Docker - How to check if curl command inside Dockerfile had response code 200

Question

Inside a Dockerfile I try to download an artifact using curl. I have checked that although the artifact doesn't exist (thus getting a 404) the docker build keeps running.

RUN curl -H 'Cache-Control: no-cache' ${STANDALONE_LOCATION} -o $JBOSS_HOME/standalone/configuration/standalone.xml

Is there a way to check that the curl response code is 200 and throw an error otherwise?

Answer 1

You can add -f (or --fail ) to the curl call, which causes curl to silently fail on server errors. From the curl manpage :

-f/--fail

(HTTP) Fail silently (no output at all) on server errors. This is mostly done to better enable scripts etc to better deal with failed attempts. In normal cases when a HTTP server fails to deliver a document, it returns an HTML document stating so (which often also describes why and more). This flag will prevent curl from outputting that and return error 22.

This method is not fail-safe and there are occasions where non-successful response codes will slip through, especially when authentication is involved (response codes 401 and 407).