diff --git a/Makefile.am b/Makefile.am index 394d2ef75e..bb27297096 100644 --- a/Makefile.am +++ b/Makefile.am @@ -114,6 +114,7 @@ MODULES = \ guix/channels.scm \ guix/gnu-maintenance.scm \ guix/self.scm \ + guix/substitutes.scm \ guix/upstream.scm \ guix/licenses.scm \ guix/lint.scm \ diff --git a/guix/narinfo.scm b/guix/narinfo.scm index d3deba28bd..2d06124017 100644 --- a/guix/narinfo.scm +++ b/guix/narinfo.scm @@ -25,7 +25,6 @@ (define-module (guix narinfo) #:use-module (guix base64) #:use-module (guix records) #:use-module (guix diagnostics) - #:use-module (guix scripts substitute) #:use-module (gcrypt hash) #:use-module (gcrypt pk-crypto) #:use-module (rnrs bytevectors) diff --git a/guix/scripts/challenge.scm b/guix/scripts/challenge.scm index cc9cbe6f27..4ec3be99ca 100644 --- a/guix/scripts/challenge.scm +++ b/guix/scripts/challenge.scm @@ -27,7 +27,7 @@ (define-module (guix scripts challenge) #:use-module (guix packages) #:use-module ((guix progress) #:hide (dump-port*)) #:use-module (guix serialization) - #:use-module (guix scripts substitute) + #:use-module (guix substitutes) #:use-module (guix narinfo) #:use-module (rnrs bytevectors) #:autoload (guix http-client) (http-fetch) diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm index fcb462b47b..5866b8bb0a 100755 --- a/guix/scripts/substitute.scm +++ b/guix/scripts/substitute.scm @@ -24,6 +24,7 @@ (define-module (guix scripts substitute) #:use-module (guix scripts) #:use-module (guix narinfo) #:use-module (guix store) + #:use-module (guix substitutes) #:use-module (guix utils) #:use-module (guix combinators) #:use-module (guix config) @@ -39,40 +40,28 @@ (define-module (guix scripts substitute) #:use-module (guix cache) #:use-module (gcrypt pk-crypto) #:use-module (guix pki) - #:use-module ((guix build utils) #:select (mkdir-p dump-port)) + #:use-module ((guix build utils) #:select (mkdir-p)) #:use-module ((guix build download) #:select (uri-abbreviation nar-uri-abbreviation (open-connection-for-uri - . guix:open-connection-for-uri) - store-path-abbreviation byte-count->string)) - #:autoload (gnutls) (error/invalid-session) + . guix:open-connection-for-uri))) #:use-module (guix progress) #:use-module ((guix build syscalls) #:select (set-thread-name)) #:use-module (ice-9 rdelim) - #:use-module (ice-9 regex) #:use-module (ice-9 match) #:use-module (ice-9 format) #:use-module (ice-9 ftw) - #:use-module (ice-9 binary-ports) - #:use-module (ice-9 vlist) #:use-module (rnrs bytevectors) #:use-module (srfi srfi-1) - #:use-module (srfi srfi-9) #:use-module (srfi srfi-11) #:use-module (srfi srfi-19) #:use-module (srfi srfi-26) #:use-module (srfi srfi-34) #:use-module (srfi srfi-35) #:use-module (web uri) - #:use-module (web http) - #:use-module (web request) - #:use-module (web response) #:use-module (guix http-client) - #:export (lookup-narinfos - lookup-narinfos/diverse - - %allow-unauthenticated-substitutes? + #:export (%allow-unauthenticated-substitutes? %error-to-file-descriptor-4? substitute-urls @@ -89,16 +78,9 @@ (define-module (guix scripts substitute) ;;; ;;; Code: -(define %narinfo-cache-directory - ;; A local cache of narinfos, to avoid going to the network. Most of the - ;; time, 'guix substitute' is called by guix-daemon as root and stores its - ;; cached data in /var/guix/…. However, when invoked from 'guix challenge' - ;; as a user, it stores its cache in ~/.cache. - (if (zero? (getuid)) - (or (and=> (getenv "XDG_CACHE_HOME") - (cut string-append <> "/guix/substitute")) - (string-append %state-directory "/substitute/cache")) - (string-append (cache-directory #:ensure? #f) "/substitute"))) +(define %narinfo-expired-cache-entry-removal-delay + ;; How often we want to remove files corresponding to expired cache entries. + (* 7 24 3600)) (define (warn-about-missing-authentication) (warning (G_ "authentication and authorization of substitutes \ @@ -112,24 +94,6 @@ (define %allow-unauthenticated-substitutes? (and=> (getenv "GUIX_ALLOW_UNAUTHENTICATED_SUBSTITUTES") (cut string-ci=? <> "yes")))) -(define %narinfo-ttl - ;; Number of seconds during which cached narinfo lookups are considered - ;; valid for substitute servers that do not advertise a TTL via the - ;; 'Cache-Control' response header. - (* 36 3600)) - -(define %narinfo-negative-ttl - ;; Likewise, but for negative lookups---i.e., cached lookup failures (404). - (* 1 3600)) - -(define %narinfo-transient-error-ttl - ;; Likewise, but for transient errors such as 504 ("Gateway timeout"). - (* 10 60)) - -(define %narinfo-expired-cache-entry-removal-delay - ;; How often we want to remove files corresponding to expired cache entries. - (* 7 24 3600)) - (define %fetch-timeout ;; Number of seconds after which networking is considered "slow". 5) @@ -169,84 +133,6 @@ (define-syntax-rule (with-timeout duration handler body ...) (sigaction SIGALRM SIG_DFL) (apply values result))))) -(define (narinfo-cache-file cache-url path) - "Return the name of the local file that contains an entry for PATH. The -entry is stored in a sub-directory specific to CACHE-URL." - ;; The daemon does not sanitize its input, so PATH could be something like - ;; "/gnu/store/foo". Gracefully handle that. - (match (store-path-hash-part path) - (#f - (leave (G_ "'~a' does not name a store item~%") path)) - ((? string? hash-part) - (string-append %narinfo-cache-directory "/" - (bytevector->base32-string (sha256 (string->utf8 cache-url))) - "/" hash-part)))) - -(define (cached-narinfo cache-url path) - "Check locally if we have valid info about PATH coming from CACHE-URL. -Return two values: a Boolean indicating whether we have valid cached info, and -that info, which may be either #f (when PATH is unavailable) or the narinfo -for PATH." - (define now - (current-time time-monotonic)) - - (define cache-file - (narinfo-cache-file cache-url path)) - - (catch 'system-error - (lambda () - (call-with-input-file cache-file - (lambda (p) - (match (read p) - (('narinfo ('version 2) - ('cache-uri cache-uri) - ('date date) ('ttl ttl) ('value #f)) - ;; A cached negative lookup. - (if (obsolete? date now ttl) - (values #f #f) - (values #t #f))) - (('narinfo ('version 2) - ('cache-uri cache-uri) - ('date date) ('ttl ttl) ('value value)) - ;; A cached positive lookup - (if (obsolete? date now ttl) - (values #f #f) - (values #t (string->narinfo value cache-uri)))) - (('narinfo ('version v) _ ...) - (values #f #f)))))) - (lambda _ - (values #f #f)))) - -(define (cache-narinfo! cache-url path narinfo ttl) - "Cache locally NARNIFO for PATH, which originates from CACHE-URL, with the -given TTL (a number of seconds or #f). NARINFO may be #f, in which case it -indicates that PATH is unavailable at CACHE-URL." - (define now - (current-time time-monotonic)) - - (define (cache-entry cache-uri narinfo) - `(narinfo (version 2) - (cache-uri ,cache-uri) - (date ,(time-second now)) - (ttl ,(or ttl - (if narinfo %narinfo-ttl %narinfo-negative-ttl))) - (value ,(and=> narinfo narinfo->string)))) - - (let ((file (narinfo-cache-file cache-url path))) - (mkdir-p (dirname file)) - (with-atomic-file-output file - (lambda (out) - (write (cache-entry cache-url narinfo) out)))) - - narinfo) - -(define (narinfo-request cache-url path) - "Return an HTTP request for the narinfo of PATH at CACHE-URL." - (let ((url (string-append cache-url "/" (store-path-hash-part path) - ".narinfo")) - (headers '((User-Agent . "GNU Guile")))) - (build-request (string->uri url) #:method 'GET #:headers headers))) - (define (at-most max-length lst) "If LST is shorter than MAX-LENGTH, return it and the empty list; otherwise return its MAX-LENGTH first elements and its tail." @@ -261,10 +147,6 @@ (define (at-most max-length lst) (values (reverse result) lst) (loop (+ 1 len) tail (cons head result))))))) -(define (read-to-eof port) - "Read from PORT until EOF is reached. The data are discarded." - (dump-port port (%make-void-port "w"))) - (define (narinfo-from-file file url) "Attempt to read a narinfo from FILE, using URL as the cache URL. Return #f if file doesn't exist, and the narinfo otherwise." @@ -277,186 +159,6 @@ (define (narinfo-from-file file url) #f (apply throw args))))) -(define %unreachable-hosts - ;; Set of names of unreachable hosts. - (make-hash-table)) - -(define* (call-with-connection-error-handling uri proc) - "Call PROC, and catch if a connection fails, print a warning and return #f." - (define host - (uri-host uri)) - - (catch #t - proc - (match-lambda* - (('getaddrinfo-error error) - (unless (hash-ref %unreachable-hosts host) - (hash-set! %unreachable-hosts host #t) ;warn only once - (warning (G_ "~a: host not found: ~a~%") - host (gai-strerror error))) - #f) - (('system-error . args) - (unless (hash-ref %unreachable-hosts host) - (hash-set! %unreachable-hosts host #t) - (warning (G_ "~a: connection failed: ~a~%") host - (strerror - (system-error-errno `(system-error ,@args))))) - #f) - (args - (apply throw args))))) - -(define* (fetch-narinfos url paths - #:key (open-connection guix:open-connection-for-uri)) - "Retrieve all the narinfos for PATHS from the cache at URL and return them." - (define update-progress! - (let ((done 0) - (total (length paths))) - (lambda () - (display "\r\x1b[K" (current-error-port)) ;erase current line - (force-output (current-error-port)) - (format (current-error-port) - (G_ "updating substitutes from '~a'... ~5,1f%") - url (* 100. (/ done total))) - (set! done (+ 1 done))))) - - (define hash-part->path - (let ((mapping (fold (lambda (path result) - (vhash-cons (store-path-hash-part path) path - result)) - vlist-null - paths))) - (lambda (hash) - (match (vhash-assoc hash mapping) - (#f #f) - ((_ . path) path))))) - - (define (handle-narinfo-response request response port result) - (let* ((code (response-code response)) - (len (response-content-length response)) - (cache (response-cache-control response)) - (ttl (and cache (assoc-ref cache 'max-age)))) - (update-progress!) - - ;; Make sure to read no more than LEN bytes since subsequent bytes may - ;; belong to the next response. - (if (= code 200) ; hit - (let ((narinfo (read-narinfo port url #:size len))) - (if (string=? (dirname (narinfo-path narinfo)) - (%store-prefix)) - (begin - (cache-narinfo! url (narinfo-path narinfo) narinfo ttl) - (cons narinfo result)) - result)) - (let* ((path (uri-path (request-uri request))) - (hash-part (basename - (string-drop-right path 8)))) ;drop ".narinfo" - (if len - (get-bytevector-n port len) - (read-to-eof port)) - (cache-narinfo! url (hash-part->path hash-part) #f - (if (or (= 404 code) (= 202 code)) - ttl - %narinfo-transient-error-ttl)) - result)))) - - (define (do-fetch uri) - (case (and=> uri uri-scheme) - ((http https) - ;; Note: Do not check HTTPS server certificates to avoid depending - ;; on the X.509 PKI. We can do it because we authenticate - ;; narinfos, which provides a much stronger guarantee. - (let* ((requests (map (cut narinfo-request url <>) paths)) - (result (begin - (update-progress!) - (call-with-connection-error-handling - uri - (lambda () - (http-multiple-get uri - handle-narinfo-response '() - requests - #:open-connection open-connection - #:verify-certificate? #f)))))) - (newline (current-error-port)) - result)) - ((file #f) - (let* ((base (string-append (uri-path uri) "/")) - (files (map (compose (cut string-append base <> ".narinfo") - store-path-hash-part) - paths))) - (filter-map (cut narinfo-from-file <> url) files))) - (else - (leave (G_ "~s: unsupported server URI scheme~%") - (if uri (uri-scheme uri) url))))) - - (do-fetch (string->uri url))) - -(define* (lookup-narinfos cache paths - #:key (open-connection guix:open-connection-for-uri)) - "Return the narinfos for PATHS, invoking the server at CACHE when no -information is available locally." - (let-values (((cached missing) - (fold2 (lambda (path cached missing) - (let-values (((valid? value) - (cached-narinfo cache path))) - (if valid? - (if value - (values (cons value cached) missing) - (values cached missing)) - (values cached (cons path missing))))) - '() - '() - paths))) - (if (null? missing) - cached - (let ((missing (fetch-narinfos cache missing - #:open-connection open-connection))) - (append cached (or missing '())))))) - -(define* (lookup-narinfos/diverse caches paths authorized? - #:key (open-connection - guix:open-connection-for-uri)) - "Look up narinfos for PATHS on all of CACHES, a list of URLS, in that order. -That is, when a cache lacks an AUTHORIZED? narinfo, look it up in the next -cache, and so on. - -Return a list of narinfos for PATHS or a subset thereof. The returned -narinfos are either AUTHORIZED?, or they claim a hash that matches an -AUTHORIZED? narinfo." - (define (select-hit result) - (lambda (path) - (match (vhash-fold* cons '() path result) - ((one) - one) - ((several ..1) - (let ((authorized (find authorized? (reverse several)))) - (and authorized - (find (cut equivalent-narinfo? <> authorized) - several))))))) - - (let loop ((caches caches) - (paths paths) - (result vlist-null) ;path->narinfo vhash - (hits '())) ;paths - (match paths - (() ;we're done - ;; Now iterate on all the HITS, and return exactly one match for each - ;; hit: the first narinfo that is authorized, or that has the same hash - ;; as an authorized narinfo, in the order of CACHES. - (filter-map (select-hit result) hits)) - (_ - (match caches - ((cache rest ...) - (let* ((narinfos (lookup-narinfos cache paths - #:open-connection open-connection)) - (definite (map narinfo-path (filter authorized? narinfos))) - (missing (lset-difference string=? paths definite))) ;XXX: perf - (loop rest missing - (fold vhash-cons result - (map narinfo-path narinfos) narinfos) - (append definite hits)))) - (() ;that's it - (filter-map (select-hit result) hits))))))) - (define (lookup-narinfo caches path authorized?) "Return the narinfo for PATH in CACHES, or #f when no substitute for PATH was found." diff --git a/guix/scripts/weather.scm b/guix/scripts/weather.scm index 97e4a73802..9e94bff5a3 100644 --- a/guix/scripts/weather.scm +++ b/guix/scripts/weather.scm @@ -32,7 +32,7 @@ (define-module (guix scripts weather) #:use-module (guix gexp) #:use-module ((guix build syscalls) #:select (terminal-columns)) #:use-module ((guix build utils) #:select (every*)) - #:use-module (guix scripts substitute) + #:use-module (guix substitutes) #:use-module (guix narinfo) #:use-module (guix http-client) #:use-module (guix ci) diff --git a/guix/substitutes.scm b/guix/substitutes.scm new file mode 100644 index 0000000000..dc94ccc8e4 --- /dev/null +++ b/guix/substitutes.scm @@ -0,0 +1,366 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès +;;; Copyright © 2014 Nikita Karetnikov +;;; Copyright © 2018 Kyle Meyer +;;; Copyright © 2020 Christopher Baines +;;; +;;; 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 . + +(define-module (guix substitutes) + #:use-module (guix narinfo) + #:use-module (guix store) + #:use-module (guix utils) + #:use-module (guix combinators) + #:use-module (guix config) + #:use-module (guix records) + #:use-module (guix diagnostics) + #:use-module (guix i18n) + #:use-module (gcrypt hash) + #:use-module (guix base32) + #:use-module (guix base64) + #:use-module (guix cache) + #:use-module (gcrypt pk-crypto) + #:use-module (guix pki) + #:use-module ((guix build utils) #:select (mkdir-p dump-port)) + #:use-module ((guix build download) + #:select ((open-connection-for-uri + . guix:open-connection-for-uri))) + #:use-module (guix progress) + #:use-module (ice-9 rdelim) + #:use-module (ice-9 regex) + #:use-module (ice-9 match) + #:use-module (ice-9 format) + #:use-module (ice-9 ftw) + #:use-module (ice-9 binary-ports) + #:use-module (ice-9 vlist) + #:use-module (rnrs bytevectors) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-11) + #:use-module (srfi srfi-19) + #:use-module (srfi srfi-26) + #:use-module (srfi srfi-34) + #:use-module (srfi srfi-35) + #:use-module (web uri) + #:use-module (web request) + #:use-module (web response) + #:use-module (guix http-client) + #:export (%narinfo-cache-directory + + call-with-connection-error-handling + + lookup-narinfos + lookup-narinfos/diverse)) + +(define %narinfo-ttl + ;; Number of seconds during which cached narinfo lookups are considered + ;; valid for substitute servers that do not advertise a TTL via the + ;; 'Cache-Control' response header. + (* 36 3600)) + +(define %narinfo-negative-ttl + ;; Likewise, but for negative lookups---i.e., cached lookup failures (404). + (* 1 3600)) + +(define %narinfo-transient-error-ttl + ;; Likewise, but for transient errors such as 504 ("Gateway timeout"). + (* 10 60)) + +(define %narinfo-cache-directory + ;; A local cache of narinfos, to avoid going to the network. Most of the + ;; time, 'guix substitute' is called by guix-daemon as root and stores its + ;; cached data in /var/guix/…. However, when invoked from 'guix challenge' + ;; as a user, it stores its cache in ~/.cache. + (if (zero? (getuid)) + (or (and=> (getenv "XDG_CACHE_HOME") + (cut string-append <> "/guix/substitute")) + (string-append %state-directory "/substitute/cache")) + (string-append (cache-directory #:ensure? #f) "/substitute"))) + +(define (narinfo-cache-file cache-url path) + "Return the name of the local file that contains an entry for PATH. The +entry is stored in a sub-directory specific to CACHE-URL." + ;; The daemon does not sanitize its input, so PATH could be something like + ;; "/gnu/store/foo". Gracefully handle that. + (match (store-path-hash-part path) + (#f + (leave (G_ "'~a' does not name a store item~%") path)) + ((? string? hash-part) + (string-append %narinfo-cache-directory "/" + (bytevector->base32-string (sha256 (string->utf8 cache-url))) + "/" hash-part)))) + +(define (cache-narinfo! cache-url path narinfo ttl) + "Cache locally NARNIFO for PATH, which originates from CACHE-URL, with the +given TTL (a number of seconds or #f). NARINFO may be #f, in which case it +indicates that PATH is unavailable at CACHE-URL." + (define now + (current-time time-monotonic)) + + (define (cache-entry cache-uri narinfo) + `(narinfo (version 2) + (cache-uri ,cache-uri) + (date ,(time-second now)) + (ttl ,(or ttl + (if narinfo %narinfo-ttl %narinfo-negative-ttl))) + (value ,(and=> narinfo narinfo->string)))) + + (let ((file (narinfo-cache-file cache-url path))) + (mkdir-p (dirname file)) + (with-atomic-file-output file + (lambda (out) + (write (cache-entry cache-url narinfo) out)))) + + narinfo) + +(define %unreachable-hosts + ;; Set of names of unreachable hosts. + (make-hash-table)) + +(define* (call-with-connection-error-handling uri proc) + "Call PROC, and catch if a connection fails, print a warning and return #f." + (define host + (uri-host uri)) + + (catch #t + proc + (match-lambda* + (('getaddrinfo-error error) + (unless (hash-ref %unreachable-hosts host) + (hash-set! %unreachable-hosts host #t) ;warn only once + (warning (G_ "~a: host not found: ~a~%") + host (gai-strerror error))) + #f) + (('system-error . args) + (unless (hash-ref %unreachable-hosts host) + (hash-set! %unreachable-hosts host #t) + (warning (G_ "~a: connection failed: ~a~%") host + (strerror + (system-error-errno `(system-error ,@args))))) + #f) + (args + (apply throw args))))) + +(define (narinfo-request cache-url path) + "Return an HTTP request for the narinfo of PATH at CACHE-URL." + (let ((url (string-append cache-url "/" (store-path-hash-part path) + ".narinfo")) + (headers '((User-Agent . "GNU Guile")))) + (build-request (string->uri url) #:method 'GET #:headers headers))) + +(define (narinfo-from-file file url) + "Attempt to read a narinfo from FILE, using URL as the cache URL. Return #f +if file doesn't exist, and the narinfo otherwise." + (catch 'system-error + (lambda () + (call-with-input-file file + (cut read-narinfo <> url))) + (lambda args + (if (= ENOENT (system-error-errno args)) + #f + (apply throw args))))) + +(define* (fetch-narinfos url paths + #:key (open-connection guix:open-connection-for-uri)) + "Retrieve all the narinfos for PATHS from the cache at URL and return them." + (define update-progress! + (let ((done 0) + (total (length paths))) + (lambda () + (display "\r\x1b[K" (current-error-port)) ;erase current line + (force-output (current-error-port)) + (format (current-error-port) + (G_ "updating substitutes from '~a'... ~5,1f%") + url (* 100. (/ done total))) + (set! done (+ 1 done))))) + + (define hash-part->path + (let ((mapping (fold (lambda (path result) + (vhash-cons (store-path-hash-part path) path + result)) + vlist-null + paths))) + (lambda (hash) + (match (vhash-assoc hash mapping) + (#f #f) + ((_ . path) path))))) + + (define (read-to-eof port) + "Read from PORT until EOF is reached. The data are discarded." + (dump-port port (%make-void-port "w"))) + + (define (handle-narinfo-response request response port result) + (let* ((code (response-code response)) + (len (response-content-length response)) + (cache (response-cache-control response)) + (ttl (and cache (assoc-ref cache 'max-age)))) + (update-progress!) + + ;; Make sure to read no more than LEN bytes since subsequent bytes may + ;; belong to the next response. + (if (= code 200) ; hit + (let ((narinfo (read-narinfo port url #:size len))) + (if (string=? (dirname (narinfo-path narinfo)) + (%store-prefix)) + (begin + (cache-narinfo! url (narinfo-path narinfo) narinfo ttl) + (cons narinfo result)) + result)) + (let* ((path (uri-path (request-uri request))) + (hash-part (basename + (string-drop-right path 8)))) ;drop ".narinfo" + (if len + (get-bytevector-n port len) + (read-to-eof port)) + (cache-narinfo! url (hash-part->path hash-part) #f + (if (or (= 404 code) (= 202 code)) + ttl + %narinfo-transient-error-ttl)) + result)))) + + (define (do-fetch uri) + (case (and=> uri uri-scheme) + ((http https) + ;; Note: Do not check HTTPS server certificates to avoid depending + ;; on the X.509 PKI. We can do it because we authenticate + ;; narinfos, which provides a much stronger guarantee. + (let* ((requests (map (cut narinfo-request url <>) paths)) + (result (begin + (update-progress!) + (call-with-connection-error-handling + uri + (lambda () + (http-multiple-get uri + handle-narinfo-response '() + requests + #:open-connection open-connection + #:verify-certificate? #f)))))) + (newline (current-error-port)) + result)) + ((file #f) + (let* ((base (string-append (uri-path uri) "/")) + (files (map (compose (cut string-append base <> ".narinfo") + store-path-hash-part) + paths))) + (filter-map (cut narinfo-from-file <> url) files))) + (else + (leave (G_ "~s: unsupported server URI scheme~%") + (if uri (uri-scheme uri) url))))) + + (do-fetch (string->uri url))) + +(define (cached-narinfo cache-url path) + "Check locally if we have valid info about PATH coming from CACHE-URL. +Return two values: a Boolean indicating whether we have valid cached info, and +that info, which may be either #f (when PATH is unavailable) or the narinfo +for PATH." + (define now + (current-time time-monotonic)) + + (define cache-file + (narinfo-cache-file cache-url path)) + + (catch 'system-error + (lambda () + (call-with-input-file cache-file + (lambda (p) + (match (read p) + (('narinfo ('version 2) + ('cache-uri cache-uri) + ('date date) ('ttl ttl) ('value #f)) + ;; A cached negative lookup. + (if (obsolete? date now ttl) + (values #f #f) + (values #t #f))) + (('narinfo ('version 2) + ('cache-uri cache-uri) + ('date date) ('ttl ttl) ('value value)) + ;; A cached positive lookup + (if (obsolete? date now ttl) + (values #f #f) + (values #t (string->narinfo value cache-uri)))) + (('narinfo ('version v) _ ...) + (values #f #f)))))) + (lambda _ + (values #f #f)))) + +(define* (lookup-narinfos cache paths + #:key (open-connection guix:open-connection-for-uri)) + "Return the narinfos for PATHS, invoking the server at CACHE when no +information is available locally." + (let-values (((cached missing) + (fold2 (lambda (path cached missing) + (let-values (((valid? value) + (cached-narinfo cache path))) + (if valid? + (if value + (values (cons value cached) missing) + (values cached missing)) + (values cached (cons path missing))))) + '() + '() + paths))) + (if (null? missing) + cached + (let ((missing (fetch-narinfos cache missing + #:open-connection open-connection))) + (append cached (or missing '())))))) + +(define* (lookup-narinfos/diverse caches paths authorized? + #:key (open-connection + guix:open-connection-for-uri)) + "Look up narinfos for PATHS on all of CACHES, a list of URLS, in that order. +That is, when a cache lacks an AUTHORIZED? narinfo, look it up in the next +cache, and so on. + +Return a list of narinfos for PATHS or a subset thereof. The returned +narinfos are either AUTHORIZED?, or they claim a hash that matches an +AUTHORIZED? narinfo." + (define (select-hit result) + (lambda (path) + (match (vhash-fold* cons '() path result) + ((one) + one) + ((several ..1) + (let ((authorized (find authorized? (reverse several)))) + (and authorized + (find (cut equivalent-narinfo? <> authorized) + several))))))) + + (let loop ((caches caches) + (paths paths) + (result vlist-null) ;path->narinfo vhash + (hits '())) ;paths + (match paths + (() ;we're done + ;; Now iterate on all the HITS, and return exactly one match for each + ;; hit: the first narinfo that is authorized, or that has the same hash + ;; as an authorized narinfo, in the order of CACHES. + (filter-map (select-hit result) hits)) + (_ + (match caches + ((cache rest ...) + (let* ((narinfos (lookup-narinfos cache paths + #:open-connection open-connection)) + (definite (map narinfo-path (filter authorized? narinfos))) + (missing (lset-difference string=? paths definite))) ;XXX: perf + (loop rest missing + (fold vhash-cons result + (map narinfo-path narinfos) narinfos) + (append definite hits)))) + (() ;that's it + (filter-map (select-hit result) hits))))))) + +;;; substitutes.scm ends here