Docker is an opensource tool used for virtualization and deliver software in the form of packages called Containers. It is one of the most important tools used in networking domain. Dockerfile is a template for building the image which contains commands needed to package the software. In this post, I am going to explain the commands ADD & COPY used in Dockerfile . ADD Command: ADD command is used to copy files, directories or files from remote URLS to destination path in the image. The source paths can contain wildcards. If the destination has relative path, it is relative to the Working directory of the image. Note that source path is always relative to the Docker build context. ADD command will not support authentication. So, if there are any protected files to be added in Dockerfile building, use other tools like curl or wget Dockerfile copying Single & Multiple files, directory using ADD inst...
Docker is an opensource tool used for virtualization and deliver software in the form of packages called Containers. It is one of the most important tools used in networking domain. Dockerfile is a template for building the image which contains commands needed to package the software. In this post, I am going to explain the commands ADD & COPY used in Dockerfile.
ADD Command:
ADD command is used to copy files, directories or files from remote URLS to destination path in the image. The source paths can contain wildcards.
If the destination has relative path, it is relative to the Working directory of the image. Note that source path is always relative to the Docker build context.
ADD command will not support authentication. So, if there are any protected files to be added in Dockerfile building, use other tools like curl or wget
Dockerfile copying Single & Multiple files, directory using ADD instruction:
Assuming the source files & directories mentioned in the below Dockerfile are present relative to the build context. Also, another assumption for below docker file is that there is minimum one java file in the path relative to the build context.
FROM ubuntu:16.04
ADD App.py /root/Manideep/
ADD config.ini Settings.ini /root/Config/
ADD *.java /root/Application/
ADD Scripts /root
Line1 specifies the base image to be Ubuntu with version 16.04. Line2 copies App.py to the Manideep directory which in /root. If in Line2, / after Manideep is not present, it copies App.py content to the file named Manideep in /root. Line 3 copies multiple files in to a single directory and while copying multiple files, the destination path must end with a /. Line 4 uses specifying source file using regular expressions and copies them in to /root/Application/ path. In line 4 also, the destination path must end with a /. Line 5 copies contents of directory Scripts to /root path.
Also note that remote files copied to image will have permissions 600.
Dockerfile copying Remote files, Local Tar Archive using ADD instruction:
Assuming the files mentioned are present in local system relative to build context and path and remote system. Please find the below Dockerfile copies remote file and local tar file to destination path of the image
FROM ubuntu:16.04
ADD https://cf-courses-data.s3.us.cloud-object-storage.appdomain.cloud/IBMDeveloperSkillsNetwork-DV0101EN-SkillsNetwork/Data%20Files/Canada.xlsx /root/
ADD pandas.tar.gz /root/Pandas/
Line1 specifies the base image to be Ubuntu with version 16.04. Line2 downloads and copies remote Excel file to /root/ path. Line 3 extracts the tar and store it contents to the /root/Pandas path. Note that extraction works only for some standards and for remaining simple tar file is copied to the destination without extraction. Also, this extraction is applicable only for local tar files
COPY Command:
COPY command purpose is also to copy files and directories from source relative to build context to destination path of the image.
The main difference between ADD and COPY is that remote files and local tar extraction is not possible with COPY command.
Dockerfile copying Single, Multiple files and directory using COPY instruction:
Assuming the files, directories mentioned in the Dockerfile are present in path relative to build context. Also, another assumption for below docker file is that there is minimum one java file in the path relative to the build context.
FROM ubuntu:16.04
COPY App.py /root/Manideep/
COPY config.ini Settings.ini /root/Config/
COPY *.java /root/Application/
COPY Scripts /root
Line1 specifies the base image to be Ubuntu with version 16.04. Line2 copies App.py to the Manideep directory which in /root. If in Line2, / after Manideep is not present, it copies App.py content to the file named Manideep in /root. Line 3 copies multiple files in to a single directory and while copying multiple files, the destination path must end with a /. Line 4 uses specifying source files using regular expression and copies them in to /root/Application/ path. In line 4 also, the destination path must end with a /. Line 5 copies contents of directory Scripts to /root path.
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