fix: read memory on Darwin without free

lib/Rex/Hardware/DarwinProbe.pm

@@ -0,0 +1,45 @@
+package Rex::Hardware::DarwinProbe;
+
+use strict;
+use warnings;
+
+sub memory_mb {
+  my (%args) = @_;
+  my $bytes    = $args{memsize}  || 0;
+  my $pagesize = $args{pagesize} || 0;
+  my $vm_stat  = $args{vm_stat}  || '';
+  my $free_pages = 0;
+  my $spec_pages = 0;
+  if ( $vm_stat =~ /Pages free:\s+(\d+)/ ) {
+    $free_pages = $1;
+  }
+  if ( $vm_stat =~ /Pages speculative:\s+(\d+)/ ) {
+    $spec_pages = $1;
+  }
+  my $total = int( $bytes / 1024 / 1024 );
+  my $free  = int( ( $free_pages + $spec_pages ) * $pagesize / 1024 / 1024 );
+  my $used  = $total - $free;
+  $used = 0 if $used < 0;
+  return {
+    total   => $total,
+    used    => $used,
+    free    => $free,
+    shared  => 0,
+    buffers => 0,
+    cached  => 0,
+  };
+}
+
+sub swap_mb {
+  my ($line) = @_;
+  $line ||= '';
+  my ( $total, $used, $free ) =
+    ( $line =~ /total = ([\d.]+)M\s+used = ([\d.]+)M\s+free = ([\d.]+)M/ );
+  return {
+    total => int( $total || 0 ),
+    used  => int( $used  || 0 ),
+    free  => int( $free  || 0 ),
+  };
+}
+
+1;

lib/Rex/Hardware/Memory.pm

@@ -14,6 +14,7 @@ use Rex::Hardware::Host;
 use Rex::Commands::Run;
 use Rex::Helper::Run;
 use Rex::Commands::Sysctl;
+use Rex::Hardware::DarwinProbe;
 
 require Rex::Hardware;
 
@@ -181,6 +182,16 @@ sub get {
       cached  => $cached
     };
   }
+  elsif ( $os eq "Darwin" ) {
+    my $bytes    = i_run "sysctl -n hw.memsize",  fail_ok => 1;
+    my $pagesize = i_run "sysctl -n hw.pagesize", fail_ok => 1;
+    my $vm_stat  = i_run "vm_stat",               fail_ok => 1;
+    $data = Rex::Hardware::DarwinProbe::memory_mb(
+      memsize  => $bytes,
+      pagesize => $pagesize,
+      vm_stat  => $vm_stat,
+    );
+  }
   else {
     # default for linux
     if ( !can_run("free") ) {

lib/Rex/Hardware/Swap.pm

@@ -12,6 +12,7 @@ our $VERSION = '9999.99.99_99'; # VERSION
 use Rex::Commands::Run;
 use Rex::Helper::Run;
 use Rex::Hardware::Host;
+use Rex::Hardware::DarwinProbe;
 
 require Rex::Hardware;
 
@@ -125,6 +126,10 @@ sub get {
       free  => $free  || 0,
     };
   }
+  elsif ( $os eq "Darwin" ) {
+    my $swap = i_run "sysctl -n vm.swapusage", fail_ok => 1;
+    $data = Rex::Hardware::DarwinProbe::swap_mb($swap);
+  }
   else {
     # linux as default
     if ( !can_run("free") ) {

xt/darwin-memory.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -eo pipefail
+root=$(cd "$(dirname "$0")/.." && pwd)
+
+set +e
+free -m >/tmp/rex-free.out 2>/tmp/rex-free.err
+red=$?
+set -e
+if [ "$red" -eq 0 ]; then
+  echo "free unexpectedly succeeded" >&2
+  exit 1
+fi
+grep -q "command not found" /tmp/rex-free.err
+
+if ! grep -q 'os eq "Darwin"' "$root/lib/Rex/Hardware/Memory.pm"; then
+  echo "Memory.pm has no Darwin branch" >&2
+  exit 1
+fi
+if ! grep -q 'os eq "Darwin"' "$root/lib/Rex/Hardware/Swap.pm"; then
+  echo "Swap.pm has no Darwin branch" >&2
+  exit 1
+fi
+
+perl -I"$root/lib" -MRex::Hardware::DarwinProbe -e '
+  my $bytes = `sysctl -n hw.memsize`;
+  my $pages = `sysctl -n hw.pagesize`;
+  my $vm = `vm_stat`;
+  my $swap = `sysctl -n vm.swapusage`;
+  chomp($bytes, $pages, $swap);
+  my $mem = Rex::Hardware::DarwinProbe::memory_mb(memsize => $bytes, pagesize => $pages, vm_stat => $vm);
+  my $sw = Rex::Hardware::DarwinProbe::swap_mb($swap);
+  my $expect = int($bytes / 1024 / 1024);
+  die "total $mem->{total} != $expect\n" unless $mem->{total} == $expect;
+  die "free larger than total\n" unless $mem->{free} <= $mem->{total};
+  die "swap total missing from [$swap]\n" unless $sw->{total} > 0;
+  print "rex darwin ok total=$mem->{total} free=$mem->{free} swap=$sw->{total} used=$sw->{used} free_swap=$sw->{free}\n";
+'