.dockerignore mentioned files are not ignored - docker

Question

I'm having in Dockerfile:
ENV DATARATOR_HOME /usr/local/share/datarator
RUN mkdir -p $DATARATOR_HOME
COPY . $DATARATOR_HOME
and .dockerignore file:
/Gemfile.lock
/coverage
/spec
*.bundle
*.so
*.o
*.a
mkmf.log
*.swp
/.*
/tmp
/log
However, once showing files in the built container, I can see also those that are supposed to be ignored:
/usr/local/share/datarator # ls -lha
total 128
drwxr-xr-x 10 root root 4.0K Mar 29 21:01 .
drwxr-xr-x 4 root root 4.0K Mar 29 21:00 ..
drwxr-xr-x 2 root root 4.0K Mar 29 21:01 .bundle
-rw-rw-r-- 1 root root 24 Mar 29 20:37 .coveralls.yml
-rw-rw-r-- 1 root root 81 Mar 29 20:37 .dockerignore
drwxrwxr-x 8 root root 4.0K Mar 29 20:37 .git
-rw-rw-r-- 1 root root 85 Mar 29 20:37 .gitignore
-rw-rw-r-- 1 root root 1.2K Mar 29 20:37 .travis.yml
-rw-rw-r-- 1 root root 509 Mar 29 20:37 .vimrc
-rw-rw-r-- 1 root root 959 Mar 29 20:37 Dockerfile
-rw-rw-r-- 1 root root 94 Mar 29 20:37 Gemfile
-rw-r--r-- 1 root root 2.7K Mar 29 21:01 Gemfile.lock
-rw-rw-r-- 1 root root 343 Mar 29 20:37 Guardfile
-rw-rw-r-- 1 root root 1.0K Mar 29 20:37 LICENSE.txt
-rw-rw-r-- 1 root root 71 Mar 29 20:37 Procfile
-rw-rw-r-- 1 root root 14.8K Mar 29 20:37 README.md
-rw-rw-r-- 1 root root 198 Mar 29 20:37 Rakefile
drwxrwxr-x 2 root root 4.0K Mar 29 20:37 bin
drwxrwxr-x 2 root root 4.0K Mar 29 20:37 config
-rw-rw-r-- 1 root root 97 Mar 29 20:37 config.ru
-rw-r--r-- 1 root root 16.0K Mar 29 21:01 datarator-0.0.1.gem
-rw-rw-r-- 1 root root 1.7K Mar 29 20:37 datarator.gemspec
drwxrwxr-x 4 root root 4.0K Mar 29 20:37 lib
drwxrwxr-x 2 root root 4.0K Mar 29 20:37 log
drwxrwxr-x 3 root root 4.0K Mar 29 20:37 spec
drwxrwxr-x 2 root root 4.0K Mar 29 20:37 tmp
How can I achieve having all those mentioned in the .dockerignore file ignored?

Answer 1

The .dockerignore rules follow the filepath/#Match.
Try (for testing) Gemfile.lock instead of /Gemfile.lock.
And check that the eol (end of line) characters are unix-style, not Windows style in your .dockerignore file.
Apparently, (docker 1.10, March 2016) using rule starting with / like /xxx ( or /.*) is not well supported.

Answer 2

Here's the complete syntax for the .dockerignore:
pattern:
{ term }
term:
'*' matches any sequence of non-Separator characters
'?' matches any single non-Separator character
'[' [ '^' ] { character-range } ']'
character class (must be non-empty)
c matches character c (c != '*', '?', '\\', '[')
'\\' c matches character c
character-range:
c matches character c (c != '\\', '-', ']')
'\\' c matches character c
lo '-' hi matches character c for lo <= c <= hi
additions:
'**' matches any number of directories (including zero)
'!' lines starting with ! (exclamation mark) can be used to make exceptions to exclusions
'#' lines starting with this character are ignored: use it for comments
Therefore, some of your matches would be changed according to the above syntax:
/Gemfile.lock --> */Gemfile.lock or **/Gemfile.lock or *.lock
/spec --> */spec or **/spec
/tmp --> in the same way
/log --> in the same way
Here are two articles to explain more:
Reference
Reference