DOCS-modin-project#7144: Add information about logging from user defi…

…ned function (modin-project#7155)

Co-authored-by: Iaroslav Igoshev <[email protected]>
Signed-off-by: arunjose696 <[email protected]>

docs/usage_guide/advanced_usage/modin_logging.rst

@@ -53,3 +53,42 @@ Disable Modin logging like so:
   LogMode.disable()
 
   # User code goes here
+
+Debugging from user defined functions:
+
+.. warning:: 
+    When attempting to use Modin logging in user defined functions that execute in workers for logging lower-level operators
+    as in example below, multiple log directories ``.modin/logs/job_**`` would be created for each worker executing the UDF.
+
+.. code-block:: python
+
+  import modin.pandas as pd
+
+  def udf(x):
+      from modin.config import LogMode
+      
+      LogMode.enable()
+      
+      return x + 1
+  
+  modin_df = pd.DataFrame([0, 1, 2, 3])
+  print(modin_df.map(udf))
+
+So the **recommended** approach would be to use a different logger as in the below snipet
+to log from user defined functions that execute on workers.
+Below is an an example to log from UDF. For this the logger config has to be specified inside the UDF that would execute on a remote worker.
+
+.. code-block:: python
+
+  import logging
+  import modin.pandas as pd
+  
+  def udf(x):
+      logging.basicConfig(filename='modin_udf.log', level=logging.INFO)
+      logging.info("This log message will be written to modin_udf.log ")
+
+      # User code goes here
+      return x + 1
+
+  modin_df = pd.DataFrame([0, 1, 2, 3])
+  print(modin_df.map(udf))