daemon: Support multiplexed build output.

This allows clients to tell whether output comes from the daemon or, if
it comes from a builder, from which builder it comes.  The latter is
particularly useful when MAX-BUILD-JOBS > 1.

* nix/libstore/build.cc (DerivationGoal::tryBuildHook)
(DerivationGoal::startBuilder): Print the child's PID in "@ build-started"
traces.
(DerivationGoal::handleChildOutput): Define 'prefix', pass it to
'writeToStderr'.
* nix/libstore/globals.cc (Settings:Settings): Initialize
'multiplexedBuildOutput'.
(Settings::update): Likewise.
* nix/libstore/globals.hh (Settings)[multiplexedBuildOutput]: New field.
Update 'printBuildTrace' documentation.
* nix/libstore/worker-protocol.hh (PROTOCOL_VERSION): Bump to 0.163.
* nix/nix-daemon/nix-daemon.cc (performOp) <wopSetOptions>: Special-case
"multiplexed-build-output" and remove "use-ssh-substituter".
* guix/store.scm (set-build-options): Add #:multiplexed-build-output?
and honor it.
(%protocol-version): Bump to #x163.
* tests/store.scm ("multiplexed-build-output"): New test.

fixlet

1 files changed, 63 insertions, 0 deletions

diff --git a/tests/store.scm b/tests/store.scm
index 2858369706..3ff526cdcf 100644
--- a/tests/store.scm
+++ b/tests/store.scm
@@ -31,6 +31,7 @@
   #:use-module (gnu packages)
   #:use-module (gnu packages bootstrap)
   #:use-module (ice-9 match)
+  #:use-module (ice-9 regex)
   #:use-module (rnrs bytevectors)
   #:use-module (rnrs io ports)
   #:use-module (web uri)
@@ -1021,4 +1022,66 @@
                  (call-with-input-file (derivation->output-path drv2)
                    read))))))
 
+(test-equal "multiplexed-build-output"
+  '("Hello from first." "Hello from second.")
+  (with-store store
+    (let* ((build  (add-text-to-store store "build.sh"
+                                      "echo Hello from $NAME.; echo > $out"))
+           (bash   (add-to-store store "bash" #t "sha256"
+                                 (search-bootstrap-binary "bash"
+                                                          (%current-system))))
+           (drv1   (derivation store "one" bash
+                               `("-e" ,build)
+                               #:inputs `((,bash) (,build))
+                               #:env-vars `(("NAME" . "first")
+                                            ("x" . ,(random-text)))))
+           (drv2   (derivation store "two" bash
+                               `("-e" ,build)
+                               #:inputs `((,bash) (,build))
+                               #:env-vars `(("NAME" . "second")
+                                            ("x" . ,(random-text))))))
+      (set-build-options store
+                         #:print-build-trace #t
+                         #:multiplexed-build-output? #t
+                         #:max-build-jobs 10)
+      (let ((port (open-output-string)))
+        ;; Send the build log to PORT.
+        (parameterize ((current-build-output-port port))
+          (build-derivations store (list drv1 drv2)))
+
+        ;; Retrieve the build log; make sure it contains valid "@ build-log"
+        ;; traces that allow us to retrieve each builder's output (we assume
+        ;; there's exactly one "build-output" trace for each builder, which is
+        ;; reasonable.)
+        (let* ((log     (get-output-string port))
+               (started (fold-matches
+                         (make-regexp "@ build-started ([^ ]+) - ([^ ]+) ([^ ]+) ([0-9]+)")
+                         log '() cons))
+               (done    (fold-matches
+                         (make-regexp "@ build-succeeded (.*) - (.*) (.*) (.*)")
+                         log '() cons))
+               (output  (fold-matches
+                         (make-regexp "@ build-log ([[:digit:]]+) ([[:digit:]]+)\n([A-Za-z .*]+)\n")
+                         log '() cons))
+               (drv-pid (lambda (name)
+                          (lambda (m)
+                            (let ((drv (match:substring m 1))
+                                  (pid (string->number
+                                        (match:substring m 4))))
+                              (and (string-suffix? name drv) pid)))))
+               (pid-log (lambda (pid)
+                          (lambda (m)
+                            (let ((n   (string->number
+                                        (match:substring m 1)))
+                                  (len (string->number
+                                        (match:substring m 2)))
+                                  (str (match:substring m 3)))
+                              (and (= pid n)
+                                   (= (string-length str) (- len 1))
+                                   str)))))
+               (pid1    (any (drv-pid "one.drv") started))
+               (pid2    (any (drv-pid "two.drv") started)))
+          (list (any (pid-log pid1) output)
+                (any (pid-log pid2) output)))))))
+
 (test-end "store")