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Debugging

Debugging with curl

If you have trouble using check_http, you can start to query the URL with curl:

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There are several ways to access the command. One way is described here: Configuring Check Email (check_mail)#ExecuteactiveCheckmanually

One other way is with cmk -N:

OMD[mysite]:~/lib/nagios/plugins$ cmk -N |grep http
  check_command                 check_mk_active-http!'-u' 'https://www.google.com/' '--ssl' '--onredirect=follow' '-j' 'CONNECT' '--sni' '-p' 'proxy_port' 'myproxyip' 'www.google.com'
  command_line                  /omd/sites/cme2mysite/lib/nagios/plugins/check_http $ARG1$
  command_name                  check_mk_active-http

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OMD[mysite]:~/lib/nagios/plugins$ lq "GET services\nColumns:host_name description check_command_expanded\nFilter: host_name = localhostmysite\nFilter: description = HTTPS HTTPSmyservicename"
localhost;HTTPS HTTPS;check_mk_active-http!'-u' 'https://www.google.com/' '--ssl' '--onredirect=follow' '-j' 'CONNECT' '--sni' '-p' 'proxy_port' 'myproxyip' 'www.google.com'

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OMD[mysite]:~/lib/nagios/plugins$ ./check_http '-u' 'https://www.google.com/' '--ssl' '--onredirect=follow' '-j' 'CONNECT' '--sni' '-p' 'proxy_port' 'myproxyip' 'www.google.com'

For a detailed log, you can use --verbose at the end of the command:

OMD[mysite]:~/lib/nagios/plugins$ ./check_http '-u' 'https://www.google.com/' '--ssl' '--onredirect=follow' '-j' 'CONNECT' '--sni' '-p' 'proxy_port' 'myproxyip' 'www.google.com' --verbose

For more information, you can use --help command flag.

OMD[mysite]:~/lib/nagios/plugins$ ./check_http --help

Debugging Regular Expressions (Regex)

In the following example, we are using regular expressions on status.cloud.google.com to gather Access Content Manager information. 

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The service check returns OK

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Running the command by hand can help debug issues as well.

OMD[mysite]:~/lib/nagios/plugins$ ./check_http -u /regional/americas --ssl -l -R 'Access Context Manager' --sni -I status.cloud.google.com -H status.cloud.google.com 
HTTP OK: HTTP/1.1 200 OK - 584329 bytes in 4.511 second response time |time=4.511160s;;;0.000000;10.000000 size=584329B;;;0;

Some important options

• Address (name / IP or Proxy)  → If you need a proxy to access the domain
• Virtual host → is necessary if you have multiple domains and one host running
• How to handle redirect → How to handle redirected pages
• Regular Expression to expect in content
→ 
• → Used to parse particular content from websites. 
• HTTP Method → Set to CONNECT if you're using a proxy
  
Disable SSL/TLS hostname extension support (SNI) →
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Useful Links

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