Update yum.py

Re-submission of comments. I've added some extras, done some general tidy up of spaces vs tabs (only spaces used now). This shouldn't now have any conflicts.

lib/python3/cmk/base/plugins/agent_based/yum.py

@@ -25,7 +25,7 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# along with this program. If not, see <http://www.gnu.org/licenses/>
 #
 #
 # Example Agent Output:
@@ -36,10 +36,13 @@
 # 4
 # 1626252300
 
+# Import the ability to manipulate and handle times in python
 from time import time
 
+# Import the ability to set certain types of variable/object
 from typing import Dict, List, NamedTuple, Optional
 
+# Import CheckMK specific libraries
 from cmk.gui.i18n import _
 from cmk.base.plugins.agent_based.agent_based_api.v1.type_defs import (
     StringTable,
@@ -53,19 +56,26 @@
     render,
 )
 
-
+# Set some default values for the plugin
 class Section(NamedTuple):
     reboot_required: Optional[bool]
     packages: int = -1
     security_packages: int = -1
     last_update_timestamp: int = -1
     error_message: Optional[str] = None
 
-
+#### Define the section that processes the output received from the
+#### agent within the 
+# <<<yum>>> section. This is called because we register the "yum"
+# agent section using the API "register" namespace
 def yum_parse(string_table: List[List[str]]) -> Section:
+    # If no results are determined to have been parsed from the agent
+	# <<<yum>>> section, flag it
     if string_table[0][0] == 'ERROR:':
         return Section(error_message=" ".join(string_table[0][1:]))
 
+    # Assess the validity of the "reboot_required" section - default to
+	# "None" if there is an error
     reboot_required = None
     try:
         if string_table[0][0] in ('yes', 'no'):
@@ -83,114 +93,164 @@ def yum_parse(string_table: List[List[str]]) -> Section:
     except KeyError:
         pass
 
+    # Return the processesed values if there has not been an error
     return Section(
         reboot_required,
         packages,
         security_packages,
         last_update_timestamp)
 
-
+#### Register the agent section we want to be referring to
 register.agent_section(
+    # Using the apiv1 "register" namespace we register the "yum" agent
+    # section and it's subsequent processing within this python script
+    # by defining the "parse_funtcion" as "yum_parse"
     name='yum',
     parse_function=yum_parse
 )
 
-
+#### Define what we do when discovery is run
 def discovery_yum(section: Section):
     yield Service()
 
 
-# the check function
+#### Define the check function that is called by the registered
+#### register.check_plugin section
 def check_yum(params: Dict[str, int], section: Section):
-    # Handle error message from agent
+    # Handle error message from agent which is set if the agent output
+    # is not a correct format
     if section.error_message:
         yield Result(state=State.UNKNOWN, summary=section.error_message)
         return
     # Check the status returned from the agent script
-	# Added additional checks to cover off a broader range of possibilities and 
-	# ensure that a value is returned (for the perf-o-meter) even when no updates are available
-	# First check if there was an error returned (-1) where the yum command failed
+    # Added additional checks to cover off a broader range of
+    # possibilities and ensure that a value is returned (for
+    # the perf-o-meter) even when no updates are available
+
+    #### Check the status of "packages" (which is the "total updates
+    #### available")
+    # First check if there was an error returned (-1) where the yum
+    # command failed
     if section.packages < 0:
         yield Result(state=State.UNKNOWN, summary='No package information available')
-	# Then check if there are "no updates of which none are security updates" but DO return a metric value
-	# of zero instead of not having a metric value at all
+    # Then check if there are "no updates of which none are security
+    # updates" but DO return a metric value of zero instead of not
+    # having a metric value at all
     elif section.packages == 0 and section.security_packages == 0:
         yield Result(state=State.OK, summary='All packages are up to date')
         yield Metric(name="normal_updates", value=section.packages)
-	# If there are "any" updates available, report the number of updates
+    # If there are "any" updates available report the number of updates
     elif section.packages > 0:
         yield Result(state=State(params.get("normal", 0)), summary=f"{section.packages} updates available")
         yield Metric(name="normal_updates", value=section.packages)
-    # If there are no updates available, but we haven't been able to check security updates, still return
-	# a metric value of zero
+    # If there are no updates available, but we haven't been able to
+    # check security updates, still return a metric value of zero
     elif section.packages == 0:
         yield Result(state=State.OK, summary=f"{section.packages} updates available")
         yield Metric(name="normal_updates", value=section.packages)
 
 
-    # Check the status of the returned number of updates that are security updates including
-	# error condition and if there are no updates or the security updates check is not possible
-    # First check if ANY updates were flagged as security updates and report the metric
+    # Check the status of the returned number of updates that are
+    # security updates including error condition and if there are no
+    # updates or the security updates check is not possible
+
+    # First check if ANY updates were flagged as security updates
+    # and report the metric
     if section.security_packages >= 0:
         yield Result(state=State(params.get("security", 0)), summary=f"{section.security_packages} security updates available")
         yield Metric(name="security_updates", value=section.security_packages)
     # If there are no updates available, report this
     elif section.security_packages == 0:
         yield Result(state=State.OK, summary=f"{section.security_packages} security updates available")
         yield Metric(name="security_updates", value=section.security_packages)
-    #If the agent reported that security update was not available, return this with a report of 0 updates
+    # If the agent reported that security update was not available,
+    # return this with a report of 0 updates
     elif section.security_packages == -2:
         yield Result(state=State.OK, summary='Security update check not available')
         yield Metric(name="security_updates", value=0)
-	# If the security update check failed with an error, report this AND a value of zero
+    # If the security update check failed with an error,
+    # report this AND a value of zero
     elif section.security_packages == -1:
         yield Metric(name="security_updates", value=0)
         yield Result(state=State.OK, summary='Security update failed')
 
-
-
-
-
-
+        
+    #### Interpret the timestamp that is returned for when the host was
+    #### last updated
+    # If the timestamp is less than zero, report that there is no
+    # valid time stamp
     if section.last_update_timestamp < 0:
         yield Result(
             state=State(params.get("last_update_state", 0)),
             summary=f"{section.last_update_timestamp} Time of last update could not be found")
         yield Metric(name="last_update_timestamp", value=section.last_update_timestamp)
+    # If not a value less than 0, assess the timestamp by first
+    # grabbing all the relevant parameters
     elif section.last_update_timestamp > 0:
+        # Get the default or WATO config state from within CheckMK api
         level = params.get("last_update_state", 0)
+        # Get the threshold for the time we are allowed to be out by
+        # from default or WATO
         last_update_time_diff = params.get("last_update_time_diff", (60*24*60*60))
+        # Get current time so we can assess the age of OUR timestamp
         current_timestamp = int(time())
-
+        # Delta the supplied timestamp and compare it to the target
+        # from the default or WATO. If the last update delta is less
+        # than the configured threshold, report OK
         if current_timestamp - section.last_update_timestamp < last_update_time_diff:
             yield Result(
                 state=State.OK,
                 summary=f"Last Update was run at {render.datetime(section.last_update_timestamp)}")
+        # If the last update delta is outside of the configured
+        # threshold but the number of configured packages is 0 then
+        # still report all is OK, is there is nothing we could possibly
+        # have updated
         elif current_timestamp - section.last_update_timestamp > last_update_time_diff and section.packages == 0:
             yield Result(
                 state=State.OK,
                 summary=f"Last Update was too long ago at {render.datetime(section.last_update_timestamp)} but there are no pending updates")
+        # Otherwise, report the level that is configured in default or
+        # WATO for being outside of the required delta time
         else:
             yield Result(
                 state=State(level),
                 summary=f"Last Update was too long ago at {render.datetime(section.last_update_timestamp)} and there are pending updates")
-
+
+    #### Assess the "reboot_required" parameters
     if section.reboot_required:
         # fallback for < 2.0.6
+        # If the reported value has been anything other than yes or no
+        # then the value will be "None" as defined in the yum_parse
+        # section if it is then report an error
         if params is None:
             level = 2
         else:
             level = params["reboot_req"]
         yield Result(state=State(level),  summary="reboot required")
 
 
-register.check_plugin(
+    #### Use the API v1 "register" namspace to assign the various
+    #### processing sections of this python file to handle that various
+    #### data,
+    # set default parameters and the general details of the service.
+    register.check_plugin(
+    # Set the unique name of the plugin
     name='yum',
+    # Set the service name that is created on a host 
     service_name=_('YUM Updates'),
+    # Set what should be called when discovery is run - in this case,
+    # call "discovery_yum" that simply creates a new service
     discovery_function=discovery_yum,
+    # Set what the "check" function is - in this case, to check the
+    # output from the agent once it has been processed by
+    # "yum_parse" we will run "check_yum"
     check_function=check_yum,
+    # Specify which agent section we need to read
     sections=["yum"],
+    # specify which ruleset to grab parameters from
     check_ruleset_name="yum",
+    # Set the default parameters (which match the ones defined in the
+    # WATO ruleset in yum_check_parameters.py)
     check_default_parameters={
         "reboot_req": 2,
         "normal": 1,