External Tool - newbie question

I am having issue with the external tool to call curl. It is a very simple POST request passing some basic command line arguments. However Knime keep erroring out with the “execution failed (exit code 2)” message. I cannot even debug this as nothing came out of the output port.

Appreciate it if anyone can provide some guidance.

Hi,
I think the GET Request and POST Request nodes can do most of the stuff cURL can do. Why don’t you use those instead? That should make the workflow much easier to port to other operating systems and solves your problem :wink:
For error code 2, the cURL documentation says:

Failed to initialize. This is mostly an internal error or a problem with the libcurl installation or system libcurl runs in.

Kind regards
Alexander

@Alexander I have a POST request that need to use SSL certificate for authentication and the standard REST extension do not support it. Please let me know if this is not the case.

Anyway I figured out the issue with curl and you are right. Basically the external tool will not return any message from the stderr if the program is throwing errors. You will just get a generic exit code.

This is a bummer as I have used other ETL tools before that handle command line call differently and IMO better. It will just run and capture any text output from stderr. The ETL tool can then analyze the error with the downstream pipes.

Hi,
You could use R or Python for the request, this was discussed here. You are right, though. It would be useful to see the error output within KNIME.
Kind regards
Alexander

2 Likes

Thanks Alexander, i will give it a try however i am not familiar with the R statistical programming language. I am more familiar with Java but the SSL certiicate implementation is overly complicated in which led me to looking at Curl.

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