Check_httpv2 fails to use semicolon in string search

Troubleshooting
1

CMK version: Community 2.5.0p16

Say you want to create a HTTP check and search for a string in the html source code.
You click Setup ➜ HTTP, TCP, email... and end up here:

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You then question your sanity because you can’t find it in the HTTP, TCP, email block where you would expect a HTTP check, but then later find it below, in the Networking section. You create a check.

You fill Search for strings ➜ Search in body ➜ Fixed string as:

MyCoolApp™ Version

because you want to match the “MyCoolApp™ Version 1.3.37” string in the footer. Your check then goes CRIT with (null) as plugin output. A closer look at the plugin command in the service details page reveals the issue:
check_mk_active-httpv2!--url https://myapp.tld --body-string 'MyCoolApp&trade

Things I found that might help narrow down the origin of the issue:

  • running it from the CLI with --body-string 'MyCoolApp™ Vers' works fine, so it’s probably not the check binary itself
  • The string also saves fine in the web interface and editing the check later brings the original string back into the input field.
  • it’s also not the nagios config generation, as etc/conf.d/check_mk_objects.cfg shows the correct call:
check_command    check_mk_active-httpv2!--url https://myapp.tld --body-string 'MyCoolApp™ Version'
2

Could you provide me with the exact output? I suspect the output also contains the semicolon at a position where parsing by the Nagios core fails. There are a few subtle differences between allowed characters for Nagios and CMC. I’ll forward to dev in that case.

3

The exact output of what, the check run via CLI? Sure (with some careful redactions):

OMD[checkmk]:~$ /opt/omd/versions/default/lib/nagios/plugins/check_httpv2 --url https://myapp.tld/backend/login --server myhost.tld --certificate-levels 14,5 --body-string 'MyAppName™ Vers'
URL to test: https://myapp.tld/backend/login, Version: HTTP/1.1, Status: 200 OK | response_time=0.019533957s;;;0;10 time_http_headers=0.019294423s;;;; time_http_body=0.000239534s;;;; response_size=9109B;;;0;
URL to test: https://myapp.tld/backend/login
Connected to server: myhost.tld
Method: GET
Version: HTTP/1.1
Status: 200 OK
Response time: 0.02 seconds
Page size: 9109 Bytes
Server certificate validity: 191 days
User agent: checkmk-active-httpv2/2.5.0
Expected string in body: MyAppName™ Vers (found)

Thanks!

4

Thanks, unfortunately, this is not enough. I also need the service name generated or the rule for service name generation. If it contains the semicolon, it most likely is the cause.

5

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Rules page:

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Rule edit:
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~/etc/nagios/conf.d/check_mk_objects.cfg

define service {
  active_checks_enabled         1
  check_command                 check_mk_active-httpv2!--url https://test.example.tld --body-string 'foo;bar'
  check_interval                1.0
  host_name                     scriptwiki
  max_check_attempts            3
  service_description           HTTPS Testcheck
  use                           check_mk_perf,check_mk_default
}

~/etc/check_mk/conf.d/wato/rules.mk

{'condition': {'host_name': ['scriptwiki']},
 'id': 'c0fbcbff-0de1-40b7-aa75-566f5fc7337d',
 'options': {'disabled': False},
 'value': {'endpoints': [{'service_name': {'name': 'Testcheck',
                                           'prefix': 'auto'},
                          'url': 'https://test.example.tld'}],
           'standard_settings': {'content': {'body': ('string', 'foo;bar')}}}},

The only semicolon I could find is in the test string. Should I look anywhere else or is this all you need?
To repro, I really just created a dummy check with foo;bar as the body search string.

6

One more:
~/tmp/nagios/status.dat

servicestatus {
	host_name=scriptwiki
	service_description=HTTPS Testcheck
	modified_attributes=0
	check_command=check_mk_active-httpv2!--url https://test.example.tld --body-string 'foo
	check_period=24X7
	notification_period=24X7
	check_interval=1.000000

I guess this is where the service detail page gets its info from. So, looks like a nagios bug then.

7

From the Nagios command definition.

NOTE: You may not include a semicolon (;) in the command_line directive, because everything after it will be ignored as a config file comment. You can work around this limitation by setting one of the $USER$ macros in your resource file to a semicolon and then referencing the appropriate $USER$ macro in the command_line directive in place of the semicolon.

; is a forbidden character inside any command definition.

8

Ahhhhh. I was hunting for that. Now it’s obvious.