docs: Updated for docker cp and its API changes

Documented changes to API to enable new `docker cp` behavior.

Added documentation on `docker cp` usage and behavior.

Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)

docs/reference/api/docker_remote_api.md

@@ -68,6 +68,23 @@ Running `docker rmi` emits an **untag** event when removing an image name.  The
 
 ### What's new
 
+`GET /containers/(id)/archive`
+
+**New!**
+Get an archive of filesystem content from a container.
+
+`PUT /containers/(id)/archive`
+
+**New!**
+Upload an archive of content to be extracted to an
+existing directory inside a container's filesystem.
+
+`POST /containers/(id)/copy`
+
+**Deprecated!**
+This copy endpoint has been deprecated in favor of the above `archive` endpoint
+which can be used to download files and directories from a container.
+
 **New!**
 The `hostConfig` option now accepts the field `GroupAdd`, which specifies a list of additional
 groups that the container process will run as.

docs/reference/api/docker_remote_api_v1.20.md

@@ -1039,6 +1039,8 @@ Status Codes:
 
 Copy files or folders of container `id`
 
+**Deprecated** in favor of the `archive` endpoint below.
+
 **Example request**:
 
     POST /containers/4fa6e0f0c678/copy HTTP/1.1
@@ -1061,6 +1063,120 @@ Status Codes:
 -   **404** – no such container
 -   **500** – server error
 
+### Retrieving information about files and folders in a container
+
+`HEAD /containers/(id)/archive`
+
+See the description of the `X-Docker-Container-Path-Stat` header in the
+folowing section.
+
+### Get an archive of a filesystem resource in a container
+
+`GET /containers/(id)/archive`
+
+Get an tar archive of a resource in the filesystem of container `id`.
+
+Query Parameters:
+
+- **path** - resource in the container's filesystem to archive. Required.
+
+    If not an absolute path, it is relative to the container's root directory.
+    The resource specified by **path** must exist. To assert that the resource
+    is expected to be a directory, **path** should end in `/` or  `/.`
+    (assuming a path separator of `/`). If **path** ends in `/.` then this
+    indicates that only the contents of the **path** directory should be
+    copied. A symlink is always resolved to its target.
+
+    **Note**: It is not possible to copy certain system files such as resources
+    under `/proc`, `/sys`, `/dev`, and mounts created by the user in the
+    container.
+
+**Example request**:
+
+        GET /containers/8cce319429b2/archive?path=/root HTTP/1.1
+
+**Example response**:
+
+        HTTP/1.1 200 OK
+        Content-Type: application/x-tar
+        X-Docker-Container-Path-Stat: eyJuYW1lIjoicm9vdCIsInBhdGgiOiIvcm9vdCIsInNpemUiOjQwOTYsIm1vZGUiOjIxNDc0ODQwOTYsIm10aW1lIjoiMjAxNC0wMi0yN1QyMDo1MToyM1oifQ==
+
+        {{ TAR STREAM }}
+
+On success, a response header `X-Docker-Container-Path-Stat` will be set to a
+base64-encoded JSON object containing some filesystem header information about
+the archived resource. The above example value would decode to the following
+JSON object (whitespace added for readability):
+
+        {
+            "name": "root",
+            "path": "/root",
+            "size": 4096,
+            "mode": 2147484096,
+            "mtime": "2014-02-27T20:51:23Z"
+        }
+
+A `HEAD` request can also be made to this endpoint if only this information is
+desired.
+
+Status Codes:
+
+- **200** - success, returns archive of copied resource
+- **400** - client error, bad parameter, details in JSON response body, one of:
+    - must specify path parameter (**path** cannot be empty)
+    - not a directory (**path** was asserted to be a directory but exists as a
+      file)
+- **404** - client error, resource not found, one of:
+    – no such container (container `id` does not exist)
+    - no such file or directory (**path** does not exist)
+- **500** - server error
+
+### Extract an archive of files or folders to a directory in a container
+
+`PUT /containers/(id)/archive`
+
+Upload a tar archive to be extracted to a path in the filesystem of container
+`id`.
+
+Query Parameters:
+
+- **path** - path to a directory in the container
+    to extract the archive's contents into. Required.
+
+    If not an absolute path, it is relative to the container's root directory.
+    The **path** resource must exist.
+- **noOverwriteDirNonDir** - If "1", "true", or "True" then it will be an error
+    if unpacking the given content would cause an existing directory to be
+    replaced with a non-directory and vice versa.
+
+**Example request**:
+
+        PUT /containers/8cce319429b2/archive?path=/vol1 HTTP/1.1
+        Content-Type: application/x-tar
+
+        {{ TAR STREAM }}
+
+**Example response**:
+
+        HTTP/1.1 200 OK
+
+Status Codes:
+
+- **200** – the content was extracted successfully
+- **400** - client error, bad parameter, details in JSON response body, one of:
+    - must specify path parameter (**path** cannot be empty)
+    - not a directory (**path** should be a directory but exists as a file)
+    - unable to overwrite existing directory with non-directory
+      (if **noOverwriteDirNonDir**)
+    - unable to overwrite existing non-directory with directory
+      (if **noOverwriteDirNonDir**)
+- **403** - client error, permission denied, the volume
+    or container rootfs is marked as read-only.
+- **404** - client error, resource not found, one of:
+    – no such container (container `id` does not exist)
+    - no such file or directory (**path** resource does not exist)
+- **500** – server error
+
 ## 2.2 Images
 
 ### List Images

docs/reference/commandline/cp.md

@@ -11,12 +11,81 @@ weight=1
 
 # cp
 
-    Usage: docker cp CONTAINER:PATH HOSTDIR|-
+Copy files/folders between a container and the local filesystem.
 
-    Copy files/folders from the PATH to the HOSTDIR.
+    Usage:  docker cp [options] CONTAINER:PATH LOCALPATH|-
+            docker cp [options] LOCALPATH|- CONTAINER:PATH
 
-Copy files or folders from a container's filesystem to the directory on the
-host. Use '-' to write the data as a tar file to `STDOUT`. `CONTAINER:PATH` is
-relative to the root of the container's filesystem.
+    --help  Print usage statement
 
+In the first synopsis form, the `docker cp` utility copies the contents of
+`PATH` from the filesystem of `CONTAINER` to the `LOCALPATH` (or stream as
+a tar archive to `STDOUT` if `-` is specified).
 
+In the second synopsis form, the contents of `LOCALPATH` (or a tar archive
+streamed from `STDIN` if `-` is specified) are copied from the local machine to
+`PATH` in the filesystem of `CONTAINER`.
+
+You can copy to or from either a running or stopped container. The `PATH` can
+be a file or directory. The `docker cp` command assumes all `CONTAINER:PATH`
+values are relative to the `/` (root) directory of the container. This means
+supplying the initial forward slash is optional; The command sees
+`compassionate_darwin:/tmp/foo/myfile.txt` and
+`compassionate_darwin:tmp/foo/myfile.txt` as identical. If a `LOCALPATH` value
+is not absolute, is it considered relative to the current working directory.
+
+Behavior is similar to the common Unix utility `cp -a` in that directories are
+copied recursively with permissions preserved if possible. Ownership is set to
+the user and primary group on the receiving end of the transfer. For example,
+files copied to a container will be created with `UID:GID` of the root user.
+Files copied to the local machine will be created with the `UID:GID` of the
+user which invoked the `docker cp` command.
+
+Assuming a path separator of `/`, a first argument of `SRC_PATH` and second
+argument of `DST_PATH`, the behavior is as follows:
+
+- `SRC_PATH` specifies a file
+    - `DST_PATH` does not exist
+        - the file is saved to a file created at `DST_PATH`
+    - `DST_PATH` does not exist and ends with `/`
+        - Error condition: the destination directory must exist.
+    - `DST_PATH` exists and is a file
+        - the destination is overwritten with the contents of the source file
+    - `DST_PATH` exists and is a directory
+        - the file is copied into this directory using the basename from
+          `SRC_PATH`
+- `SRC_PATH` specifies a directory
+    - `DST_PATH` does not exist
+        - `DST_PATH` is created as a directory and the *contents* of the source
+           directory are copied into this directory
+    - `DST_PATH` exists and is a file
+        - Error condition: cannot copy a directory to a file
+    - `DST_PATH` exists and is a directory
+        - `SRC_PATH` does not end with `/.`
+            - the source directory is copied into this directory
+        - `SRC_PAPTH` does end with `/.`
+            - the *content* of the source directory is copied into this
+              directory
+
+The command requires `SRC_PATH` and `DST_PATH` to exist according to the above
+rules. If `SRC_PATH` is local and is a symbolic link, the symbolic link, not
+the target, is copied.
+
+A colon (`:`) is used as a delimiter between `CONTAINER` and `PATH`, but `:`
+could also be in a valid `LOCALPATH`, like `file:name.txt`. This ambiguity is
+resolved by requiring a `LOCALPATH` with a `:` to be made explicit with a
+relative or absolute path, for example:
+
+    `/path/to/file:name.txt` or `./file:name.txt`
+
+It is not possible to copy certain system files such as resources under
+`/proc`, `/sys`, `/dev`, and mounts created by the user in the container.
+
+Using `-` as the first argument in place of a `LOCALPATH` will stream the
+contents of `STDIN` as a tar archive which will be extracted to the `PATH` in
+the filesystem of the destination container. In this case, `PATH` must specify
+a directory.
+
+Using `-` as the second argument in place of a `LOCALPATH` will stream the
+contents of the resource from the source container as a tar archive to
+`STDOUT`.

man/docker-cp.1.md

@@ -2,69 +2,150 @@
 % Docker Community
 % JUNE 2014
 # NAME
-docker-cp - Copy files or folders from a container's PATH to a HOSTDIR
-or to STDOUT.
+docker-cp - Copy files/folders between a container and the local filesystem.
 
 # SYNOPSIS
 **docker cp**
 [**--help**]
-CONTAINER:PATH HOSTDIR|-
+CONTAINER:PATH LOCALPATH|-
+LOCALPATH|- CONTAINER:PATH
 
 # DESCRIPTION
 
-Copy files or folders from a `CONTAINER:PATH` to the `HOSTDIR` or to `STDOUT`. 
-The `CONTAINER:PATH` is relative to the root of the container's filesystem. You
-can copy from either a running or stopped container. 
+In the first synopsis form, the `docker cp` utility copies the contents of
+`PATH` from the filesystem of `CONTAINER` to the `LOCALPATH` (or stream as
+a tar archive to `STDOUT` if `-` is specified).
 
-The `PATH` can be a file or directory. The `docker cp` command assumes all
-`PATH` values start at the `/` (root) directory. This means supplying the
-initial forward slash is optional; The command sees
+In the second synopsis form, the contents of `LOCALPATH` (or a tar archive
+streamed from `STDIN` if `-` is specified) are copied from the local machine to
+`PATH` in the filesystem of `CONTAINER`.
+
+You can copy to or from either a running or stopped container. The `PATH` can
+be a file or directory. The `docker cp` command assumes all `CONTAINER:PATH`
+values are relative to the `/` (root) directory of the container. This means
+supplying the initial forward slash is optional; The command sees
 `compassionate_darwin:/tmp/foo/myfile.txt` and
-`compassionate_darwin:tmp/foo/myfile.txt` as identical.
+`compassionate_darwin:tmp/foo/myfile.txt` as identical. If a `LOCALPATH` value
+is not absolute, is it considered relative to the current working directory.
+
+Behavior is similar to the common Unix utility `cp -a` in that directories are
+copied recursively with permissions preserved if possible. Ownership is set to
+the user and primary group on the receiving end of the transfer. For example,
+files copied to a container will be created with `UID:GID` of the root user.
+Files copied to the local machine will be created with the `UID:GID` of the
+user which invoked the `docker cp` command.
+
+Assuming a path separator of `/`, a first argument of `SRC_PATH` and second
+argument of `DST_PATH`, the behavior is as follows:
+
+- `SRC_PATH` specifies a file
+    - `DST_PATH` does not exist
+        - the file is saved to a file created at `DST_PATH`
+    - `DST_PATH` does not exist and ends with `/`
+        - Error condition: the destination directory must exist.
+    - `DST_PATH` exists and is a file
+        - the destination is overwritten with the contents of the source file
+    - `DST_PATH` exists and is a directory
+        - the file is copied into this directory using the basename from
+          `SRC_PATH`
+- `SRC_PATH` specifies a directory
+    - `DST_PATH` does not exist
+        - `DST_PATH` is created as a directory and the *contents* of the source
+           directory are copied into this directory
+    - `DST_PATH` exists and is a file
+        - Error condition: cannot copy a directory to a file
+    - `DST_PATH` exists and is a directory
+        - `SRC_PATH` does not end with `/.`
+            - the source directory is copied into this directory
+        - `SRC_PAPTH` does end with `/.`
+            - the *content* of the source directory is copied into this
+              directory
+
+The command requires `SRC_PATH` and `DST_PATH` to exist according to the above
+rules. If `SRC_PATH` is local and is a symbolic link, the symbolic link, not
+the target, is copied.
+
+A colon (`:`) is used as a delimiter between `CONTAINER` and `PATH`, but `:`
+could also be in a valid `LOCALPATH`, like `file:name.txt`. This ambiguity is
+resolved by requiring a `LOCALPATH` with a `:` to be made explicit with a
+relative or absolute path, for example:
+
+    `/path/to/file:name.txt` or `./file:name.txt`
+
+It is not possible to copy certain system files such as resources under
+`/proc`, `/sys`, `/dev`, and mounts created by the user in the container.
+
+Using `-` as the first argument in place of a `LOCALPATH` will stream the
+contents of `STDIN` as a tar archive which will be extracted to the `PATH` in
+the filesystem of the destination container. In this case, `PATH` must specify
+a directory.
+
+Using `-` as the second argument in place of a `LOCALPATH` will stream the
+contents of the resource from the source container as a tar archive to
+`STDOUT`.
+
+# OPTIONS
+**--help**
+  Print usage statement
+
+# EXAMPLES
+
+Suppose a container has finished producing some output as a file it saves
+to somewhere in its filesystem. This could be the output of a build job or
+some other computation. You can copy these outputs from the container to a
+location on your local host.
 
-The `HOSTDIR` refers to a directory on the host. If you do not specify an
-absolute path for your `HOSTDIR` value, Docker creates the directory relative to
-where you run the `docker cp` command. For example, suppose you want to copy the
-`/tmp/foo` directory from a container to the `/tmp` directory on your host. If
-you run `docker cp` in your `~` (home) directory on the host:
+If you want to copy the `/tmp/foo` directory from a container to the
+existing `/tmp` directory on your host. If you run `docker cp` in your `~`
+(home) directory on the local host:
 
 		$ docker cp compassionate_darwin:tmp/foo /tmp
 
 Docker creates a `/tmp/foo` directory on your host. Alternatively, you can omit
-the leading slash in the command. If you execute this command from your home directory:
+the leading slash in the command. If you execute this command from your home
+directory:
 
 		$ docker cp compassionate_darwin:tmp/foo tmp
 
-Docker creates a `~/tmp/foo` subdirectory.  
+If `~/tmp` does not exist, Docker will create it and copy the contents of
+`/tmp/foo` from the container into this new directory. If `~/tmp` already
+exists as a directory, then Docker will copy the contents of `/tmp/foo` from
+the container into a directory at `~/tmp/foo`.
 
-When copying files to an existing `HOSTDIR`, the `cp` command adds the new files to
-the directory. For example, this command:
+When copying a single file to an existing `LOCALPATH`, the `docker cp` command
+will either overwrite the contents of `LOCALPATH` if it is a file or place it
+into `LOCALPATH` if it is a directory, overwriting an existing file of the same
+name if one exists. For example, this command:
 
-		$ docker cp sharp_ptolemy:/tmp/foo/myfile.txt /tmp
+		$ docker cp sharp_ptolemy:/tmp/foo/myfile.txt /test
 
-Creates a `/tmp/foo` directory on the host containing the `myfile.txt` file. If
-you repeat the command but change the filename:
+If `/test` does not exist on the local machine, it will be created as a file
+with the contents of `/tmp/foo/myfile.txt` from the container. If `/test`
+exists as a file, it will be overwritten. Lastly, if `/tmp` exists as a
+directory, the file will be copied to `/test/myfile.txt`.
 
-		$ docker cp sharp_ptolemy:/tmp/foo/secondfile.txt /tmp
+Next, suppose you want to copy a file or folder into a container. For example,
+this could be a configuration file or some other input to a long running
+computation that you would like to place into a created container before it
+starts. This is useful because it does not require the configuration file or
+other input to exist in the container image.
 
-Your host's `/tmp/foo` directory will contain both files:
+If you have a file, `config.yml`, in the current directory on your local host
+and wish to copy it to an existing directory at `/etc/my-app.d` in a container,
+this command can be used:
 
-		$ ls /tmp/foo
-		myfile.txt secondfile.txt
-		
-Finally, use '-' to write the data as a `tar` file to STDOUT.
+		$ docker cp config.yml myappcontainer:/etc/my-app.d
 
-# OPTIONS
-**--help**
-  Print usage statement
+If you have several files in a local directory `/config` which you need to copy
+to a directory `/etc/my-app.d` in a container:
 
-# EXAMPLES
-An important shell script file, created in a bash shell, is copied from
-the exited container to the current dir on the host:
+		$ docker cp /config/. myappcontainer:/etc/my-app.d
 
-    # docker cp c071f3c3ee81:setup.sh .
+The above command will copy the contents of the local `/config` directory into
+the directory `/etc/my-app.d` in the container.
 
 # HISTORY
 April 2014, Originally compiled by William Henry (whenry at redhat dot com)
 based on docker.com source material and internal work.
 June 2014, updated by Sven Dowideit <SvenDowideit@home.org.au>
+May 2015, updated by Josh Hawn <josh.hawn@docker.com>