When you’re using .dockerignore to ignore files within directories, it works a little differently than .gitignore.

To ignore a file across all subdirectories, prefix the filename with **. For example, to ignore the file file.txt in all subdirectories, add the following to .dockerignore:

**file.txt

To ignore a specific file extension across all subdirectories, prefix the file extension with **/*. In this example, all files with the .txt extension will be ignored by Docker:

**/*.txt

Also, keep in mind that .dockerignore should be in the root of the context you are passing in to Docker or it won’t be taken into account.