Trivial attach implementation

py_experimenter/database_connector.py

@@ -8,8 +8,14 @@
 
 from py_experimenter import utils
 from py_experimenter.config import DatabaseCfg, Keyfield
-from py_experimenter.exceptions import (CreatingTableError, DatabaseConnectionError, EmptyFillDatabaseCallError, NoExperimentsLeftException,
-                                        NoPausedExperimentsException, TableHasWrongStructureError)
+from py_experimenter.exceptions import (
+    CreatingTableError,
+    DatabaseConnectionError,
+    EmptyFillDatabaseCallError,
+    NoExperimentsLeftException,
+    NoPausedExperimentsException,
+    TableHasWrongStructureError,
+)
 from py_experimenter.experiment_status import ExperimentStatus
 
 
@@ -267,6 +273,9 @@ def random_order_string():
     def _get_pull_experiment_query(self, order_by: str):
         return f"SELECT `id` FROM {self.database_configuration.table_name} WHERE status = 'created' ORDER BY {order_by} LIMIT 1"
 
+    def pull_experiment(self, experiment_id: int) -> Dict[str, Any]:
+        pass  # TODO Get keyfields for the allready existing experiment
+
     def _write_to_database(self, combinations: List[Dict[str, str]]) -> None:
         columns = list(combinations[0].keys())
         values = [list(combination.values()) for combination in combinations]

py_experimenter/experimenter.py

@@ -12,10 +12,7 @@
 from py_experimenter.config import PyExperimenterCfg
 from py_experimenter.database_connector_lite import DatabaseConnectorLITE
 from py_experimenter.database_connector_mysql import DatabaseConnectorMYSQL
-from py_experimenter.exceptions import (
-    InvalidConfigError,
-    NoExperimentsLeftException,
-)
+from py_experimenter.exceptions import InvalidConfigError, NoExperimentsLeftException
 from py_experimenter.experiment_status import ExperimentStatus
 from py_experimenter.result_processor import ResultProcessor
 
@@ -234,7 +231,7 @@ def add_experiment_and_execute(
         self, keyfield_values: Dict, experiment_function: Callable[[Dict, Dict, ResultProcessor], Optional[ExperimentStatus]]
     ) -> None:
         """
-        Add one new experiment to the database table with status CREATED_FOR_EXECUTION and execute it. 
+        Add one new experiment to the database table with status CREATED_FOR_EXECUTION and execute it.
 
         The given `keyfield_values` are added to the database table. The status of the experiment is set to `Running`.
         Then _execute_experiment is called with the given `experiment_function` and the `keyfield_values`, to immidiately start
@@ -334,6 +331,27 @@ def unpause_experiment(self, experiment_id: int, experiment_function: Callable)
 
         self._delete_codecarbon_config()
 
+    def attach(self, experiment_function: Callable, experiment_id) -> None:
+        """
+        Executes the given `own_function` on the allready running experiment.
+
+        :param experiment_function: The function that should be executed..
+        :type own_function: Callable
+        :param experiment_id: The id of the experiment to be executed.
+        :type experiment_id: int
+        :raises ValueError: If the database provider is sqlite.
+        """
+        if self.config.database_configuration.provider == "sqlite":
+            raise ValueError("Attaching is not supported for sqlite databases")
+        if self.use_codecarbon:
+            self.logger.warning(
+                "CodeCarbon is not supported for attached functions. Therefore the emissions are only tracked for the main experiment."
+            )
+
+        result_processor = ResultProcessor(self.config.database_configuration, self.db_connector, experiment_id=experiment_id, logger=self.logger)
+
+        return experiment_function(result_processor)
+
     def _worker(self, experiment_function: Callable[[Dict, Dict, ResultProcessor], None], random_order: bool) -> None:
         """
         Worker that repeatedly pulls open experiments from the database table and executes them.