[hillol-nexthop]

Rebased onto main now that #1477, #1487 and #1488 have landed; the diff shows only this PR's commits.

Stack (bottom → top): #1477 → #1487 → #1488 (landed) → #1489 (this PR) → #1490 → #1491

Summary

Adds config protocol bgp policy routing-policy <name> term <seq-num> [description <string>] and delete protocol bgp policy routing-policy <name> term <seq-num> — the seq-num-keyed term level of the routing-policy family (stacked on #1488). Covers (bare create) and (description). The term's action and match levels land as follow-up subcommand PRs stacked on this one.

Design: term is a real CLI11 subcommand with its own handler, unlike the sibling policy families (which token-parse their nested level inside the parent's ObjectArgType). It mirrors the config interface … switchport chain: the policy name arrives in the term handler through the ancestor-args tuple. What that required, and the trade-offs it carries:

• positionals_at_end() is dropped from the routing-policy parent so CLI11 can classify term after the policy name. Consequence: a policy-level attribute value that spells term is stolen by subcommand matching (documented in the traits; same exposure as the interface chain).
• A mixed command (routing-policy X description y term 10) parses, but only the leaf runs; the term handler explicitly rejects it instead of silently dropping the policy attribute.
• A policy literally named term cannot be configured (the token is claimed by the subcommand).

Command behavior:

• term dispatcher keyed by (policy name from parent) + <seq-num>, writing bgp_policy.BgpPolicyTerm in .policies.bgp_policy_statements[].policy_entries[]:
  • description <string> (, multi-token free text)
  • bare create () seeds the term name from the seq-num (next_term_id references terms by name, so every term gets a stable identity)
• shared BgpRoutingPolicyCliUtils.h lookup/create helpers used by the policy dispatcher, the term subcommand, and both deletes; phantom-create rollback covers the term and a policy implicitly created for it.
• delete removes a single term by seq-num; the policy and its other terms stay.

Delete is idempotent. Deleting an absent target is a success with a Warning: (nothing is saved), so a replayed script never fails on something already gone; the reference guards still return Error:.

Sample usage

$ fboss2-dev config protocol bgp policy routing-policy EXPORT-POLICY term 10
Successfully created BGP routing-policy EXPORT-POLICY term 10
Config saved to: ~/.fboss2/bgp_config.json

$ fboss2-dev config protocol bgp policy routing-policy EXPORT-POLICY term 10 description deny private asns
Successfully set description to: deny private asns for routing-policy EXPORT-POLICY term 10

$ fboss2-dev delete protocol bgp policy routing-policy EXPORT-POLICY term 10
Successfully deleted BGP routing-policy EXPORT-POLICY term 10

Idempotent delete, recorded on a lab device:

$ fboss2-dev delete protocol bgp policy routing-policy RM100 term 99
Warning: BGP routing-policy RM100 has no term 99; nothing to delete

Test plan

Unit (delete) — fboss2_cmd_config_test:

$ fboss2_cmd_config_test --gtest_filter=*DeleteBgpPolicyRoutingPolicyTerm*
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.argValidation (58 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteExistingTerm (124 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteLastTermLeavesPolicy (128 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteUnknownTermWarns (116 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteTermTwiceIsIdempotent (132 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteTermFromUnknownPolicyWarns (57 ms)
[==========] 6 tests from 1 test suites ran.
[  PASSED  ] 6 tests.

Unit — fboss2_cmd_config_test:

$ fboss2_cmd_config_test --gtest_filter=*RoutingPolicyTerm*
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.argValidation (78 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.bareCreateTerm (105 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.setTermDescription (76 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.termsAreKeyedBySeqNum (154 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.reReferenceReportsExisting (112 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.termOnExistingPolicyKeepsPolicyAttributes (111 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.emptyDescriptionRejected (57 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.rejectedValueOnExistingPolicyKeepsPolicy (101 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.rejectedValueOnExistingTermKeepsTerm (75 ms)
[       OK ] CmdConfigBgpPolicyRoutingPolicyTermTestFixture.policyAttributeAlongsideTermRejected (50 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.argValidation (48 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteExistingTerm (170 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteLastTermLeavesPolicy (87 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteUnknownTermRejected (66 ms)
[       OK ] CmdDeleteBgpPolicyRoutingPolicyTermTestFixture.deleteTermFromUnknownPolicyRejected (80 ms)
[==========] 15 tests from 2 test suites ran. (1379 ms total)
[  PASSED  ] 15 tests.

Integration — fboss2_integration_test on a lab device with bgp_pp active:

$ fboss2_integration_test --gtest_filter='ConfigBgpPolicyRoutingPolicyTermTest.*'
[       OK ] ConfigBgpPolicyRoutingPolicyTermTest.SetTermAttributesAndCommit (1273 ms)
[       OK ] ConfigBgpPolicyRoutingPolicyTermTest.DeleteTermAndCommit (3439 ms)
[==========] 2 tests from 1 test suite ran.
[  PASSED  ] 2 tests.

Based-on: #1488