,6 +26,7 @@ from collections import OrderedDict
 from six.moves.urllib.parse import quote
 
 from ...utilities.locks import RLock as FileRLock
+from ...utilities.attrs import readonly
 from ...binding.artifacts import Artifacts
 from ...backend_interface.task.development.worker import DevWorker
 from ...backend_api import Session
@@ -61,6 +62,7 @@ class Task(IdObjectBase, AccessMixin, SetupUploadMixin):
 
     _anonymous_dataview_id = '__anonymous__'
     _development_tag = 'development'
+    archived_tag = readonly('archived')
     _default_configuration_section_name = 'General'
     _legacy_parameters_section_name = 'Args'
     _force_requirements = {}
@@ -841,6 +843,26 @@ class Task(IdObjectBase, AccessMixin, SetupUploadMixin):
             merged into a single key-value pair dictionary.
         :param kwargs: Key-value pairs, merged into the parameters dictionary created from ``args``.
         """
+        def stringify(value):
+            # return empty string if value is None
+            if value is None:
+                return ""
+
+            str_value = str(value)
+            if isinstance(value, (tuple, list, dict)) and 'None' in re.split(r'[ ,\[\]{}()]', str_value):
+                # If we have None in the string we have to use json to replace it with null,
+                # otherwise we end up with None as string when running remotely
+                try:
+                    str_json = json.dumps(value)
+                    # verify we actually have a null in the string, otherwise prefer the str cast
+                    # This is because we prefer to have \' as in str and not \" used in json
+                    if 'null' in re.split(r'[ ,\[\]{}()]', str_json):
+                        return str_json
+                except TypeError:
+                    # if we somehow failed to json serialize, revert to previous std casting
+                    pass
+            return str_value
+
         if not all(isinstance(x, (dict, Iterable)) for x in args):
             raise ValueError('only dict or iterable are supported as positional arguments')
 
@@ -886,7 +908,7 @@ class Task(IdObjectBase, AccessMixin, SetupUploadMixin):
             parameters.update(new_parameters)
 
             # force cast all variables to strings (so that we can later edit them in UI)
-            parameters = {k: str(v) if v is not None else "" for k, v in parameters.items()}
+            parameters = {k: stringify(v) for k, v in parameters.items()}
 
             if use_hyperparams:
                 # build nested dict from flat parameters dict:
@@ -971,6 +993,25 @@ class Task(IdObjectBase, AccessMixin, SetupUploadMixin):
         params = self.get_parameters()
         return params.get(name, default)
 
+    def delete_parameter(self, name):
+        # type: (str) -> bool
+        """
+        Delete a parameter byt it's full name Section/name.
+
+        :param name: Parameter name in full, i.e. Section/name. For example, 'Args/batch_size'
+        :return: True if the parameter was deleted successfully
+        """
+        if not Session.check_min_api_version('2.9'):
+            raise ValueError("Delete hyper parameter is not supported by your trains-server, "
+                             "upgrade to the latest version")
+        with self._edit_lock:
+            paramkey = tasks.ParamKey(section=name.split('/', 1)[0], name=name.split('/', 1)[1])
+            res = self.send(tasks.DeleteHyperParamsRequest(
+                task=self.id, hyperparams=[paramkey]), raise_on_errors=False)
+            self.reload()
+
+        return res.ok()
+
     def update_parameters(self, *args, **kwargs):
         # type: (*dict, **Any) -> ()
         """
@@ -1678,6 +1719,8 @@ class Task(IdObjectBase, AccessMixin, SetupUploadMixin):
             extra['hyperparams'] = task.hyperparams
         if hasattr(task, 'configuration'):
             extra['configuration'] = task.configuration
+        if getattr(task, 'system_tags', None):
+            extra['system_tags'] = [t for t in task.system_tags if t not in (cls._development_tag, cls.archived_tag)]
 
         req = tasks.CreateRequest(
             name=name or task.name,