gnu: Add AutoSSH service.

* gnu/services/ssh.scm (<autossh-configuration>): New record type.
(autossh-service-type): New variable.
(autossh-service-activation, autossh-file-name): New procedures.
* doc/guix.texi (Networking Services): Document this.

Signed-off-by: Oleg Pykhalov <go.wigust@gmail.com>
This commit is contained in:
pinoaffe 2020-05-05 09:31:11 +02:00 committed by Oleg Pykhalov
parent 4c4ae8b595
commit 051f3254cd
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2 changed files with 180 additions and 1 deletions

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@ -79,6 +79,7 @@ Copyright @copyright{} 2020 Naga Malleswari@*
Copyright @copyright{} 2020 Brice Waegeneire@*
Copyright @copyright{} 2020 R Veera Kumar@*
Copyright @copyright{} 2020 Pierre Langlois@*
Copyright @copyright{} 2020 pinoaffe@*
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
@ -14390,6 +14391,80 @@ Whether to enable password-based authentication.
@end table
@end deftp
@cindex AutoSSH
@deffn {Scheme Variable} autossh-service-type
This is the type for the @uref{https://www.harding.motd.ca/autossh,
AutoSSH} program that runs a copy of @code{ssh} and monitors it,
restarting it as necessary should it die or stop passing traffic.
AutoSSH can be run manually from the commandline by passing arguments to
the binary @code{autossh} from the package @code{autossh}, but it can
also be run as a guix service. This latter usecase is documented here.
AutoSSH can be used to forward local traffic to a remote machine using an SSH tunnel,
and it respects the @file{~/.ssh/config} of the user it is run as.
For example, to specify a service running autossh as the user @code{pino}
and forwarding all local connections to port @code{8081} to @code{remote:8081}
using an SSH tunnel, add this call to the operating system's @code{services} field:
@lisp
(service autossh-service-type
(autossh-configuration
(user "pino")
(ssh-options (list "-T" "-N" "-L" "8081:localhost:8081" "remote.net"))))
@end lisp
@end deffn
@deftp {Data Type} autossh-configuration
This data type represents the configuration of an AutoSSH service.
@table @asis
@item @code{user} (default @code{"autossh"})
The user as which the AutoSSH service is to be run.
This assumes that the specified user exists.
@item @code{poll} (default @code{600})
Specifies the connection poll time in seconds.
@item @code{first-poll} (default @code{#f})
Specifies how long autossh waits before the first connection test in seconds.
After this first test, polling is resumed at the pace defined in @code{poll}.
When set to @code{#f}, the first poll is not treated specially and
will also use the connection poll specified in @code{poll}
@item @code{gate-time} (default @code{30})
Specifies (in seconds) how long an SSH connection must be active
before it is considered successful.
@item @code{log-level} (default @code{1})
The log level, corresponding to the levels used by syslog
(so @code{0} is the most silent while @code{7} is the chattiest.)
@item @code{max-start} (default @code{#f})
The maximum number of times SSH may be (re)started before AutoSSH exits.
When set to @code{#f}, no maximum is configured and AutoSSH may restart indefinitely.
@item @code{message} (default @code{""})
The message to append to the echo message sent when testing connections.
@item @code{port} (default @code{"0"})
The ports used for monitoring the connection. When set to @code{"0"},
monitoring is disabled. When set to @code{"n"} where @code{n} is a positive integer,
ports @code{n} and @code{n+1} are used for monitoring the connection, such that
port @code{n} is the base monitoring port and @code{n+1} is the echo port.
When set to @code{"n:m"} where @code{n} and @code{m} are positive integers,
the ports @code{n} and @code{n+1} are used for monitoring the connection, such
that port @code{n} is the base monitoring port and @code{m} is the echo port.
@item @code{ssh-options} (default @code{'()})
The list of commandline arguments to pass to ssh when it is run.
Options @code{-f} and @code{-M ....} are reserved for AutoSSH
and may cause undefined behaviour.
@end table
@end deftp
@defvr {Scheme Variable} %facebook-host-aliases
This variable contains a string for use in @file{/etc/hosts}
(@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each

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@ -4,6 +4,7 @@
;;; Copyright © 2016 Julien Lepiller <julien@lepiller.eu>
;;; Copyright © 2017 Clément Lassieur <clement@lassieur.org>
;;; Copyright © 2019 Ricardo Wurmus <rekado@elephly.net>
;;; Copyright © 2020 pinoaffe <pinoaffe@airmail.cc>
;;;
;;; This file is part of GNU Guix.
;;;
@ -45,7 +46,11 @@ (define-module (gnu services ssh)
dropbear-configuration
dropbear-configuration?
dropbear-service-type
dropbear-service))
dropbear-service
autossh-configuration
autossh-configuration?
autossh-service-type))
;;; Commentary:
;;;
@ -628,4 +633,103 @@ (define* (dropbear-service #:optional (config (dropbear-configuration)))
object."
(service dropbear-service-type config))
;;;
;;; AutoSSH.
;;;
(define-record-type* <autossh-configuration>
autossh-configuration make-autossh-configuration
autossh-configuration?
(user autossh-configuration-user
(default "autossh"))
(poll autossh-configuration-poll
(default 600))
(first-poll autossh-configuration-first-poll
(default #f))
(gate-time autossh-configuration-gate-time
(default 30))
(log-level autossh-configuration-log-level
(default 1))
(max-start autossh-configuration-max-start
(default #f))
(message autossh-configuration-message
(default ""))
(port autossh-configuration-port
(default "0"))
(ssh-options autossh-configuration-ssh-options
(default '())))
(define (autossh-file-name config file)
"Return a path in /var/run/autossh/ that is writable
by @code{user} from @code{config}."
(string-append "/var/run/autossh/"
(autossh-configuration-user config)
"/" file))
(define (autossh-shepherd-service config)
(shepherd-service
(documentation "Automatically set up ssh connections (and keep them alive).")
(provision '(autossh))
(start #~(make-forkexec-constructor
(list #$(file-append autossh "/bin/autossh")
#$@(autossh-configuration-ssh-options config))
#:user #$(autossh-configuration-user config)
#:group (passwd:gid (getpw #$(autossh-configuration-user config)))
#:pid-file #$(autossh-file-name config "pid")
#:log-file #$(autossh-file-name config "log")
#:environment-variables
'(#$(string-append "AUTOSSH_PIDFILE="
(autossh-file-name config "pid"))
#$(string-append "AUTOSSH_LOGFILE="
(autossh-file-name config "log"))
#$(string-append "AUTOSSH_POLL="
(number->string
(autossh-configuration-poll config)))
#$(string-append "AUTOSSH_FIRST_POLL="
(number->string
(or
(autossh-configuration-first-poll config)
(autossh-configuration-poll config))))
#$(string-append "AUTOSSH_GATETIME="
(number->string
(autossh-configuration-gate-time config)))
#$(string-append "AUTOSSH_LOGLEVEL="
(number->string
(autossh-configuration-log-level config)))
#$(string-append "AUTOSSH_MAXSTART="
(number->string
(or (autossh-configuration-max-start config)
-1)))
#$(string-append "AUTOSSH_MESSAGE="
(autossh-configuration-message config))
#$(string-append "AUTOSSH_PORT="
(autossh-configuration-port config)))))
(stop #~(make-kill-destructor))))
(define (autossh-service-activation config)
(with-imported-modules '((guix build utils))
#~(begin
(use-modules (guix build utils))
(define %user
(getpw #$(autossh-configuration-user config)))
(let* ((directory #$(autossh-file-name config ""))
(log (string-append directory "/log")))
(mkdir-p directory)
(chown directory (passwd:uid %user) (passwd:gid %user))
(call-with-output-file log (const #t))
(chown log (passwd:uid %user) (passwd:gid %user))))))
(define autossh-service-type
(service-type
(name 'autossh)
(description "Automatically set up ssh connections (and keep them alive).")
(extensions
(list (service-extension shepherd-root-service-type
(compose list autossh-shepherd-service))
(service-extension activation-service-type
autossh-service-activation)))
(default-value (autossh-configuration))))
;;; ssh.scm ends here