guix-devel/guix/scripts/system/search.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017, 2018 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 system search)
#:use-module (guix ui)
#:use-module (guix utils)
#:use-module (gnu services)
#:use-module (gnu services shepherd)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-34)
#:use-module (ice-9 regex)
#:use-module (ice-9 match)
#:export (service-type->recutils
find-service-types
guix-system-search))
;;; Commentary:
;;;
;;; Implement the 'guix system search' command, which searches among the
;;; available service types.
;;;
;;; Code:
(define service-type-name*
(compose symbol->string service-type-name))
(define (service-type-default-shepherd-services type)
"Return the list of Shepherd services created by default instances of TYPE,
provided TYPE has a default value."
(match (guard (c ((service-error? c) #f))
(service type))
(#f '())
((? service? service)
(let* ((extension (find (lambda (extension)
(eq? (service-extension-target extension)
shepherd-root-service-type))
(service-type-extensions type)))
(compute (and extension (service-extension-compute extension))))
(if compute
(compute (service-value service))
'())))))
(define (service-type-shepherd-names type)
"Return the default names of Shepherd services created for TYPE."
(match (map shepherd-service-provision
(service-type-default-shepherd-services type))
(((names . _) ...)
names)))
(define* (service-type->recutils type port
#:optional (width (%text-width))
#:key (extra-fields '()))
"Write to PORT a recutils record of TYPE, arranging to fit within WIDTH
columns."
(define width*
;; The available number of columns once we've taken into account space for
;; the initial "+ " prefix.
(if (> width 2) (- width 2) width))
(define (extensions->recutils extensions)
(let ((list (string-join (map (compose service-type-name*
service-extension-target)
extensions))))
(string->recutils
(fill-paragraph list width*
(string-length "extends: ")))))
;; Note: Don't i18n field names so that people can post-process it.
(format port "name: ~a~%" (service-type-name type))
(format port "location: ~a~%"
(or (and=> (service-type-location type) location->string)
(G_ "unknown")))
(format port "extends: ~a~%"
(extensions->recutils (service-type-extensions type)))
;; If possible, display the list of *default* Shepherd service names. Note
;; that we may not always be able to do this (e.g., if the service type
;; lacks a default value); furthermore, it could be that the service
;; generates Shepherd services with different names if we give it different
;; parameters (this is the case, for instance, for
;; 'console-font-service-type'.)
(match (service-type-shepherd-names type)
(() #f)
(names (format port "shepherdnames:~{ ~a~}~%" names)))
(when (service-type-description type)
(format port "~a~%"
(string->recutils
(string-trim-right
(parameterize ((%text-width width*))
(texi->plain-text
(string-append "description: "
(or (and=> (service-type-description type) P_)
""))))
#\newline))))
(for-each (match-lambda
((field . value)
(let ((field (symbol->string field)))
(format port "~a: ~a~%"
field
(fill-paragraph (object->string value) width*
(string-length field))))))
extra-fields)
(newline port))
(define (service-type-description-string type)
"Return the rendered and localised description of TYPE, a service type."
(and=> (service-type-description type)
(compose texi->plain-text P_)))
(define %service-type-metrics
;; Metrics used to estimate the relevance of a search result.
`((,service-type-name* . 3)
(,service-type-description-string . 2)
(,(lambda (type)
(match (and=> (service-type-location type) location-file)
((? string? file)
(basename file ".scm"))
(#f
"")))
. 1)))
(define (find-service-types regexps)
"Return two values: the list of service types whose name or description
matches at least one of REGEXPS sorted by relevance, and the list of relevance
scores."
(let ((matches (fold-service-types
(lambda (type result)
(match (relevance type regexps
%service-type-metrics)
((? zero?)
result)
(score
(cons (list type score) result))))
'())))
(unzip2 (sort matches
(lambda (m1 m2)
(match m1
((type1 score1)
(match m2
((type2 score2)
(if (= score1 score2)
(string>? (service-type-name* type1)
(service-type-name* type2))
(> score1 score2)))))))))))
(define (guix-system-search . args)
(with-error-handling
(let ((regexps (map (cut make-regexp* <> regexp/icase) args)))
(leave-on-EPIPE
(let-values (((services scores)
(find-service-types regexps)))
(for-each (lambda (service score)
(service-type->recutils service
(current-output-port)
#:extra-fields
`((relevance . ,score))))
services
scores))))))