guix/guix/scripts/copy.scm
Ludovic Courtès 681af1fb78
scripts: Commands warn when passed zero arguments.
This is a followup to 3f8326237d.

* guix/scripts/archive.scm (export-from-store): Warn then FILES is
empty.
* guix/scripts/build.scm (guix-build): Likewise.
* guix/scripts/copy.scm (warn-if-empty): New procedure.
(send-to-remote-host, retrieve-from-remote-host): Call it.
* guix/scripts/edit.scm (guix-edit): Warn when SPECS is empty.
* guix/scripts/environment.scm (guix-environment): Warn when MANIFEST
has zero entries.
* guix/scripts/graph.scm (guix-graph): Warn then ITEMS is empty.
* guix/scripts/package.scm (process-actions): Warn when FILES and TRANS
are both empty.
2021-05-28 11:36:02 +02:00

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016, 2017, 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix scripts copy)
#:use-module (guix ui)
#:use-module (guix scripts)
#:use-module (guix ssh)
#:use-module ((ssh session) #:select (disconnect!))
#:use-module (guix store)
#:use-module ((guix status) #:select (with-status-verbosity))
#:use-module (guix utils)
#:use-module (guix derivations)
#:use-module (guix scripts build)
#:use-module ((guix scripts archive) #:select (options->derivations+files))
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-37)
#:use-module (ice-9 match)
#:use-module (ice-9 format)
#:export (guix-copy))
;;;
;;; Exchanging store items over SSH.
;;;
(define (ssh-spec->user+host+port spec)
"Parse SPEC, a string like \"user@host:port\" or just \"host\", and return
three values: the user name (or #f), the host name, and the TCP port
number (or #f) corresponding to SPEC."
(define tokens
(char-set #\@ #\:))
(match (string-tokenize spec (char-set-complement tokens))
((host)
(values #f host #f))
((left right)
(if (string-index spec #\@)
(values left right #f)
(values #f left (string->number right))))
((user host port)
(match (string->number port)
((? integer? port)
(values user host port))
(x
(leave (G_ "~a: invalid TCP port number~%") port))))
(x
(leave (G_ "~a: invalid SSH specification~%") spec))))
(define (warn-if-empty items)
(when (null? items)
(warning (G_ "no arguments specified, nothing to copy~%"))))
(define (send-to-remote-host local target opts)
"Send ITEMS to TARGET. ITEMS is a list of store items or package names; for ;
package names, build the underlying packages before sending them."
(let-values (((user host port)
(ssh-spec->user+host+port target))
((drv items)
(options->derivations+files local opts)))
(warn-if-empty items)
(and (build-derivations local drv)
(let* ((session (open-ssh-session host #:user user
#:port (or port 22)))
(remote (connect-to-remote-daemon session))
(sent (send-files local items remote
#:recursive? #t)))
(close-connection remote)
(format #t "~{~a~%~}" sent)
sent))))
(define (retrieve-from-remote-host local source opts)
"Retrieve ITEMS from SOURCE."
(let*-values (((user host port)
(ssh-spec->user+host+port source))
((session)
(open-ssh-session host #:user user #:port (or port 22)))
((remote)
(connect-to-remote-daemon session)))
;; TODO: Here we could to compute and build the derivations on REMOTE
;; rather than on LOCAL (one-off offloading) but that is currently too
;; slow due to the many RPC round trips. So we just assume that REMOTE
;; contains ITEMS.
(let*-values (((drv items)
(options->derivations+files local opts))
((retrieved)
(begin
(warn-if-empty items)
(retrieve-files local items remote #:recursive? #t))))
(close-connection remote)
(disconnect! session)
(format #t "~{~a~%~}" retrieved)
retrieved)))
;;;
;;; Options.
;;;
(define (show-help)
(display (G_ "Usage: guix copy [OPTION]... ITEMS...
Copy ITEMS to or from the specified host over SSH.\n"))
(display (G_ "
--to=HOST send ITEMS to HOST"))
(display (G_ "
--from=HOST receive ITEMS from HOST"))
(display (G_ "
-v, --verbosity=LEVEL use the given verbosity LEVEL"))
(newline)
(show-build-options-help)
(newline)
(display (G_ "
-h, --help display this help and exit"))
(display (G_ "
-V, --version display version information and exit"))
(newline)
(show-bug-report-information))
(define %options
;; Specifications of the command-line options.
(cons* (option '("to") #t #f
(lambda (opt name arg result)
(alist-cons 'destination arg result)))
(option '("from") #t #f
(lambda (opt name arg result)
(alist-cons 'source arg result)))
(option '(#\v "verbosity") #t #f
(lambda (opt name arg result)
(let ((level (string->number* arg)))
(alist-cons 'verbosity level
(alist-delete 'verbosity result)))))
(option '(#\n "dry-run") #f #f
(lambda (opt name arg result)
(alist-cons 'dry-run? #t result)))
(option '(#\h "help") #f #f
(lambda args
(show-help)
(exit 0)))
(option '(#\V "version") #f #f
(lambda args
(show-version-and-exit "guix copy")))
(option '(#\s "system") #t #f
(lambda (opt name arg result)
(alist-cons 'system arg
(alist-delete 'system result eq?))))
%standard-build-options))
(define %default-options
`((system . ,(%current-system))
(substitutes? . #t)
(offload? . #t)
(graft? . #t)
(print-build-trace? . #t)
(print-extended-build-trace? . #t)
(multiplexed-build-output? . #t)
(debug . 0)
(verbosity . 3)))
;;;
;;; Entry point.
;;;
(define-command (guix-copy . args)
(category plumbing)
(synopsis "copy store items remotely over SSH")
(with-error-handling
(let* ((opts (parse-command-line args %options (list %default-options)))
(source (assoc-ref opts 'source))
(target (assoc-ref opts 'destination)))
(with-store store
(set-build-options-from-command-line store opts)
(with-build-handler (build-notifier #:use-substitutes?
(assoc-ref opts 'substitutes?)
#:verbosity
(assoc-ref opts 'verbosity)
#:dry-run?
(assoc-ref opts 'dry-run?))
(with-status-verbosity (assoc-ref opts 'verbosity)
(cond (target (send-to-remote-host store target opts))
(source (retrieve-from-remote-host store source opts))
(else (leave (G_ "use '--to' or '--from'~%"))))))))))