205 lines
7.5 KiB
Scheme
205 lines
7.5 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (guix ssh)
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#:use-module (guix store)
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#:autoload (guix ui) (N_)
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#:use-module (ssh channel)
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#:use-module (ssh popen)
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#:use-module (ssh session)
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#:use-module (ssh dist)
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#:use-module (ssh dist node)
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#:use-module (srfi srfi-11)
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#:use-module (ice-9 match)
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#:export (connect-to-remote-daemon
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send-files
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retrieve-files
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remote-store-host
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file-retrieval-port))
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;;; Commentary:
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;;;
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;;; This module provides tools to support communication with remote stores
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;;; over SSH, using Guile-SSH.
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;;;
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;;; Code:
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(define* (connect-to-remote-daemon session
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#:optional
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(socket-name "/var/guix/daemon-socket/socket"))
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"Connect to the remote build daemon listening on SOCKET-NAME over SESSION,
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an SSH session. Return a <nix-server> object."
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(define redirect
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;; Code run in SESSION to redirect the remote process' stdin/stdout to the
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;; daemon's socket, à la socat. The SSH protocol supports forwarding to
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;; Unix-domain sockets but libssh doesn't have an API for that, hence this
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;; hack.
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`(begin
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(use-modules (ice-9 match) (rnrs io ports))
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(let ((sock (socket AF_UNIX SOCK_STREAM 0))
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(stdin (current-input-port))
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(stdout (current-output-port)))
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(setvbuf stdin _IONBF)
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(setvbuf stdout _IONBF)
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(connect sock AF_UNIX ,socket-name)
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(let loop ()
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(match (select (list stdin sock) '() (list stdin stdout sock))
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((reads writes ())
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(when (memq stdin reads)
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(match (get-bytevector-some stdin)
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((? eof-object?)
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(primitive-exit 0))
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(bv
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(put-bytevector sock bv))))
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(when (memq sock reads)
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(match (get-bytevector-some sock)
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((? eof-object?)
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(primitive-exit 0))
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(bv
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(put-bytevector stdout bv))))
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(loop))
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(_
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(primitive-exit 1)))))))
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(let ((channel
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(open-remote-pipe* session OPEN_BOTH
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;; Sort-of shell-quote REDIRECT.
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"guile" "-c"
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(object->string
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(object->string redirect)))))
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(open-connection #:port channel)))
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(define (store-import-channel session)
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"Return an output port to which archives to be exported to SESSION's store
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can be written."
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;; Using the 'import-paths' RPC on a remote store would be slow because it
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;; makes a round trip every time 32 KiB have been transferred. This
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;; procedure instead opens a separate channel to use the remote
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;; 'import-paths' procedure, which consumes all the data in a single round
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;; trip.
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(define import
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`(begin
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(use-modules (guix))
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(with-store store
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(setvbuf (current-input-port) _IONBF)
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;; FIXME: Exceptions are silently swallowed. We should report them
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;; somehow.
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(import-paths store (current-input-port)))))
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(open-remote-output-pipe session
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(string-join
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`("guile" "-c"
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,(object->string
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(object->string import))))))
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(define (store-export-channel session files)
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"Return an input port from which an export of FILES from SESSION's store can
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be read."
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;; Same as above: this is more efficient than calling 'export-paths' on a
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;; remote store.
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(define export
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`(begin
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(use-modules (guix))
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(with-store store
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(setvbuf (current-output-port) _IONBF)
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;; FIXME: Exceptions are silently swallowed. We should report them
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;; somehow.
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(export-paths store ',files (current-output-port)))))
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(open-remote-input-pipe session
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(string-join
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`("guile" "-c"
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,(object->string
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(object->string export))))))
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(define* (send-files local files remote
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#:key (log-port (current-error-port)))
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"Send the subset of FILES from LOCAL (a local store) that's missing to
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REMOTE, a remote store."
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;; Compute the subset of FILES missing on SESSION and send them.
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(let* ((session (channel-get-session (nix-server-socket remote)))
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(node (make-node session))
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(missing (node-eval node
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`(begin
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(use-modules (guix)
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(srfi srfi-1) (srfi srfi-26))
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(with-store store
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(remove (cut valid-path? store <>)
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',files)))))
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(count (length missing))
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(port (store-import-channel session)))
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(format log-port (N_ "sending ~a store item to '~a'...~%"
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"sending ~a store items to '~a'...~%" count)
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count (session-get session 'host))
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;; Send MISSING in topological order.
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(export-paths local missing port)
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;; Tell the remote process that we're done. (In theory the end-of-archive
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;; mark of 'export-paths' would be enough, but in practice it's not.)
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(channel-send-eof port)
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;; Wait for completion of the remote process.
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(let ((result (zero? (channel-get-exit-status port))))
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(close-port port)
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result)))
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(define (remote-store-session remote)
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"Return the SSH channel beneath REMOTE, a remote store as returned by
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'connect-to-remote-daemon', or #f."
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(channel-get-session (nix-server-socket remote)))
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(define (remote-store-host remote)
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"Return the name of the host REMOTE is connected to, where REMOTE is a
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remote store as returned by 'connect-to-remote-daemon'."
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(match (remote-store-session remote)
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(#f #f)
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((? session? session)
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(session-get session 'host))))
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(define (file-retrieval-port files remote)
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"Return an input port from which to retrieve FILES (a list of store items)
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from REMOTE, along with the number of items to retrieve (lower than or equal
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to the length of FILES.)"
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(values (store-export-channel (remote-store-session remote) files)
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(length files)))
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(define* (retrieve-files local files remote
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#:key (log-port (current-error-port)))
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"Retrieve FILES from REMOTE and import them using the 'import-paths' RPC on
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LOCAL."
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(let-values (((port count)
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(file-retrieval-port files remote)))
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(format #t (N_ "retrieving ~a store item from '~a'...~%"
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"retrieving ~a store items from '~a'...~%" count)
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count (remote-store-host remote))
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(let ((result (import-paths local port)))
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(close-port port)
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result)))
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;;; ssh.scm ends here
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