guix-devel/guix/scripts/substitute.scm

981 lines
37 KiB
Scheme
Executable File
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2014 Nikita Karetnikov <nikita@karetnikov.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)
#:use-module (guix ui)
#:use-module (guix store)
#:use-module (guix utils)
#:use-module (guix config)
#:use-module (guix records)
#:use-module (guix serialization)
#:use-module (guix hash)
#:use-module (guix base32)
#:use-module (guix base64)
#:use-module (guix pk-crypto)
#:use-module (guix pki)
#:use-module ((guix build utils) #:select (mkdir-p dump-port))
#:use-module ((guix build download)
#:select (progress-proc uri-abbreviation
open-connection-for-uri
store-path-abbreviation byte-count->string))
#: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 (rnrs io ports)
#: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 (narinfo-signature->canonical-sexp
narinfo?
narinfo-path
narinfo-uri
narinfo-uri-base
narinfo-compression
narinfo-file-hash
narinfo-file-size
narinfo-hash
narinfo-size
narinfo-references
narinfo-deriver
narinfo-system
narinfo-signature
narinfo-hash->sha256
assert-valid-narinfo
lookup-narinfos
lookup-narinfos/diverse
read-narinfo
write-narinfo
guix-substitute))
;;; 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"))
(string-append %state-directory "/substitute/cache")))
(define %allow-unauthenticated-substitutes?
;; Whether to allow unchecked substitutes. This is useful for testing
;; purposes, and should be avoided otherwise.
(and (and=> (getenv "GUIX_ALLOW_UNAUTHENTICATED_SUBSTITUTES")
(cut string-ci=? <> "yes"))
(begin
(warning (_ "authentication and authorization of substitutes \
disabled!~%"))
#t)))
(define %narinfo-ttl
;; Number of seconds during which cached narinfo lookups are considered
;; valid. This is a reasonable default value (corresponds to the TTL for
;; nginx's .nar cache on hydra.gnu.org) but we'd rather want publishers to
;; state what their TTL is in /nix-cache-info. (XXX)
(* 36 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))
(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))
"Return a binary input port to URI and the number of bytes it's expected to
provide."
(case (uri-scheme uri)
((file)
(let ((port (open-file (uri-path uri)
(if buffered? "rb" "r0b"))))
(values port (stat:size (stat port)))))
((http https)
(guard (c ((http-get-error? c)
(leave (_ "download from '~a' failed: ~a, ~s~%")
(uri->string (http-get-error-uri c))
(http-get-error-code c)
(http-get-error-reason c))))
;; 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 timeout?
%fetch-timeout
0)
(begin
(warning (_ "while fetching ~a: server is somewhat slow~%")
(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-connection-for-uri uri))
(unless (or buffered? (not (file-port? port)))
(setvbuf port _IONBF)))
(http-fetch uri #:text? #f #:port port))))))
(else
(leave (_ "unsupported substitute URI scheme: ~a~%")
(uri->string uri)))))
(define-record-type <cache-info>
(%make-cache-info url store-directory wants-mass-query?)
cache-info?
(url cache-info-url)
(store-directory cache-info-store-directory)
(wants-mass-query? cache-info-wants-mass-query?))
(define (download-cache-info url)
"Download the information for the cache at URL. Return a <cache-info>
object on success, or #f on failure."
(define (download 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 (string-append url "/nix-cache-info"))
(lambda (properties)
(alist->record properties
(cut %make-cache-info url <...>)
'("StoreDir" "WantMassQuery")))))
(define-record-type <narinfo>
(%make-narinfo path uri uri-base compression file-hash file-size nar-hash nar-size
references deriver system signature contents)
narinfo?
(path narinfo-path)
(uri narinfo-uri)
(uri-base narinfo-uri-base) ; URI of the cache it originates from
(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)
(signature narinfo-signature) ; canonical sexp
;; The original contents of a narinfo file. This field is needed because we
;; want to preserve the exact textual representation for verification purposes.
;; See <https://lists.gnu.org/archive/html/guix-devel/2014-02/msg00340.html>
;; for more information.
(contents narinfo-contents))
(define (narinfo-hash->sha256 hash)
"If the string HASH denotes a sha256 hash, return it as a bytevector.
Otherwise return #f."
(and (string-prefix? "sha256:" hash)
(nix-base32-string->bytevector (string-drop hash 7))))
(define (narinfo-signature->canonical-sexp str)
"Return the value of a narinfo's 'Signature' field as a canonical sexp."
(match (string-split str #\;)
((version _ sig)
(let ((maybe-number (string->number version)))
(cond ((not (number? maybe-number))
(leave (_ "signature version must be a number: ~s~%")
version))
;; Currently, there are no other versions.
((not (= 1 maybe-number))
(leave (_ "unsupported signature version: ~a~%")
maybe-number))
(else
(let ((signature (utf8->string (base64-decode sig))))
(catch 'gcry-error
(lambda ()
(string->canonical-sexp signature))
(lambda (key proc err)
(leave (_ "signature is not a valid \
s-expression: ~s~%")
signature))))))))
(x
(leave (_ "invalid format of the signature field: ~a~%") x))))
(define (narinfo-maker str cache-url)
"Return a narinfo constructor for narinfos originating from CACHE-URL. STR
must contain the original contents of a narinfo file."
(lambda (path url compression file-hash file-size nar-hash nar-size
references deriver system signature)
"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)))
cache-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
(false-if-exception
(and=> signature narinfo-signature->canonical-sexp))
str)))
(define* (assert-valid-signature narinfo signature hash
#:optional (acl (current-acl)))
"Bail out if SIGNATURE, a canonical sexp representing the signature of
NARINFO, doesn't match HASH, a bytevector containing the hash of NARINFO."
(let ((uri (uri->string (narinfo-uri narinfo))))
(signature-case (signature hash acl)
(valid-signature #t)
(invalid-signature
(leave (_ "invalid signature for '~a'~%") uri))
(hash-mismatch
(leave (_ "hash mismatch for '~a'~%") uri))
(unauthorized-key
(leave (_ "'~a' is signed with an unauthorized key~%") uri))
(corrupt-signature
(leave (_ "signature on '~a' is corrupt~%") uri)))))
(define* (read-narinfo port #:optional url
#:key size)
"Read a narinfo from PORT. If URL is true, it must be a string used to
build full URIs from relative URIs found while reading PORT. When SIZE is
true, read at most SIZE bytes from PORT; otherwise, read as much as possible.
No authentication and authorization checks are performed here!"
(let ((str (utf8->string (if size
(get-bytevector-n port size)
(get-bytevector-all port)))))
(alist->record (call-with-input-string str fields->alist)
(narinfo-maker str url)
'("StorePath" "URL" "Compression"
"FileHash" "FileSize" "NarHash" "NarSize"
"References" "Deriver" "System"
"Signature"))))
(define (narinfo-sha256 narinfo)
"Return the sha256 hash of NARINFO as a bytevector, or #f if NARINFO lacks a
'Signature' field."
(let ((contents (narinfo-contents narinfo)))
(match (string-contains contents "Signature:")
(#f #f)
(index
(let ((above-signature (string-take contents index)))
(sha256 (string->utf8 above-signature)))))))
(define* (assert-valid-narinfo narinfo
#:optional (acl (current-acl))
#:key (verbose? #t))
"Raise an exception if NARINFO lacks a signature, has an invalid signature,
or is signed by an unauthorized key."
(let ((hash (narinfo-sha256 narinfo)))
(if (not hash)
(if %allow-unauthenticated-substitutes?
narinfo
(leave (_ "substitute at '~a' lacks a signature~%")
(uri->string (narinfo-uri narinfo))))
(let ((signature (narinfo-signature narinfo)))
(unless %allow-unauthenticated-substitutes?
(assert-valid-signature narinfo signature hash acl)
(when verbose?
;; Visually separate substitutions with a newline.
(format (current-error-port)
"~%Found valid signature for ~a~%From ~a~%"
(narinfo-path narinfo)
(uri->string (narinfo-uri narinfo)))))
narinfo))))
(define* (valid-narinfo? narinfo #:optional (acl (current-acl)))
"Return #t if NARINFO's signature is not valid."
(or %allow-unauthenticated-substitutes?
(let ((hash (narinfo-sha256 narinfo))
(signature (narinfo-signature narinfo)))
(and hash signature
(signature-case (signature hash acl)
(valid-signature #t)
(else #f))))))
(define (write-narinfo narinfo port)
"Write NARINFO to PORT."
(put-bytevector port (string->utf8 (narinfo-contents narinfo))))
(define (narinfo->string narinfo)
"Return the external representation of NARINFO."
(call-with-output-string (cut write-narinfo narinfo <>)))
(define (string->narinfo str cache-uri)
"Return the narinfo represented by STR. Assume CACHE-URI as the base URI of
the cache STR originates form."
(call-with-input-string str (cut read-narinfo <> cache-uri)))
(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 (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."
(string-append %narinfo-cache-directory "/"
(bytevector->base32-string (sha256 (string->utf8 cache-url)))
"/" (store-path-hash-part path)))
(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 1)
('cache-uri cache-uri)
('date date) ('value #f))
;; A cached negative lookup.
(if (obsolete? date now %narinfo-negative-ttl)
(values #f #f)
(values #t #f)))
(('narinfo ('version 1)
('cache-uri cache-uri)
('date date) ('value value))
;; A cached positive lookup
(if (obsolete? date now %narinfo-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)
"Cache locally NARNIFO for PATH, which originates from CACHE-URL. 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 1)
(cache-uri ,cache-uri)
(date ,(time-second now))
(value ,(and=> narinfo narinfo->string))))
(let ((file (narinfo-cache-file cache-url path)))
(catch 'system-error
(lambda ()
(mkdir-p (dirname file))
(with-atomic-file-output file
(lambda (out)
(write (cache-entry cache-url narinfo) out))))
(lambda args
;; We may not have write access to the local cache when called from an
;; unprivileged process such as 'guix challenge'.
(unless (= EACCES (system-error-errno args))
(apply throw args)))))
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")))
(build-request (string->uri url) #:method 'GET)))
(define (http-multiple-get base-uri proc seed requests)
"Send all of REQUESTS to the server at BASE-URI. Call PROC for each
response, passing it the request object, the response, a port from which to
read the response body, and the previous result, starting with SEED, à la
'fold'. Return the final result."
(let connect ((requests requests)
(result seed))
;; (format (current-error-port) "connecting (~a requests left)..."
;; (length requests))
(let ((p (open-connection-for-uri base-uri)))
;; For HTTPS, P is not a file port and does not support 'setvbuf'.
(when (file-port? p)
(setvbuf p _IOFBF (expt 2 16)))
;; Send all of REQUESTS in a row.
;; XXX: Do our own caching to work around inefficiencies when
;; communicating over TLS: <http://bugs.gnu.org/22966>.
(let-values (((buffer get) (open-bytevector-output-port)))
;; On Guile > 2.0.9, inherit the HTTP proxying property from P.
(when (module-variable (resolve-interface '(web http))
'http-proxy-port?)
(set-http-proxy-port?! buffer (http-proxy-port? p)))
(for-each (cut write-request <> buffer) requests)
(put-bytevector p (get))
(force-output p))
;; Now start processing responses.
(let loop ((requests requests)
(result result))
(match requests
(()
(reverse result))
((head tail ...)
(let* ((resp (read-response p))
(body (response-body-port resp))
(result (proc head resp body result)))
;; The server can choose to stop responding at any time, in which
;; case we have to try again. Check whether that is the case.
;; Note that even upon "Connection: close", we can read from BODY.
(match (assq 'connection (response-headers resp))
(('connection 'close)
(close-port p)
(connect tail result)) ;try again
(_
(loop tail result)))))))))) ;keep going
(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."
(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)
"Retrieve all the narinfos for PATHS from the cache at URL and return them."
(define update-progress!
(let ((done 0))
(lambda ()
(display #\cr (current-error-port))
(force-output (current-error-port))
(format (current-error-port)
(_ "updating list of substitutes from '~a'... ~5,1f%")
url (* 100. (/ done (length paths))))
(set! done (+ 1 done)))))
(define (handle-narinfo-response request response port result)
(let ((len (response-content-length response)))
;; Make sure to read no more than LEN bytes since subsequent bytes may
;; belong to the next response.
(case (response-code response)
((200) ; hit
(let ((narinfo (read-narinfo port url #:size len)))
(cache-narinfo! url (narinfo-path narinfo) narinfo)
(update-progress!)
(cons narinfo result)))
((404) ; failure
(let* ((path (uri-path (request-uri request)))
(hash-part (string-drop-right path 8))) ; drop ".narinfo"
(if len
(get-bytevector-n port len)
(read-to-eof port))
(cache-narinfo! url
(find (cut string-contains <> hash-part) paths)
#f)
(update-progress!)
result))
(else ; transient failure
(if len
(get-bytevector-n port len)
(read-to-eof port))
result))))
(define (do-fetch uri)
(case (and=> uri uri-scheme)
((http https)
(let ((requests (map (cut narinfo-request url <>) paths)))
(update-progress!)
(let ((result (http-multiple-get uri
handle-narinfo-response '()
requests)))
(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 (_ "~s: unsupported server URI scheme~%")
(if uri (uri-scheme uri) url)))))
(define cache-info
(download-cache-info url))
(and cache-info
(if (string=? (cache-info-store-directory cache-info)
(%store-prefix))
(do-fetch (string->uri url))
(begin
(warning (_ "'~a' uses different store '~a'; ignoring it~%")
url (cache-info-store-directory cache-info))
#f))))
(define (lookup-narinfos cache paths)
"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)))
(append cached (or missing '()))))))
(define (lookup-narinfos/diverse caches paths)
"Look up narinfos for PATHS on all of CACHES, a list of URLS, in that order.
That is, when a cache lacks a narinfo, look it up in the next cache, and so
on. Return a list of narinfos for PATHS or a subset thereof."
(let loop ((caches caches)
(paths paths)
(result '()))
(match paths
(() ;we're done
result)
(_
(match caches
((cache rest ...)
(let* ((narinfos (lookup-narinfos cache paths))
(hits (map narinfo-path narinfos))
(missing (lset-difference string=? paths hits))) ;XXX: perf
(loop rest missing (append narinfos result))))
(() ;that's it
result))))))
(define (lookup-narinfo caches path)
"Return the narinfo for PATH in CACHES, or #f when no substitute for PATH
was found."
(match (lookup-narinfos/diverse caches (list path))
((answer) answer)
(_ #f)))
(define (remove-expired-cached-narinfos directory)
"Remove expired narinfo entries from DIRECTORY. 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 1) ('cache-uri _) ('date date)
('value #f))
(obsolete? date now %narinfo-negative-ttl))
(('narinfo ('version 1) ('cache-uri _) ('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 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 directory
(lambda (file)
(= (string-length file) 32)))))
(define (narinfo-cache-directories)
"Return the list of narinfo cache directories (one per cache URL.)"
(map (cut string-append %narinfo-cache-directory "/" <>)
(scandir %narinfo-cache-directory
(lambda (item)
(and (not (member item '("." "..")))
(file-is-directory?
(string-append %narinfo-cache-directory
"/" item)))))))
(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)
(for-each remove-expired-cached-narinfos
(narinfo-cache-directories))
(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))
(make-custom-binary-input-port "progress-port-proc"
read! #f #f
(cut close-port port)))
(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 [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))
;;;
;;; Daemon/substituter protocol.
;;;
(define (display-narinfo-data narinfo)
"Write to the current output port the contents of NARINFO in the format
expected by the daemon."
(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)))
(define* (process-query command
#:key cache-urls acl)
"Reply to COMMAND, a query as written by the daemon to this process's
standard input. Use ACL as the access-control list against which to check
authorized substitutes."
(define (valid? obj)
(valid-narinfo? obj acl))
(match (string-tokenize command)
(("have" paths ..1)
;; Return the subset of PATHS available in CACHE-URLS.
(let ((substitutable (lookup-narinfos/diverse cache-urls paths)))
(for-each (lambda (narinfo)
(format #t "~a~%" (narinfo-path narinfo)))
(filter valid? substitutable))
(newline)))
(("info" paths ..1)
;; Reply info about PATHS if it's in CACHE-URLS.
(let ((substitutable (lookup-narinfos/diverse cache-urls paths)))
(for-each display-narinfo-data (filter valid? substitutable))
(newline)))
(wtf
(error "unknown `--query' command" wtf))))
(define* (process-substitution store-item destination
#:key cache-urls acl)
"Substitute STORE-ITEM (a store file name) from CACHE-URLS, and write it to
DESTINATION as a nar file. Verify the substitute against ACL."
(let* ((narinfo (lookup-narinfo cache-urls store-item))
(uri (narinfo-uri narinfo)))
;; Make sure it is signed and everything.
(assert-valid-narinfo narinfo acl)
;; Tell the daemon what the expected hash of the Nar itself is.
(format #t "~a~%" (narinfo-hash narinfo))
(format (current-error-port) "Downloading ~a~:[~*~; (~a installed)~]...~%"
(store-path-abbreviation store-item)
;; Use the Nar size as an estimate of the installed size.
(narinfo-size narinfo)
(and=> (narinfo-size narinfo)
(cute byte-count->string <>)))
(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)
#:abbreviation
store-path-abbreviation)))
(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)
;; Skip a line after what 'progress-proc' printed.
(newline (current-error-port))
(every (compose zero? cdr waitpid) pids))))
;;;
;;; Entry point.
;;;
(define (check-acl-initialized)
"Warn if the ACL is uninitialized."
(define (singleton? acl)
;; True if ACL contains just the user's public key.
(and (file-exists? %public-key-file)
(let ((key (call-with-input-file %public-key-file
(compose string->canonical-sexp
get-string-all))))
(match acl
((thing)
(equal? (canonical-sexp->string thing)
(canonical-sexp->string key)))
(_
#f)))))
(let ((acl (acl->public-keys (current-acl))))
(when (or (null? acl) (singleton? acl))
(warning (_ "ACL for archive imports seems to be uninitialized, \
substitutes may be unavailable\n")))))
(define (daemon-options)
"Return a list of name/value pairs denoting build daemon options."
(define %not-newline
(char-set-complement (char-set #\newline)))
(match (getenv "_NIX_OPTIONS")
(#f ;should not happen when called by the daemon
'())
(newline-separated
;; Here we get something of the form "OPTION1=VALUE1\nOPTION2=VALUE2\n".
(filter-map (lambda (option=value)
(match (string-index option=value #\=)
(#f ;invalid option setting
#f)
(equal-sign
(cons (string-take option=value equal-sign)
(string-drop option=value (+ 1 equal-sign))))))
(string-tokenize newline-separated %not-newline)))))
(define (find-daemon-option option)
"Return the value of build daemon option OPTION, or #f if it could not be
found."
(assoc-ref (daemon-options) option))
(define-syntax-rule (or* a b)
(let ((first a))
(if (or (not first) (string-null? first))
b
first)))
(define %cache-urls
(match (and=> (or* (find-daemon-option "untrusted-substitute-urls") ;client
(find-daemon-option "substitute-urls")) ;admin
string-tokenize)
((urls ...)
urls)
(#f
;; This can only happen when this script is not invoked by the
;; daemon.
'("http://hydra.gnu.org"))))
(define (guix-substitute . args)
"Implement the build daemon's substituter protocol."
(mkdir-p %narinfo-cache-directory)
(maybe-remove-expired-cached-narinfo)
(check-acl-initialized)
;; 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.
(when (null? %cache-urls)
(exit 0))
;; Say hello (see above.)
(newline)
(force-output (current-output-port))
(with-networking
(with-error-handling ; for signature errors
(match args
(("--query")
(let ((acl (current-acl)))
(let loop ((command (read-line)))
(or (eof-object? command)
(begin
(process-query command
#:cache-urls %cache-urls
#:acl acl)
(loop (read-line)))))))
(("--substitute" store-path destination)
;; Download STORE-PATH and add store it as a Nar in file DESTINATION.
(process-substitution store-path destination
#:cache-urls %cache-urls
#:acl (current-acl)))
(("--version")
(show-version-and-exit "guix substitute"))
(("--help")
(show-help))
(opts
(leave (_ "~a: unrecognized options~%") opts))))))
;;; Local Variables:
;;; eval: (put 'with-timeout 'scheme-indent-function 1)
;;; End:
;;; substitute.scm ends here