extsearch: support publicinbox.*.boost parameter

This behaves identically the lei external "boost" parameter in
prioritizing raw messages for extindex.

Relying exclusively on the config file order doesn't work well
for mirrors since it's impossible to guarantee config file
ordering via grokmirror hooks.

Config file ordering remains the default if boost is
unconfigured, or in case of ties.

Note: I chose the name "boost" rather than "priority" or "rank"
since I always get confused by whether higher or lower numbers
take precedence when it comes to kernel scheduling.  "weight" is
also a part of Xapian API terminology, which we currently do not
expose to configuration (but may in the future).

1 files changed, 28 insertions, 15 deletions

diff --git a/lib/PublicInbox/ExtSearchIdx.pm b/lib/PublicInbox/ExtSearchIdx.pm
index 0e27bba6..357312b8 100644
--- a/lib/PublicInbox/ExtSearchIdx.pm
+++ b/lib/PublicInbox/ExtSearchIdx.pm
@@ -44,7 +44,7 @@ sub new {
                 topdir => $dir,
                 creat => $opt->{creat},
                 ibx_map => {}, # (newsgroup//inboxdir) => $ibx
-                ibx_list => [],
+                ibx_cfg => [], # by config section order
                 indexlevel => $l,
                 transact_bytes => 0,
                 total_bytes => 0,
@@ -62,7 +62,8 @@ sub new {
 sub attach_inbox {
         my ($self, $ibx) = @_;
         $self->{ibx_map}->{$ibx->eidx_key} //= do {
-                push @{$self->{ibx_list}}, $ibx;
+                delete $self->{-ibx_ary}; # invalidate cache
+                push @{$self->{ibx_cfg}}, $ibx;
                 $ibx;
         }
 }
@@ -388,7 +389,7 @@ sub _ibx_for ($$$) {
         my ($self, $sync, $smsg) = @_;
         my $ibx_id = delete($smsg->{ibx_id}) // die '{ibx_id} unset';
         my $pos = $sync->{id2pos}->{$ibx_id} // die "$ibx_id no pos";
-        $self->{ibx_list}->[$pos] // die "BUG: ibx for $smsg->{blob} not mapped"
+        $self->{-ibx_ary}->[$pos] // die "BUG: ibx for $smsg->{blob} not mapped"
 }
 
 sub _fd_constrained ($) {
@@ -402,7 +403,7 @@ sub _fd_constrained ($) {
                         chomp($soft = `sh -c 'ulimit -n'`);
                 }
                 if (defined($soft)) {
-                        my $want = scalar(@{$self->{ibx_list}}) + 64; # estimate
+                        my $want = scalar(@{$self->{-ibx_ary}}) + 64; # estimate
                         my $ret = $want > $soft;
                         if ($ret) {
                                 warn <<EOF;
@@ -524,10 +525,10 @@ BUG? #$docid $smsg->{blob} is not referenced by inboxes during reindex
                 return;
         }
 
-        # we sort {xr3r} in the reverse order of {ibx_list} so we can
+        # we sort {xr3r} in the reverse order of ibx_sorted so we can
         # hit the common case in _reindex_finalize without rereading
         # from git (or holding multiple messages in memory).
-        my $id2pos = $sync->{id2pos}; # index in {ibx_list}
+        my $id2pos = $sync->{id2pos}; # index in ibx_sorted
         @$xr3 = sort {
                 $id2pos->{$b->[0]} <=> $id2pos->{$a->[0]}
                                 ||
@@ -621,6 +622,17 @@ EOF
         undef;
 }
 
+sub ibx_sorted ($) {
+        my ($self) = @_;
+        $self->{-ibx_ary} //= do {
+                # highest boost first, stable for config-ordering tiebreaker
+                use sort 'stable';
+                [ sort {
+                        ($b->{boost} // 0) <=> ($a->{boost} // 0)
+                  } @{$self->{ibx_cfg}} ];
+        }
+}
+
 sub eidxq_process ($$) { # for reindexing
         my ($self, $sync) = @_;
 
@@ -638,7 +650,7 @@ sub eidxq_process ($$) { # for reindexing
         $sync->{id2pos} //= do {
                 my %id2pos;
                 my $pos = 0;
-                $id2pos{$_->{-ibx_id}} = $pos++ for @{$self->{ibx_list}};
+                $id2pos{$_->{-ibx_id}} = $pos++ for (@{ibx_sorted($self)});
                 \%id2pos;
         };
         my ($del, $iter);
@@ -829,7 +841,7 @@ sub eidx_reindex {
                 warn "E: aborting --reindex\n";
                 return;
         }
-        for my $ibx (@{$self->{ibx_list}}) {
+        for my $ibx (@{ibx_sorted($self)}) {
                 _reindex_inbox($self, $sync, $ibx);
                 last if $sync->{quit};
         }
@@ -959,7 +971,7 @@ sub eidx_sync { # main entry point
         local $SIG{QUIT} = $quit;
         local $SIG{INT} = $quit;
         local $SIG{TERM} = $quit;
-        for my $ibx (@{$self->{ibx_list}}) {
+        for my $ibx (@{ibx_sorted($self)}) {
                 $ibx->{-ibx_id} //= $self->{oidx}->ibx_id($ibx->eidx_key);
         }
         if (delete($opt->{dedupe})) {
@@ -973,7 +985,7 @@ sub eidx_sync { # main entry point
 
         # don't use $_ here, it'll get clobbered by reindex_checkpoint
         if ($opt->{scan} // 1) {
-                for my $ibx (@{$self->{ibx_list}}) {
+                for my $ibx (@{ibx_sorted($self)}) {
                         last if $sync->{quit};
                         sync_inbox($self, $sync, $ibx);
                 }
@@ -1115,7 +1127,7 @@ sub idx_init { # similar to V2Writable
                 }
                 undef $dh;
         }
-        for my $ibx (@{$self->{ibx_list}}) {
+        for my $ibx (@{ibx_sorted($self)}) {
                 # create symlinks for multi-pack-index
                 $git_midx += symlink_packs($ibx, $pd);
                 # add new lines to our alternates file
@@ -1180,7 +1192,8 @@ sub eidx_reload { # -extindex --watch SIGHUP handler
                 my $pr = $self->{-watch_sync}->{-opt}->{-progress};
                 $pr->('reloading ...') if $pr;
                 delete $self->{-resync_queue};
-                @{$self->{ibx_list}} = ();
+                delete $self->{-ibx_ary};
+                $self->{ibx_cfg} = [];
                 %{$self->{ibx_map}} = ();
                 delete $self->{-watch_sync}->{id2pos};
                 my $cfg = PublicInbox::Config->new;
@@ -1194,7 +1207,7 @@ sub eidx_reload { # -extindex --watch SIGHUP handler
 
 sub eidx_resync_start ($) { # -extindex --watch SIGUSR1 handler
         my ($self) = @_;
-        $self->{-resync_queue} //= [ @{$self->{ibx_list}} ];
+        $self->{-resync_queue} //= [ @{ibx_sorted($self)} ];
         PublicInbox::DS::requeue($self); # trigger our ->event_step
 }
 
@@ -1225,9 +1238,9 @@ sub eidx_watch { # public-inbox-extindex --watch main loop
         require PublicInbox::Sigfd;
         my $idler = PublicInbox::InboxIdle->new($self->{cfg});
         if (!$self->{cfg}) {
-                $idler->watch_inbox($_) for @{$self->{ibx_list}};
+                $idler->watch_inbox($_) for (@{ibx_sorted($self)});
         }
-        $_->subscribe_unlock(__PACKAGE__, $self) for @{$self->{ibx_list}};
+        $_->subscribe_unlock(__PACKAGE__, $self) for (@{ibx_sorted($self)});
         my $pr = $opt->{-progress};
         $pr->("performing initial scan ...\n") if $pr;
         my $sync = eidx_sync($self, $opt); # initial sync