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Url

URL checks if one or more Url can

  • be contacted before a timeout,
  • provides an http response code of 200 (OK)
  • contains a specific pattern / string in the body of the response.

It can verify TLS/SSL certificates. It can follow redirets. It reports URL response time. It can pass a Host header to query specfic virtual-host.

This check can be used from a remote server to monitor various URL and Webservices. It can also be configured locally on a single Webserver to monitor a local single instance. If the provided URL is an application status (e.g. php-fpm /status with pattern "pong"), you can have a basic (or not so basic) application monitor.

Configure

# conf.yml
url:
    www.cavaliba.com:
        url               : https://www.cavaliba.com/
        [allow_redirects] : yes ; default = no
        [ssl_verify]      : yes ; default = no
        [host]            : optionnal hostname header (Host: xxx) ; default to None
        [timeout]         : float (sec) ; default = 4 ; e.g. : 5.2
        [http_proxy]      : http://[login[:pass]@proxyhost:port  ; use noenv value to skip os/env           
        [https_proxy]     : https://[login[:pass]]@proxyhost:port  ; default to http_proxy
        [username]        : login to be provided to basic/digest auth by remote webserver
        [password]        : password to be provided to basic/digest auth by remote webserver
        [http_code]       : expected code ; default 200
        [pattern]         : pattern expected in response (default none) 
        [pattern_reject]  : pattern to NOT find in response (default none)

pattern: 

default: non
a string / regexp (python re.) which MUST be present in the response body
new 2.3 : pattern is also looked for in response header as a test list of `key: value`

pattern_reject: 

new: 2.0
default: none   
a string / regexp (python re.) which MUST NOT be present in the response body
useful to check for no error message in a status page
new 2.3 : pattern is also looked for in response header as a test list of `key: value`

allow_redirects:

CMT will follow HTTP redirects

ssl_verify:

CMT will check for a valid TLS certificate (CA, validity, host)

host: 

add a Host: header to specify which target/virtualhost to query

timeout:

socket timeout value (no bytes lapse) ; default : 4 secs. Float accepted

http_proxy:

default : use os/env wide settings.
if defined, use specified proxy for http requests. 
http://[login[:pass]]@proxyhost:port
use noenv value to skip os/env (direct access)

https_proxy

default : http_proxy 
if defined, use specified proxy for https (TLS/SSL) requests. 
https://[login[:pass]]@proxyhost:port

username, password

new in 2.0
default : no authentication sent to remote server

http_code

new in 2.0
default : 200
expected http_code in response
useful to check non-200 responses like redirects 30X, forbidden 40X, webservice specials 20X, etc.

Alerts

This check sends an alert and adds alert fields if an URL isn't responding properly.

Alert message:

  • no response to query (timeout / no response)
  • bad http code response
  • expected pattern not found in response body (or response headers since v2.3)

Output to Metrology

This module sends one message for each URL, with the following fields:

cmt_check: url
+
cmt_url:  url string
cmt_url_name: url name
cmt_url_status: ok/nok
cmt_url_msec: int        [response time in millisecond if available]

CLI usage and output

$ ./cmt.py urls

Check url 
cmt_url_name           www.cavaliba.com  () 
cmt_url                https://www.cavaliba.com/  () 
cmt_url_msec           96 ms () 
OK                     www.cavaliba.com - https://www.cavaliba.com/ [Host: ] - http=200 - 96 ms ; pattern OK

Check url 
cmt_url_name           www_non_existing  () 
cmt_url                http://www.nonexisting/  () 
NOK                    www_non_existing - http://www.nonexisting/ [Host: ] - no response to query

Check url 
cmt_url_name           demo.cavaliba.com  () 
cmt_url                http://demo.cavaliba.com/  () 
cmt_url_msec           187 ms () 
OK                     demo.cavaliba.com - http://demo.cavaliba.com/ [Host: ] - http=200 - 187 ms ; pattern OK