NAME

nbdkit-curl-plugin - nbdkit curl plugin (HTTP, FTP, SSH and other protocols)

SYNOPSIS

 nbdkit -r curl [url=]http://example.com/disk.img
 nbdkit -r curl [url=]sftp://you@example.com/~/disk.img

DESCRIPTION

"nbdkit-curl-plugin" is a plugin for nbdkit(1) which turns content served over HTTP, FTP, SSH, and more, into a Network Block Device. It uses a library called libcurl (also known as cURL) to read data from URLs. The exact list of protocols that libcurl can handle depends on how it was compiled, but most versions will handle HTTP, HTTPS, FTP, FTPS and SFTP (see: "curl -V"). For more information about libcurl, see http://curl.haxx.se.

Note: This plugin supports writes. However:

• For HTTP, you may not want nbdkit to issue PUT requests to the remote server (which probably doesn't understand them).
• SFTP helpfully truncates the target file when you open it for writing. Not useful!

To force nbdkit to use a readonly connection, pass the -r flag.

 nbdkit -r curl http://example.com/disk.img

 nbdkit -r curl sftp://example.com/~/disk.img

 nbdkit -r curl sftp://example.com/~/disk.img username=fred password=-

PARAMETERS

password=PASSWORD

Set the password to use when connecting to the remote server.

Note that passing this on the command line is not secure on shared machines.

password=-

Ask for the password (interactively) when nbdkit starts up.

password=+FILENAME

Read the password from the named file. This is the most secure method to supply a password, as long as you set the permissions on the file appropriately.

sslverify=0

Don't verify the SSL certificate of the remote host.

timeout=SECS

Set the timeout for requests.

timeout=0

Use the default libcurl timeout for requests.

unix_socket_path=PATH

Instead of using a TCP connection, connect to the server over the named Unix domain socket. See "CURLOPT_UNIX_SOCKET_PATH" in curl_easy_setopt(3).

url=URL

The URL of the remote disk image. This is passed to libcurl directly via "CURLOPT_URL" in curl_easy_setopt(3).

This parameter is required.

In nbdkit ≥ 1.8.2, "url=" may be omitted.

user=USERNAME

Set the username to use when connecting to the remote server. This may also be set in the URL (eg. "http://foo@example.com/disk.img")

DEBUG FLAG

-D curl.verbose=1

This enables very verbose curl debugging. See CURLOPT_VERBOSE(3). This is mainly useful if you suspect there is a bug inside libcurl itself.

SEE ALSO

curl(1), libcurl(3), CURLOPT_VERBOSE(3), nbdkit(1), nbdkit-plugin(3).

AUTHORS

Richard W.M. Jones

Parts derived from Alexander Graf's "QEMU Block driver for CURL images".

COPYRIGHT

Copyright (C) 2014 Red Hat Inc.

LICENSE

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.