Dockerfile copy keep subdirectory structure

To merge a local directory into a directory within an image, do this. It will not delete files already present within the image. It will only add files that are present locally, overwriting the files in the image if a file of the same name already exists.

COPY ./local-path/. /image-path/

Alternatively you can use a "." instead of *, as this will take all the files in the working directory, include the folders and subfolders:

FROM ubuntu
COPY . /
RUN ls -la /

Remove star from COPY, with this Dockerfile:

FROM ubuntu
COPY files/ /files/
RUN ls -la /files/*

Structure is there:

$ docker build .
Sending build context to Docker daemon 5.632 kB
Sending build context to Docker daemon 
Step 0 : FROM ubuntu
 ---> d0955f21bf24
Step 1 : COPY files/ /files/
 ---> 5cc4ae8708a6
Removing intermediate container c6f7f7ec8ccf
Step 2 : RUN ls -la /files/*
 ---> Running in 08ab9a1e042f
/files/folder1:
total 8
drwxr-xr-x 2 root root 4096 May 13 16:04 .
drwxr-xr-x 4 root root 4096 May 13 16:05 ..
-rw-r--r-- 1 root root    0 May 13 16:04 file1
-rw-r--r-- 1 root root    0 May 13 16:04 file2

/files/folder2:
total 8
drwxr-xr-x 2 root root 4096 May 13 16:04 .
drwxr-xr-x 4 root root 4096 May 13 16:05 ..
-rw-r--r-- 1 root root    0 May 13 16:04 file1
-rw-r--r-- 1 root root    0 May 13 16:04 file2
 ---> 03ff0a5d0e4b
Removing intermediate container 08ab9a1e042f
Successfully built 03ff0a5d0e4b