select/match a Section in Python
I'm trying to match each section of any Link State type from OSPF Database as shown in CLI_Output below using following regex in python:
regex = r'\n\n(\s+\S+( \S+)?(.+?)\n\n)(\s+\S+( \S+)?)?'
section = re.findall(regex,_original_result, re.M)
But I get only (the 1st) one line after the heading line
i.e.
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link Count
10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2
here my CLI-Output:
CLI_Output = '''
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link Count
10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2
10.200.254.252 10.200.254.252 97 0x80000003 0x00501E 3
Net Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
10.189.254.242 10.189.254.242 1452 0x80001cf4 0xefab
10.189.0.242 10.189.0.242 1452 0x80001cf4 0xefab
Summary Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Route
10.189.127.0 10.189.254.242 10 0x80001cde 0x6602 10.189.127.0/29
10.200.0.0 10.200.254.251 130 0x80000001 0x002675 10.200.0.0/16
172.18.200.1 10.200.254.251 109 0x80000001 0x00B5CB 172.18.200.1/32
ASBR-Summary Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
10.189.127.3 10.189.254.242 10 0x80001c30 0xc14a
Router Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum Link Count
10.189.127.3 10.189.127.3 1707 0x80001d5e 0xa509 1
10.189.254.242 10.189.254.242 10 0x80001ce0 0x8ec2 1
Net Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum
10.189.127.2 10.189.254.243 70 0x80001c31 0xdb72
Summary Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum Route
10.189.254.240 10.189.254.242 371 0x80001cda 0x8a71 10.189.254.240/29
10.189.254.240 10.189.254.243 1813 0x80001cda 0x8476 10.189.254.240/29
ASBR-Summary Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum
10.189.7.250 10.189.254.242 1442 0x8000154f 0x165e
10.189.7.250 10.189.254.243 1242 0x8000154d 0x1461
Router Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# Checksum Link Count
10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2
10.189.254.243 10.189.254.243 1552 0x80001ce8 0x164e 1
Net Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# Checksum
10.200.254.241 10.200.254.251 1277 80000001 ef90 0002
Summary Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# Checksum Route
0.0.0.0 10.200.254.251 1317 80000001 b7b0 0002 0.0.0.0/0
0.0.0.0 10.200.254.252 1317 80000001 b1b5 0002 0.0.0.0/0
NSSA-external Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# CkSum Flag Route Tag
10.200.1.0 172.18.200.1 365 800011cb 6f90 0031 E2 10.200.1.0/24 0
10.200.2.0 172.18.200.1 1735 800011c7 6c96 0031 E2 10.200.2.0/24 0
10.200.3.0 172.18.200.1 1775 800011c9 5da2 0031 E2 10.200.3.0/24 0
AS External Link States
Link ID ADV Router Age Seq# CkSum Flag Route Tag
0.0.0.0 10.189.7.250 384 800129e9 9a51 0012 E2 0.0.0.0/0 0
2.3.4.0 10.189.7.250 1154 80007a7a 1fe2 0012 E2 2.3.4.0/24 0
10.112.0.0 10.189.7.250 1084 8000d7e3 b31d 0012 E2 10.112.0.0/21 0
Could someone help me, how should my regex looks for to get the complete section?
i.e.
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link Count
10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2
10.200.254.252 10.200.254.252 97 0x80000003 0x00501E 3
Many thanks in advance Matrix154
asked on Stack Overflow Jan 16, 2019 by 
matrix154
matrix1542 Answers
Like I mentioned in my comments, I believe reading line by line is easier:
record = 0
results = []
for line in CLI_Output.split("\n"):
# skip empty lines
if line == "" and record < 2:
continue
# if Router Link is in header
if line.find('Router Link') > -1:
record = 1
continue
# headers
if record == 1:
record = 2
continue
# If we are here, we are getting the data lines
if record == 2 and line != "":
results.append(line)
elif line == "":
record = 0 # use break here if you want to stop after the first chunk
print(results)
Results:
['10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2',
'10.200.254.252 10.200.254.252 97 0x80000003 0x00501E 3',
'10.189.127.3 10.189.127.3 1707 0x80001d5e 0xa509 1',
'10.189.254.242 10.189.254.242 10 0x80001ce0 0x8ec2 1',
'10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2',
'10.189.254.243 10.189.254.243 1552 0x80001ce8 0x164e 1']
Though it doesn't mean it's not possible using regex, but it's more complex, like, it's honestly hard to make sense of the below if you are not used to the syntax:
^\ +(.+) Router Link States\s*(?:\([^)]+\))?\s+Link ID.+\s+((?:[^\r\n]+[\r\n]?)+)
answered on Stack Overflow Jan 17, 2019 by 
Jerry
JerryI have written many codes in perl and php and am new to python. A section selection in perl or php is easier, so I wanted to do the same in python but unfortunately unsuccessfull
@Jerry: Many thanks to you! I followed your suggestion to read the CLI Output line by line. Here is my code that i wish to share here. Maybe others need it too
import re
g = globals()
def ParseText(_original_result):
ls_types = []
dic = {}
(ls_name, area_id, area_type) = ('', '', '')
for line in _original_result.split("\n"):
if (line.strip() and not re.search('Link ID\s+', line)):
regex = r'^\s+(\S+|\S+ \S+) Link States'
ls = re.findall(regex, line, re.S)
if ls: ls_types.append(re.sub('(\s|-)', '_', ls[0]))
ls_types = list(set(ls_types))
for line in _original_result.split("\n"):
if (line.strip() and not re.search('Link ID\s+', line)):
matcher = list(re.finditer(r'^\s+(?P<ls_name>\S+( \S+)?) Link States( \(Area (?P<area_id>\S+)( \[(?P<area_type>\S+)\])?\))?', line, re.S|re.M))
if matcher:
ls_name = re.sub('(\s|-)', '_', matcher[0]['ls_name'])
if not ls_name in g:
g[ls_name] = { 'area_id': [], 'area_type': [], 'link_id': [], 'adv_rtr': [], 'age': [], 'sumary': [], 'ext_route_type': [], 'ext_route': [], 'tag': [], '$_columns' : ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag'] }
area_id = matcher[0]['area_id']
if matcher[0]['area_type']:
area_type = matcher[0]['area_type']
else:
if area_id == '0.0.0.0': area_type = 'backbone'
else: area_type = 'normal'
else:
matcher = list(re.finditer(r'^(?P<lnk_id>\S+)\s+(?P<adv_rtr>\S+)\s+(?P<age>\d+)(\s+\S+){2}(\s+(\d+\s+)?((?P<sumary>\S+)|(?P<ext_route_type>\S+)\s+(?P<ext_route>\S+)\s+(?P<tag>\d+)))?$', line, re.M|re.S))
if matcher:
if ls_name != 'AS_External':
g[ls_name]['area_id'].append(area_id)
g[ls_name]['area_type'].append(area_type)
g[ls_name]['link_id'].append(matcher[0]['lnk_id'])
g[ls_name]['adv_rtr'].append(matcher[0]['adv_rtr'])
g[ls_name]['age'].append(matcher[0]['age'])
if matcher[0]['sumary']:
g[ls_name]['sumary'].append(matcher[0]['sumary'])
if matcher[0]['ext_route_type']:
g[ls_name]['ext_route_type'].append(matcher[0]['ext_route_type'])
if matcher[0]['ext_route']:
g[ls_name]['ext_route'].append(matcher[0]['ext_route'])
if matcher[0]['tag']:
g[ls_name]['tag'].append(matcher[0]['tag'])
for LS in g:
if LS in ls_types:
dic[LS]= g[LS]
return dic
CLI_Output = '''
Forinet $get router info ospf database brief
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link Count
10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2
10.189.254.242 10.189.254.242 371 0x80001ce0 0x2847 1
10.189.254.243 10.189.254.243 1552 0x80001ce8 0x164e 1
10.200.254.251 10.200.254.251 93 0x80000003 0x002052 3
10.200.254.252 10.200.254.252 97 0x80000003 0x00501E 3
Net Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
10.189.254.242 10.189.254.242 1452 0x80001cf4 0xefab
Summary Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Route
10.189.127.0 10.189.254.242 10 0x80001cde 0x6602 10.189.127.0/29
10.189.127.0 10.189.254.243 1452 0x80001cdc 0x6405 10.189.127.0/29
10.200.0.0 10.200.254.251 130 0x80000001 0x002675 10.200.0.0/16
10.200.0.0 10.200.254.252 146 0x80000001 0x00207A 10.200.0.0/16
172.18.200.1 10.200.254.251 109 0x80000001 0x00B5CB 172.18.200.1/32
172.18.200.1 10.200.254.252 108 0x80000001 0x00AFD0 172.18.200.1/32
ASBR-Summary Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
10.189.127.3 10.189.254.242 10 0x80001c30 0xc14a
10.189.127.3 10.189.254.243 60 0x80001c4b 0x856a
Router Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum Link Count
10.189.127.3 10.189.127.3 1707 0x80001d5e 0xa509 1
10.189.254.242 10.189.254.242 10 0x80001ce0 0x8ec2 1
10.189.254.243 10.189.254.243 70 0x80001ce6 0x80c7 1
Net Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum
10.189.127.2 10.189.254.243 70 0x80001c31 0xdb72
Summary Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum Route
10.189.254.240 10.189.254.242 371 0x80001cda 0x8a71 10.189.254.240/29
10.189.254.240 10.189.254.243 1813 0x80001cda 0x8476 10.189.254.240/29
10.200.254.250 10.189.254.242 1442 0x80001548 0x0673 10.189.254.250/32
10.200.254.250 10.189.254.243 1242 0x80001548 0xff78 10.189.254.250/32
ASBR-Summary Link States (Area 1.1.1.1)
Link ID ADV Router Age Seq# Checksum
10.189.7.250 10.189.254.242 1442 0x8000154f 0x165e
10.189.7.250 10.189.254.243 1242 0x8000154d 0x1461
Router Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# Checksum Link Count
10.189.7.250 10.189.7.250 1102 0x80012fa1 0x6b32 2
10.189.254.242 10.189.254.242 371 0x80001ce0 0x2847 1
10.189.254.243 10.189.254.243 1552 0x80001ce8 0x164e 1
Net Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# Checksum
10.200.254.241 10.200.254.251 1277 80000001 ef90 0002
Summary Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# Checksum Route
0.0.0.0 10.200.254.251 1317 80000001 b7b0 0002 0.0.0.0/0
0.0.0.0 10.200.254.252 1317 80000001 b1b5 0002 0.0.0.0/0
NSSA-external Link States (Area 2.2.2.2 [NSSA])
Link ID ADV Router Age Seq# CkSum Flag Route Tag
10.200.1.0 172.18.200.1 365 800011cb 6f90 0031 E2 10.200.1.0/24 0
10.200.2.0 172.18.200.1 1735 800011c7 6c96 0031 E2 10.200.2.0/24 0
10.200.3.0 172.18.200.1 1775 800011c9 5da2 0031 E2 10.200.3.0/24 0
10.200.4.0 172.18.200.1 1555 800011c9 43be 0031 E2 10.200.4.0/22 0
10.200.8.0 172.18.200.1 1585 800011c8 28d3 0031 E2 10.200.8.0/24 0
10.200.234.0 172.18.200.1 1525 800011c7 6aaf 0031 E2 10.200.234.0/24 0
AS External Link States
Link ID ADV Router Age Seq# CkSum Flag Route Tag
0.0.0.0 10.189.7.250 384 800129e9 9a51 0012 E2 0.0.0.0/0 0
2.3.4.0 10.189.7.250 1154 80007a7a 1fe2 0012 E2 2.3.4.0/24 0
10.112.0.0 10.189.7.250 1084 8000d7e3 b31d 0012 E2 10.112.0.0/21 0
10.112.189.0 10.189.7.250 144 8000e95e 84fa 0012 E2 10.112.189.0/24 0
10.158.189.0 10.189.7.250 124 800129db 9df5 0012 E2 10.158.189.0/24 0
10.180.128.0 10.189.7.250 1264 800129da 15ad 0012 E2 10.180.128.0/21 0
10.188.0.0 10.189.7.250 1314 800129d5 2b4d 0012 E2 10.188.0.0/18 0
10.189.0.0 10.189.7.250 1344 800129d8 320a 0012 E2 10.189.0.0/21 0
10.189.8.0 10.189.7.250 1504 8000d057 0801 0012 E2 10.189.8.0/23 0
10.189.10.0 10.189.7.250 334 800129da e246 0012 E2 10.189.10.0/24 0
10.189.11.0 10.189.7.250 1534 800129da d750 0012 E2 10.189.11.0/24 0
10.189.14.0 10.189.7.250 1204 800129e5 a079 0012 E2 10.189.14.0/24 0
10.189.15.0 10.189.7.250 784 8000c59c 2ca1 0012 E2 10.189.15.0/29 0
10.189.20.0 10.189.7.250 914 800129e0 68b0 0012 E2 10.189.20.0/24 0
'''
print (ParseText(CLI_Output))
The Output look like this (the order while apendig is sticky, so no worry about reordering issue:
{
'Router': {
'area_id': ['0.0.0.0', '0.0.0.0', '0.0.0.0', '0.0.0.0', '0.0.0.0', '1.1.1.1', '1.1.1.1', '1.1.1.1', '2.2.2.2', '2.2.2.2', '2.2.2.2'],
'area_type': ['backbone', 'backbone', 'backbone', 'backbone', 'backbone', 'normal', 'normal', 'normal', 'NSSA', 'NSSA', 'NSSA'],
'link_id': ['10.189.7.250', '10.189.254.242', '10.189.254.243', '10.200.254.251', '10.200.254.252', '10.189.127.3', '10.189.254.242', '10.189.254.243', '10.189.7.250', '10.189.254.242', '10.189.254.243'],
'adv_rtr': ['10.189.7.250', '10.189.254.242', '10.189.254.243', '10.200.254.251', '10.200.254.252', '10.189.127.3', '10.189.254.242', '10.189.254.243', '10.189.7.250', '10.189.254.242', '10.189.254.243'],
'age': ['1102', '371', '1552', '93', '97', '1707', '10', '70', '1102', '371', '1552'],
'sumary': ['2', '1', '1', '3', '3', '1', '1', '1', '2', '1', '1'],
'ext_route_type': [],
'ext_route': [],
'tag': [],
'$_columns': ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag']
},
'Net': {
'area_id': ['0.0.0.0', '1.1.1.1', '2.2.2.2'],
'area_type': ['backbone', 'normal', 'NSSA'], 'link_id':['10.189.254.242', '10.189.127.2', '10.200.254.241'],
'adv_rtr': ['10.189.254.242', '10.189.254.243', '10.200.254.251'],
'age': ['1452', '70', '1277'],
'sumary': ['0002'],
'ext_route_type': [],
'ext_route': [],
'tag': [],
'$_columns': ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag']
},
'Summary': {
'area_id': ['0.0.0.0', '0.0.0.0', '0.0.0.0', '0.0.0.0', '0.0.0.0', '0.0.0.0', '1.1.1.1', '1.1.1.1', '1.1.1.1', '1.1.1.1', '2.2.2.2', '2.2.2.2'],
'area_type': ['backbone', 'backbone', 'backbone', 'backbone','backbone', 'backbone', 'normal', 'normal', 'normal', 'normal', 'NSSA', 'NSSA'],
'link_id': ['10.189.127.0', '10.189.127.0', '10.200.0.0', '10.200.0.0', '172.18.200.1', '172.18.200.1', '10.189.254.240', '10.189.254.240', '10.200.254.250', '10.200.254.250', '0.0.0.0', '0.0.0.0'],
'adv_rtr': ['10.189.254.242', '10.189.254.243', '10.200.254.251', '10.200.254.252', '10.200.254.251', '10.200.254.252', '10.189.254.242', '10.189.254.243', '10.189.254.242', '10.189.254.243', '10.200.254.251', '10.200.254.252'],
'age': ['10', '1452', '130', '146', '109', '108', '371', '1813', '1442', '1242', '1317', '1317'],
'sumary': ['10.189.127.0/29', '10.189.127.0/29', '10.200.0.0/16', '10.200.0.0/16', '172.18.200.1/32', '172.18.200.1/32', '10.189.254.240/29', '10.189.254.240/29', '10.189.254.250/32', '10.189.254.250/32', '0.0.0.0/0', '0.0.0.0/0'],
'ext_route_type': [],
'ext_route': [],
'tag': [],
'$_columns': ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag']
},
'ASBR_Summary': {
'area_id': ['0.0.0.0', '0.0.0.0', '1.1.1.1', '1.1.1.1'],
'area_type': ['backbone', 'backbone', 'normal', 'normal'],
'link_id': ['10.189.127.3', '10.189.127.3', '10.189.7.250', '10.189.7.250'],
'adv_rtr': ['10.189.254.242', '10.189.254.243', '10.189.254.242', '10.189.254.243'],
'age': ['10', '60', '1442', '1242'],
'sumary': [],
'ext_route_type': [],
'ext_route': [],
'tag': [],
'$_columns': ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag']
},
'NSSA_external': {
'area_id': ['2.2.2.2', '2.2.2.2', '2.2.2.2', '2.2.2.2', '2.2.2.2', '2.2.2.2'],
'area_type': ['NSSA', 'NSSA', 'NSSA', 'NSSA', 'NSSA', 'NSSA'],
'link_id': ['10.200.1.0', '10.200.2.0', '10.200.3.0', '10.200.4.0', '10.200.8.0', '10.200.234.0'],
'adv_rtr': ['172.18.200.1', '172.18.200.1', '172.18.200.1', '172.18.200.1', '172.18.200.1', '172.18.200.1'],
'age': ['365', '1735', '1775', '1555', '1585', '1525'], 'sumary':[],
'ext_route_type': ['E2', 'E2', 'E2', 'E2', 'E2', 'E2'],
'ext_route': ['10.200.1.0/24', '10.200.2.0/24', '10.200.3.0/24', '10.200.4.0/22', '10.200.8.0/24', '10.200.234.0/24'], 'tag':['0', '0', '0', '0', '0', '0'],
'$_columns': ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag']
},
'AS_External': {
'area_id': [],
'area_type': [],
'link_id': ['0.0.0.0', '2.3.4.0', '10.112.0.0', '10.112.189.0', '10.158.189.0', '10.180.128.0', '10.188.0.0', '10.189.0.0', '10.189.8.0', '10.189.10.0', '10.189.11.0', '10.189.14.0', '10.189.15.0', '10.189.20.0'],
'adv_rtr': ['10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250', '10.189.7.250'],
'age': ['384', '1154', '1084', '144', '124', '1264', '1314', '1344', '1504', '334', '1534', '1204', '784', '914'],
'sumary': [],
'ext_route_type': ['E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2', 'E2'],
'ext_route': ['0.0.0.0/0', '2.3.4.0/24', '10.112.0.0/21', '10.112.189.0/24', '10.158.189.0/24', '10.180.128.0/21', '10.188.0.0/18', '10.189.0.0/21', '10.189.8.0/23', '10.189.10.0/24', '10.189.11.0/24', '10.189.14.0/24', '10.189.15.0/29', '10.189.20.0/24'],
'tag': ['0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0'],
'$_columns': ['area_id', 'area_type', 'link_id', 'adv_rtr', 'age', 'sumary', 'ext_route_type', 'ext_route', 'tag']
}
}
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