guix-devel/guix/scripts/substitute-binary.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014 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 substitute-binary)
#:use-module (guix ui)
#:use-module (guix store)
#:use-module (guix utils)
#:use-module (guix config)
#:use-module (guix records)
#:use-module (guix nar)
#:use-module ((guix build utils) #:select (mkdir-p))
#:use-module ((guix build download)
#:select (progress-proc uri-abbreviation))
#:use-module (ice-9 rdelim)
#:use-module (ice-9 regex)
#:use-module (ice-9 match)
#:use-module (ice-9 threads)
#:use-module (ice-9 format)
#:use-module (ice-9 ftw)
#:use-module (ice-9 binary-ports)
#: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 (web uri)
#:use-module (guix http-client)
#:export (guix-substitute-binary))
;;; Comment:
;;;
;;; This is the "binary substituter". It is invoked by the daemon do check
;;; for the existence of available "substitutes" (pre-built binaries), and to
;;; actually use them as a substitute to building things locally.
;;;
;;; If possible, substitute a binary for the requested store path, using a Nix
;;; "binary cache". This program implements the Nix "substituter" protocol.
;;;
;;; Code:
(define %narinfo-cache-directory
;; A local cache of narinfos, to avoid going to the network.
(or (and=> (getenv "XDG_CACHE_HOME")
(cut string-append <> "/guix/substitute-binary"))
(string-append %state-directory "/substitute-binary/cache")))
(define %narinfo-ttl
;; Number of seconds during which cached narinfo lookups are considered
;; valid.
(* 24 3600))
(define %narinfo-negative-ttl
;; Likewise, but for negative lookups---i.e., cached lookup failures.
(* 3 3600))
(define %narinfo-expired-cache-entry-removal-delay
;; How often we want to remove files corresponding to expired cache entries.
(* 7 24 3600))
;; In Guile 2.0.9, `regexp-exec' is thread-unsafe, so work around it.
;; See <http://bugs.gnu.org/14404>.
(set! regexp-exec
(let ((real regexp-exec)
(lock (make-mutex)))
(lambda args
(with-mutex lock
(apply real args)))))
(define fields->alist
;; The narinfo format is really just like recutils.
recutils->alist)
(define %fetch-timeout
;; Number of seconds after which networking is considered "slow".
5)
(define %random-state
(seed->random-state (+ (ash (cdr (gettimeofday)) 32) (getpid))))
(define-syntax-rule (with-timeout duration handler body ...)
"Run BODY; when DURATION seconds have expired, call HANDLER, and run BODY
again."
(begin
(sigaction SIGALRM
(lambda (signum)
(sigaction SIGALRM SIG_DFL)
handler))
(alarm duration)
(call-with-values
(lambda ()
(let try ()
(catch 'system-error
(lambda ()
body ...)
(lambda args
;; Before Guile v2.0.9-39-gfe51c7b, the SIGALRM triggers EINTR
;; because of the bug at
;; <http://lists.gnu.org/archive/html/guile-devel/2013-06/msg00050.html>.
;; When that happens, try again. Note: SA_RESTART cannot be
;; used because of <http://bugs.gnu.org/14640>.
(if (= EINTR (system-error-errno args))
(begin
;; Wait a little to avoid bursts.
(usleep (random 3000000 %random-state))
(try))
(apply throw args))))))
(lambda result
(alarm 0)
(sigaction SIGALRM SIG_DFL)
(apply values result)))))
(define* (fetch uri #:key (buffered? #t) (timeout? #t) (quiet-404? #f))
"Return a binary input port to URI and the number of bytes it's expected to
provide. If QUIET-404? is true, HTTP 404 error conditions are passed through
to the caller without emitting an error message."
(case (uri-scheme uri)
((file)
(let ((port (open-file (uri-path uri)
(if buffered? "rb" "r0b"))))
(values port (stat:size (stat port)))))
((http)
(guard (c ((http-get-error? c)
(let ((code (http-get-error-code c)))
(if (and (= code 404) quiet-404?)
(raise c)
(leave (_ "download from '~a' failed: ~a, ~s~%")
(uri->string (http-get-error-uri c))
code (http-get-error-reason c))))))
;; On Guile 2.0.5, `http-fetch' fetches the whole thing at once. So
;; honor TIMEOUT? to disable the timeout when fetching a nar.
;;
;; Test this with:
;; sudo tc qdisc add dev eth0 root netem delay 1500ms
;; and then cancel with:
;; sudo tc qdisc del dev eth0 root
(let ((port #f))
(with-timeout (if (or timeout? (guile-version>? "2.0.5"))
%fetch-timeout
0)
(begin
(warning (_ "while fetching ~a: server is unresponsive~%")
(uri->string uri))
(warning (_ "try `--no-substitutes' if the problem persists~%"))
;; Before Guile v2.0.9-39-gfe51c7b, EINTR was reported to the user,
;; and thus PORT had to be closed and re-opened. This is not the
;; case afterward.
(unless (or (guile-version>? "2.0.9")
(version>? (version) "2.0.9.39"))
(when port
(close-port port))))
(begin
(when (or (not port) (port-closed? port))
(set! port (open-socket-for-uri uri #:buffered? buffered?)))
(http-fetch uri #:text? #f #:port port))))))))
(define-record-type <cache>
(%make-cache url store-directory wants-mass-query?)
cache?
(url cache-url)
(store-directory cache-store-directory)
(wants-mass-query? cache-wants-mass-query?))
(define (open-cache url)
"Open the binary cache at URL. Return a <cache> object on success, or #f on
failure."
(define (download-cache-info url)
;; Download the `nix-cache-info' from URL, and return its contents as an
;; list of key/value pairs.
(and=> (false-if-exception (fetch (string->uri url)))
fields->alist))
(and=> (download-cache-info (string-append url "/nix-cache-info"))
(lambda (properties)
(alist->record properties
(cut %make-cache url <...>)
'("StoreDir" "WantMassQuery")))))
(define-record-type <narinfo>
(%make-narinfo path uri compression file-hash file-size nar-hash nar-size
references deriver system)
narinfo?
(path narinfo-path)
(uri narinfo-uri)
(compression narinfo-compression)
(file-hash narinfo-file-hash)
(file-size narinfo-file-size)
(nar-hash narinfo-hash)
(nar-size narinfo-size)
(references narinfo-references)
(deriver narinfo-deriver)
(system narinfo-system))
(define (narinfo-maker cache-url)
"Return a narinfo constructor for narinfos originating from CACHE-URL."
(lambda (path url compression file-hash file-size nar-hash nar-size
references deriver system)
"Return a new <narinfo> object."
(%make-narinfo path
;; Handle the case where URL is a relative URL.
(or (string->uri url)
(string->uri (string-append cache-url "/" url)))
compression file-hash
(and=> file-size string->number)
nar-hash
(and=> nar-size string->number)
(string-tokenize references)
(match deriver
((or #f "") #f)
(_ deriver))
system)))
(define* (read-narinfo port #:optional url)
"Read a narinfo from PORT in its standard external form. If URL is true, it
must be a string used to build full URIs from relative URIs found while
reading PORT."
(alist->record (fields->alist port)
(narinfo-maker url)
'("StorePath" "URL" "Compression"
"FileHash" "FileSize" "NarHash" "NarSize"
"References" "Deriver" "System")))
(define (write-narinfo narinfo port)
"Write NARINFO to PORT."
(define (empty-string-if-false x)
(or x ""))
(define (number-or-empty-string x)
(if (number? x)
(number->string x)
""))
(object->fields narinfo
`(("StorePath" . ,narinfo-path)
("URL" . ,(compose uri->string narinfo-uri))
("Compression" . ,narinfo-compression)
("FileHash" . ,(compose empty-string-if-false
narinfo-file-hash))
("FileSize" . ,(compose number-or-empty-string
narinfo-file-size))
("NarHash" . ,(compose empty-string-if-false
narinfo-hash))
("NarSize" . ,(compose number-or-empty-string
narinfo-size))
("References" . ,(compose string-join narinfo-references))
("Deriver" . ,(compose empty-string-if-false
narinfo-deriver))
("System" . ,narinfo-system))
port))
(define (narinfo->string narinfo)
"Return the external representation of NARINFO."
(call-with-output-string (cut write-narinfo narinfo <>)))
(define (string->narinfo str)
"Return the narinfo represented by STR."
(call-with-input-string str (cut read-narinfo <>)))
(define (fetch-narinfo cache path)
"Return the <narinfo> record for PATH, or #f if CACHE does not hold PATH."
(define (download url)
;; Download the .narinfo from URL, and return its contents as a list of
;; key/value pairs. Don't emit an error message upon 404.
(false-if-exception (fetch (string->uri url)
#:quiet-404? #t)))
(and (string=? (cache-store-directory cache) (%store-prefix))
(and=> (download (string-append (cache-url cache) "/"
(store-path-hash-part path)
".narinfo"))
(cute read-narinfo <> (cache-url cache)))))
(define (obsolete? date now ttl)
"Return #t if DATE is obsolete compared to NOW + TTL seconds."
(time>? (subtract-duration now (make-time time-duration 0 ttl))
(make-time time-monotonic 0 date)))
(define %lookup-threads
;; Number of threads spawned to perform lookup operations. This means we
;; can have this many simultaneous HTTP GET requests to the server, which
;; limits the impact of connection latency.
20)
(define (lookup-narinfo cache path)
"Check locally if we have valid info about PATH, otherwise go to CACHE and
check what it has."
(define now
(current-time time-monotonic))
(define cache-file
(string-append %narinfo-cache-directory "/"
(store-path-hash-part path)))
(define (cache-entry narinfo)
`(narinfo (version 0)
(date ,(time-second now))
(value ,(and=> narinfo narinfo->string))))
(let*-values (((valid? cached)
(catch 'system-error
(lambda ()
(call-with-input-file cache-file
(lambda (p)
(match (read p)
(('narinfo ('version 0) ('date date)
('value #f))
;; A cached negative lookup.
(if (obsolete? date now %narinfo-negative-ttl)
(values #f #f)
(values #t #f)))
(('narinfo ('version 0) ('date date)
('value value))
;; A cached positive lookup
(if (obsolete? date now %narinfo-ttl)
(values #f #f)
(values #t (string->narinfo value))))))))
(lambda _
(values #f #f)))))
(if valid?
cached ; including negative caches
(let* ((cache (force cache))
(narinfo (and cache (fetch-narinfo cache path))))
;; Cache NARINFO only when CACHE was actually accessible. This
;; avoids caching negative hits when in fact we just lacked network
;; access.
(when cache
(with-atomic-file-output cache-file
(lambda (out)
(write (cache-entry narinfo) out))))
narinfo))))
(define (remove-expired-cached-narinfos)
"Remove expired narinfo entries from the cache. The sole purpose of this
function is to make sure `%narinfo-cache-directory' doesn't grow
indefinitely."
(define now
(current-time time-monotonic))
(define (expired? file)
(catch 'system-error
(lambda ()
(call-with-input-file file
(lambda (port)
(match (read port)
(('narinfo ('version 0) ('date date)
('value #f))
(obsolete? date now %narinfo-negative-ttl))
(('narinfo ('version 0) ('date date)
('value _))
(obsolete? date now %narinfo-ttl))
(_ #t)))))
(lambda args
;; FILE may have been deleted.
#t)))
(for-each (lambda (file)
(let ((file (string-append %narinfo-cache-directory
"/" file)))
(when (expired? file)
;; Wrap in `false-if-exception' because FILE might have been
;; deleted in the meantime (TOCTTOU).
(false-if-exception (delete-file file)))))
(scandir %narinfo-cache-directory
(lambda (file)
(= (string-length file) 32)))))
(define (maybe-remove-expired-cached-narinfo)
"Remove expired narinfo entries from the cache if deemed necessary."
(define now
(current-time time-monotonic))
(define expiry-file
(string-append %narinfo-cache-directory "/last-expiry-cleanup"))
(define last-expiry-date
(or (false-if-exception
(call-with-input-file expiry-file read))
0))
(when (obsolete? last-expiry-date now %narinfo-expired-cache-entry-removal-delay)
(remove-expired-cached-narinfos)
(call-with-output-file expiry-file
(cute write (time-second now) <>))))
(define (progress-report-port report-progress port)
"Return a port that calls REPORT-PROGRESS every time something is read from
PORT. REPORT-PROGRESS is a two-argument procedure such as that returned by
`progress-proc'."
(define total 0)
(define (read! bv start count)
(let ((n (match (get-bytevector-n! port bv start count)
((? eof-object?) 0)
(x x))))
(set! total (+ total n))
(report-progress total (const n))
;; XXX: We're not in control, so we always return anyway.
n))
;; Since `http-fetch' in Guile 2.0.5 returns all the data once it's done,
;; don't pretend to report any progress in that case.
(if (guile-version>? "2.0.5")
(make-custom-binary-input-port "progress-port-proc"
read! #f #f
(cut close-port port))
(begin
(format (current-error-port) (_ "Downloading, please wait...~%"))
(format (current-error-port)
(_ "(Please consider upgrading Guile to get proper progress report.)~%"))
port)))
(define %cache-url
(or (getenv "GUIX_BINARY_SUBSTITUTE_URL")
"http://hydra.gnu.org"))
(define-syntax with-networking
(syntax-rules ()
"Catch DNS lookup errors and gracefully exit."
;; Note: no attempt is made to catch other networking errors, because DNS
;; lookup errors are typically the first one, and because other errors are
;; a subset of `system-error', which is harder to filter.
((_ exp ...)
(catch 'getaddrinfo-error
(lambda () exp ...)
(lambda (key error)
(leave (_ "host name lookup error: ~a~%")
(gai-strerror error)))))))
;;;
;;; Help.
;;;
(define (show-help)
(display (_ "Usage: guix substitute-binary [OPTION]...
Internal tool to substitute a pre-built binary to a local build.\n"))
(display (_ "
--query report on the availability of substitutes for the
store file names passed on the standard input"))
(display (_ "
--substitute STORE-FILE DESTINATION
download STORE-FILE and store it as a Nar in file
DESTINATION"))
(newline)
(display (_ "
-h, --help display this help and exit"))
(display (_ "
-V, --version display version information and exit"))
(newline)
(show-bug-report-information))
;;;
;;; Entry point.
;;;
(define n-par-map*
;; We want the ability to run many threads in parallel, regardless of the
;; number of cores. However, Guile 2.0.5 has a bug whereby 'n-par-map' ends
;; up consuming a lot of memory, possibly leading to death. Thus, resort to
;; 'par-map' on 2.0.5.
(if (guile-version>? "2.0.5")
n-par-map
(lambda (n proc lst)
(par-map proc lst))))
(define (guix-substitute-binary . args)
"Implement the build daemon's substituter protocol."
(mkdir-p %narinfo-cache-directory)
(maybe-remove-expired-cached-narinfo)
;; Starting from commit 22144afa in Nix, we are allowed to bail out directly
;; when we know we cannot substitute, but we must emit a newline on stdout
;; when everything is alright.
(let ((uri (string->uri %cache-url)))
(case (uri-scheme uri)
((http)
;; Exit gracefully if there's no network access.
(let ((host (uri-host uri)))
(catch 'getaddrinfo-error
(lambda ()
(getaddrinfo host))
(lambda (key error)
(warning (_ "failed to look up host '~a' (~a), \
substituter disabled~%")
host (gai-strerror error))
(exit 0)))))
(else #t)))
;; Say hello (see above.)
(newline)
(force-output (current-output-port))
(with-networking
(match args
(("--query")
(let ((cache (delay (open-cache %cache-url))))
(let loop ((command (read-line)))
(or (eof-object? command)
(begin
(match (string-tokenize command)
(("have" paths ..1)
;; Return the subset of PATHS available in CACHE.
(let ((substitutable
(if cache
(n-par-map* %lookup-threads
(cut lookup-narinfo cache <>)
paths)
'())))
(for-each (lambda (narinfo)
(when narinfo
(format #t "~a~%" (narinfo-path narinfo))))
(filter narinfo? substitutable))
(newline)))
(("info" paths ..1)
;; Reply info about PATHS if it's in CACHE.
(let ((substitutable
(if cache
(n-par-map* %lookup-threads
(cut lookup-narinfo cache <>)
paths)
'())))
(for-each (lambda (narinfo)
(format #t "~a\n~a\n~a\n"
(narinfo-path narinfo)
(or (and=> (narinfo-deriver narinfo)
(cute string-append
(%store-prefix) "/"
<>))
"")
(length (narinfo-references narinfo)))
(for-each (cute format #t "~a/~a~%"
(%store-prefix) <>)
(narinfo-references narinfo))
(format #t "~a\n~a\n"
(or (narinfo-file-size narinfo) 0)
(or (narinfo-size narinfo) 0)))
(filter narinfo? substitutable))
(newline)))
(wtf
(error "unknown `--query' command" wtf)))
(loop (read-line)))))))
(("--substitute" store-path destination)
;; Download STORE-PATH and add store it as a Nar in file DESTINATION.
(let* ((cache (delay (open-cache %cache-url)))
(narinfo (lookup-narinfo cache store-path))
(uri (narinfo-uri narinfo)))
;; Tell the daemon what the expected hash of the Nar itself is.
(format #t "~a~%" (narinfo-hash narinfo))
(format (current-error-port) "downloading `~a' from `~a'~:[~*~; (~,1f MiB installed)~]...~%"
store-path (uri->string uri)
;; Use the Nar size as an estimate of the installed size.
(narinfo-size narinfo)
(and=> (narinfo-size narinfo)
(cute / <> (expt 2. 20))))
(let*-values (((raw download-size)
;; Note that Hydra currently generates Nars on the fly
;; and doesn't specify a Content-Length, so
;; DOWNLOAD-SIZE is #f in practice.
(fetch uri #:buffered? #f #:timeout? #f))
((progress)
(let* ((comp (narinfo-compression narinfo))
(dl-size (or download-size
(and (equal? comp "none")
(narinfo-size narinfo))))
(progress (progress-proc (uri-abbreviation uri)
dl-size
(current-error-port))))
(progress-report-port progress raw)))
((input pids)
(decompressed-port (and=> (narinfo-compression narinfo)
string->symbol)
progress)))
;; Unpack the Nar at INPUT into DESTINATION.
(restore-file input destination)
(every (compose zero? cdr waitpid) pids))))
(("--version")
(show-version-and-exit "guix substitute-binary"))
(("--help")
(show-help))
(opts
(leave (_ "~a: unrecognized options~%") opts)))))
;;; Local Variables:
;;; eval: (put 'with-timeout 'scheme-indent-function 1)
;;; End:
;;; substitute-binary.scm ends here