diff --git a/creation/lib/cWDictFile.py b/creation/lib/cWDictFile.py
index 80159e923..85ba23175 100644
--- a/creation/lib/cWDictFile.py
+++ b/creation/lib/cWDictFile.py
@@ -1,16 +1,12 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   Classes needed to handle dictionary files
 #   And other support functions
-#
+
+# TODO: in this file there are several directory creation functions. Use what's available in
+#  Python 3 and reduce custom code
 
 import copy
 import io
@@ -209,7 +205,7 @@ def save(
             with open(filepath, "wb") as fd:
                 self.save_into_fd(fd, sort_keys, set_readonly, reset_changed, want_comments)
         except OSError as e:
-            raise DictFileError(f"Error creating or writing to {filepath}: {e}")
+            raise DictFileError(f"Error creating or writing to {filepath}: {e}") from e
 
         # ensure that the file permissions are 644
         # This is to minimize a security risk where we load python code from
@@ -257,7 +253,7 @@ def save_into_fd(self, fd, sort_keys=None, set_readonly=True, reset_changed=True
                 fd.write(b"%s\n" % footer.encode(BINARY_ENCODING))
         except AttributeError as e:
             # .encode() attribute may be missing because bytes are passed
-            raise DictFileError(f"str received while writing {self.fname} ({type(self).__name__}): {e}")
+            raise DictFileError(f"str received while writing {self.fname} ({type(self).__name__}): {e}") from e
 
         if set_readonly:
             self.set_readonly(True)
@@ -336,7 +332,7 @@ def load(self, dir=None, fname=None, change_self=True, erase_first=True, set_not
             with fd:
                 self.load_from_fd(fd, erase_first, set_not_changed)
         except RuntimeError as e:
-            raise DictFileError(f"File {filepath}: {str(e)}")
+            raise DictFileError(f"File {filepath}: {str(e)}") from e
 
         if change_self:
             self.dir = dir
@@ -372,7 +368,7 @@ def load_from_fd(self, fd, erase_first=True, set_not_changed=True):
             try:
                 self.parse_val(line.decode(BINARY_ENCODING))
             except RuntimeError as e:
-                raise DictFileError("Line %i: %s" % (idx, str(e)))
+                raise DictFileError("Line %i: %s" % (idx, str(e))) from e
 
         if set_not_changed:
             self.changed = False  # the memory copy is now same as the one on disk
@@ -394,7 +390,7 @@ def load_from_str(self, data, erase_first=True, set_not_changed=True):
             try:
                 self.load_from_fd(fd, erase_first, set_not_changed)
             except RuntimeError as e:
-                raise DictFileError("Memory buffer: %s" % (str(e)))
+                raise DictFileError("Memory buffer: %s" % (str(e))) from e
         return
 
     def is_equal(self, other, compare_dir=False, compare_fname=False, compare_keys=None):
@@ -913,7 +909,7 @@ def add_from_file(self, key, val, filepath, allow_overwrite=False):
             with open(filepath, "rb") as fd:
                 self.add_from_fd(key, val, fd, allow_overwrite)
         except OSError as e:
-            raise DictFileError("Could not open file or read from it: %s" % filepath)
+            raise DictFileError("Could not open file or read from it: %s" % filepath) from e
 
     def format_val(self, key, want_comments):
         """Print lines: only the file name (key) the first item of the value tuple if not None
@@ -988,12 +984,12 @@ def save_files(self, allow_overwrite=False):
             try:
                 fd = open(filepath, "wb")
             except OSError as e:
-                raise DictFileError("Could not create file %s" % filepath)
+                raise DictFileError("Could not create file %s" % filepath) from None
             try:
                 with fd:
                     fd.write(fdata)
             except OSError as e:
-                raise DictFileError("Error writing into file %s" % filepath)
+                raise DictFileError("Error writing into file %s" % filepath) from None
 
 
 class FileDictFile(SimpleFileDictFile):
@@ -1125,8 +1121,10 @@ def add(
         # TODO: check parameters!!
         try:
             int(val[2])  # to check if is integer. Period must be int or convertible to int
-        except (ValueError, IndexError):
-            raise DictFileError("Values '%s' not (real_fname,cache/exec,period,prefix,cond_download,config_out)" % val)
+        except (ValueError, IndexError) as e:
+            raise DictFileError(
+                "Values '%s' not (real_fname,cache/exec,period,prefix,cond_download,config_out)" % val
+            ) from e
 
         if len(val) == self.DATA_LENGTH:
             # Alt: return self.add_from_str(key, val[:self.DATA_LENGTH-1], val[self.DATA_LENGTH-1], allow_overwrite)
@@ -1411,6 +1409,7 @@ def add_extended(
         elif user_name == True:
             user_name = "+"
 
+        # TODO: check .add end set allow_overwrite=False above instead allow_overwrite=0
         self.add(key, (type_str, val_default, condor_name, req_str, export_condor_str, user_name), allow_overwrite)
 
     def format_val(self, key, want_comments):
@@ -1551,7 +1550,7 @@ def save(
             with open(filepath, "wb") as fd:
                 self.save_into_fd(fd, sort_keys, set_readonly, reset_changed, want_comments)
         except OSError as e:
-            raise RuntimeError(f"Error creating or writing to {filepath}: {e}")
+            raise RuntimeError(f"Error creating or writing to {filepath}: {e}") from e
         chmod(filepath, 0o755)
 
         return
@@ -1597,17 +1596,17 @@ def __init__(self, dir, dir_name):
         self.dir = dir
         self.dir_name = dir_name
 
+    # TODO: there is os.mkdirs with fail_if_exists
     def create_dir(self, fail_if_exists=True):
         if os.path.isdir(self.dir):
             if fail_if_exists:
                 raise RuntimeError(f"Cannot create {self.dir_name} dir {self.dir}, already exists.")
             else:
                 return False  # already exists, nothing to do
-
         try:
             os.mkdir(self.dir)
         except OSError as e:
-            raise RuntimeError(f"Failed to create {self.dir_name} dir: {e}")
+            raise RuntimeError(f"Failed to create {self.dir_name} dir: {e}") from None
         return True
 
     def delete_dir(self):
@@ -1619,6 +1618,7 @@ def __init__(self, dir, chmod, dir_name):
         simpleDirSupport.__init__(self, dir, dir_name)
         self.chmod = chmod
 
+    # TODO: there is os.mkdirs with fail_if_exists
     def create_dir(self, fail_if_exists=True):
         if os.path.isdir(self.dir):
             if fail_if_exists:
@@ -1629,7 +1629,7 @@ def create_dir(self, fail_if_exists=True):
         try:
             os.mkdir(self.dir, self.chmod)
         except OSError as e:
-            raise RuntimeError(f"Failed to create {self.dir_name} dir: {e}")
+            raise RuntimeError(f"Failed to create {self.dir_name} dir: {e}") from None
         return True
 
 
@@ -1641,6 +1641,7 @@ def __init__(self, target_dir, symlink, dir_name):
         self.symlink = symlink
         self.dir_name = dir_name
 
+    # TODO: there is os.mkdirs with fail_if_exists, check if something similar for symlink
     def create_dir(self, fail_if_exists=True):
         if os.path.islink(self.symlink):
             if fail_if_exists:
@@ -1651,7 +1652,7 @@ def create_dir(self, fail_if_exists=True):
         try:
             os.symlink(self.target_dir, self.symlink)
         except OSError as e:
-            raise RuntimeError(f"Failed to create {self.dir_name} symlink: {e}")
+            raise RuntimeError(f"Failed to create {self.dir_name} symlink: {e}") from None
         return True
 
     def delete_dir(self):
@@ -1667,6 +1668,7 @@ def __init__(self):
     def add_dir_obj(self, dir_obj):
         self.dir_list.append(dir_obj)
 
+    # TODO: there is os.mkdirs with fail_if_exists
     def create_dirs(self, fail_if_exists=True):
         created_dirs = []
         try:
diff --git a/creation/lib/cWParams.py b/creation/lib/cWParams.py
index ab5197348..a7a61b28d 100644
--- a/creation/lib/cWParams.py
+++ b/creation/lib/cWParams.py
@@ -267,7 +267,7 @@ def __init__(self, usage_prefix, src_dir, argv):
             # create derived values
             self.derive()
         except RuntimeError as e:
-            raise RuntimeError("Unexpected error occurred loading the configuration file.\n\n%s" % e)
+            raise RuntimeError("Unexpected error occurred loading the configuration file.\n\n%s" % e) from e
 
     def derive(self):
         return  # by default nothing... children should overwrite this
@@ -308,9 +308,9 @@ def load_file(self, fname):
         try:
             self.data = xmlParse.xmlfile2dict(fname, use_ord_dict=True)
         except xml.parsers.expat.ExpatError as e:
-            raise RuntimeError("XML error parsing config file: %s" % e)
+            raise RuntimeError("XML error parsing config file: %s" % e) from e
         except OSError as e:
-            raise RuntimeError("Config file error: %s" % e)
+            raise RuntimeError("Config file error: %s" % e) from e
         self.subparams = self.get_subparams_class()(self.data)
         return
 
diff --git a/creation/lib/cvWParamDict.py b/creation/lib/cvWParamDict.py
index 0dedd3f0e..326712a21 100644
--- a/creation/lib/cvWParamDict.py
+++ b/creation/lib/cvWParamDict.py
@@ -56,7 +56,7 @@ def translate_match_attrs(loc_str, match_attrs_name, match_attrs):
         try:
             translated_attrs[attr_name] = translations[attr_type]
         except KeyError as e:
-            raise RuntimeError(f"Invalid {loc_str} {match_attrs_name} attr type '{attr_type}'")
+            raise RuntimeError(f"Invalid {loc_str} {match_attrs_name} attr type '{attr_type}'") from e
 
     return translated_attrs
 
@@ -106,9 +106,9 @@ def validate_match(loc_str, match_str, factory_attrs, job_attrs, attr_dict, poli
         match_obj = compile(match_str, "<string>", "exec")
         eval(match_obj, env)
     except KeyError as e:
-        raise RuntimeError(f"Invalid {loc_str} match_expr '{match_str}': Missing attribute {e}")
+        raise RuntimeError(f"Invalid {loc_str} match_expr '{match_str}': Missing attribute {e}") from e
     except Exception as e:
-        raise RuntimeError(f"Invalid {loc_str} match_expr '{match_str}': {e}")
+        raise RuntimeError(f"Invalid {loc_str} match_expr '{match_str}': {e}") from e
 
     # Validate the match(job, glidein) from the policy modules
     for pmodule in policy_modules:
@@ -118,9 +118,9 @@ def validate_match(loc_str, match_str, factory_attrs, job_attrs, attr_dict, poli
         except KeyError as e:
             raise RuntimeError(
                 f"Error in {loc_str} policy module's {pmodule.name}.match(job, glidein): Missing attribute {e}"
-            )
+            ) from e
         except Exception as e:
-            raise RuntimeError(f"Error in {loc_str} policy module's {pmodule.name}.match(job, glidein): {e}")
+            raise RuntimeError(f"Error in {loc_str} policy module's {pmodule.name}.match(job, glidein): {e}") from e
 
     return
 
@@ -770,7 +770,7 @@ def add_attr_unparsed(attr_name, params, dicts, description):
     try:
         add_attr_unparsed_real(attr_name, params, dicts)
     except RuntimeError as e:
-        raise RuntimeError(f"Error parsing attr {description}[{attr_name}]: {str(e)}")
+        raise RuntimeError(f"Error parsing attr {description}[{attr_name}]: {str(e)}") from e
 
 
 def validate_attribute(attr_name, attr_val):
diff --git a/creation/lib/xmlConfig.py b/creation/lib/xmlConfig.py
index 95d4641ba..12c528199 100644
--- a/creation/lib/xmlConfig.py
+++ b/creation/lib/xmlConfig.py
@@ -217,7 +217,7 @@ def check_sort_key(self):
             try:
                 LIST_TAGS[self.tag](child)
             except KeyError as e:
-                raise RuntimeError(child.err_str('missing "%s" attribute' % e))
+                raise RuntimeError(child.err_str('missing "%s" attribute' % e)) from None
 
     # this creates references into other rather than deep copies for efficiency
     def merge(self, other):
@@ -293,7 +293,7 @@ def validate(self):
         try:
             period = int(self["period"])
         except ValueError:
-            raise RuntimeError(self.err_str("period must be an int"))
+            raise RuntimeError(self.err_str("period must be an int")) from None
 
         if is_exec + is_wrapper + is_tar > 1:
             raise RuntimeError(self.err_str('must be exactly one of type "executable", "wrapper", or "untar"'))
diff --git a/creation/reconfig_glidein b/creation/reconfig_glidein
index 413297b32..36ba7a743 100755
--- a/creation/reconfig_glidein
+++ b/creation/reconfig_glidein
@@ -292,7 +292,7 @@ if __name__ == "__main__":
             main(conf, update_scripts, update_def_cfg, comment=comment)
 
         except RuntimeError as e:
-            raise ReconfigError(str(e))
+            raise ReconfigError(str(e)) from e
 
     except ReconfigError as re:
         print2(re)
diff --git a/factory/glideFactory.py b/factory/glideFactory.py
index 6260ddcc1..79404a9b3 100755
--- a/factory/glideFactory.py
+++ b/factory/glideFactory.py
@@ -3,21 +3,11 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   This is the main of the glideinFactory
 #
 # Arguments:
 #   $1 = glidein submit_dir
-#
-# Author:
-#   Igor Sfiligoi (Apr 9th 2007 - moved old glideFactory to glideFactoryEntry)
-#
 
 import copy
 import fcntl
@@ -168,12 +158,11 @@ def write_descript(glideinDescript, frontendDescript, monitor_dir):
 
 
 def generate_log_tokens(startup_dir, glideinDescript):
-    """
-    Generate the JSON Web Tokens used to authenticate with the remote HTTP log server.
+    """Generate the JSON Web Tokens used to authenticate with the remote HTTP log server.
     Note: tokens are generated for disabled entries too
 
     Args:
-        startup_dir: Path to the glideinsubmit directory
+        startup_dir (str|Path): Path to the glideinsubmit directory
         glideinDescript: Factory config's glidein description object
 
     Returns:
@@ -805,7 +794,6 @@ def increase_process_limit(new_limit=10000):
             logSupport.log.info("Raised RLIMIT_NPROC from %d to %d" % (soft, new_limit))
         except ValueError:
             logSupport.log.info("Warning: could not raise RLIMIT_NPROC " "from %d to %d" % (soft, new_limit))
-
     else:
         logSupport.log.info("RLIMIT_NPROC already %d, not changing to %d" % (soft, new_limit))
 
@@ -969,8 +957,10 @@ def main(startup_dir):
             % (pid_obj.mypid, err)
         )
         raise
+    # TODO: use a single try.. except.. finally when moving to Python 3.8 or above (dropping 3.6)
     try:
         try:
+            # Spawn the EntryGroup processes handling the work
             spawn(
                 sleep_time,
                 advertize_rate,
@@ -981,11 +971,13 @@ def main(startup_dir):
                 restart_attempts,
                 restart_interval,
             )
-        except KeyboardInterrupt as e:
-            raise e
+        # No need for special handling of KeyboardInterrupt
+        # It is not in Exception so it will remain un-handled
+        # except KeyboardInterrupt as e:
+        #   raise e  # raise e is re-raising a different exceptoin from here? Use raise instead?
         except HUPException as e:
             # inside spawn(), outermost try will catch HUPException,
-            # then the code within the finally will run
+            # then the code within the finally clouse of spawn() will run
             # which will terminate glideFactoryEntryGroup children processes
             # and then the following 3 lines will be executed.
             logSupport.log.info("Received SIGHUP, reload config uid = %d" % os.getuid())
@@ -1004,8 +996,12 @@ def main(startup_dir):
                     "/etc/gwms-factory/glideinWMS.xml",
                 ],
             )
-        except:
-            logSupport.log.exception("Exception occurred spawning the factory: ")
+            # TODO: verify. This is invoking reconfig but how is the Factory/EntryGroups re-started?
+            #    Should there be an infinite loop around spawn?
+        except Exception as e:
+            # Exception excludes SystemExit, KeyboardInterrupt, GeneratorExit
+            # Log the exception and exit
+            logSupport.log.exception("Exception occurred spawning the factory: ", e)
     finally:
         pid_obj.relinquish()
 
@@ -1016,14 +1012,18 @@ def main(startup_dir):
 #
 ############################################################
 class HUPException(Exception):
+    """Used to catch SIGHUP and trigger a reconfig"""
+
     pass
 
 
 def termsignal(signr, frame):
+    """Signal handler. Raise KeyboardInterrupt when receiving SIGTERN or SIGQUIT"""
     raise KeyboardInterrupt("Received signal %s" % signr)
 
 
 def hupsignal(signr, frame):
+    """Signal handler. Raise HUPException when receiving SIGHUP. Used to trigger a reconfig and restart."""
     signal.signal(signal.SIGHUP, signal.SIG_IGN)
     raise HUPException("Received signal %s" % signr)
 
diff --git a/factory/glideFactoryCredentials.py b/factory/glideFactoryCredentials.py
index 94ebd438f..5a71ca01c 100644
--- a/factory/glideFactoryCredentials.py
+++ b/factory/glideFactoryCredentials.py
@@ -1,14 +1,6 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
-
-
 import base64
 import gzip
 import io
@@ -191,11 +183,11 @@ def process_global(classad, glidein_descript, frontend_descript):
             msg = "updating credential for %s" % username
             logSupport.log.debug(msg)
             update_credential_file(username, cred_id, cred_data, request_clientname)
-    except:
+    except Exception as e:
         logSupport.log.debug(f"\nclassad {classad}\nfrontend_descript {frontend_descript}\npub_key_obj {pub_key_obj})")
         error_str = "Error occurred processing the globals classads."
         logSupport.log.exception(error_str)
-        raise CredentialError(error_str)
+        raise CredentialError(error_str) from e
 
 
 def get_key_obj(pub_key_obj, classad):
@@ -211,11 +203,11 @@ def get_key_obj(pub_key_obj, classad):
         try:
             sym_key_obj = pub_key_obj.extract_sym_key(classad["ReqEncKeyCode"])
             return sym_key_obj
-        except:
+        except Exception as e:
             logSupport.log.debug(f"\nclassad {classad}\npub_key_obj {pub_key_obj}\n")
             error_str = "Symmetric key extraction failed."
             logSupport.log.exception(error_str)
-            raise CredentialError(error_str)
+            raise CredentialError(error_str) from e
     else:
         error_str = "Classad does not contain a key.  We cannot decrypt."
         raise CredentialError(error_str)
diff --git a/factory/glideFactoryDowntimeLib.py b/factory/glideFactoryDowntimeLib.py
index eba605d17..3a2906947 100644
--- a/factory/glideFactoryDowntimeLib.py
+++ b/factory/glideFactoryDowntimeLib.py
@@ -1,19 +1,9 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   This module implements the functions needed to
 #   handle the downtimes
-#
-# Author:
-#   Igor Sfiligoi (July 7th 2008)
-#
 
 import fcntl
 import os.path
@@ -22,22 +12,38 @@
 from glideinwms.lib import timeConversion
 
 
-#
-# Handle a downtime file
-#
-# Each line in the file has two entries
-# start_time   end_time
-# expressed in utime
-# if end_time is None, the downtime does not have a set expiration
-#  (i.e. it runs forever)
 class DowntimeFile:
+    """Handle a downtime file
+
+    space separated  file with downtime information
+    Each line has space-separated values
+    The first line is a comment (starts with #) and header line :
+     "#%-29s %-30s %-20s %-30s %-20s # %s\n" % ("Start", "End", "Entry", "Frontend", "Sec_Class", "Comment")
+    Each non-comment line in the file has at least two entries
+      start_time   end_time
+      expressed in utime
+    if end_time is None, the downtime does not have a set expiration
+    (i.e. it runs forever)
+    Additional entries are used to limit the scope (Entry, Frontend, Sec_Class) and to add a comment
+    """
+
     def __init__(self, fname):
         self.fname = fname
 
-    # return a list of downtime periods (utimes)
-    # a value of None idicates "forever"
-    # for example: [(1215339200,1215439170),(1215439271,None)]
     def read(self, raise_on_error=False):
+        """Return a list of downtime periods (utimes)
+        a value of None idicates "forever"
+        for example: `[(1215339200,1215439170),(1215439271,None)]`
+
+        Args:
+            raise_on_error (bool): if not True mask all the exceptions
+
+        Returns:
+            list: list of downtime periods [(start, end), ...]
+                a value of None idicates "forever", no start time, or no end time
+                timestamps are in seconds from epoch (utime)
+                `[]` returned when `raise_on_error` is False (default) and there is no downtime file
+        """
         return read(self.fname, raise_on_error)
 
     def printDowntime(self, entry="Any", check_time=None):
@@ -49,14 +55,27 @@ def checkDowntime(self, entry="Any", frontend="Any", security_class="Any", check
         self.downtime_comment = msg
         return rtn
 
-    # add a scheduled downtime
     def addPeriod(
         self, start_time, end_time, entry="All", frontend="All", security_class="All", comment="", create_if_empty=True
     ):
+        """Add a scheduled downtime
+        Maintin a lock (fcntl.LOCK_EX) on the downtime file while writing
+        entry, frontend, and security_class default to "All"
+
+        Args:
+            start_time (int): start time in seconds from Epoch
+            end_time (int): end time in seconds from Epoch
+            entry (str): entry  name or "All"
+            frontend (str): frontend name os "All"
+            security_class (str): security class name or "All"
+            comment (str): comment to add
+            create_if_empty (bool): if False, raise FileNotFoundError if there is not already a downtime file
+
+        Returns:
+            int: 0
+        """
         return addPeriod(self.fname, start_time, end_time, entry, frontend, security_class, comment, create_if_empty)
 
-    # start a downtime that we don't know when it will end
-    # if start_time==None, use current time
     def startDowntime(
         self,
         start_time=None,
@@ -67,17 +86,55 @@ def startDowntime(
         comment="",
         create_if_empty=True,
     ):
+        """start a downtime that we don't know when it will end
+        if start_time==None, use current time
+        entry, frontend, and security_class default to "All"
+
+        Args:
+            start_time (int|None): start time in seconds from Epoch
+            end_time (int|None): end time in seconds from Epoch
+            entry (str): entry  name or "All"
+            frontend (str): frontend name os "All"
+            security_class (str): security class name or "All"
+            comment (str): comment to add
+            create_if_empty (bool): if False, raise FileNotFoundError if there is not already a downtime file
+
+        Returns:
+
+        """
         if start_time is None:
             start_time = int(time.time())
         return self.addPeriod(start_time, end_time, entry, frontend, security_class, comment, create_if_empty)
 
-    # end a downtime (not a scheduled one)
-    # if end_time==None, use current time
     def endDowntime(self, end_time=None, entry="All", frontend="All", security_class="All", comment=""):
+        """End a downtime (not a scheduled one)
+        if end_time==None, use current time
+        entry, frontend, and security_class default to "All"
+
+        Args:
+            end_time (int|None): end time in seconds from Epoch. If end_time==None, default, use current time
+            entry (str): entry  name or "All"
+            frontend (str): frontend name os "All"
+            security_class (str): security class name or "All"
+            comment (str): comment to add
+
+        Returns:
+            int: number of records closed
+        """
         return endDowntime(self.fname, end_time, entry, frontend, security_class, comment)
 
-    # if cut time<0, use current_time-abs(cut_time)
     def purgeOldPeriods(self, cut_time=None, raise_on_error=False):
+        """Purge old downtime periods
+        if cut time<0, use current_time-abs(cut_time)
+
+        Args:
+            cut_time (int): cut time in seconds from epoch, if cut_time==None or 0, use current time,
+                if cut time<0, use current_time-abs(cut_time)
+            raise_on_error (bool): if not True, mask all exceptions
+
+        Returns:
+            int: number of records purged
+        """
         return purgeOldPeriods(self.fname, cut_time, raise_on_error)
 
 
@@ -85,17 +142,29 @@ def purgeOldPeriods(self, cut_time=None, raise_on_error=False):
 # INTERNAL - Do not use
 #############################
 
-# return a list of downtime periods (utimes)
-# a value of None idicates "forever"
-# for example: [(1215339200,1215439170),(1215439271,None)]
+
 def read(fname, raise_on_error=False):
+    """Return a list of downtime periods (utimes)
+    a value of None idicates "forever"
+    for example: `[(1215339200,1215439170),(1215439271,None)]`
+
+    Args:
+        fname (str|Path): downtimes file
+        raise_on_error (bool): if not True mask all the exceptions
+
+    Returns:
+        list: list of downtime periods [(start, end), ...]
+            a value of None idicates "forever", no start time, or no end time
+            timestamps are in seconds from epoch (utime)
+            `[]` returned when `raise_on_error` is False (default) and there is no file
+    """
     try:
         with open(fname) as fd:
             fcntl.flock(fd, fcntl.LOCK_SH)
             lines = fd.readlines()
     except OSError as e:
         if raise_on_error:
-            raise
+            raise  # re-rise the exact same exception like no except
         else:
             return []  # no file -> no downtimes
 
@@ -120,7 +189,7 @@ def read(fname, raise_on_error=False):
             start_time = timeConversion.extractISO8601_Local(arr[0])
         except ValueError as e:
             if raise_on_error:
-                raise ValueError("%s:%i: 1st element: %s" % (fname, lnr, e))
+                raise ValueError("%s:%i: 1st element: %s" % (fname, lnr, e)) from e
             else:
                 continue  # ignore errors
 
@@ -131,7 +200,7 @@ def read(fname, raise_on_error=False):
                 end_time = timeConversion.extractISO8601_Local(arr[1])
         except ValueError as e:
             if raise_on_error:
-                raise ValueError("%s:%i: 2nd element: %s" % (fname, lnr, e))
+                raise ValueError("%s:%i: 2nd element: %s" % (fname, lnr, e)) from e
             else:
                 continue  # ignore errors
 
@@ -191,8 +260,22 @@ def printDowntime(fname, entry="Any", check_time=None):
                 print("%-30s Up  \tAll:All" % (entry))
 
 
-# if check_time==None, use current time
 def checkDowntime(fname, entry="Any", frontend="Any", security_class="Any", check_time=None):
+    """Check if there is a downtime at `check_time`
+    if check_time==None, use current time
+    "All" (default) is a wildcard for entry, frontend and security_class
+
+    Args:
+        fname (str|Path): Downtime file
+        entry (str): entry  name or "All"
+        frontend (str): frontend name os "All"
+        security_class (str): security class name or "All"
+        check_time: time to check in seconds from epoch, if check_time==None, use current time
+
+    Returns:
+        (str, bool): tuple with the comment string and True is in downtime
+            or ("", False) is not in downtime
+    """
     if check_time is None:
         check_time = int(time.time())
     time_list = read(fname)
@@ -224,9 +307,25 @@ def checkDowntime(fname, entry="Any", frontend="Any", security_class="Any", chec
 def addPeriod(
     fname, start_time, end_time, entry="All", frontend="All", security_class="All", comment="", create_if_empty=True
 ):
+    """Add a downtime period
+    Maintin a lock (fcntl.LOCK_EX) on the downtime file while writing
+
+    Args:
+        fname (str|Path): downtime file
+        start_time (int): start time in seconds from Epoch
+        end_time (int): end time in seconds from Epoch
+        entry (str): entry  name or "All"
+        frontend (str): frontend name os "All"
+        security_class (str): security class name or "All"
+        comment (str): comment to add
+        create_if_empty (bool): if False, raise FileNotFoundError if there is not already a downtime file
+
+    Returns:
+        int: 0
+    """
     exists = os.path.isfile(fname)
     if (not exists) and (not create_if_empty):
-        raise OSError("[Errno 2] No such file or directory: '%s'" % fname)
+        raise FileNotFoundError("[Errno 2] No such file or directory: '%s'" % fname)
 
     comment = comment.replace("\n", " ")
     comment = comment.replace("\r", " ")
@@ -256,9 +355,20 @@ def addPeriod(
     return 0
 
 
-# if cut_time==None or 0, use current time
-# if cut time<0, use current_time-abs(cut_time)
 def purgeOldPeriods(fname, cut_time=None, raise_on_error=False):
+    """Purge old rules using cut_time
+    if cut_time==None or 0, use current time
+    if cut time<0, use current_time-abs(cut_time)
+
+    Args:
+        fname (str|Path): downtime file
+        cut_time (int): cut time in seconds from epoch, if cut_time==None or 0, use current time,
+            if cut time<0, use current_time-abs(cut_time)
+        raise_on_error (bool): if not True, mask all exceptions
+
+    Returns:
+        int: number of records purged
+    """
     if cut_time is None:
         cut_time = int(time.time())
     elif cut_time <= 0:
@@ -268,7 +378,7 @@ def purgeOldPeriods(fname, cut_time=None, raise_on_error=False):
         fd = open(fname, "r+")
     except OSError as e:
         if raise_on_error:
-            raise
+            raise  # re-rise the exact same exception like no except
         else:
             return 0  # no file -> nothing to purge
     with fd:
@@ -303,7 +413,7 @@ def purgeOldPeriods(fname, cut_time=None, raise_on_error=False):
                     end_time = timeConversion.extractISO8601_Local(arr[1])
             except ValueError as e:
                 if raise_on_error:
-                    raise ValueError("%s:%i: 2nd element: %s" % (fname, lnr, e))
+                    raise ValueError("%s:%i: 2nd element: %s" % (fname, lnr, e)) from e
                 else:
                     outlines.append(long_line)
                     continue  # unknown, pass on
@@ -328,9 +438,22 @@ def purgeOldPeriods(fname, cut_time=None, raise_on_error=False):
     return cut_nr
 
 
-# end a downtime (not a scheduled one)
-# if end_time==None, use current time
 def endDowntime(fname, end_time=None, entry="All", frontend="All", security_class="All", comment=""):
+    """End a downtime (not a scheduled one)
+    if end_time==None, use current time
+    "All" (default) is a wildcard for entry, frontend and security_class
+
+    Args:
+        fname (str|Path): Downtime file
+        end_time (int): end time in seconds from epoch, if end_time==None, use current time
+        entry (str): entry  name or "All"
+        frontend (str): frontend name os "All"
+        security_class (str): security class name or "All"
+        comment (str): comment to add
+
+    Returns:
+        int: Number of downtime records closed
+    """
     comment = comment.replace("\r", " ")
     comment = comment.replace("\n", " ")
     if end_time is None:
diff --git a/factory/glideFactoryEntry.py b/factory/glideFactoryEntry.py
index 6973537d4..dce9d187a 100644
--- a/factory/glideFactoryEntry.py
+++ b/factory/glideFactoryEntry.py
@@ -3,15 +3,8 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   Entry class
-#
 
 
 import copy
@@ -375,7 +368,7 @@ def queryQueuedGlideins(self):
             self.log.info("Schedd %s not responding, skipping" % self.scheddName)
             tb = traceback.format_exception(sys.exc_info()[0], sys.exc_info()[1], sys.exc_info()[2])
             self.log.warning("getCondorQData failed, traceback: %s" % "".join(tb))
-            raise e
+            raise
 
     def glideinsWithinLimits(self, condorQ):
         """
diff --git a/factory/glideFactoryInterface.py b/factory/glideFactoryInterface.py
index fc2013f26..b25008a23 100644
--- a/factory/glideFactoryInterface.py
+++ b/factory/glideFactoryInterface.py
@@ -1,19 +1,9 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   This module implements the functions needed to advertize
 #   and get commands from the Collector
-#
-# Author:
-#   Igor Sfiligoi (Sept 7th 2006)
-#
 
 import fcntl
 import os
diff --git a/factory/glideFactoryLib.py b/factory/glideFactoryLib.py
index c20c20fe1..f5111f748 100644
--- a/factory/glideFactoryLib.py
+++ b/factory/glideFactoryLib.py
@@ -1571,21 +1571,32 @@ def escapeParam(param_str):
 
 
 def executeSubmit(log, factoryConfig, username, schedd, exe_env, submitFile):
+    """Submit Glideins using the `condor_submit` command in a custom environment
+
+    Args:
+        log: logger to use
+        factoryConfig:
+        username:
+        schedd (str): HTCSS schedd name
+        exe_env (list): environment list
+        submitFile (str): path os the submit file
+
+    Returns:
+        list: list of submitted Glideins
+    """
     # check to see if the username for the proxy is
     # same as the factory username
+    submit_out = []
     try:
         submit_out = condorExe.iexe_cmd(f"condor_submit -name {schedd} {submitFile}", child_env=env_list2dict(exe_env))
-
     except condorExe.ExeError as e:
-        submit_out = []
         msg = "condor_submit failed: %s" % str(e)
         log.error(msg)
-        raise RuntimeError(msg)
+        raise RuntimeError(msg) from e
     except Exception as e:
-        submit_out = []
         msg = "condor_submit failed: Unknown error: %s" % str(e)
         log.error(msg)
-        raise RuntimeError(msg)
+        raise RuntimeError(msg) from e
     return submit_out
 
 
@@ -1602,17 +1613,17 @@ def submitGlideins(
     log=logSupport.log,
     factoryConfig=None,
 ):
-
-    """Submit the glidein
+    """Submit the Glideins
+    Calls `executeSubmit` to run the HTCSS command
 
     Args:
         entry_name (str):
-        client_name (str):
+        client_name (str): client (e.g. Frontend group) name
         nr_glideins (int):
         idle_lifetime (int):
         frontend_name (str):
         submit_credentials (dict):
-        client_web client_web (str): None means client did not pass one, backwards compatibility
+        client_web (str): None means client did not pass one, backwards compatibility
         params:
         status_sf (dict): keys are GlideinEntrySubmitFile(s) and values is a  jobStatus/numJobs dict
         log:
@@ -1646,11 +1657,11 @@ def submitGlideins(
             log=log,
             factoryConfig=factoryConfig,
         )
-    except:
+    except Exception as e:
         msg = "Failed to setup execution environment."
         log.error(msg)
         log.exception(msg)
-        raise RuntimeError(msg)
+        raise RuntimeError(msg) from e
 
     if username != MY_USERNAME:
         # need to push all the relevant env variables through
@@ -1702,14 +1713,22 @@ def submitGlideins(
         log.info("Submitted %i glideins to %s: %s" % (len(submitted_jids), schedd, submitted_jids))
 
 
-# remove the glideins in the list
 def removeGlideins(schedd_name, jid_list, force=False, log=logSupport.log, factoryConfig=None):
-    ####
-    # We are assuming the gfactory to be
-    # a condor superuser and thus does not need
-    # identity switching to remove jobs
-    ####
+    """Remove the Glideins in the list
 
+    We are assuming the gfactory to be a condor superuser or the only user owning jobs (Glideins)
+    and thus does not need identity switching to remove jobs
+
+    Args:
+        schedd_name (str): HTCSS schedd name
+        jid_list:
+        force:
+        log:
+        factoryConfig:
+
+    Returns:
+        None
+    """
     if factoryConfig is None:
         factoryConfig = globals()["factoryConfig"]
 
@@ -1746,14 +1765,21 @@ def removeGlideins(schedd_name, jid_list, force=False, log=logSupport.log, facto
     log.info("Removed %i glideins on %s: %s" % (len(removed_jids), schedd_name, removed_jids))
 
 
-# release the glideins in the list
 def releaseGlideins(schedd_name, jid_list, log=logSupport.log, factoryConfig=None):
-    ####
-    # We are assuming the gfactory to be
-    # a condor superuser and thus does not need
-    # identity switching to release jobs
-    ####
+    """Release the glideins in the list
+
+    We are assuming the gfactory to be a condor superuser or the only user owning jobs (Glideins)
+    and thus does not need identity switching to release jobs
+
+    Args:
+        schedd_name:
+        jid_list:
+        log:
+        factoryConfig:
 
+    Returns:
+
+    """
     if factoryConfig is None:
         factoryConfig = globals()["factoryConfig"]
 
@@ -2017,10 +2043,13 @@ def get_submit_environment(
                 msg = "Error setting up submission environment (bad key)"
                 log.debug(msg)
                 log.exception(msg)
+                # Known error, can continue without the missing elements
+                #  (from the one missing to the end of the section)
             except Exception:
                 msg = "Error setting up submission environment (in %s section)" % grid_type
                 log.debug(msg)
                 log.exception(msg)
+                # Unknown error, re-raise to stop the environment build
                 raise
         else:
             proxy = submit_credentials.security_credentials.get("SubmitProxy", "")
@@ -2054,6 +2083,7 @@ def get_submit_environment(
         msg = "Error setting up submission environment: %s" % str(e)
         log.debug(msg)
         log.exception(msg)
+        # Exception logged, continuing. No valid environment, returning None
 
 
 def isGlideinWithinHeldLimits(jobInfo, factoryConfig=None):
diff --git a/factory/tools/lib/gWftArgsHelper.py b/factory/tools/lib/gWftArgsHelper.py
index d01869287..07645f68f 100644
--- a/factory/tools/lib/gWftArgsHelper.py
+++ b/factory/tools/lib/gWftArgsHelper.py
@@ -1,22 +1,15 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   Argument parser helper
-#
 
 
 def str2int_range(str, min, max):
     try:
         val = int(str)
     except ValueError as e:
-        raise ValueError("Must be a number.")
+        raise ValueError("Must be a number.") from None
     if (val < min) or (val > max):
         raise ValueError("Must be in the range %i-%i." % (min, max))
     return val
@@ -36,12 +29,12 @@ def parse_date(str):
     try:
         mon = str2int_range(arr[1], 1, 12)
     except ValueError as e:
-        raise ValueError(f"Invalid month '{arr[1]}'. {e}")
+        raise ValueError(f"Invalid month '{arr[1]}'. {e}") from None
 
     try:
         day = str2int_range(arr[2], 1, 31)
     except ValueError as e:
-        raise ValueError(f"Invalid day '{arr[2]}'. {e}")
+        raise ValueError(f"Invalid day '{arr[2]}'. {e}") from None
 
     return (year, mon, day)
 
@@ -53,16 +46,16 @@ def parse_time(str):
     try:
         hour = str2int_range(arr[0], 0, 23)
     except ValueError as e:
-        raise ValueError(f"Invalid hour '{arr[0]}'. {e}")
+        raise ValueError(f"Invalid hour '{arr[0]}'. {e}") from None
 
     try:
         min = str2int_range(arr[1], 0, 59)
     except ValueError as e:
-        raise ValueError(f"Invalid minute '{arr[1]}'. {e}")
+        raise ValueError(f"Invalid minute '{arr[1]}'. {e}") from None
 
     try:
         sec = str2int_range(arr[2], 0, 59)
     except ValueError as e:
-        raise ValueError(f"Invalid second '{arr[2]}'. {e}")
+        raise ValueError(f"Invalid second '{arr[2]}'. {e}") from None
 
     return (hour, min, sec)
diff --git a/lib/classadSupport.py b/lib/classadSupport.py
index e45612b79..a9ebc84eb 100644
--- a/lib/classadSupport.py
+++ b/lib/classadSupport.py
@@ -1,15 +1,8 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
 # Description: This module describes base classes for classads and advertisers
-#
-# Author:
-#   Parag Mhashilkar
-#
+
 
 import os
 import string
@@ -79,7 +72,7 @@ def writeToFile(self, filename, append=True):
 
         try:
             f = open(filename, o_flag)
-        except:
+        except Exception:
             raise
 
         with f:
diff --git a/lib/condorExe.py b/lib/condorExe.py
index 1d1b63fe2..a64d2a71a 100644
--- a/lib/condorExe.py
+++ b/lib/condorExe.py
@@ -1,18 +1,8 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   This module implements the functions to execute condor commands
-#
-# Author:
-#   Igor Sfiligoi (Sept 7th 2006)
-#
 
 
 import os
@@ -162,9 +152,9 @@ def iexe_cmd(cmd, stdin_data=None, child_env=None):
         try:
             logSupport.log.error(msg)
             logSupport.log.debug(generate_bash_script(cmd, os.environ))
-        except:
+        except Exception:
             pass
-        raise ExeError(msg)
+        raise ExeError(msg) from ex
 
     return stdout_data.splitlines()
 
diff --git a/lib/condorLogParser.py b/lib/condorLogParser.py
index ced47ff73..3b1d04810 100644
--- a/lib/condorLogParser.py
+++ b/lib/condorLogParser.py
@@ -1,19 +1,9 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #   This module implements classes and functions to parse
 #   the condor log files.
-#
-# Author:
-#   Igor Sfiligoi (Feb 1st 2007)
-#
 
 # NOTE:
 # Inactive files are log files that have only completed or removed entries
@@ -1384,8 +1374,8 @@ def loadCache(fname):
     """
     try:
         data = util.file_pickle_load(fname)
-    except Exception:
-        raise RuntimeError("Could not read %s" % fname)
+    except Exception as e:
+        raise RuntimeError("Could not read %s" % fname) from e
     return data
 
 
diff --git a/lib/condorMonitor.py b/lib/condorMonitor.py
index 45cdba314..b05e2f927 100644
--- a/lib/condorMonitor.py
+++ b/lib/condorMonitor.py
@@ -390,7 +390,7 @@ def executeAll(self, joblist=None, attributes=None, values=None):
                 "Error querying schedd %s in pool %s using python bindings (qedit of job/attr/val %s/%s/%s): %s"
                 % (s, p, j1, j2, j3, ex)
             )
-            raise QueryError(err_str)
+            raise QueryError(err_str) from ex
 
 
 #
@@ -502,7 +502,7 @@ def fetch(self, constraint=None, format_list=None):
                 "Error executing htcondor query to pool %s with constraint %s and format_list %s: %s. Env is %s"
                 % (self.pool_name, constraint, format_list, ex, os.environ)
             )
-            raise QueryError(err_str).with_traceback(sys.exc_info()[2])
+            raise QueryError(err_str) from ex
 
     def fetch_using_exe(self, constraint=None, format_list=None):
         """Return the results obtained from executing the HTCondor query command
@@ -648,7 +648,7 @@ def fetch_using_bindings(self, constraint=None, format_list=None):
             if self.pool_name is not None:
                 p = self.pool_name
             err_str = f"Error querying schedd {s} in pool {p} using python bindings: {ex}"
-            raise PBError(err_str).with_traceback(sys.exc_info()[2])
+            raise PBError(err_str) from ex
         finally:
             self.security_obj.restore_state()
 
@@ -698,7 +698,7 @@ def fetch_using_bindings(self, constraint=None, format_list=None):
             if self.pool_name is not None:
                 p = self.pool_name
             err_str = f"Error querying pool {p} using python bindings: {ex}"
-            raise PBError(err_str).with_traceback(sys.exc_info()[2])
+            raise PBError(err_str) from ex
         finally:
             self.security_obj.restore_state()
 
@@ -988,9 +988,9 @@ def xml2list(xml_data):
         try:
             p.Parse(" ".join(xml_data[found_xml:]), 1)
         except TypeError as e:
-            raise RuntimeError("Failed to parse XML data, TypeError: %s" % e)
-        except:
-            raise RuntimeError("Failed to parse XML data, generic error")
+            raise RuntimeError("Failed to parse XML data, TypeError: %s" % e) from e
+        except Exception as e:
+            raise RuntimeError("Failed to parse XML data, generic error") from e
     # else no xml, so return an empty list
 
     return xml2list_data
diff --git a/lib/fork.py b/lib/fork.py
index e49c93c4a..25f8a3841 100644
--- a/lib/fork.py
+++ b/lib/fork.py
@@ -96,26 +96,23 @@ def add(i, j): return i+j
 
 ###############################
 def fetch_fork_result(r, pid):
-    """
-    Used with fork clients
+    """Used with fork clients to retrieve results
     Can raise:
     OSError if Bad file descriptor or file already closed or if waitpid syscall returns -1
     FetchError if a os.read error was encountered
-    Possible errors from os.read (catched here):
+    Possible errors from os.read and pickle.load (catched here):
     - EOFError if the forked process failed an nothing was written to the pipe, if cPickle finds an empty string
-    - IOError failure for an I/O-related reason, e.g., "pipe file not found" or "disk full".
-    - OSError other system-related error
-
-    @type r: pipe
-    @param r: Input pipe
+    - IOError failure for an I/O-related reason, e.g., "pipe file not found" or "disk full"
+    - OSError other system-related error (includes both former OSError and IOError since Py3.4)
+    - pickle.UnpicklingError incomplete pickled data
 
-    @type pid: int
-    @param pid: pid of the child
+    Args:
+        r (pipe): Input pipe
+        pid (int): pid of the child
 
-    @rtype: Object
-    @return: Unpickled object
+    Returns:
+        Object: Unpickled object
     """
-
     rin = b""
     out = None
     try:
@@ -129,10 +126,11 @@ def fetch_fork_result(r, pid):
         etype, evalue, etraceback = sys.exc_info()
         # Adding message in case close/waitpid fail and preempt raise
         logSupport.log.exception("Re-raising exception during read: %s" % err)
+        # Removed .with_traceback(etraceback) since already in the chaining
         raise FetchError(
             "Exception during read probably due to worker failure, original exception and trace %s: %s"
             % (etype, evalue)
-        ).with_traceback(etraceback)
+        ) from err
     finally:
         os.close(r)
         os.waitpid(pid, 0)
@@ -140,17 +138,15 @@ def fetch_fork_result(r, pid):
 
 
 def fetch_fork_result_list(pipe_ids):
-    """
-    Read the output pipe of the children, used after forking to perform work
+    """Read the output pipe of the children, used after forking to perform work
     and after forking to entry.writeStats()
 
-    @type pipe_ids: dict
-    @param pipe_ids: Dictinary of pipe and pid
+    Args:
+        pipe_ids (dict): Dictionary of pipe and pid
 
-    @rtype: dict
-    @return: Dictionary of fork_results
+    Returns:
+        dict: Dictionary of fork_results
     """
-
     out = {}
     failures = 0
     failed = []
@@ -179,11 +175,11 @@ def fetch_ready_fork_result_list(pipe_ids):
     on the pipes to consume, read the data and close the pipe.
     and after forking to entry.writeStats()
 
-    @type pipe_ids: dict
-    @param pipe_ids: Dictinary of pipe and pid
+    Args:
+        pipe_ids (dict): Dictionary of pipe and pid
 
-    @rtype: dict
-    @return: Dictionary of work_done
+    Returns:
+        dict: Dictionary of work_done
     """
 
     # Timeout for epoll/poll in milliseconds: -1 is blocking, 0 non blocking, >0 timeout
diff --git a/lib/pidSupport.py b/lib/pidSupport.py
index c35feb04b..cc2b1fcf8 100644
--- a/lib/pidSupport.py
+++ b/lib/pidSupport.py
@@ -1,18 +1,8 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description:
 #  Handle pid lock files
-#
-# Author:
-#   Igor Sfiligoi
-#
 
 import fcntl
 import os
@@ -73,9 +63,9 @@ def register(self, pid=None, started_time=None):  # if none, will default to os.
         try:
             fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
             self.lock_in_place = True
-        except OSError:
+        except OSError as e:
             fd.close()
-            raise AlreadyRunning("Another process already running. Unable to acquire lock %s" % self.pid_fname)
+            raise AlreadyRunning("Another process already running. Unable to acquire lock %s" % self.pid_fname) from e
         fd.seek(0)
         fd.truncate()
         fd.write(self.format_pid_file_content())
@@ -152,8 +142,8 @@ def parse_pid_file_content(self, lines):
 
         try:
             pid = int(pidarr[1])
-        except:
-            raise RuntimeError("Corrupted lock file: invalid PID")
+        except Exception:
+            raise RuntimeError("Corrupted lock file: invalid PID") from None
 
         self.mypid = pid
         return
@@ -204,7 +194,7 @@ def parse_pid_file_content(self, lines):
 
         try:
             pid = int(pidarr[1])
-        except:
+        except Exception:
             raise RuntimeError("Corrupted lock file: invalid PID")
 
         pidarr = lines[1].split(":")
@@ -213,8 +203,8 @@ def parse_pid_file_content(self, lines):
 
         try:
             parent_pid = int(pidarr[1])
-        except:
-            raise RuntimeError("Corrupted lock file: invalid Parent PID")
+        except Exception:
+            raise RuntimeError("Corrupted lock file: invalid Parent PID") from None
 
         self.mypid = pid
         self.parent_pid = parent_pid
diff --git a/lib/pubCrypto.py b/lib/pubCrypto.py
index afec97ada..f9211f839 100644
--- a/lib/pubCrypto.py
+++ b/lib/pubCrypto.py
@@ -141,7 +141,7 @@ def __init__(
             # This helps operator understand which file might be corrupted so that they can try to delete it
             e.key_fname = key_fname
             e.cwd = os.getcwd()
-            raise
+            raise e from e  # Need to raise a new exception to have the modified values (only raise keeps the original)
         return
 
     ###########################################
@@ -169,7 +169,7 @@ def load(self, key_str=None, key_fname=None):
                 bio = M2Crypto.BIO.MemoryBuffer(key_str)
                 self._load_from_bio(bio)
             except M2Crypto.RSA.RSAError as e:
-                raise PubCryptoError("M2Crypto.RSA.RSAError: %s" % e)
+                raise PubCryptoError("M2Crypto.RSA.RSAError: %s" % e) from e
         elif key_fname is not None:
             bio = M2Crypto.BIO.openfile(key_fname)
             if bio is None:
diff --git a/lib/subprocessSupport.py b/lib/subprocessSupport.py
index 26c5ff019..4f0fd7362 100644
--- a/lib/subprocessSupport.py
+++ b/lib/subprocessSupport.py
@@ -88,7 +88,7 @@ def iexe_cmd(cmd, useShell=False, stdin_data=None, child_env=None, text=True):
 
     except OSError as e:
         err_str = "Error running '%s'\nStdout:%s\nStderr:%s\nException OSError:%s"
-        raise RuntimeError(err_str % (cmd, stdoutdata, stderrdata, e))
-    if exitStatus:
+        raise RuntimeError(err_str % (cmd, stdoutdata, stderrdata, e)) from e
+    if exitStatus:  # True if exitStatus<>0
         raise CalledProcessError(exitStatus, cmd, output="".join(stderrdata))
     return stdoutdata
diff --git a/lib/symCrypto.py b/lib/symCrypto.py
index a12fbf80f..f8c21e2f2 100644
--- a/lib/symCrypto.py
+++ b/lib/symCrypto.py
@@ -1,13 +1,6 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
-
 """symCrypto - This module defines classes to perform symmetric key cryptography (shared or hidden key)
 
 It uses M2Crypto: https://github.com/mcepl/M2Crypto
diff --git a/lib/util.py b/lib/util.py
index 1ab1360bb..406451f7f 100644
--- a/lib/util.py
+++ b/lib/util.py
@@ -201,11 +201,13 @@ def print_funct(*args, **kwargs):
 def conditional_raise(mask_exceptions):
     """Auxiliary function to handle conditional raising
 
-    :param mask_exceptions: callback function and arguments to use if an exception happens (Default: None)
-      The callback function can access the exception via sys.exc_info()
-      If a function is not provided, the exception is re-risen
-      if provided it is called using mask_exceptions[0](*mask_exceptions[1:])
-    :return: None
+    Args:
+        mask_exceptions: callback function and arguments to use if an exception happens (Default: None)
+            The callback function can access the exception via sys.exc_info()
+            If a function is not provided, the exception is re-risen
+            if provided it is called using mask_exceptions[0](*mask_exceptions[1:])
+    Returns:
+        None
     """
     if mask_exceptions and hasattr(mask_exceptions[0], "__call__"):
         # protect and report
@@ -221,21 +223,24 @@ def file_pickle_dump(fname, content, tmp_type="PID", mask_exceptions=None, proto
     """Serialize and save content
 
     To avoid inconsistent content
-    @param fname: file storing the serialized content
-    @param content: content to serialize
-    @param tmp_type: tmp file type as defined in file_get_tmp (Default: PID, .$PID.tmp suffix)
-    @param mask_exceptions: callback function and arguments to use if an exception happens (Default: None)
-      The callback function can access the exception via sys.exc_info()
-      If a function is not provided, the exception is re-risen
-      if provided it is called using mask_exceptions[0](*mask_exceptions[1:])
-    @param protocol: Pickle protocol to be used (Default: pickle.HIGHEST_PROTOCOL, 5 as of py3.8)
-    @return: True if the saving was successful, False or an exception otherwise
+    Args:
+        fname: file storing the serialized content
+        content: content to serialize
+        tmp_type: tmp file type as defined in file_get_tmp (Default: PID, .$PID.tmp suffix)
+        mask_exceptions: callback function and arguments to use if an exception happens (Default: None)
+          The callback function can access the exception via sys.exc_info()
+          If a function is not provided, the exception is re-risen
+          if provided it is called using mask_exceptions[0](*mask_exceptions[1:])
+        protocol: Pickle protocol to be used (Default: pickle.HIGHEST_PROTOCOL, 5 as of py3.8)
+
+    Returns:
+        bool: True if the saving was successful, False or an exception otherwis
     """
     tmp_fname = file_get_tmp(fname, tmp_type)
     try:
         with open(tmp_fname, "wb") as pfile:
             pickle.dump(content, pfile, protocol)
-    except:
+    except Exception:
         conditional_raise(mask_exceptions)
         return False
     else:
@@ -247,23 +252,28 @@ def file_pickle_load(fname, mask_exceptions=None, default=None, expiration=-1, r
     """Load a serialized dictionary
 
     This implementation does not use file locking, it relies on the atomicity of file movement/replacement and deletion
-    @param fname: name of the file with the serialized data
-    @param mask_exceptions: callback function and arguments to use if an exception happens (Default: None)
-      The callback function can access the exception via sys.exc_info()
-      If a function is not provided, the exception is re-risen
-      if provided it is called using mask_exceptions[0](*mask_exceptions[1:])
-    @param default: value returned if the unpickling fails (Default: None)
-    @param expiration: input file expiration in seconds (Default: -1)
-      -1 file never expires
-      0  file always expires after reading
-    @param remove_expired: remove expired file (Default: False)
-      NOTE: if you remove the obsolete file from the reader you may run into a race condition with undesired effects:
-      1. the reader detects the obsolete file, 2. the writer writes a new version, 3. the reader deletes the new version
-      This can happen only in cycles where there is an obsolete data file to start with, so the number of data files
-      lost because of this is smaller than the occurrences of obsoleted files. When the expiration time is much bigger
-      than the loop time of the writer this is generally acceptable.
-    @param last_time: last time a file has been used, persistent to keep history (Default: {}, first time called)
-    @return: python objects (e.g. data dictionary)
+
+    Args:
+        fname: name of the file with the serialized data
+        mask_exceptions: callback function and arguments to use if an exception happens (Default: None)
+          The callback function can access the exception via sys.exc_info()
+          If a function is not provided, the exception is re-risen
+          if provided it is called using mask_exceptions[0](*mask_exceptions[1:])
+        default: value returned if the unpickling fails (Default: None)
+        expiration (int): input file expiration in seconds (Default: -1)
+          -1 file never expires
+          0  file always expires after reading
+        remove_expired (bool): remove expired file (Default: False)
+          NOTE: if you remove the obsolete file from the reader you may run into a race condition with undesired effects:
+          1. the reader detects the obsolete file, 2. the writer writes a new version, 3. the reader deletes the new version
+          This can happen only in cycles where there is an obsolete data file to start with, so the number of data files
+          lost because of this is smaller than the occurrences of obsoleted files. When the expiration time is much bigger
+          than the loop time of the writer this is generally acceptable.
+        last_time (dict): last time a file has been used, persistent to keep history (Default: {}, first time called)
+          Dictionary file_name->time
+
+    Returns:
+        Object: python objects (e.g. data dictionary)
     """
     data = default
     try:
@@ -293,18 +303,15 @@ def file_pickle_load(fname, mask_exceptions=None, default=None, expiration=-1, r
             # the file produced at the next iteration will be used
             try:
                 os.remove(fname)
-            except:
+            except OSError:
                 pass
         conditional_raise(mask_exceptions)
-    except:
+    except Exception:
         conditional_raise(mask_exceptions)
     return data
 
 
 # One writer, avoid partial write due to code, OS or file system problems
-# from factory/glideFactoryMonitoring
-#     KEL this exact method is also in glideinFrontendMonitoring.py
-# TODO: replace all definitions with this one
 
 
 def file_tmp2final(
@@ -343,7 +350,7 @@ def file_tmp2final(
             pass
     try:
         os.replace(tmp_fname, fname)
-    except:
+    except Exception:
         # print "Failed renaming %s into %s" % (tmp_fname, fname)
         conditional_raise(mask_exceptions)
         return False
@@ -399,7 +406,6 @@ def safe_boolcomp(value, expected):
     Returns:
         bool: True if str(value).lower() is True
     """
-
     return str(value).lower() == str(expected).lower()
 
 
@@ -416,7 +422,6 @@ def str2bool(val):
 
 def handle_hooks(basedir, script_dir):
     """The function itaretes over the script_dir directory and executes any script found there"""
-
     dirname = os.path.join(basedir, script_dir)
     if not os.path.isdir(dirname):
         return
@@ -437,12 +442,10 @@ def hash_nc(data, len=None):
     Returns:
         str: Hash
     """
-
     # TODO set md5 usedforsecurity to False when updating to Python 3.9
     out = b32encode(md5(force_bytes(data)).digest()).decode(BINARY_ENCODING_ASCII)
     if len:
         out = out[:len]
-
     return out
 
 
diff --git a/lib/xmlFormat.py b/lib/xmlFormat.py
index 53d28fb49..dd9408554 100644
--- a/lib/xmlFormat.py
+++ b/lib/xmlFormat.py
@@ -1,17 +1,7 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description: general purpose XML formatter
-#
-# Author:
-#  Igor Sfiligoi (part of the CDF CAF)
-#
 
 
 import string
@@ -46,7 +36,7 @@
 
 ##########################################################
 #
-# The following Global varables are used to set defaults
+# The following Global variables are used to set defaults
 # When the user does not specify anything
 #
 ##########################################################
diff --git a/lib/xmlParse.py b/lib/xmlParse.py
index 2da431995..7f60c518d 100644
--- a/lib/xmlParse.py
+++ b/lib/xmlParse.py
@@ -1,17 +1,7 @@
 # SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
 # SPDX-License-Identifier: Apache-2.0
 
-#
-# Project:
-#   glideinWMS
-#
-# File Version:
-#
 # Description: general purpose XML decoder
-#
-# Author:
-#  Igor Sfiligoi (Mar 27th, 2007)
-#
 
 import xml.dom.minidom
 
@@ -101,7 +91,7 @@ def xmlfile2dict(
     try:
         doc = xml.dom.minidom.parse(fname)
     except xml.parsers.expat.ExpatError as e:
-        raise CorruptXML(f"XML corrupt in file {fname}: {e}")
+        raise CorruptXML(f"XML corrupt in file {fname}: {e}") from e
 
     data = domel2dict(doc.documentElement, use_ord_dict, always_singular_list)