Performance Improvements and Bug Fixes

[mikewiebe]

Summary

This PR improves performance and fixes idempotence and diff-calculation issues in dcnm_interface, dcnm_inventory, and dcnm_network. The changes focus on reducing expensive repeated controller calls, correcting merge behavior when controller payloads are incomplete, and preserving TOR attachments correctly across VPC and non-VPC topologies.

Changes

• dcnm_interface: Added bulk interface retrieval via IF_WITH_SNO and introduced per-switch/per-interface caching so merged, deleted, and overridden workflows can avoid repeated per-interface GET calls.
• dcnm_interface: Prefetches interface policy details up front for targeted switches, including VPC and AA_FEX cases, so diff generation uses cached lookups instead of repeated controller round-trips.
• dcnm_interface: Reworked overridden-state lookup paths to use precomputed sets and dictionaries for direct interface, member, and VPC peer/member checks, reducing repeated linear scans during replace/default calculations.
• dcnm_interface: Flattened delete-deploy requests into a single deploy payload instead of posting multiple interface-type-specific deploy calls.
• dcnm_interface: Limited the extra follow-up deploy call to check_deploy=true, avoiding unnecessary deploy retries when deployment verification is not requested.
• dcnm_interface: Fixed merged diff handling when optional nvPairs keys are missing from the current controller payload, so playbook-specified values such as native VLAN settings are still reconciled correctly.
• dcnm_inventory: Added cached inventory lookup by IP and cached POAP inventory lookup by serial number to eliminate repeated scans of controller responses.
• dcnm_inventory: Reused existing inventory data for already-known switches during create flows so the module can skip unnecessary test-reachability calls in idempotent and no-op scenarios.
• dcnm_inventory: Added helpers to iterate and group create payloads, then consolidated switch imports by shared role/configuration to reduce redundant work and improve diff formatting.
• dcnm_inventory: Optimized rediscovery, switch health polling, LAN credential lookup, and role assignment by replacing repeated nested loops with set- and dict-based lookups.
• dcnm_inventory: Batched ND role assignments into a single API call instead of posting per switch.
• dcnm_inventory: Reduced retry windows for role-assignment polling and config-save retries while keeping bounded retry behavior.
• dcnm_inventory: Fixed save/deploy-only reruns so a second merged call can still honor save and deploy even when there is no new create diff.
• dcnm_network: Added logical-name inventory mapping so attachment parsing can distinguish leaf interface ports from TOR interface ports when reading portNames from controller state.
• dcnm_network: Added VPC TOR normalization so one-sided tor_ports intent in the playbook is mirrored across VPC peers before diffing.
• dcnm_network: Fixed merged TOR-port handling so merged updates append new TOR ports without dropping existing ones.
• dcnm_network: Preserved original attachment state during VPC peer backfill so merged and replaced flows do not accidentally blank peer TOR attachments.
• dcnm_network: Improved parsing of controller attachment state so TOR-only and mixed leaf/TOR attachment strings are converted back into the correct internal model.

Test Coverage

• Added and updated unit coverage for dcnm_interface bulk-fetch caching, grouped interface payloads, overridden-state lookup behavior, and the merged missing-native-VLAN regression.
• Added unit fixtures and regression tests for dcnm_network TOR attachment handling, including:
  • VPC leaf pair connected to a TOR pair
  • VPC leaf pair connected to a single TOR
  • Single leaf connected to a single TOR
  • TOR-only merged updates and idempotence
• Expanded integration coverage in tests/integration/targets/dcnm_network/tests/dcnm/standalone/merged.yaml to validate merged behavior, preserved TOR ports, controller query state, and idempotence across all three supported TOR topologies.

Impact

• Improves controller interaction efficiency for large interface and inventory operations.
• Fixes merged-state behavior when current controller payloads omit optional interface keys.
• Fixes TOR attachment merge and replace behavior so existing TOR ports are not removed unexpectedly.
• Strengthens unit and integration coverage around the performance changes and TOR/VPC attachment regressions.