REST custom sensor - dynamic channels

Hi there,

The current state of the sensor is BETA, therefore it is a bit more complicated to get dynamic results. However the following template should work:

{
  "prtg": {
    "result": [
      {
        "value": {
            "Error Status ["+ #1 +"]": $.result.Plan..({ @.label : lookup(@.error, "OK")}).*
        },
        "limitmode": 1,
        "LimitMinError": 0,
        "LimitErrorMsg": "The value for 'error' is not 'Ok'!"
      }
    ]
  }
}

Please note that PRTG can't monitor strings in dedicated channels, therefore I applied a lookup on the "Ok" value. This returns "0" if "OK" is found and "-1" if it is not found.

Best regards.

Thanks for the reply. This give me the expected results if I use rest.exe via the command line:

{
  "prtg": {
    "result": [
      {
        "channelid": 0,
        "Value": 164,
        "Unit": "TimeResponse",
        "ShowChart": 0,
        "ShowTable": 0
      },
      {
        "channel": "Error Status [Label 1]",
        "Value": -1,
        "LimitMinError": 0,
        "LimitErrorMsg": "The value for 'error' is not 'Ok'!",
        "LimitMode": 1
      },
      {
        "channel": "Error Status [Label 2]",
        "Value": 0,
        "LimitMinError": 0,
        "LimitErrorMsg": "The value for 'error' is not 'Ok'!",
        "LimitMode": 1
      },
      {
        "channel": "Error Status [Label 3]",
        "Value": 0,
        "LimitMinError": 0,
        "LimitErrorMsg": "The value for 'error' is not 'Ok'!",
        "LimitMode": 1
      }
    ]
  }
}

But when I add it as a PRTG sensor i'm not getting the list of channels:

Any other suggestions?

Hi there,

Does it display any error message?
Have you made sure that the URL is correct (device address + url in the sensor)?

Best regards.

Hi, thanks.

Yes I've checked that the details are the same, and added it as a new sensor a couple of times to make sure. There is no error message - the sensor status is OK, log just shows the status as Up.

Hi there,

Have you enabled the "Write Result to Disk" option and have you checked the returned logs under ""C:\ProgramData\Paessler\PRTG Network Monitor\Logs (Sensors)\"?

best regards.

Thanks. I've enabled that and it's still only giving me one channel.

Result of Sensor 5124.txt

{
  "prtg": {
    "result": [
      {
        "channelid": 0,
        "Value": 13,
        "Unit": "TimeResponse",
        "ShowChart": 0,
        "ShowTable": 0
      }
    ]
  }
}

Hi there,

Please add a new HTTP Advanced Sensor under this device with the same URL that the REST Custom Sensor uses and enable the "Store latest HTML result". In the Logs folder of the sensors you should get three logs for the HTTP sensor. Please check them if the correct website is monitored.

best regards.

Hi. I copied the URL from the REST sensor and used it to create a new HTTP Advanced sensor, the logs indicate that it's connecting as expected.

Result of Sensor 5125.txt included sections of the JSON file split up like this (i've replaced url, host:port~ and more children):

Stat Connected.
Sent 7/11/2019 9:27:50 AM: GET ~url~ <EOL>
sensorid: 5125<EOL>
Cookie: UserCulture=en-US<EOL>
Host: ~host:port~ <EOL>
Accept: text/html, */*<EOL>
Accept-Encoding: identity<EOL>
User-Agent: Mozilla/5.0 (compatible; PRTG Network Monitor (www.paessler.com); Windows)<EOL>
<EOL>
Recv 7/11/2019 9:27:50 AM: HTTP/1.1 200 <EOL>
X-Frame-Options: SAMEORIGIN<EOL>
Content-Type: application/json;charset=ISO-8859-1<EOL>
Transfer-Encoding: chunked<EOL>
Date: Wed, 10 Jul 2019 23:27:49 GMT<EOL>
<EOL>
2000<EOL>
{"executionTime":{"millis":91,"seconds":0},"result":{"Plan":[{"error":"OK","TimeOut":0,"label":"Label 1","planId":135,"planParts":{"childParts":[{ ~more children~ ... <EOL>
<EOL>
Stat Disconnected.

Result of Sensor 5125-A.txt just included the whole JSON file.

Thanks