daemon: Run 'guix substitute' directly and assume a single substituter.

The daemon had a mechanism that allows it to handle a list of
substituters and try them sequentially; this removes it.

* nix/scripts/substitute.in: Remove.
* nix/local.mk (nodist_pkglibexec_SCRIPTS): Remove.
* config-daemon.ac: Don't output 'nix/scripts/substitute'.
* nix/libstore/build.cc (SubstitutionGoal)[subs, sub, hasSubstitute]:
Remove.
[tryNext]: Make private.
(SubstitutionGoal::SubstitutionGoal, SubstitutionGoal::init): Remove now
unneeded initializers.
(SubstitutionGoal::tryNext): Adjust to assume a single substituter: call
'amDone' upfront when we couldn't find substitutes.
(SubstitutionGoal::tryToRun): Adjust to run 'guix substitute' via
'settings.guixProgram'.
(SubstitutionGoal::finished): Call 'amDone(ecFailed)' upon failure
instead of setting 'state' to 'tryNext'.
* nix/libstore/globals.hh (Settings)[substituters]: Remove.
* nix/libstore/local-store.cc (LocalStore::~LocalStore): Adjust to
handle a single substituter.
(LocalStore::startSubstituter): Remove 'path' parameter.  Adjust to
invoke 'settings.guixProgram'.  Don't refer to 'run.program', which no
longer exists.
(LocalStore::querySubstitutablePaths): Adjust for 'runningSubstituters'
being a singleton instead of a list.
(LocalStore::querySubstitutablePathInfos): Likewise, and remove
'substituter' parameter.
* nix/libstore/local-store.hh (RunningSubstituter)[program]: Remove.
(LocalStore)[runningSubstituters]: Remove.
[runningSubstituter]: New field.
[querySubstitutablePathInfos]: Remove 'substituter' parameter.
[startSubstituter]: Remove 'substituter' parameter.
* nix/nix-daemon/guix-daemon.cc (main): Remove references to
'settings.substituters'.
* nix/nix-daemon/nix-daemon.cc (performOp): Ignore the user's
"build-use-substitutes" value when 'settings.useSubstitutes' is false.

1 files changed, 19 insertions, 33 deletions

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index 9f1f88933a..ad53b81413 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -2863,15 +2863,6 @@ private:
     /* The store path that should be realised through a substitute. */
     Path storePath;
 
-    /* The remaining substituters. */
-    Paths subs;
-
-    /* The current substituter. */
-    Path sub;
-
-    /* Whether any substituter can realise this path */
-    bool hasSubstitute;
-
     /* Path info returned by the substituter's query info operation. */
     SubstitutablePathInfo info;
 
@@ -2897,6 +2888,8 @@ private:
     typedef void (SubstitutionGoal::*GoalState)();
     GoalState state;
 
+    void tryNext();
+
 public:
     SubstitutionGoal(const Path & storePath, Worker & worker, bool repair = false);
     ~SubstitutionGoal();
@@ -2914,7 +2907,6 @@ public:
 
     /* The states. */
     void init();
-    void tryNext();
     void gotInfo();
     void referencesValid();
     void tryToRun();
@@ -2930,7 +2922,6 @@ public:
 
 SubstitutionGoal::SubstitutionGoal(const Path & storePath, Worker & worker, bool repair)
     : Goal(worker)
-    , hasSubstitute(false)
     , repair(repair)
 {
     this->storePath = storePath;
@@ -2980,37 +2971,31 @@ void SubstitutionGoal::init()
     if (settings.readOnlyMode)
         throw Error(format("cannot substitute path `%1%' - no write access to the store") % storePath);
 
-    subs = settings.substituters;
-
     tryNext();
 }
 
 
 void SubstitutionGoal::tryNext()
 {
-    trace("trying next substituter");
+    trace("trying substituter");
 
-    if (subs.size() == 0) {
+    SubstitutablePathInfos infos;
+    PathSet dummy(singleton<PathSet>(storePath));
+    worker.store.querySubstitutablePathInfos(dummy, infos);
+    SubstitutablePathInfos::iterator k = infos.find(storePath);
+    if (k == infos.end()) {
         /* None left.  Terminate this goal and let someone else deal
            with it. */
         debug(format("path `%1%' is required, but there is no substituter that can build it") % storePath);
         /* Hack: don't indicate failure if there were no substituters.
            In that case the calling derivation should just do a
            build. */
-        amDone(hasSubstitute ? ecFailed : ecNoSubstituters);
-        return;
+        amDone(ecNoSubstituters);
+	return;
     }
 
-    sub = subs.front();
-    subs.pop_front();
-
-    SubstitutablePathInfos infos;
-    PathSet dummy(singleton<PathSet>(storePath));
-    worker.store.querySubstitutablePathInfos(sub, dummy, infos);
-    SubstitutablePathInfos::iterator k = infos.find(storePath);
-    if (k == infos.end()) { tryNext(); return; }
+    /* Found a substitute.  */
     info = k->second;
-    hasSubstitute = true;
 
     /* To maintain the closure invariant, we first have to realise the
        paths referenced by this one. */
@@ -3098,7 +3083,8 @@ void SubstitutionGoal::tryToRun()
 
     /* Fill in the arguments. */
     Strings args;
-    args.push_back(baseNameOf(sub));
+    args.push_back("guix");
+    args.push_back("substitute");
     args.push_back("--substitute");
     args.push_back(storePath);
     args.push_back(destPath);
@@ -3111,9 +3097,9 @@ void SubstitutionGoal::tryToRun()
         if (dup2(outPipe.writeSide, STDOUT_FILENO) == -1)
             throw SysError("cannot dup output pipe into stdout");
 
-        execv(sub.c_str(), stringsToCharPtrs(args).data());
+        execv(settings.guixProgram.c_str(), stringsToCharPtrs(args).data());
 
-        throw SysError(format("executing `%1%'") % sub);
+        throw SysError(format("executing `%1% substitute'") % settings.guixProgram);
     });
 
     pid.setSeparatePG(true);
@@ -3126,7 +3112,9 @@ void SubstitutionGoal::tryToRun()
     state = &SubstitutionGoal::finished;
 
     if (settings.printBuildTrace)
-        printMsg(lvlError, format("@ substituter-started %1% %2%") % storePath % sub);
+	/* The second element in the message used to be the name of the
+	   substituter but we're left with only one.  */
+        printMsg(lvlError, format("@ substituter-started %1% substitute") % storePath);
 }
 
 
@@ -3192,9 +3180,7 @@ void SubstitutionGoal::finished()
                 % storePath % status % e.msg());
         }
 
-        /* Try the next substitute. */
-        state = &SubstitutionGoal::tryNext;
-        worker.wakeUp(shared_from_this());
+	amDone(ecFailed);
         return;
     }