Docker build giving STDOut errors, but no sign of actual error

Hi everyone,

I’m not very knowledgeable on docker - so please go easy on me. Recently started getting an issue with docker Build command such that it appears that normal output is coming out as a STDout error - this causes the pipeline to stop at the end of the step (on the failOnStderr check). Didn’t seem to happen until recently, and… I didn’t change anything (well I don’t think so anyway). But I’ve dug through as many logs as I could find but can’t find a real error among them

output I’m getting looks like (and this is just an example from a lot of errors in the output);

##[error]#21 3.276 Build started... 

##[error]#21 17.68 Build succeeded. 

##[error]#21 DONE 20.1s 

#22 exporting to image 
#22 exporting layers

##[error]#22 exporting layers 3.8s done` 

any ideas? I asked MS dev ops for help and they said it’s not their problem. I’m a bit lost on this, if I could actually see an actual error, I’m sure I could get a grip on it :frowning:

Expected behavior

normal output shouldn’t be flagged as error

Actual behavior

normal output seems to be flagged as error

Additional Information

Steps to reproduce the behavior

This presumably is very specific to docker use within my azure pipeline - but any docker build command seems to be doing this within the context of my pipeline. commands such as;

script: |
          docker build . -f $(dockerfilePath) --target build -t build:$(tag)

(where the path is pointing to a docker file that does lots of stuff- but stuff like; RUN dotnet build “xxxxx.sln” -c Release -o /app/build -maxcpucount:1

Found a blog post that sounds very much like what I have been seeing - only downside is that someone far smarter than myself doesn’t know the underlying cause :slight_smile: