Use subs instead of global variables for local & binary cache store

Otherwise the `include`-test would fail: this test defines a `hydra.conf`
with an `include` statement. However, the file to be included is created
after the test base is set up. This means that - among others - the
`Hydra::Helper::Nix` module is loaded before the file to include exists.
Since the global variables are directly initialized and try to read from
the config, the test fails, because loading the config at that time
doesn't work. Delaying this into a subrouting solves the issue.

I decided against messing around with the config mechanism here since I
consider this behavior to be correct.

The local store gets (i.e. `Hydra::Store->new()` w/o args) cached in the
Perl bindings already[1], however this isn't the case for the binary
cache store. Because of that, a `state` variable is used to cache the
binary cache store. At runtime, the location of that store doesn't
change anyways.

[1] https://github.com/NixOS/nix/blob/e3ccb7e42a55529d8d50544e7e0cebb5cbc606cf/perl/lib/Nix/Store.xs#L88-L96

src/lib/Hydra/Base/Controller/NixChannel.pm

@@ -29,7 +29,7 @@ sub getChannelData {
         my $outputs = {};
         foreach my $output (@outputs) {
             my $outPath = $output->get_column("outpath");
-            next if $checkValidity && !$BINARY_CACHE_STORE->isValidPath($outPath);
+            next if $checkValidity && !binaryCacheStore()->isValidPath($outPath);
             $outputs->{$output->get_column("outname")} = $outPath;
             push @storePaths, $outPath;
             # Put the system type in the manifest (for top-level

src/lib/Hydra/Controller/Build.pm

@@ -79,8 +79,8 @@ sub build_GET {
     # XXX: If the derivation is content-addressed then this will always return
     # false because `$_->path` will be empty
     $c->stash->{available} =
-        all { $_->path && $BINARY_CACHE_STORE->isValidPath($_->path) } $build->buildoutputs->all;
-    $c->stash->{drvAvailable} = $MACHINE_LOCAL_STORE->isValidPath $build->drvpath;
+        all { $_->path && binaryCacheStore()->isValidPath($_->path) } $build->buildoutputs->all;
+    $c->stash->{drvAvailable} = machineLocalStore()->isValidPath($build->drvpath);
 
     if ($build->finished && $build->iscachedbuild) {
         my $path = ($build->buildoutputs)[0]->path or undef;
@@ -304,7 +304,7 @@ sub output : Chained('buildChain') PathPart Args(1) {
     error($c, "This build is not finished yet.") unless $build->finished;
     my $output = $build->buildoutputs->find({name => $outputName});
     notFound($c, "This build has no output named ‘$outputName’") unless defined $output;
-    gone($c, "Output is no longer available.") unless $BINARY_CACHE_STORE->isValidPath($output->path);
+    gone($c, "Output is no longer available.") unless binaryCacheStore()->isValidPath($output->path);
 
     $c->response->header('Content-Disposition', "attachment; filename=\"build-${\$build->id}-${\$outputName}.nar.bz2\"");
     $c->stash->{current_view} = 'NixNAR';
@@ -421,15 +421,15 @@ sub getDependencyGraph {
             };
         $$done{$path} = $node;
         my @refs;
-        foreach my $ref ($BINARY_CACHE_STORE->queryReferences($path)) {
+        foreach my $ref (binaryCacheStore()->queryReferences($path)) {
             next if $ref eq $path;
             next unless $runtime || $ref =~ /\.drv$/;
             getDependencyGraph($self, $c, $runtime, $done, $ref);
             push @refs, $ref;
         }
         # Show in reverse topological order to flatten the graph.
         # Should probably do a proper BFS.
-        my @sorted = reverse $BINARY_CACHE_STORE->topoSortPaths(@refs);
+        my @sorted = reverse binaryCacheStore()->topoSortPaths(@refs);
         $node->{refs} = [map { $$done{$_} } @sorted];
     }
 
@@ -442,7 +442,7 @@ sub build_deps : Chained('buildChain') PathPart('build-deps') {
     my $build = $c->stash->{build};
     my $drvPath = $build->drvpath;
 
-    error($c, "Derivation no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($drvPath);
+    error($c, "Derivation no longer available.") unless machineLocalStore()->isValidPath($drvPath);
 
     $c->stash->{buildTimeGraph} = getDependencyGraph($self, $c, 0, {}, $drvPath);
 
@@ -457,7 +457,7 @@ sub runtime_deps : Chained('buildChain') PathPart('runtime-deps') {
 
     requireLocalStore($c);
 
-    error($c, "Build outputs no longer available.") unless all { $BINARY_CACHE_STORE->isValidPath($_) } @outPaths;
+    error($c, "Build outputs no longer available.") unless all { binaryCacheStore()->isValidPath($_) } @outPaths;
 
     my $done = {};
     $c->stash->{runtimeGraph} = [ map { getDependencyGraph($self, $c, 1, $done, $_) } @outPaths ];
@@ -477,7 +477,7 @@ sub nix : Chained('buildChain') PathPart('nix') CaptureArgs(0) {
     if (isLocalStore) {
         foreach my $out ($build->buildoutputs) {
             notFound($c, "Path " . $out->path . " is no longer available.")
-                unless $BINARY_CACHE_STORE->isValidPath($out->path);
+                unless binaryCacheStore()->isValidPath($out->path);
         }
     }
 

src/lib/Hydra/Controller/Root.pm

@@ -395,7 +395,7 @@ sub narinfo :Path :Args(StrMatch[NARINFO_REGEX]) {
         my ($hash) = $narinfo =~ NARINFO_REGEX;
 
         die("Hash length was not 32") if length($hash) != 32;
-        my $path = $BINARY_CACHE_STORE->queryPathFromHashPart($hash);
+        my $path = binaryCacheStore()->queryPathFromHashPart($hash);
 
         if (!$path) {
             $c->response->status(404);

src/lib/Hydra/Helper/Nix.pm

@@ -1,5 +1,7 @@
 package Hydra::Helper::Nix;
 
+use feature 'state';
+
 use strict;
 use warnings;
 use Exporter;
@@ -40,12 +42,18 @@ our @EXPORT = qw(
     registerRoot
     restartBuilds
     run
-    $MACHINE_LOCAL_STORE
-    $BINARY_CACHE_STORE
+    machineLocalStore
+    binaryCacheStore
     );
 
-our $MACHINE_LOCAL_STORE = Nix::Store->new();
-our $BINARY_CACHE_STORE = Nix::Store->new(getStoreUri());
+sub machineLocalStore {
+    return Nix::Store->new();
+}
+sub binaryCacheStore {
+    state $binaryCache; # Stores with a custom URL aren't cached by the perl bindings.
+    $binaryCache = Nix::Store->new(getStoreUri()) if not $binaryCache;
+    return $binaryCache;
+}
 
 
 sub getHydraHome {
@@ -499,7 +507,7 @@ sub restartBuilds {
     $builds = $builds->search({ finished => 1 });
 
     foreach my $build ($builds->search({}, { columns => ["drvpath"] })) {
-        next if !$MACHINE_LOCAL_STORE->isValidPath($build->drvpath);
+        next if !machineLocalStore()->isValidPath($build->drvpath);
         registerRoot $build->drvpath;
     }
 

src/lib/Hydra/Plugin/BazaarInput.pm

@@ -37,9 +37,9 @@ sub fetchInput {
     (my $cachedInput) = $self->{db}->resultset('CachedBazaarInputs')->search(
         {uri => $uri, revision => $revision});
 
-    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    machineLocalStore()->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && machineLocalStore()->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
     } else {
@@ -57,7 +57,7 @@ sub fetchInput {
         ($sha256, $storePath) = split ' ', $stdout;
 
         # FIXME: time window between nix-prefetch-bzr and addTempRoot.
-        $MACHINE_LOCAL_STORE->addTempRoot($storePath);
+        machineLocalStore()->addTempRoot($storePath);
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedBazaarInputs')->create(

src/lib/Hydra/Plugin/DarcsInput.pm

@@ -57,7 +57,7 @@ sub fetchInput {
         {uri => $uri, revision => $revision},
         {rows => 1});
 
-    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && machineLocalStore()->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
         $revision = $cachedInput->revision;
@@ -74,8 +74,8 @@ sub fetchInput {
         die "darcs changes --count failed" if $? != 0;
 
         system "rm", "-rf", "$tmpDir/export/_darcs";
-        $storePath = $MACHINE_LOCAL_STORE->addToStore("$tmpDir/export", 1, "sha256");
-        $sha256 = $MACHINE_LOCAL_STORE->queryPathHash($storePath);
+        $storePath = machineLocalStore()->addToStore("$tmpDir/export", 1, "sha256");
+        $sha256 = machineLocalStore()->queryPathHash($storePath);
         $sha256 =~ s/sha256://;
 
         $self->{db}->txn_do(sub {

src/lib/Hydra/Plugin/GitInput.pm

@@ -186,9 +186,9 @@ sub fetchInput {
         {uri => $uri, branch => $branch, revision => $revision, isdeepclone => defined($deepClone) ? 1 : 0},
         {rows => 1});
 
-    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    machineLocalStore()->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && machineLocalStore()->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
         $revision = $cachedInput->revision;
@@ -217,7 +217,7 @@ sub fetchInput {
         ($sha256, $storePath) = split ' ', grab(cmd => ["nix-prefetch-git", $clonePath, $revision], chomp => 1);
 
         # FIXME: time window between nix-prefetch-git and addTempRoot.
-        $MACHINE_LOCAL_STORE->addTempRoot($storePath);
+        machineLocalStore()->addTempRoot($storePath);
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedGitInputs')->update_or_create(

src/lib/Hydra/Plugin/MercurialInput.pm

@@ -67,9 +67,9 @@ sub fetchInput {
     (my $cachedInput) = $self->{db}->resultset('CachedHgInputs')->search(
         {uri => $uri, branch => $branch, revision => $revision});
 
-    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    machineLocalStore()->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && machineLocalStore()->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
     } else {
@@ -84,7 +84,7 @@ sub fetchInput {
         ($sha256, $storePath) = split ' ', $stdout;
 
         # FIXME: time window between nix-prefetch-hg and addTempRoot.
-        $MACHINE_LOCAL_STORE->addTempRoot($storePath);
+        machineLocalStore()->addTempRoot($storePath);
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedHgInputs')->update_or_create(

src/lib/Hydra/Plugin/PathInput.pm

@@ -29,7 +29,7 @@ sub fetchInput {
         {srcpath => $uri, lastseen => {">", $timestamp - $timeout}},
         {rows => 1, order_by => "lastseen DESC"});
 
-    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && machineLocalStore()->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
         $timestamp = $cachedInput->timestamp;
@@ -45,7 +45,7 @@ sub fetchInput {
         }
         chomp $storePath;
 
-        $sha256 = ($MACHINE_LOCAL_STORE->queryPathInfo($storePath, 0))[1] or die;
+        $sha256 = (machineLocalStore()->queryPathInfo($storePath, 0))[1] or die;
 
         ($cachedInput) = $self->{db}->resultset('CachedPathInputs')->search(
             {srcpath => $uri, sha256hash => $sha256});

src/lib/Hydra/Plugin/SubversionInput.pm

@@ -44,7 +44,7 @@ sub fetchInput {
     (my $cachedInput) = $self->{db}->resultset('CachedSubversionInputs')->search(
         {uri => $uri, revision => $revision});
 
-    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    machineLocalStore()->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
     if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
@@ -61,16 +61,16 @@ sub fetchInput {
         die "error checking out Subversion repo at `$uri':\n$stderr" if $res;
 
         if ($type eq "svn-checkout") {
-            $storePath = $MACHINE_LOCAL_STORE->addToStore($wcPath, 1, "sha256");
+            $storePath = machineLocalStore()->addToStore($wcPath, 1, "sha256");
         } else {
             # Hm, if the Nix Perl bindings supported filters in
             # addToStore(), then we wouldn't need to make a copy here.
             my $tmpDir = File::Temp->newdir("hydra-svn-export.XXXXXX", CLEANUP => 1, TMPDIR => 1) or die;
             (system "svn", "export", $wcPath, "$tmpDir/source", "--quiet") == 0 or die "svn export failed";
-            $storePath = $MACHINE_LOCAL_STORE->addToStore("$tmpDir/source", 1, "sha256");
+            $storePath = machineLocalStore()->addToStore("$tmpDir/source", 1, "sha256");
         }
 
-        $sha256 = $MACHINE_LOCAL_STORE->queryPathHash($storePath); $sha256 =~ s/sha256://;
+        $sha256 = machineLocalStore()->queryPathHash($storePath); $sha256 =~ s/sha256://;
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedSubversionInputs')->update_or_create(

src/lib/Hydra/View/NARInfo.pm

@@ -16,7 +16,7 @@ sub process {
 
     $c->response->content_type('text/x-nix-narinfo'); # !!! check MIME type
 
-    my ($deriver, $narHash, $time, $narSize, $refs) = $MACHINE_LOCAL_STORE->queryPathInfo($storePath, 1);
+    my ($deriver, $narHash, $time, $narSize, $refs) = machineLocalStore()->queryPathInfo($storePath, 1);
 
     my $info;
     $info .= "StorePath: $storePath\n";
@@ -27,8 +27,8 @@ sub process {
     $info .= "References: " . join(" ", map { basename $_ } @{$refs}) . "\n";
     if (defined $deriver) {
         $info .= "Deriver: " . basename $deriver . "\n";
-        if ($MACHINE_LOCAL_STORE->isValidPath($deriver)) {
-            my $drv = $MACHINE_LOCAL_STORE->derivationFromPath($deriver);
+        if (machineLocalStore()->isValidPath($deriver)) {
+            my $drv = machineLocalStore()->derivationFromPath($deriver);
             $info .= "System: $drv->{platform}\n";
         }
     }

src/script/hydra-eval-jobset

@@ -85,14 +85,14 @@ sub attrsToSQL {
 # Fetch a store path from 'eval_substituter' if not already present.
 sub getPath {
     my ($path) = @_;
-    return 1 if $MACHINE_LOCAL_STORE->isValidPath($path);
+    return 1 if machineLocalStore()->isValidPath($path);
 
     my $substituter = $config->{eval_substituter};
 
     system("nix", "--experimental-features", "nix-command", "copy", "--from", $substituter, "--", $path)
         if defined $substituter;
 
-    return $MACHINE_LOCAL_STORE->isValidPath($path);
+    return machineLocalStore()->isValidPath($path);
 }
 
 
@@ -143,7 +143,7 @@ sub fetchInputBuild {
         , version => $version
         , outputName => $mainOutput->name
         };
-    if ($MACHINE_LOCAL_STORE->isValidPath($prevBuild->drvpath)) {
+    if (machineLocalStore()->isValidPath($prevBuild->drvpath)) {
         $result->{drvPath} = $prevBuild->drvpath;
     }
 
@@ -233,7 +233,7 @@ sub fetchInputEval {
         my $out = $build->buildoutputs->find({ name => "out" });
         next unless defined $out;
         # FIXME: Should we fail if the path is not valid?
-        next unless $MACHINE_LOCAL_STORE->isValidPath($out->path);
+        next unless machineLocalStore()->isValidPath($out->path);
         $jobs->{$build->get_column('job')} = $out->path;
     }
 

src/script/hydra-update-gc-roots

@@ -46,15 +46,15 @@ sub keepBuild {
         $build->finished && ($build->buildstatus == 0 || $build->buildstatus == 6))
     {
         foreach my $path (split / /, $build->get_column('outpaths')) {
-            if ($MACHINE_LOCAL_STORE->isValidPath($path)) {
+            if (machineLocalStore()->isValidPath($path)) {
                 addRoot $path;
             } else {
                 print STDERR "    warning: output ", $path, " has disappeared\n" if $build->finished;
             }
         }
     }
     if (!$build->finished || ($keepFailedDrvs && $build->buildstatus != 0)) {
-        if ($MACHINE_LOCAL_STORE->isValidPath($build->drvpath)) {
+        if (machineLocalStore()->isValidPath($build->drvpath)) {
             addRoot $build->drvpath;
         } else {
             print STDERR "    warning: derivation ", $build->drvpath, " has disappeared\n";