;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2020 Simon South <simon@simonsouth.net>
;;;
;;; 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 (gnu services file-sharing)
#:use-module (gcrypt base16)
#:use-module (gcrypt hash)
#:use-module (gcrypt random)
#:use-module (gnu services)
#:use-module (gnu services admin)
#:use-module (gnu services configuration)
#:use-module (gnu services shepherd)
#:use-module (gnu packages admin)
#:use-module (gnu packages bittorrent)
#:use-module (gnu packages gnupg)
#:use-module (gnu packages guile)
#:use-module (gnu system shadow)
#:use-module (guix diagnostics)
#:use-module (guix gexp)
#:use-module (guix i18n)
#:use-module (guix modules)
#:use-module (guix packages)
#:use-module (guix records)
#:use-module (ice-9 format)
#:use-module (ice-9 match)
#:use-module (rnrs bytevectors)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:export (transmission-daemon-configuration
transmission-daemon-service-type
transmission-password-hash
transmission-random-salt))
;;;
;;; Transmission Daemon.
;;;
(define %transmission-daemon-user "transmission")
(define %transmission-daemon-group "transmission")
(define %transmission-daemon-configuration-directory
"/var/lib/transmission-daemon")
(define %transmission-daemon-log-file
"/var/log/transmission.log")
(define %transmission-salt-length 8)
(define (transmission-password-hash password salt)
"Returns a string containing the result of hashing @var{password} together
with @var{salt}, in the format recognized by Transmission clients for their
@code{rpc-password} configuration setting.
@var{salt} must be an eight-character string. The
@code{transmission-random-salt} procedure can be used to generate a suitable
salt value at random."
(if (not (and (string? salt)
(eq? (string-length salt) %transmission-salt-length)))
(raise (formatted-message
(G_ "salt value must be a string of ~d characters")
%transmission-salt-length))
(string-append "{"
(bytevector->base16-string
(sha1 (string->utf8 (string-append password salt))))
salt)))
(define (transmission-random-salt)
"Returns a string containing a random, eight-character salt value of the
type generated and used by Transmission clients, suitable for passing to the
@code{transmission-password-hash} procedure."
;; This implementation matches a portion of Transmission's tr_ssha1
;; function. See libtransmission/crypto-utils.c in the Transmission source
;; distribution.
(let ((salter (string-append "0123456789"
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"./")))
(list->string
(map (lambda (u8)
(string-ref salter (modulo u8 (string-length salter))))
(bytevector->u8-list
(gen-random-bv %transmission-salt-length %gcry-strong-random))))))
(define (uglify-field-name field-name)
(string-delete #\? (symbol->string field-name)))
(define (serialize-field field-name val)
;; "Serialize" each configuration field as a G-expression containing a
;; name-value pair, the collection of which will subsequently be serialized
;; to disk as a JSON object.
#~(#$(uglify-field-name field-name) . #$val))
(define serialize-boolean serialize-field)
(define serialize-integer serialize-field)
(define serialize-rational serialize-field)
(define serialize-string serialize-field)
(define-maybe string)
;; Override the definition of "serialize-maybe-string", as we need to output a
;; name-value pair for the JSON builder.
(set! serialize-maybe-string
(lambda (field-name val)
(serialize-string field-name (maybe-value val ""))))
(define (string-list? val)
(and (list? val)
(and-map (lambda (x)
(and (string? x)
(not (string-index x #\,))))
val)))
(define (serialize-string-list field-name val)
(serialize-field field-name (string-join val ",")))
(define days
'((sunday . #b0000001)
(monday . #b0000010)
(tuesday . #b0000100)
(wednesday . #b0001000)
(thursday . #b0010000)
(friday . #b0100000)
(saturday . #b1000000)))
(define day-lists
(list (cons 'weekdays '(monday tuesday wednesday thursday friday))
(cons 'weekends '(saturday sunday))
(cons 'all (map car days))))
(define (day-list? val)
(or (and (symbol? val)
(assq val day-lists))
(and (list? val)
(and-map (lambda (x)
(and (symbol? x)
(assq x days)))
val))))
(define (serialize-day-list field-name val)
(serialize-integer field-name
(reduce logior
#b0000000
(map (lambda (day)
(assq-ref days day))
(if (symbol? val)
(assq-ref day-lists val)
val)))))
(define encryption-modes
'((prefer-unencrypted-connections . 0)
(prefer-encrypted-connections . 1)
(require-encrypted-connections . 2)))
(define (encryption-mode? val)
(and (symbol? val)
(assq val encryption-modes)))
(define (serialize-encryption-mode field-name val)
(serialize-integer field-name (assq-ref encryption-modes val)))
(define serialize-file-like serialize-field)
(define (file-object? val)
(or (string? val)
(file-like? val)))
(define (serialize-file-object field-name val)
(if (file-like? val)
(serialize-file-like field-name val)
(serialize-string field-name val)))
(define-maybe file-object)
(set! serialize-maybe-file-object
(lambda (field-name val)
(if (maybe-value-set? val)
(serialize-file-object field-name val)
(serialize-string field-name ""))))
(define (file-object-list? val)
(and (list? val)
(and-map file-object? val)))
(define serialize-file-object-list serialize-field)
(define message-levels
'((none . 0)
(error . 1)
(info . 2)
(debug . 3)))
(define (message-level? val)
(and (symbol? val)
(assq val message-levels)))
(define (serialize-message-level field-name val)
(serialize-integer field-name (assq-ref message-levels val)))
(define (non-negative-integer? val)
(and (integer? val)
(not (negative? val))))
(define serialize-non-negative-integer serialize-integer)
(define (non-negative-rational? val)
(and (rational? val)
(not (negative? val))))
(define serialize-non-negative-rational serialize-rational)
(define (port-number? val)
(and (integer? val)
(>= val 1)
(<= val 65535)))
(define serialize-port-number serialize-integer)
(define preallocation-modes
'((none . 0)
(fast . 1)
(sparse . 1)
(full . 2)))
(define (preallocation-mode? val)
(and (symbol? val)
(assq val preallocation-modes)))
(define (serialize-preallocation-mode field-name val)
(serialize-integer field-name (assq-ref preallocation-modes val)))
(define tcp-types-of-service
'((default . "default")
(low-cost . "lowcost")
(throughput . "throughput")
(low-delay . "lowdelay")
(reliability . "reliability")))
(define (tcp-type-of-service? val)
(and (symbol? val)
(assq val tcp-types-of-service)))
(define (serialize-tcp-type-of-service field-name val)
(serialize-string field-name (assq-ref tcp-types-of-service val)))
(define (transmission-password-hash? val)
(and (string? val)
(= (string-length val) 49)
(eqv? (string-ref val 0) #\{)
(string-every char-set:hex-digit val 1 41)))
(define serialize-transmission-password-hash serialize-string)
(define-maybe transmission-password-hash)
(set! serialize-maybe-transmission-password-hash serialize-maybe-string)
(define (umask? val)
(and (integer? val)
(>= val #o000)
(<= val #o777)))
(define serialize-umask serialize-integer) ; must use decimal representation
(define-configuration transmission-daemon-configuration
;; Settings internal to this service definition.
(transmission
(file-like transmission)
"The Transmission package to use.")
(stop-wait-period
(non-negative-integer 10)
"The period, in seconds, to wait when stopping the service for
@command{transmission-daemon} to exit before killing its process. This allows
the daemon time to complete its housekeeping and send a final update to
trackers as it shuts down. On slow hosts, or hosts with a slow network
connection, this value may need to be increased.")
;; Files and directories.
(download-dir
(string (string-append %transmission-daemon-configuration-directory
"/downloads"))
"The directory to which torrent files are downloaded.")
(incomplete-dir-enabled?
(boolean #f)
"If @code{#t}, files will be held in @code{incomplete-dir} while their
torrent is being downloaded, then moved to @code{download-dir} once the
torrent is complete. Otherwise, files for all torrents (including those still
being downloaded) will be placed in @code{download-dir}.")
(incomplete-dir
maybe-string
"The directory in which files from incompletely downloaded torrents will be
held when @code{incomplete-dir-enabled?} is @code{#t}.")
(umask
(umask #o022)
"The file mode creation mask used for downloaded files. (See the
@command{umask} man page for more information.)")
(rename-partial-files?
(boolean #t)
"When @code{#t}, ``.part'' is appended to the name of partially downloaded
files.")
(preallocation
(preallocation-mode 'fast)
"The mode by which space should be preallocated for downloaded files, one
of @code{none}, @code{fast} (or @code{sparse}) and @code{full}. Specifying
@code{full} will minimize disk fragmentation at a cost to file-creation
speed.")
(watch-dir-enabled?
(boolean #f)
"If @code{#t}, the directory specified by @code{watch-dir} will be watched
for new @file{.torrent} files and the torrents they describe added
automatically (and the original files removed, if
@code{trash-original-torrent-files?} is @code{#t}).")
(watch-dir
maybe-string
"The directory to be watched for @file{.torrent} files indicating new
torrents to be added, when @code{watch-dir-enabled} is @code{#t}.")
(trash-original-torrent-files?
(boolean #f)
"When @code{#t}, @file{.torrent} files will be deleted from the watch
directory once their torrent has been added (see
@code{watch-directory-enabled?}).")
;; Bandwidth limits.
(speed-limit-down-enabled?
(boolean #f)
"When @code{#t}, the daemon's download speed will be limited to the rate
specified by @code{speed-limit-down}.")
(speed-limit-down
(non-negative-integer 100)
"The default global-maximum download speed, in kilobytes per second.")
(speed-limit-up-enabled?
(boolean #f)
"When @code{#t}, the daemon's upload speed will be limited to the rate
specified by @code{speed-limit-up}.")
(speed-limit-up
(non-negative-integer 100)
"The default global-maximum upload speed, in kilobytes per second.")
(alt-speed-enabled?
(boolean #f)
"When @code{#t}, the alternate speed limits @code{alt-speed-down} and
@code{alt-speed-up} are used (in place of @code{speed-limit-down} and
@code{speed-limit-up}, if they are enabled) to constrain the daemon's
bandwidth usage. This can be scheduled to occur automatically at certain
times during the week; see @code{alt-speed-time-enabled?}.")
(alt-speed-down
(non-negative-integer 50)
"The alternate global-maximum download speed, in kilobytes per second.")
(alt-speed-up
(non-negative-integer 50)
"The alternate global-maximum upload speed, in kilobytes per second.")
;; Bandwidth-limit scheduling.
(alt-speed-time-enabled?
(boolean #f)
"When @code{#t}, the alternate speed limits @code{alt-speed-down} and
@code{alt-speed-up} will be enabled automatically during the periods specified
by @code{alt-speed-time-day}, @code{alt-speed-time-begin} and
@code{alt-time-speed-end}.")
(alt-speed-time-day
(day-list 'all)
"The days of the week on which the alternate-speed schedule should be used,
specified either as a list of days (@code{sunday}, @code{monday}, and so on)
or using one of the symbols @code{weekdays}, @code{weekends} or @code{all}.")
(alt-speed-time-begin
(non-negative-integer 540)
"The time of day at which to enable the alternate speed limits,
expressed as a number of minutes since midnight.")
(alt-speed-time-end
(non-negative-integer 1020)
"The time of day at which to disable the alternate speed limits,
expressed as a number of minutes since midnight.")
;; Peer networking.
(bind-address-ipv4
(string "0.0.0.0")
"The IP address at which to listen for peer connections, or ``0.0.0.0'' to
listen at all available IP addresses.")
(bind-address-ipv6
(string "::")
"The IPv6 address at which to listen for peer connections, or ``::'' to
listen at all available IPv6 addresses.")
(peer-port-random-on-start?
(boolean #f)
"If @code{#t}, when the daemon starts it will select a port at random on
which to listen for peer connections, from the range specified (inclusively)
by @code{peer-port-random-low} and @code{peer-port-random-high}. Otherwise,
it listens on the port specified by @code{peer-port}.")
(peer-port-random-low
(port-number 49152)
"The lowest selectable port number when @code{peer-port-random-on-start?}
is @code{#t}.")
(peer-port-random-high
(port-number 65535)
"The highest selectable port number when @code{peer-port-random-on-start}
is @code{#t}.")
(peer-port
(port-number 51413)
"The port on which to listen for peer connections when
@code{peer-port-random-on-start?} is @code{#f}.")
(port-forwarding-enabled?
(boolean #t)
"If @code{#t}, the daemon will attempt to configure port-forwarding on an
upstream gateway automatically using @acronym{UPnP} and @acronym{NAT-PMP}.")
(encryption
(encryption-mode 'prefer-encrypted-connections)
"The encryption preference for peer connections, one of
@code{prefer-unencrypted-connections}, @code{prefer-encrypted-connections} or
@code{require-encrypted-connections}.")
(peer-congestion-algorithm
maybe-string
"The TCP congestion-control algorithm to use for peer connections,
specified using a string recognized by the operating system in calls to
@code{setsockopt} (or leave it unset, in which case the operating-system
default is used).
Note that on GNU/Linux systems, the kernel must be configured to allow
processes to use a congestion-control algorithm not in the default set;
otherwise, it will deny these requests with ``Operation not permitted''. To
see which algorithms are available on your system and which are currently
permitted for use, look at the contents of the files
@file{tcp_available_congestion_control} and
@file{tcp_allowed_congestion_control} in the @file{/proc/sys/net/ipv4}
directory.
As an example, to have Transmission Daemon use
@uref{http://www-ece.rice.edu/networks/TCP-LP/, the TCP Low Priority
congestion-control algorithm}, you'll need to modify your kernel configuration
to build in support for the algorithm, then update your operating-system
configuration to allow its use by adding a @code{sysctl-service-type}
service (or updating the existing one's configuration) with lines like the
following:
@lisp
(service sysctl-service-type
(sysctl-configuration
(settings
(\"net.ipv4.tcp_allowed_congestion_control\" .
\"reno cubic lp\"))))
@end lisp
The Transmission Daemon configuration can then be updated with
@lisp
(peer-congestion-algorithm \"lp\")
@end lisp
and the system reconfigured to have the changes take effect.")
(peer-socket-tos
(tcp-type-of-service 'default)
"The type of service to request in outgoing @acronym{TCP} packets,
one of @code{default}, @code{low-cost}, @code{throughput}, @code{low-delay}
and @code{reliability}.")
(peer-limit-global
(non-negative-integer 200)
"The global limit on the number of connected peers.")
(peer-limit-per-torrent
(non-negative-integer 50)
"The per-torrent limit on the number of connected peers.")
(upload-slots-per-torrent
(non-negative-integer 14)
"The maximum number of peers to which the daemon will upload data
simultaneously for each torrent.")
(peer-id-ttl-hours
(non-negative-integer 6)
"The maximum lifespan, in hours, of the peer ID associated with each public
torrent before it is regenerated.")
;; Peer blocklists.
(blocklist-enabled?
(boolean #f)
"When @code{#t}, the daemon will ignore peers mentioned in the blocklist it
has most recently downloaded from @code{blocklist-url}.")
(blocklist-url
maybe-string
"The URL of a peer blocklist (in @acronym{P2P}-plaintext or eMule
@file{.dat} format) to be periodically downloaded and applied when
@code{blocklist-enabled?} is @code{#t}.")
;; Queueing.
(download-queue-enabled?
(boolean #t)
"If @code{#t}, the daemon will be limited to downloading at most
@code{download-queue-size} non-stalled torrents simultaneously.")
(download-queue-size
(non-negative-integer 5)
"The size of the daemon's download queue, which limits the number of
non-stalled torrents it will download at any one time when
@code{download-queue-enabled?} is @code{#t}.")
(seed-queue-enabled?
(boolean #f)
"If @code{#t}, the daemon will be limited to seeding at most
@code{seed-queue-size} non-stalled torrents simultaneously.")
(seed-queue-size
(non-negative-integer 10)
"The size of the daemon's seed queue, which limits the number of
non-stalled torrents it will seed at any one time when
@code{seed-queue-enabled?} is @code{#t}.")
(queue-stalled-enabled?
(boolean #t)
"When @code{#t}, the daemon will consider torrents for which it has not
shared data in the past @code{queue-stalled-minutes} minutes to be stalled and
not count them against its @code{download-queue-size} and
@code{seed-queue-size} limits.")
(queue-stalled-minutes
(non-negative-integer 30)
"The maximum period, in minutes, a torrent may be idle before it is
considered to be stalled, when @code{queue-stalled-enabled?} is @code{#t}.")
;; Seeding limits.
(ratio-limit-enabled?
(boolean #f)
"When @code{#t}, a torrent being seeded will automatically be paused once
it reaches the ratio specified by @code{ratio-limit}.")
(ratio-limit
(non-negative-rational 2.0)
"The ratio at which a torrent being seeded will be paused, when
@code{ratio-limit-enabled?} is @code{#t}.")
(idle-seeding-limit-enabled?
(boolean #f)
"When @code{#t}, a torrent being seeded will automatically be paused once
it has been idle for @code{idle-seeding-limit} minutes.")
(idle-seeding-limit
(non-negative-integer 30)
"The maximum period, in minutes, a torrent being seeded may be idle before
it is paused, when @code{idle-seeding-limit-enabled?} is @code{#t}.")
;; BitTorrent extensions.
(dht-enabled?
(boolean #t)
"Enable @uref{http://bittorrent.org/beps/bep_0005.html, the distributed
hash table (@acronym{DHT}) protocol}, which supports the use of trackerless
torrents.")
(lpd-enabled?
(boolean #f)
"Enable @url{https://en.wikipedia.org/wiki/Local_Peer_Discovery, local peer
discovery} (@acronym{LPD}), which allows the discovery of peers on the local
network and may reduce the amount of data sent over the public Internet.")
(pex-enabled?
(boolean #t)
"Enable @url{https://en.wikipedia.org/wiki/Peer_exchange, peer
exchange} (@acronym{PEX}), which reduces the daemon's reliance on external
trackers and may improve its performance.")
(utp-enabled?
(boolean #t)
"Enable @url{http://bittorrent.org/beps/bep_0029.html, the micro transport
protocol} (@acronym{uTP}), which aims to reduce the impact of BitTorrent
traffic on other users of the local network while maintaining full utilization
of the available bandwidth.")
;; Remote procedure call (RPC) interface.
(rpc-enabled?
(boolean #t)
"If @code{#t}, enable the remote procedure call (@acronym{RPC}) interface,
which allows remote control of the daemon via its Web interface, the
@command{transmission-remote} command-line client, and similar tools.")
(rpc-bind-address
(string "0.0.0.0")
"The IP address at which to listen for @acronym{RPC} connections, or
``0.0.0.0'' to listen at all available IP addresses.")
(rpc-port
(port-number 9091)
"The port on which to listen for @acronym{RPC} connections.")
(rpc-url
(string "/transmission/")
"The path prefix to use in the @acronym{RPC}-endpoint @acronym{URL}.")
(rpc-authentication-required?
(boolean #f)
"When @code{#t}, clients must authenticate (see @code{rpc-username} and
@code{rpc-password}) when using the @acronym{RPC} interface. Note this has
the side effect of disabling host-name whitelisting (see
@code{rpc-host-whitelist-enabled?}.")
(rpc-username
maybe-string
"The username required by clients to access the @acronym{RPC} interface
when @code{rpc-authentication-required?} is @code{#t}.")
(rpc-password
maybe-transmission-password-hash
"The password required by clients to access the @acronym{RPC} interface
when @code{rpc-authentication-required?} is @code{#t}. This must be specified
using a password hash in the format recognized by Transmission clients, either
copied from an existing @file{settings.json} file or generated using the
@code{transmission-password-hash} procedure.")
(rpc-whitelist-enabled?
(boolean #t)
"When @code{#t}, @acronym{RPC} requests will be accepted only when they
originate from an address specified in @code{rpc-whitelist}.")
(rpc-whitelist
(string-list '("127.0.0.1" "::1"))
"The list of IP and IPv6 addresses from which @acronym{RPC} requests will
be accepted when @code{rpc-whitelist-enabled?} is @code{#t}. Wildcards may be
specified using @samp{*}.")
(rpc-host-whitelist-enabled?
(boolean #t)
"When @code{#t}, @acronym{RPC} requests will be accepted only when they are
addressed to a host named in @code{rpc-host-whitelist}. Note that requests to
``localhost'' or ``localhost.'', or to a numeric address, are always accepted
regardless of these settings.
Note also this functionality is disabled when
@code{rpc-authentication-required?} is @code{#t}.")
(rpc-host-whitelist
(string-list '())
"The list of host names recognized by the @acronym{RPC} server when
@code{rpc-host-whitelist-enabled?} is @code{#t}.")
;; Miscellaneous.
(message-level
(message-level 'info)
"The minimum severity level of messages to be logged (to
@file{/var/log/transmission.log}) by the daemon, one of @code{none} (no
logging), @code{error}, @code{info} and @code{debug}.")
(start-added-torrents?
(boolean #t)
"When @code{#t}, torrents are started as soon as they are added; otherwise,
they are added in ``paused'' state.")
(script-torrent-done-enabled?
(boolean #f)
"When @code{#t}, the script specified by
@code{script-torrent-done-filename} will be invoked each time a torrent
completes.")
(script-torrent-done-filename
maybe-file-object
"A file name or file-like object specifying a script to run each time a
torrent completes, when @code{script-torrent-done-enabled?} is @code{#t}.")
(scrape-paused-torrents-enabled?
(boolean #t)
"When @code{#t}, the daemon will scrape trackers for a torrent even when
the torrent is paused.")
(cache-size-mb
(non-negative-integer 4)
"The amount of memory, in megabytes, to allocate for the daemon's in-memory
cache. A larger value may increase performance by reducing the frequency of
disk I/O.")
(prefetch-enabled?
(boolean #t)
"When @code{#t}, the daemon will try to improve I/O performance by hinting
to the operating system which data is likely to be read next from disk to
satisfy requests from peers."))
(define (transmission-daemon-shepherd-service config)
"Return a <shepherd-service> for Transmission Daemon with CONFIG."
(let ((transmission
(transmission-daemon-configuration-transmission config))
(stop-wait-period
(transmission-daemon-configuration-stop-wait-period config)))
(list
(shepherd-service
(provision '(transmission-daemon transmission bittorrent))
(requirement '(networking))
(documentation "Share files using the BitTorrent protocol.")
(start #~(make-forkexec-constructor
'(#$(file-append transmission "/bin/transmission-daemon")
"--config-dir"
#$%transmission-daemon-configuration-directory
"--foreground")
#:user #$%transmission-daemon-user
#:group #$%transmission-daemon-group
#:directory #$%transmission-daemon-configuration-directory
#:log-file #$%transmission-daemon-log-file
#:environment-variables
'("CURL_CA_BUNDLE=/etc/ssl/certs/ca-certificates.crt")))
(stop #~(lambda (pid)
(kill pid SIGTERM)
;; Transmission Daemon normally needs some time to shut down,
;; as it will complete some housekeeping and send a final
;; update to trackers before it exits.
;;
;; Wait a reasonable period for it to stop before continuing.
;; If we don't do this, restarting the service can fail as the
;; new daemon process finds the old one still running and
;; attached to the port used for peer connections.
(let wait-before-killing ((period #$stop-wait-period))
(if (zero? (car (waitpid pid WNOHANG)))
(if (positive? period)
(begin
(sleep 1)
(wait-before-killing (- period 1)))
(begin
(format #t
#$(G_ "Wait period expired; killing \
transmission-daemon (pid ~a).~%")
pid)
(display #$(G_ "(If you see this message \
regularly, you may need to increase the value
of 'stop-wait-period' in the service configuration.)\n"))
(kill pid SIGKILL)))))
#f))
(actions
(list
(shepherd-action
(name 'reload)
(documentation "Reload the settings file from disk.")
(procedure #~(lambda (pid)
(if pid
(begin
(kill pid SIGHUP)
(display #$(G_ "Service transmission-daemon has \
been asked to reload its settings file.")))
(display #$(G_ "Service transmission-daemon is not \
running."))))))))))))
(define %transmission-daemon-accounts
(list (user-group
(name %transmission-daemon-group)
(system? #t))
(user-account
(name %transmission-daemon-user)
(group %transmission-daemon-group)
(comment "Transmission Daemon service account")
(home-directory %transmission-daemon-configuration-directory)
(shell (file-append shadow "/sbin/nologin"))
(system? #t))))
(define %transmission-daemon-log-rotations
(list (log-rotation
(files (list %transmission-daemon-log-file)))))
(define (transmission-daemon-computed-settings-file config)
"Return a @code{computed-file} object that, when unquoted in a G-expression,
produces a Transmission settings file (@file{settings.json}) matching CONFIG."
(let ((settings
;; "Serialize" the configuration settings as a list of G-expressions
;; containing a name-value pair, which will ultimately be sorted and
;; serialized to the settings file as a JSON object.
(map
(lambda (field)
((configuration-field-serializer field)
(configuration-field-name field)
((configuration-field-getter field) config)))
(filter
(lambda (field)
;; Omit configuration fields that are used only internally by
;; this service definition.
(not (memq (configuration-field-name field)
'(transmission stop-wait-period))))
transmission-daemon-configuration-fields))))
(computed-file
"settings.json"
(with-extensions (list guile-gcrypt guile-json-4)
(with-imported-modules (source-module-closure '((json builder)))
#~(begin
(use-modules (json builder))
(with-output-to-file #$output
(lambda ()
(scm->json (sort-list '(#$@settings)
(lambda (x y)
(string<=? (car x) (car y))))
#:pretty #t)))))))))
(define (transmission-daemon-activation config)
"Return the Transmission Daemon activation GEXP for CONFIG."
(let ((config-dir %transmission-daemon-configuration-directory)
(incomplete-dir-enabled
(transmission-daemon-configuration-incomplete-dir-enabled? config))
(incomplete-dir
(transmission-daemon-configuration-incomplete-dir config))
(watch-dir-enabled
(transmission-daemon-configuration-watch-dir-enabled? config))
(watch-dir
(transmission-daemon-configuration-watch-dir config)))
(with-imported-modules (source-module-closure '((guix build utils)))
#~(begin
(use-modules (guix build utils))
(let ((owner (getpwnam #$%transmission-daemon-user)))
(define (mkdir-p/perms directory perms)
(mkdir-p directory)
(chown directory (passwd:uid owner) (passwd:gid owner))
(chmod directory perms))
;; Create the directories Transmission Daemon is configured to use
;; and assign them suitable permissions.
(for-each (lambda (directory-specification)
(apply mkdir-p/perms directory-specification))
'(#$@(append
`((,config-dir #o750))
(if incomplete-dir-enabled
`((,incomplete-dir #o750))
'())
(if watch-dir-enabled
`((,watch-dir #o770))
'())))))
;; Generate and activate the daemon's settings file, settings.json.
(activate-special-files
'((#$(string-append config-dir "/settings.json")
#$(transmission-daemon-computed-settings-file config))))))))
(define transmission-daemon-service-type
(service-type
(name 'transmission)
(extensions
(list (service-extension shepherd-root-service-type
transmission-daemon-shepherd-service)
(service-extension account-service-type
(const %transmission-daemon-accounts))
(service-extension rottlog-service-type
(const %transmission-daemon-log-rotations))
(service-extension activation-service-type
transmission-daemon-activation)))
(default-value (transmission-daemon-configuration))
(description "Share files using the BitTorrent protocol.")))
(define (generate-transmission-daemon-documentation)
(generate-documentation
`((transmission-daemon-configuration
,transmission-daemon-configuration-fields))
'transmission-daemon-configuration))
