调整Textfsm模板以完整解析Nokia 7750 VPLS配置的所有mesh-sdp

配置片段示例 #

vpls 100 customer 10 create
    description "Customer A VPLS"
    mesh-sdp 1:100 create
    mesh-sdp 1:101 create
    mesh-sdp 2:200 create
vpls 200 customer 20 create
    description "Customer B VPLS"
    mesh-sdp 3:300 create

预期解析结果 #

现有问题模板 #

Value VPLS_ID (\d+)
Value CUSTOMER_ID (\d+)
Value MESH_SDP (\S+)

Start
  ^vpls ${VPLS_ID} customer ${CUSTOMER_ID} create -> Record
  ^\s+mesh-sdp ${MESH_SDP} create -> Record

问题分析 #

现有模板匹配到vpls ... create或mesh-sdp ... create就立即执行Record，导致每个VPLS实例的第一个mesh-sdp会和VPLS基础信息分开记录，后续的mesh-sdp无法关联到对应的VPLS和客户ID，最终只能保留第一个条目。

修正后的Textfsm模板 #

Value VPLS_ID (\d+)
Value CUSTOMER_ID (\d+)
Value MESH_SDP (\S+)

Start
  ^vpls ${VPLS_ID} customer ${CUSTOMER_ID} create -> VplsSection

VplsSection
  ^\s+mesh-sdp ${MESH_SDP} create -> Record
  ^vpls ${VPLS_ID} customer ${CUSTOMER_ID} create -> Clear; VplsSection
  ^exit -> Start

模板逻辑说明 #

• 新增VplsSection状态：进入该状态后，会持续保留当前匹配到的VPLS_ID和CUSTOMER_ID上下文
• 每匹配到一个mesh-sdp就执行Record，自动关联当前状态下的VPLS和客户信息
• 匹配到新的vpls条目时，执行Clear清空旧变量，切换到新的VplsSection状态
• 遇到配置中的exit层级退出命令时，回到Start状态等待下一个VPLS实例

验证代码 #

import textfsm
from io import StringIO

# 待解析配置
config = """vpls 100 customer 10 create
    description "Customer A VPLS"
    mesh-sdp 1:100 create
    mesh-sdp 1:101 create
    mesh-sdp 2:200 create
vpls 200 customer 20 create
    description "Customer B VPLS"
    mesh-sdp 3:300 create
"""

# 修正后的模板内容
template_content = """Value VPLS_ID (\d+)
Value CUSTOMER_ID (\d+)
Value MESH_SDP (\S+)

Start
  ^vpls ${VPLS_ID} customer ${CUSTOMER_ID} create -> VplsSection

VplsSection
  ^\s+mesh-sdp ${MESH_SDP} create -> Record
  ^vpls ${VPLS_ID} customer ${CUSTOMER_ID} create -> Clear; VplsSection
  ^exit -> Start
"""

# 执行解析
template = textfsm.TextFSM(StringIO(template_content))
result = template.ParseText(config)

# 输出结果
print("解析结果:")
print(template.header)
for row in result:
    print(row)

运行代码后，会输出所有关联正确的VPLS与Mesh-SDP条目，与预期结果一致。

内容的提问来源于stack exchange，提问作者finopat