[Nexthop] NOS-6643..NOS-6648: fboss2 config/delete protocol bgp policy as-path-list

Adds the first BGP policy object-type command family, under a new `policy`
grouping node beneath `protocol bgp` (sibling to global/neighbor/peer-group):

  config protocol bgp policy as-path-list <name> [description <string>]
  delete protocol bgp policy as-path-list <name>

The list's `entry <seq-num>` level is a CLI11 subcommand of its own and
lands in the next commit, so this one owns only the list level.

- Follows the dispatcher shape the neighbor/peer-group families use: one
  factory per value shape from the shared BgpCliAttrHandlers.h, named
  setters that do nothing but assign the thrift field, and a registry that
  is one line per attribute. Writes bgp_policy.BgpPolicies.aspath_lists[]
  through the typed ConfigSession — no new session plumbing, since
  BgpConfig.policies already exists.
- Lookup/create helpers live in BgpAsPathListCliUtils.h, including the
  entry-level helpers, so the delete command and the entry subcommand in
  the next commit share them rather than re-deriving the scan.
- A rejected value leaves nothing staged: a list implicitly created for the
  failed command is rolled back before returning.
- There is no per-entry delete; `delete ... as-path-list <name>` removes the
  whole list.

- unit tests (10): CmdConfigBgpPolicyAsPathListTest (6) covering arg
  validation, bare create, the description round-trip, named lists staying
  distinct, re-reference reporting the existing list and unknown-attribute
  rejection, plus CmdDeleteBgpPolicyAsPathListTest (4).
- integration tests (2): ConfigBgpPolicyAsPathListTest stages and commits,
  then asserts against bgpd's running config via the getRunningConfig RPC,
  confirming bgpd accepts and adopts the .policies blob end to end.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: hillol-nexthop

cmake/CliFboss2.cmake

@@ -882,6 +882,11 @@ add_library(fboss2_config_lib
   fboss/cli/fboss2/commands/config/protocol/bgp/neighbor/CmdConfigProtocolBgpNeighbor.h
   fboss/cli/fboss2/commands/config/protocol/bgp/peer-group/CmdConfigProtocolBgpPeerGroup.cpp
   fboss/cli/fboss2/commands/config/protocol/bgp/peer-group/CmdConfigProtocolBgpPeerGroup.h
+  fboss/cli/fboss2/commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.cpp
+  fboss/cli/fboss2/commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.h
+  fboss/cli/fboss2/commands/config/protocol/bgp/policy/as-path-list/BgpAsPathListCliUtils.h
+  fboss/cli/fboss2/commands/config/protocol/bgp/policy/as-path-list/CmdConfigProtocolBgpPolicyAsPathList.cpp
+  fboss/cli/fboss2/commands/config/protocol/bgp/policy/as-path-list/CmdConfigProtocolBgpPolicyAsPathList.h
   fboss/cli/fboss2/commands/config/ptp/CmdConfigPtp.cpp
   fboss/cli/fboss2/commands/config/ptp/CmdConfigPtp.h
   fboss/cli/fboss2/commands/config/ptp/transparent_clock/CmdConfigPtpTransparentClock.cpp
@@ -990,6 +995,10 @@ add_library(fboss2_config_lib
   fboss/cli/fboss2/commands/delete/protocol/bgp/neighbor/CmdDeleteProtocolBgpNeighbor.h
   fboss/cli/fboss2/commands/delete/protocol/bgp/peer-group/CmdDeleteProtocolBgpPeerGroup.cpp
   fboss/cli/fboss2/commands/delete/protocol/bgp/peer-group/CmdDeleteProtocolBgpPeerGroup.h
+  fboss/cli/fboss2/commands/delete/protocol/bgp/policy/CmdDeleteProtocolBgpPolicy.cpp
+  fboss/cli/fboss2/commands/delete/protocol/bgp/policy/CmdDeleteProtocolBgpPolicy.h
+  fboss/cli/fboss2/commands/delete/protocol/bgp/policy/as-path-list/CmdDeleteProtocolBgpPolicyAsPathList.cpp
+  fboss/cli/fboss2/commands/delete/protocol/bgp/policy/as-path-list/CmdDeleteProtocolBgpPolicyAsPathList.h
   fboss/cli/fboss2/commands/delete/protocol/CmdDeleteProtocol.h
   fboss/cli/fboss2/commands/delete/protocol/static/CmdDeleteProtocolStatic.cpp
   fboss/cli/fboss2/commands/delete/protocol/static/CmdDeleteProtocolStatic.h

fboss/cli/fboss2/BUCK

@@ -1108,6 +1108,8 @@ cpp_library(
         "commands/config/protocol/bgp/global/CmdConfigProtocolBgpGlobal.cpp",
         "commands/config/protocol/bgp/neighbor/CmdConfigProtocolBgpNeighbor.cpp",
         "commands/config/protocol/bgp/peer-group/CmdConfigProtocolBgpPeerGroup.cpp",
+        "commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.cpp",
+        "commands/config/protocol/bgp/policy/as-path-list/CmdConfigProtocolBgpPolicyAsPathList.cpp",
         "commands/config/protocol/static/CmdConfigProtocolStatic.cpp",
         "commands/config/protocol/static/route/add/CmdConfigProtocolStaticRouteAdd.cpp",
         "commands/config/ptp/CmdConfigPtp.cpp",
@@ -1162,6 +1164,8 @@ cpp_library(
         "commands/delete/protocol/bgp/CmdDeleteProtocolBgp.cpp",
         "commands/delete/protocol/bgp/neighbor/CmdDeleteProtocolBgpNeighbor.cpp",
         "commands/delete/protocol/bgp/peer-group/CmdDeleteProtocolBgpPeerGroup.cpp",
+        "commands/delete/protocol/bgp/policy/CmdDeleteProtocolBgpPolicy.cpp",
+        "commands/delete/protocol/bgp/policy/as-path-list/CmdDeleteProtocolBgpPolicyAsPathList.cpp",
         "commands/delete/protocol/static/CmdDeleteProtocolStatic.cpp",
         "commands/delete/protocol/static/route/CmdDeleteProtocolStaticRoute.cpp",
         "commands/delete/qos/CmdDeleteQos.cpp",
@@ -1222,6 +1226,9 @@ cpp_library(
         "commands/config/protocol/bgp/global/CmdConfigProtocolBgpGlobal.h",
         "commands/config/protocol/bgp/neighbor/CmdConfigProtocolBgpNeighbor.h",
         "commands/config/protocol/bgp/peer-group/CmdConfigProtocolBgpPeerGroup.h",
+        "commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.h",
+        "commands/config/protocol/bgp/policy/as-path-list/BgpAsPathListCliUtils.h",
+        "commands/config/protocol/bgp/policy/as-path-list/CmdConfigProtocolBgpPolicyAsPathList.h",
         "commands/config/protocol/static/CmdConfigProtocolStatic.h",
         "commands/config/protocol/static/route/StaticRouteUtils.h",
         "commands/config/protocol/static/route/add/CmdConfigProtocolStaticRouteAdd.h",
@@ -1277,6 +1284,8 @@ cpp_library(
         "commands/delete/protocol/bgp/CmdDeleteProtocolBgp.h",
         "commands/delete/protocol/bgp/neighbor/CmdDeleteProtocolBgpNeighbor.h",
         "commands/delete/protocol/bgp/peer-group/CmdDeleteProtocolBgpPeerGroup.h",
+        "commands/delete/protocol/bgp/policy/CmdDeleteProtocolBgpPolicy.h",
+        "commands/delete/protocol/bgp/policy/as-path-list/CmdDeleteProtocolBgpPolicyAsPathList.h",
         "commands/delete/protocol/static/CmdDeleteProtocolStatic.h",
         "commands/delete/protocol/static/route/CmdDeleteProtocolStaticRoute.h",
         "commands/delete/qos/CmdDeleteQos.h",

fboss/cli/fboss2/CmdListConfig.cpp

@@ -40,6 +40,8 @@
 #include "fboss/cli/fboss2/commands/config/protocol/bgp/global/CmdConfigProtocolBgpGlobal.h"
 #include "fboss/cli/fboss2/commands/config/protocol/bgp/neighbor/CmdConfigProtocolBgpNeighbor.h"
 #include "fboss/cli/fboss2/commands/config/protocol/bgp/peer-group/CmdConfigProtocolBgpPeerGroup.h"
+#include "fboss/cli/fboss2/commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.h"
+#include "fboss/cli/fboss2/commands/config/protocol/bgp/policy/as-path-list/CmdConfigProtocolBgpPolicyAsPathList.h"
 #include "fboss/cli/fboss2/commands/config/protocol/static/CmdConfigProtocolStatic.h"
 #include "fboss/cli/fboss2/commands/config/protocol/static/route/add/CmdConfigProtocolStaticRouteAdd.h"
 #include "fboss/cli/fboss2/commands/config/ptp/CmdConfigPtp.h"
@@ -90,6 +92,8 @@
 #include "fboss/cli/fboss2/commands/delete/protocol/bgp/CmdDeleteProtocolBgp.h"
 #include "fboss/cli/fboss2/commands/delete/protocol/bgp/neighbor/CmdDeleteProtocolBgpNeighbor.h"
 #include "fboss/cli/fboss2/commands/delete/protocol/bgp/peer-group/CmdDeleteProtocolBgpPeerGroup.h"
+#include "fboss/cli/fboss2/commands/delete/protocol/bgp/policy/CmdDeleteProtocolBgpPolicy.h"
+#include "fboss/cli/fboss2/commands/delete/protocol/bgp/policy/as-path-list/CmdDeleteProtocolBgpPolicyAsPathList.h"
 #include "fboss/cli/fboss2/commands/delete/protocol/static/CmdDeleteProtocolStatic.h"
 #include "fboss/cli/fboss2/commands/delete/protocol/static/route/CmdDeleteProtocolStaticRoute.h"
 #include "fboss/cli/fboss2/commands/delete/qos/CmdDeleteQos.h"
@@ -383,6 +387,21 @@ const CommandTree& kConfigCommandTree() {
                           commandHandler<CmdConfigProtocolBgpNeighbor>,
                           argRegistrar<CmdConfigProtocolBgpNeighborTraits>,
                       },
+                      {
+                          "policy",
+                          "Configure BGP policy objects",
+                          commandHandler<CmdConfigProtocolBgpPolicy>,
+                          argRegistrar<CmdConfigProtocolBgpPolicyTraits>,
+                          {{
+                              "as-path-list",
+                              "Configure BGP AS-path list: <name> "
+                              "[<attribute> <value> ...] (description)",
+                              commandHandler<
+                                  CmdConfigProtocolBgpPolicyAsPathList>,
+                              argRegistrar<
+                                  CmdConfigProtocolBgpPolicyAsPathListTraits>,
+                          }},
+                      },
                   },
               },
               {
@@ -711,6 +730,19 @@ const CommandTree& kConfigCommandTree() {
                     "Delete a BGP peer-group: <name>",
                     commandHandler<CmdDeleteProtocolBgpPeerGroup>,
                     argRegistrar<CmdDeleteProtocolBgpPeerGroupTraits>,
+                },
+                {
+                    "policy",
+                    "Delete BGP policy objects",
+                    commandHandler<CmdDeleteProtocolBgpPolicy>,
+                    argTypeHandler<CmdDeleteProtocolBgpPolicyTraits>,
+                    {{
+                        "as-path-list",
+                        "Delete a BGP AS-path list: <name>",
+                        commandHandler<CmdDeleteProtocolBgpPolicyAsPathList>,
+                        argRegistrar<
+                            CmdDeleteProtocolBgpPolicyAsPathListTraits>,
+                    }},
                 }},
            },
            {

fboss/cli/fboss2/commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.cpp

@@ -0,0 +1,30 @@
+/*
+ *  Copyright (c) 2004-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#include "fboss/cli/fboss2/commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.h"
+
+#include "fboss/cli/fboss2/CmdHandler.cpp"
+
+namespace facebook::fboss {
+
+CmdConfigProtocolBgpPolicyTraits::RetType
+CmdConfigProtocolBgpPolicy::queryClient(const HostInfo& /* hostInfo */) {
+  return "BGP policy configuration. Use subcommands: as-path-list";
+}
+
+void CmdConfigProtocolBgpPolicy::printOutput(const RetType& output) {
+  std::cout << output << std::endl;
+}
+
+// Explicit template instantiation
+template void
+CmdHandler<CmdConfigProtocolBgpPolicy, CmdConfigProtocolBgpPolicyTraits>::run();
+
+} // namespace facebook::fboss

fboss/cli/fboss2/commands/config/protocol/bgp/policy/CmdConfigProtocolBgpPolicy.h

@@ -0,0 +1,40 @@
+/*
+ *  Copyright (c) 2004-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#pragma once
+
+#include "fboss/cli/fboss2/CmdHandler.h"
+#include "fboss/cli/fboss2/commands/config/protocol/bgp/CmdConfigProtocolBgp.h"
+
+namespace facebook::fboss {
+
+// Grouping node for `config protocol bgp policy <object-type> ...`. Holds no
+// state of its own; the per-object-type dispatchers (as-path-list, and later
+// community-list/prefix-list/routing-policy) are its subcommands. Mirrors
+// CmdConfigProtocolBgp.
+struct CmdConfigProtocolBgpPolicyTraits : public WriteCommandTraits {
+  using ParentCmd = CmdConfigProtocolBgp;
+  using ObjectArgType = std::monostate;
+  using RetType = std::string;
+};
+
+class CmdConfigProtocolBgpPolicy : public CmdHandler<
+                                       CmdConfigProtocolBgpPolicy,
+                                       CmdConfigProtocolBgpPolicyTraits> {
+ public:
+  using ObjectArgType = CmdConfigProtocolBgpPolicyTraits::ObjectArgType;
+  using RetType = CmdConfigProtocolBgpPolicyTraits::RetType;
+
+  RetType queryClient(const HostInfo& hostInfo);
+
+  void printOutput(const RetType& output);
+};
+
+} // namespace facebook::fboss

fboss/cli/fboss2/commands/config/protocol/bgp/policy/as-path-list/BgpAsPathListCliUtils.h

@@ -0,0 +1,87 @@
+/*
+ *  Copyright (c) 2004-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#pragma once
+
+#include <neteng/fboss/bgp/public_tld/configerator/structs/neteng/fboss/bgp/gen-cpp2/bgp_config_types.h>
+#include <algorithm>
+#include <cstdint>
+#include <string>
+#include "configerator/structs/neteng/bgp_policy/thrift/gen-cpp2/bgp_policy_types.h"
+
+/**
+ * Lookup/create helpers for the as-path-list CLI family, shared between the
+ * list-level dispatcher (CmdConfigProtocolBgpPolicyAsPathList), the entry
+ * subcommand (CmdConfigProtocolBgpPolicyAsPathListEntry), and the delete
+ * counterparts. An AsPathList is keyed by name; an AsPathListEntry (in
+ * as_path_list[]) is keyed by sequence_number.
+ */
+namespace facebook::fboss::bgpcli {
+
+inline bool asPathListExists(
+    const bgp::thrift::BgpConfig& cfg,
+    const std::string& name) {
+  if (!cfg.policies().has_value()) {
+    return false;
+  }
+  const auto& lists = *cfg.policies()->aspath_lists();
+  return std::any_of(lists.begin(), lists.end(), [&](const auto& list) {
+    return *list.name() == name;
+  });
+}
+
+// Find the as-path-list keyed by name, creating it if absent. Setting an
+// attribute on a not-yet-created list implicitly creates it, so command
+// ordering stays forgiving; a bare `as-path-list <name>` creates one
+// explicitly. AsPathList's only key field is `name`.
+inline bgp::bgp_policy::AsPathList& findOrCreateAsPathList(
+    bgp::thrift::BgpConfig& cfg,
+    const std::string& name) {
+  auto& lists = *cfg.policies().ensure().aspath_lists();
+  for (auto& list : lists) {
+    if (*list.name() == name) {
+      return list;
+    }
+  }
+  lists.emplace_back();
+  auto& list = lists.back();
+  list.name() = name;
+  return list;
+}
+
+inline bool asPathListEntryExists(
+    const bgp::bgp_policy::AsPathList& list,
+    int64_t seqNum) {
+  const auto& entries = *list.as_path_list();
+  return std::any_of(entries.begin(), entries.end(), [&](const auto& entry) {
+    return entry.sequence_number().has_value() &&
+        *entry.sequence_number() == seqNum;
+  });
+}
+
+// Find the entry keyed by sequence_number within a list, creating it if
+// absent. sequence_number is the entry's identity.
+inline bgp::bgp_policy::AsPathListEntry& findOrCreateAsPathListEntry(
+    bgp::bgp_policy::AsPathList& list,
+    int64_t seqNum) {
+  auto& entries = *list.as_path_list();
+  for (auto& entry : entries) {
+    if (entry.sequence_number().has_value() &&
+        *entry.sequence_number() == seqNum) {
+      return entry;
+    }
+  }
+  entries.emplace_back();
+  auto& entry = entries.back();
+  entry.sequence_number() = seqNum;
+  return entry;
+}
+
+} // namespace facebook::fboss::bgpcli