firefox-prometheus-metrics

#!//Users/rjbs/.plenv/versions/5.38.0/bin/perl5.38.0
use v5.36.0;

use Compress::LZ4;
use JSON::MaybeXS;
use Path::Tiny;

# I should not really hardcode the profile path.  But I don't want to look at
# them all, because it seems sometimes ancient ones linger.  I'll sort it out
# if this ever breaks. -- rjbs, 2024-04-14
my $profiles_root = path('/Users/rjbs/Library/Application Support/Firefox/Profiles');
my $backups_dir   = $profiles_root->child('eoone60x.default-release-1/sessionstore-backups');
my $backup_file   = $backups_dir->child('recovery.jsonlz4');

# This is some nonsense container data.  I learned this trick from this blog
# post's code: https://alexandre.deverteuil.net/post/firefox-tabs-analysis/
my $bytes = $backup_file->slurp;
substr $bytes, 0, 8, '';

my $json  = decompress($bytes);
my $data  = decode_json($json);

my $tab_count = 0;
my $window_count = 0;

for my $window ($data->{windows}->@*) {
  $window_count++;
  for my $tab ($window->{tabs}->@*) {
    # I don't use this, but just in case, now I have it.
    my $live = $tab->{entries}[-1];
    # $live->{url} # <-- real url
    $tab_count++;
  }
}

say "firefox_open_windows $window_count";
say "firefox_open_tabs $tab_count";