How to create the 'dockercontainer' sensor?

Hey.

I’m trying to add the sensor for dockercontainers via the Powershell CLI

My code so far:

$Device = Get-Device -Id 1754

$Key = "-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----"

$Cert = "-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----"

$Params = $Device | New-SensorParameters -Verbose -RawType "dockercontainer" -QueryParameters @{
    dockerport_ = 2376
    key_ = "$Key"
    cert_ = "$Cert"
}
$Params

And I get the following error New-SensorParameters : An unspecified error occurred while trying to resolve sensor targets. Specified sensor type may not be valid on this device, or sensor query target parameters may be incorrect. Check the Device 'Host' is still valid or try adding sensor with the PRTG UI.

I tried some variations and debugging the script and the creation process via the PRTG UI and noticed that the UI sends a POST request to addsensor3.htm but with my code a GET request will be sent.

Does anyone have any idea what I’m doing wrong or has a hint? I feel like I’m missing something.

Thanks for your Help.

[lordmilko]

I think I may have solved it!

Are you doing this in PowerShell or the PowerShell ISE? If PowerShell, can you try using the ISE instead?

I noticed when I type everything up in the ISE and hit F5 it runs without issue. When I save that script, open a regular PowerShell and then run the script, I get the same error as you! How can the same script generate different results in different circumstances?

The answer is that the response URI returned in PowerShell contains newlines (\n) whereas in the ISE the URI is all a single line. This appears to trip up our attempt to extract the tmpid from the response, resulting in a tmpid of <number>\n<certificate>. PrtgAPI later tries to convert this string to a number, fails, and assumes it didn’t get a tmpid.

The solution to this is to simply modify the tmpid extraction regex to treat the input string as a single line. I’m not sure whether you need to be running your code in a script automatically all the time or whether this is just a one time thing, however are you able to advise if using the ISE resolves the issue?

Regards, lordmilko

[lordmilko]

I tested your code on my own Docker instance and it worked fine. Are you sure the ID your Docker server’s PRTG device is 1754? I only get the error you get when I target a server that is not running the Docker Daemon

My Docker Daemon runs on Windows; the contents of my daemon.json are as follows

{
    "hosts": ["tcp://0.0.0.0:2376", "npipe://"],
    "data-root": "d:\\docker",
    "experimental":  true,
    "tlsverify": false,
    "tlscacert": "D:\\docker\\certs.d\\ca.pem",
    "tlscert": "D:\\docker\\certs.d\\server-cert.pem",
    "tlskey": "D:\\docker\\certs.d\\server-key.pem"
}