lxml_parsing_with_periods.py

from lxml import etree, objectify

with open("config_no_build_trigger.xml") as xml_file:
    config = xml_file.read()

root = objectify.fromstring(config.encode())

try:
    _ = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
except AttributeError:
    # Add org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty
    # XML element
    root.properties.__setattr__("org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty", "")

try:
    trigger_prop = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    _ = trigger_prop.triggers
except AttributeError:
    # Add trigger XML element
    trigger_prop = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    _ = trigger_prop.triggers = objectify.Element("triggers")

try:
    trigger_prop = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    _ = trigger_prop.triggers.__getattr__("hudson.triggers.TimerTrigger")
except AttributeError:
    # Add hudson.triggers.TimerTrigger XML element
    trigger_prop = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    _ = trigger_prop.triggers.__setattr__("hudson.triggers.TimerTrigger", "")

try:
    trigger = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    trigger.triggers.__getattr__(
        "hudson.triggers.TimerTrigger"
    ).spec
except AttributeError:
    # Add spec XML element
    trigger = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    trigger.triggers.__getattr__(
        "hudson.triggers.TimerTrigger"
    ).spec = objectify.Element("spec")

# Modify the schedule
try:
    trigger = root.properties.__getattr__(
        "org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty"
    )
    trigger.triggers.__getattr__(
        "hudson.triggers.TimerTrigger"
    ).spec = "H 18 * * *"
except AttributeError:
    print(f"ERROR: Unable to add schedule!")

objectify.deannotate(root)
etree.cleanup_namespaces(root)

config_xml = etree.tostring(root, pretty_print=True, encoding=str)
with open("new_config.xml", "w") as xml_file:
    xml_file.write(config_xml)