daemon: Run 'guix substitute --substitute' as an agent.

This avoids spawning one substitute process per substitution.

* nix/libstore/build.cc (class Worker)[substituter]: New field.
[outPipe, logPipe, pid]: Remove.
(class SubstitutionGoal)[expectedHashStr, status, substituter]: New fields.
(SubstitutionGoal::timedOut): Adjust to check 'substituter'.
(SubstitutionGoal::tryToRun): Remove references to 'outPipe' and
'logPipe'.  Run "guix substitute --substitute" as an 'Agent'.  Send the
request with 'writeLine'.
(SubstitutionGoal::finished): Likewise.
(SubstitutionGoal::handleChildOutput): Change to fill in
'expectedHashStr' and 'status'.
(SubstitutionGoal::handleEOF): Call 'wakeUp' unconditionally.
(SubstitutionGoal::~SubstitutionGoal): Adjust to check 'substituter'.
* guix/scripts/substitute.scm (process-substitution): Write "success\n"
to stdout upon success.
(%error-to-file-descriptor-4?): New variable.
(guix-substitute): Set 'current-error-port' to file descriptor 4
unless (%error-to-file-descriptor-4?) is false.
Remove "--substitute" arguments.  Loop reading line from stdin.
* tests/substitute.scm <top level>: Call '%error-to-file-descriptor-4?'.
(request-substitution): New procedure.
("substitute, no signature")
("substitute, invalid hash")
("substitute, unauthorized key")
("substitute, authorized key")
("substitute, unauthorized narinfo comes first")
("substitute, unsigned narinfo comes first")
("substitute, first narinfo is unsigned and has wrong hash")
("substitute, first narinfo is unsigned and has wrong refs")
("substitute, two invalid narinfos")
("substitute, narinfo with several URLs"): Adjust to new "guix
substitute --substitute" calling convention.

1 files changed, 55 insertions, 40 deletions

diff --git a/tests/substitute.scm b/tests/substitute.scm
index bd5b6305b0..b86ce09425 100644
--- a/tests/substitute.scm
+++ b/tests/substitute.scm
@@ -58,6 +58,14 @@ it writes to GUIX-WARNING-PORT a messages that matches ERROR-RX."
                   (let ((message (get-output-string error-output)))
                     (->bool (string-match error-rx message))))))))))
 
+(define (request-substitution item destination)
+  "Run 'guix substitute --substitute' to fetch ITEM to DESTINATION."
+  (parameterize ((guix-warning-port (current-error-port)))
+    (with-input-from-string (string-append "substitute " item " "
+                                           destination "\n")
+      (lambda ()
+        (guix-substitute "--substitute")))))
+
 (define %public-key
   ;; This key is known to be in the ACL by default.
   (call-with-input-file (string-append %config-directory "/signing-key.pub")
@@ -184,6 +192,11 @@ a file for NARINFO."
 ;; Transmit these options to 'guix substitute'.
 (substitute-urls (list (getenv "GUIX_BINARY_SUBSTITUTE_URL")))
 
+;; Never use file descriptor 4, unlike what happens when invoked by the
+;; daemon.
+(%error-to-file-descriptor-4? #f)
+
+
 (test-equal "query narinfo without signature"
   ""                                              ; not substitutable
 
@@ -284,10 +297,12 @@ System: mips64el-linux\n")
 (test-quit "substitute, no signature"
     "no valid substitute"
   (with-narinfo %narinfo
-    (guix-substitute "--substitute"
-                     (string-append (%store-prefix)
-                                    "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                     "foo")))
+    (with-input-from-string (string-append "substitute "
+                                           (%store-prefix)
+                                           "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo"
+                                           " foo\n")
+      (lambda ()
+        (guix-substitute "--substitute")))))
 
 (test-quit "substitute, invalid hash"
     "no valid substitute"
@@ -295,10 +310,12 @@ System: mips64el-linux\n")
   (with-narinfo (string-append %narinfo "Signature: "
                                (signature-field "different body")
                                "\n")
-    (guix-substitute "--substitute"
-                     (string-append (%store-prefix)
-                                    "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                     "foo")))
+    (with-input-from-string (string-append "substitute "
+                                           (%store-prefix)
+                                           "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo"
+                                           " foo\n")
+      (lambda ()
+        (guix-substitute "--substitute")))))
 
 (test-quit "substitute, unauthorized key"
     "no valid substitute"
@@ -307,10 +324,12 @@ System: mips64el-linux\n")
                                 %narinfo
                                 #:public-key %wrong-public-key)
                                "\n")
-    (guix-substitute "--substitute"
-                     (string-append (%store-prefix)
-                                    "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                     "foo")))
+    (with-input-from-string (string-append "substitute "
+                                           (%store-prefix)
+                                           "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo"
+                                           " foo\n")
+      (lambda ()
+        (guix-substitute "--substitute")))))
 
 (test-equal "substitute, authorized key"
   "Substitutable data."
@@ -319,10 +338,9 @@ System: mips64el-linux\n")
     (dynamic-wind
       (const #t)
       (lambda ()
-        (guix-substitute "--substitute"
-                         (string-append (%store-prefix)
-                                        "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                         "substitute-retrieved")
+        (request-substitution (string-append (%store-prefix)
+                                             "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
+                              "substitute-retrieved")
         (call-with-input-file "substitute-retrieved" get-string-all))
       (lambda ()
         (false-if-exception (delete-file "substitute-retrieved"))))))
@@ -352,10 +370,9 @@ System: mips64el-linux\n")
                           (map (cut string-append "file://" <>)
                                (list %alternate-substitute-directory
                                      %main-substitute-directory))))
-            (guix-substitute "--substitute"
-                             (string-append (%store-prefix)
-                                            "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                             "substitute-retrieved"))
+            (request-substitution (string-append (%store-prefix)
+                                                 "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
+                                  "substitute-retrieved"))
           (call-with-input-file "substitute-retrieved" get-string-all))
         (lambda ()
           (false-if-exception (delete-file "substitute-retrieved")))))))
@@ -381,10 +398,9 @@ System: mips64el-linux\n")
                           (map (cut string-append "file://" <>)
                                (list %alternate-substitute-directory
                                      %main-substitute-directory))))
-            (guix-substitute "--substitute"
-                             (string-append (%store-prefix)
-                                            "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                             "substitute-retrieved"))
+            (request-substitution (string-append (%store-prefix)
+                                                 "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
+                                  "substitute-retrieved"))
           (call-with-input-file "substitute-retrieved" get-string-all))
         (lambda ()
           (false-if-exception (delete-file "substitute-retrieved")))))))
@@ -417,10 +433,9 @@ System: mips64el-linux\n")
                           (map (cut string-append "file://" <>)
                                (list %alternate-substitute-directory
                                      %main-substitute-directory))))
-            (guix-substitute "--substitute"
-                             (string-append (%store-prefix)
-                                            "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                             "substitute-retrieved"))
+            (request-substitution (string-append (%store-prefix)
+                                                 "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
+                                  "substitute-retrieved"))
           (call-with-input-file "substitute-retrieved" get-string-all))
         (lambda ()
           (false-if-exception (delete-file "substitute-retrieved")))))))
@@ -451,10 +466,9 @@ System: mips64el-linux\n")
                           (map (cut string-append "file://" <>)
                                (list %alternate-substitute-directory
                                      %main-substitute-directory))))
-            (guix-substitute "--substitute"
-                             (string-append (%store-prefix)
-                                            "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                             "substitute-retrieved"))
+            (request-substitution (string-append (%store-prefix)
+                                                 "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
+                                  "substitute-retrieved"))
           (call-with-input-file "substitute-retrieved" get-string-all))
         (lambda ()
           (false-if-exception (delete-file "substitute-retrieved")))))))
@@ -470,10 +484,12 @@ System: mips64el-linux\n")
                                    #:public-key %wrong-public-key))
         %main-substitute-directory
 
-      (guix-substitute "--substitute"
-                       (string-append (%store-prefix)
-                                      "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                       "substitute-retrieved"))))
+      (with-input-from-string (string-append "substitute "
+                                             (%store-prefix)
+                                             "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo"
+                                             " substitute-retrieved\n")
+        (lambda ()
+          (guix-substitute "--substitute"))))))
 
 (test-equal "substitute, narinfo with several URLs"
   "Substitutable data."
@@ -513,10 +529,9 @@ System: mips64el-linux\n")))
           (parameterize ((substitute-urls
                           (list (string-append "file://"
                                                %main-substitute-directory))))
-            (guix-substitute "--substitute"
-                             (string-append (%store-prefix)
-                                            "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
-                             "substitute-retrieved"))
+            (request-substitution (string-append (%store-prefix)
+                                                 "/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-foo")
+                                  "substitute-retrieved"))
           (call-with-input-file "substitute-retrieved" get-string-all))
         (lambda ()
           (false-if-exception (delete-file "substitute-retrieved")))))))