Docker Dockerfiles COPY Instruction
Example
COPY has two forms:
COPY <src>... <dest>
COPY ["<src>",... "<dest>"] (this form is required for paths containing whitespace)
The COPY instruction copies new files or directories from <src> and adds them to the filesystem of the container at the path <dest>.
Multiple <src> resource may be specified but they must be relative to the source directory that is being built (the context of the build).
Each <src> may contain wildcards and matching will be done using Go’s filepath.Match rules. For example:
COPY hom* /mydir/ # adds all files starting with "hom"
COPY hom?.txt /mydir/ # ? is replaced with any single character, e.g., "home.txt"
The <dest> is an absolute path, or a path relative to WORKDIR, into which the source will be copied inside the destination container.
COPY test relativeDir/ # adds "test" to `WORKDIR`/relativeDir/
COPY test /absoluteDir/ # adds "test" to /absoluteDir/
All new files and directories are created with a UID and GID of 0.
Note: If you build using stdin (docker build - < somefile), there is no build context, so COPY can’t be used.
COPY obeys the following rules:
-
The
<src>path must be inside the context of the build; you cannotCOPY../something /something, because the first step of a docker build is to send the context directory (and subdirectories) to the docker daemon. -
If
<src>is a directory, the entire contents of the directory are copied, including filesystem metadata. Note: The directory itself is not copied, just its contents. -
If
<src>is any other kind of file, it is copied individually along with its metadata. In this case, if<dest>ends with a trailing slash /, it will be considered a directory and the contents of<src>will be written at<dest>/base(<src>). -
If multiple
<src>resources are specified, either directly or due to the use of a wildcard, then<dest>must be a directory, and it must end with a slash/. -
If
<dest>does not end with a trailing slash, it will be considered a regular file and the contents of<src>will be written at<dest>. -
If
<dest>doesn’t exist, it is created along with all missing directories in its path.
