CopyIgnoredFile#

Output#

Attempting to Copy file "./tmp/Dockerfile" that is excluded by .dockerignore

Description#

When you use the Add or Copy instructions from within a Dockerfile, you should ensure that the files to be copied into the image do not match a pattern present in .dockerignore.

Files which match the patterns in a .dockerignore file are not present in the context of the image when it is built. Trying to copy or add a file which is missing from the context will result in a build error.

Examples#

With the given .dockerignore file:

*/tmp/*

❌ Bad: Attempting to Copy file "./tmp/Dockerfile" that is excluded by .dockerignore

FROM scratch
COPY ./tmp/helloworld.txt /helloworld.txt

✅ Good: Copying a file which is not excluded by .dockerignore

FROM scratch
COPY ./forever/helloworld.txt /helloworld.txt