scripts: Add 'publish' command.

* guix/scripts/publish.scm: New file.
* po/guix/POTFILES.in: Add it.
* tests/publish.scm: New file.
* Makefile.am (MODULES): Add script module.
  (SCM_TESTS): Add test module.
* doc/guix.texi ("Invoking guix publish"): New node.

5 files changed, 412 insertions, 2 deletions

diff --git a/Makefile.am b/Makefile.am
index cf709986ed..e15e43fdd4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -105,6 +105,7 @@ MODULES =					\
   guix/scripts/import/gnu.scm			\
   guix/scripts/import/nix.scm			\
   guix/scripts/environment.scm			\
+  guix/scripts/publish.scm			\
   guix.scm					\
   $(GNU_SYSTEM_MODULES)
 
@@ -180,7 +181,8 @@ SCM_TESTS =					\
   tests/profiles.scm				\
   tests/syscalls.scm				\
   tests/gremlin.scm				\
-  tests/lint.scm
+  tests/lint.scm				\
+  tests/publish.scm
 
 if HAVE_GUILE_JSON
 
diff --git a/doc/guix.texi b/doc/guix.texi
index f7f22e5b8a..f1dea45f1d 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -121,6 +121,7 @@ Utilities
 * Invoking guix refresh::       Updating package definitions.
 * Invoking guix lint::          Finding errors in package definitions.
 * Invoking guix environment::   Setting up development environments.
+* Invoking guix publish::       Sharing substitutes.
 
 GNU Distribution
 
@@ -2527,7 +2528,7 @@ To illustrate the idea, here is an example of a gexp:
   #~(begin
       (mkdir #$output)
       (chdir #$output)
-      (symlink (string-append #$coreutils "/bin/ls") 
+      (symlink (string-append #$coreutils "/bin/ls")
                "list-files")))
 @end example
 
@@ -2777,6 +2778,7 @@ programming interface of Guix in a convenient way.
 * Invoking guix refresh::       Updating package definitions.
 * Invoking guix lint::          Finding errors in package definitions.
 * Invoking guix environment::   Setting up development environments.
+* Invoking guix publish::       Sharing substitutes.
 @end menu
 
 @node Invoking guix build
@@ -3439,6 +3441,54 @@ environment.
 It also supports all of the common build options that @command{guix
 build} supports (@pxref{Invoking guix build, common build options}).
 
+@node Invoking guix publish
+@section Invoking @command{guix publish}
+
+The purpose of @command{guix publish} is to enable users to easily share
+their store with others.  When @command{guix publish} runs, it spawns an
+HTTP server which allows anyone with network access to obtain
+substitutes from it.  This means that any machine running Guix can also
+act as if it were a build farm, since the HTTP interface is
+Hydra-compatible.
+
+For security, each substitute is signed, allowing recipients to check
+their authenticity and integrity (@pxref{Substitutes}).  Because
+@command{guix publish} uses the system's signing key, which is only
+readable by the system administrator, it must run as root.
+
+The general syntax is:
+
+@example
+guix publish @var{options}@dots{}
+@end example
+
+Running @command{guix publish} without any additional arguments will
+spawn an HTTP server on port 8080:
+
+@example
+guix publish
+@end example
+
+Once a publishing server has been authorized (@pxref{Invoking guix
+archive}), the daemon may download substitutes from it:
+
+@example
+guix-daemon --substitute-urls=http://example.org:8080
+@end example
+
+The following options are available:
+
+@table @code
+@item --port=@var{port}
+@itemx -p @var{port}
+Listen for HTTP requests on @var{port}.
+
+@item --repl[=@var{port}]
+@itemx -r [@var{port}]
+Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
+Reference Manual}) on @var{port} (37146 by default).
+@end table
+
 @c *********************************************************************
 @node GNU Distribution
 @chapter GNU Distribution
diff --git a/guix/scripts/publish.scm b/guix/scripts/publish.scm
new file mode 100644
index 0000000000..c7c66fefbe
--- /dev/null
+++ b/guix/scripts/publish.scm
@@ -0,0 +1,243 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 David Thompson <davet@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 publish)
+  #:use-module ((system repl server) #:prefix repl:)
+  #:use-module (ice-9 binary-ports)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 regex)
+  #:use-module (rnrs io ports)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-2)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-37)
+  #:use-module (web http)
+  #:use-module (web request)
+  #:use-module (web response)
+  #:use-module (web server)
+  #:use-module (web uri)
+  #:use-module (guix base32)
+  #:use-module (guix base64)
+  #:use-module (guix config)
+  #:use-module (guix derivations)
+  #:use-module (guix hash)
+  #:use-module (guix pki)
+  #:use-module (guix pk-crypto)
+  #:use-module (guix store)
+  #:use-module (guix serialization)
+  #:use-module (guix ui)
+  #:export (guix-publish))
+
+(define (show-help)
+  (format #t (_ "Usage: guix publish [OPTION]...
+Publish ~a over HTTP.\n") %store-directory)
+  (display (_ "
+  -p, --port=PORT        listen on PORT"))
+  (display (_ "
+  -r, --repl[=PORT]      spawn REPL server on PORT"))
+  (newline)
+  (display (_ "
+  -h, --help             display this help and exit"))
+  (display (_ "
+  -V, --version          display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %options
+  (list (option '(#\h "help") #f #f
+                (lambda _
+                  (show-help)
+                  (exit 0)))
+        (option '(#\V "version") #f #f
+                (lambda _
+                  (show-version-and-exit "guix publish")))
+        (option '(#\p "port") #t #f
+                (lambda (opt name arg result)
+                  (alist-cons 'port (string->number* arg) result)))
+        (option '(#\r "repl") #f #t
+                (lambda (opt name arg result)
+                  ;; If port unspecified, use default Guile REPL port.
+                  (let ((port (and arg (string->number* arg))))
+                    (alist-cons 'repl (or port 37146) result))))))
+
+(define %default-options
+  '((port . 8080)
+    (repl . #f)))
+
+(define (lazy-read-file-sexp file)
+  "Return a promise to read the canonical sexp from FILE."
+  (delay
+    (call-with-input-file file
+      (compose string->canonical-sexp
+               get-string-all))))
+
+(define %private-key
+  (lazy-read-file-sexp %private-key-file))
+
+(define %public-key
+  (lazy-read-file-sexp %public-key-file))
+
+(define %nix-cache-info
+  `(("StoreDir" . ,%store-directory)
+    ("WantMassQuery" . 0)
+    ("Priority" . 100)))
+
+(define (load-derivation file)
+  "Read the derivation from FILE."
+  (call-with-input-file file read-derivation))
+
+(define (signed-string s)
+  "Sign the hash of the string S with the daemon's key."
+  (let* ((public-key (force %public-key))
+         (hash (bytevector->hash-data (sha256 (string->utf8 s))
+                                      #:key-type (key-type public-key))))
+    (signature-sexp hash (force %private-key) public-key)))
+
+(define base64-encode-string
+  (compose base64-encode string->utf8))
+
+(define (narinfo-string store-path path-info key)
+  "Generate a narinfo key/value string for STORE-PATH using the details in
+PATH-INFO.  The narinfo is signed with KEY."
+  (let* ((url        (string-append "nar/" (basename store-path)))
+         (hash       (bytevector->base32-string
+                      (path-info-hash path-info)))
+         (size       (path-info-nar-size path-info))
+         (references (string-join
+                      (map basename (path-info-references path-info))
+                      " "))
+         (deriver (path-info-deriver path-info))
+         (base-info  (format #f
+                             "StorePath: ~a
+URL: ~a
+Compression: none
+NarHash: sha256:~a
+NarSize: ~d
+References: ~a~%"
+                             store-path url hash size references))
+         ;; Do not render a "Deriver" or "System" line if we are rendering
+         ;; info for a derivation.
+         (info (if (string-null? deriver)
+                   base-info
+                   (let ((drv (load-derivation deriver)))
+                     (format #f "~aSystem: ~a~%Deriver: ~a~%"
+                             base-info (derivation-system drv)
+                             (basename deriver)))))
+         (signature  (base64-encode-string
+                      (canonical-sexp->string (signed-string info)))))
+    (format #f "~aSignature: 1;~a;~a~%" info (gethostname) signature)))
+
+(define (not-found request)
+  "Render 404 response for REQUEST."
+  (values (build-response #:code 404)
+          (string-append "Resource not found: "
+                         (uri-path (request-uri request)))))
+
+(define (render-nix-cache-info)
+  "Render server information."
+  (values '((content-type . (text/plain)))
+          (lambda (port)
+            (for-each (match-lambda
+                       ((key . value)
+                        (format port "~a: ~a~%" key value)))
+                      %nix-cache-info))))
+
+(define (render-narinfo store request hash)
+  "Render metadata for the store path corresponding to HASH."
+  (let* ((store-path (hash-part->path store hash))
+         (path-info (and (not (string-null? store-path))
+                         (query-path-info store store-path))))
+    (if path-info
+        (values '((content-type . (application/x-nix-narinfo)))
+                (cut display
+                     (narinfo-string store-path path-info (force %private-key))
+                     <>))
+        (not-found request))))
+
+(define (render-nar request store-item)
+  "Render archive of the store path corresponding to STORE-ITEM."
+  (let ((store-path (string-append %store-directory "/" store-item)))
+    ;; The ISO-8859-1 charset *must* be used otherwise HTTP clients will
+    ;; interpret the byte stream as UTF-8 and arbitrarily change invalid byte
+    ;; sequences.
+    (if (file-exists? store-path)
+        (values '((content-type . (application/x-nix-archive
+                                   (charset . "ISO-8859-1"))))
+                (lambda (port)
+                  (write-file store-path port)))
+        (not-found request))))
+
+(define extract-narinfo-hash
+  (let ((regexp (make-regexp "^([a-df-np-sv-z0-9]{32}).narinfo$")))
+    (lambda (str)
+      "Return the hash within the narinfo resource string STR, or false if STR
+is invalid."
+      (and=> (regexp-exec regexp str)
+             (cut match:substring <> 1)))))
+
+(define (get-request? request)
+  "Return #t if REQUEST uses the GET method."
+  (eq? (request-method request) 'GET))
+
+(define (request-path-components request)
+  "Split the URI path of REQUEST into a list of component strings.  For
+example: \"/foo/bar\" yields '(\"foo\" \"bar\")."
+  (split-and-decode-uri-path (uri-path (request-uri request))))
+
+(define (make-request-handler store)
+  (lambda (request body)
+    (format #t "~a ~a~%"
+            (request-method request)
+            (uri-path (request-uri request)))
+    (if (get-request? request) ; reject POST, PUT, etc.
+        (match (request-path-components request)
+          ;; /nix-cache-info
+          (("nix-cache-info")
+           (render-nix-cache-info))
+          ;; /<hash>.narinfo
+          (((= extract-narinfo-hash (? string? hash)))
+           (render-narinfo store request hash))
+          ;; /nar/<store-item>
+          (("nar" store-item)
+           (render-nar request store-item))
+          (_ (not-found request)))
+        (not-found request))))
+
+(define (run-publish-server port store)
+  (run-server (make-request-handler store)
+              'http
+              `(#:addr ,INADDR_ANY
+                #:port ,port)))
+
+(define (guix-publish . args)
+  (with-error-handling
+    (let* ((opts (args-fold* args %options
+                             (lambda (opt name arg result)
+                               (leave (_ "~A: unrecognized option~%") name))
+                             (lambda (arg result)
+                               (leave (_ "~A: extraneuous argument~%") arg))
+                             %default-options))
+           (port (assoc-ref opts 'port))
+           (repl-port (assoc-ref opts 'repl)))
+      (format #t (_ "publishing ~a on port ~d~%") %store-directory port)
+      (when repl-port
+        (repl:spawn-server (repl:make-tcp-server-socket #:port repl-port)))
+      (with-store store
+        (run-publish-server (assoc-ref opts 'port) store)))))
diff --git a/po/guix/POTFILES.in b/po/guix/POTFILES.in
index 39115f970b..5ac9201295 100644
--- a/po/guix/POTFILES.in
+++ b/po/guix/POTFILES.in
@@ -13,6 +13,7 @@ guix/scripts/substitute.scm
 guix/scripts/authenticate.scm
 guix/scripts/system.scm
 guix/scripts/lint.scm
+guix/scripts/publish.scm
 guix/gnu-maintenance.scm
 guix/ui.scm
 guix/http-client.scm
diff --git a/tests/publish.scm b/tests/publish.scm
new file mode 100644
index 0000000000..60f57a8ddb
--- /dev/null
+++ b/tests/publish.scm
@@ -0,0 +1,114 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 David Thompson <davet@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 (test-publish)
+  #:use-module (guix scripts publish)
+  #:use-module (guix tests)
+  #:use-module (guix config)
+  #:use-module (guix utils)
+  #:use-module (guix hash)
+  #:use-module (guix store)
+  #:use-module (guix base32)
+  #:use-module (guix base64)
+  #:use-module ((guix serialization) #:select (restore-file))
+  #:use-module (guix pk-crypto)
+  #:use-module (web client)
+  #:use-module (web response)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-64)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 rdelim))
+
+(define %store
+  (open-connection-for-tests))
+
+(define %reference (add-text-to-store %store "ref" "foo"))
+
+(define %item (add-text-to-store %store "item" "bar" (list %reference)))
+
+(define (http-get-body uri)
+  (call-with-values (lambda () (http-get uri))
+    (lambda (response body) body)))
+
+(define (publish-uri route)
+  (string-append "http://localhost:6789" route))
+
+;; Run a local publishing server in a separate thread.
+(call-with-new-thread
+ (lambda ()
+   (guix-publish "--port=6789"))) ; attempt to avoid port collision
+
+;; Wait until the server is accepting connections.
+(let ((conn (socket PF_INET SOCK_STREAM 0)))
+  (let loop ()
+    (unless (false-if-exception
+             (connect conn AF_INET (inet-pton AF_INET "127.0.0.1") 6789))
+      (loop))))
+
+(test-begin "publish")
+
+(test-equal "/nix-cache-info"
+  (format #f "StoreDir: ~a\nWantMassQuery: 0\nPriority: 100\n"
+          %store-directory)
+  (http-get-body (publish-uri "/nix-cache-info")))
+
+(test-equal "/*.narinfo"
+  (let* ((info (query-path-info %store %item))
+         (unsigned-info
+          (format #f
+                  "StorePath: ~a
+URL: nar/~a
+Compression: none
+NarHash: sha256:~a
+NarSize: ~d
+References: ~a~%"
+                  %item
+                  (basename %item)
+                  (bytevector->base32-string
+                   (path-info-hash info))
+                  (path-info-nar-size info)
+                  (basename (first (path-info-references info)))))
+         (signature (base64-encode
+                     (string->utf8
+                      (canonical-sexp->string
+                       ((@@ (guix scripts publish) signed-string)
+                        unsigned-info))))))
+    (format #f "~aSignature: 1;~a;~a~%"
+            unsigned-info (gethostname) signature))
+  (utf8->string
+   (http-get-body
+    (publish-uri
+     (string-append "/" (store-path-hash-part %item) ".narinfo")))))
+
+(test-equal "/nar/*"
+  "bar"
+  (call-with-temporary-output-file
+   (lambda (temp port)
+     (let ((nar (utf8->string
+                 (http-get-body
+                  (publish-uri
+                   (string-append "/nar/" (basename %item)))))))
+       (call-with-input-string nar (cut restore-file <> temp)))
+     (call-with-input-file temp read-string))))
+
+(test-end "publish")
+
+
+(exit (= (test-runner-fail-count (test-runner-current)) 0))