Refactor fw_rules_xml.py to use match/case and fix multiple parsing bugs

[Copilot]

The script was refactored to use match/case statements and split into helper functions, but introduced bugs that prevented correct Excel output generation and caused crashes on missing XML elements.

Changes

Bug Fixes

• Variable initialization: All local variables now initialized to empty strings in helper functions to prevent NameError on missing XML elements
• Safe element access: Replaced unsafe indexed access (element[0].text) with iteration over children:

  # Before (crashes if element structure differs)
  addresses_in_set = addresses_in_set + address_set[0].text + '\n'
  
  # After (safely iterates all children)
  for addr_child in child:
      if addr_child.tag == 'name':
          addresses_in_set += get_text_object(addr_child) + '\n'

• Single-write Excel output: Accumulate all rows during parsing, write each sheet once at end with context manager instead of repeatedly overwriting sheets
• CLI defaults: Initialize inputfile='srx.xml' and outputfile='test.xlsx' before argument parsing

Code Structure

• Split monolithic main() into focused helpers: get_address(), get_application(), get_policy(), get_term(), get_submatch(), etc.
• All functions accept correct element type and return flattened lists matching DataFrame column order
• Consistent use of match/case throughout for tag matching
• Added get_text_object() helper for null-safe text extraction

Documentation

• Updated README with CLI usage examples and output sheet descriptions

Original prompt

The commit f6673e2 refactored fw_rules_xml.py to use match/case and split main() into many functions, and added CLI parsing. However the rewrite introduced multiple bugs and behavioral changes that prevent it from producing the same Excel output and can crash on some inputs. Create a patch that preserves match/case and fixes the following issues so behavior is equivalent to the original script:

Required fixes to implement in the patch:

1. Initialize CLI defaults before getopt parsing and validate values after parsing. Use defaults: inputfile='srx.xml', outputfile='test.xlsx' when flags are not provided.

2. Ensure all local variables that may be referenced without being set are initialized to empty strings at the start of each helper function (e.g., name, description, ip_prefix, addresses_in_set, from_zone_name, to_zone_name, subpol_name, sub_match_source_addr, sub_match_dest_addr, sub_match_app, protocol, source_port, dest_port, term_label, term_label_dest_port, term_label_protocol, application_in_set). This prevents NameError on missing XML elements.

3. Replace indexed child access like element[0] with iteration over child elements and use get_tag_object/get_text_object consistently. E.g., in get_address_set, iterate each 'address' child and extract its text properly.

4. Accumulate rows for Addresses, Address-sets, Applications, Policies, Application-sets in lists and write each sheet once after parsing completes. Do not call df.to_excel repeatedly for the same sheet (which overwrites previous content). Keep using pandas.ExcelWriter with a context manager: with pd.ExcelWriter(outputfile, engine='xlsxwriter') as writer: ...

5. Fix get_term/get_application/get_submatch/get_subpolicy/get_policy signatures and calls so they accept the correct element and return flattened lists matching DataFrame column ordering. Specifically:

   • get_term(term_element): iterate children of and build term_label. Return term_label string.
   • get_application(application): iterate children of , call get_term when encountering a 'term' child, and return flattened list [name, source_port, dest_port, protocol, term_label].
   • get_submatch(subpolicy_match_element): iterate children of and collect source-address, destination-address, application entries as newline-separated strings; return flattened [source_addr_str, dest_addr_str, app_str].
   • get_subpolicy(policy_item): iterate children of sub-element, use get_submatch for 'match', and return flattened [subpol_name, source_addr_str, dest_addr_str, app_str] (or in the order needed by get_policy).
   • get_policy(policy_item): iterate children of and return flattened [from_zone_name, to_zone_name, subpol_name, source_addr_str, dest_addr_str, app_str]. Ensure ordering matches DataFrame columns used when writing Policies.

6. Ensure read flow preserves original traversal ordering: iterate root -> configuration -> children and call the appropriate handlers; those handlers should append rows to the accumulating lists.

7. Use writer.close() implicitly via context manager; write each DataFrame once after accumulation. Use consistent DataFrame column ordering matching the original script: Addresses ['Name','Description','IP Address'], Address-sets ['Name','Description','Addresses'], Policies ['from-zone-name','to-zone-name','name','source-address','destination-address','application'], Applications ['Name','Source Port','Destination Port','Protocol','Term'], Application-sets ['Name','Applications'].

8. Keep match/case usage (Python 3.10+). Add a short comment at top noting Python 3.10+ is required.

Deliverable instructions:

• Update fw_rules_xml.py in-place on a new branch and open a pull request that applies these fixes. The PR should reference commit f6673e2 and explain the changes and why they were necessary.
• Ensure the patch runs without NameError on reasonable sample srx.xml files and produces worksheets with all items (not only last element per sheet).

If additional design choices are needed (e.g., exact term_label formatting), preserve the original format: newline-separated values where the original concatenated with '\n'.

Please create the branch, apply the fixes to fw_rules_xml.py, and open the PR with this problem statement as the description.

This pull request was created as a result of the following prompt from Copilot chat.

The commit f6673e2 refactored fw_rules_xml.py to use match/case and split main() into many functions, and added CLI parsing. However the rewrite introduced multiple bugs and behavioral changes that prevent it from producing the same Excel output and can crash on some inputs. Create a patch that preserves match/case and fixes the following issues so behavior is equivalent to the original script:

Required fixes to implement in the patch:

1. Initialize CLI defaults before getopt parsing and validate values after parsing. Use defaults: inputfile='srx.xml', outputfile='test.xlsx' when flags are not provided.

2. Ensure all local variables that may be referenced without being set are initialized to empty strings at the start of each helper function (e.g., name, description, ip_prefix, addresses_in_set, from_zone_name, to_zone_name, subpol_name, sub_match_source_addr, sub_match_dest_addr, sub_match_app, protocol, source_port, dest_port, term_label, term_label_dest_port, term_label_protocol, application_in_set). This prevents NameError on missing XML elements.

3. Replace indexed child access like element[0] with iteration over child elements and use get_tag_object/get_text_object consistently. E.g., in get_address_set, iterate each 'address' child and extract its text properly.

4. Accumulate rows for Addresses, Address-sets, Applications, Policies, Application-sets in lists and write each sheet once after parsing completes. Do not call df.to_excel repeatedly for the same sheet (which overwrites previous content). Keep using pandas.ExcelWriter with a context manager: with pd.ExcelWriter(outputfile, engine='xlsxwriter') as writer: ...

5. Fix get_term/get_application/get_submatch/get_subpolicy/get_policy signatures and calls so they accept the correct element and return flattened lists matching DataFrame column ordering. Specifically:

   • get_term(term_element): iterate children of and build term_label. Return term_label string.
   • get_application(application): iterate children of , call get_term when encountering a 'term' child, and return flattened list [name, source_port, dest_port, protocol, term_label].
   • get_submatch(subpolicy_match_element): iterate children of and collect source-address, destination-address, application entries as newline-separated strings; return flattened [source_addr_str, dest_addr_str, app_str].
   • get_subpolicy(policy_item): iterate children of sub-element, use get_submatch for 'match', and return flattened [subpol_name, source_addr_str, dest_addr_str, app_str] (or in the order needed by get_policy).
   • get_policy(policy_item): iterate children of and return flattened [from_zone_name, to_zone_name, subpol_name, source_addr_str, dest_addr_str, app_str]. Ensure ordering matches DataFrame columns used when writing Policies.

6. Ensure read flow preserves original traversal ordering: iterate root -> configuration -> children and call the appropriate handlers; those handlers should append rows to the accumulating lists.

7. Use writer.close() implicitly via context manager; write each DataFrame once after accumulation. Use consistent DataFrame column ordering matching the original script: Addresses ['Name','Description','IP Address'], Address-sets ['Name','Description','Addresses'], Policies ['from-zone-name','to-zone-name','name','source-address','destination-address','application'], Applications ['Name','Source Port','Destination Port','Protocol','Term'], Application-sets ['Name','Applications'].

8. Keep match/case usage (Python 3.10+). Add a short comment at top noting Python 3.10+ is required.

Deliverable instructions:

• Update fw_rules_xml.py in-place on a new branch and open a pull request that applies these fixes. The PR should reference commit f6673e2 and explain the changes and why they were necessary.
• Ensure the patch runs without NameError on reasonable sample srx.xml files and produces worksheets with all items (not only last element per sheet).

If additional design choices are needed (e.g., exact term_label formatting), preserve the original format: newline-separated values where the original concatenated with '\n'.

Please create the branch, apply the fixes to fw_rules_xml.py, and open the PR with this problem statement as the description.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.