File Coverage

blib/lib/DBI/Gofer/Execute.pm

Criterion	Covered	Total	%
statement	249	295	84.4
branch	99	156	63.4
condition	57	115	49.5
subroutine	23	25	92.0
pod	0	11	0.0
total	428	602	71.1

package DBI::Gofer::Execute;

#   $Id: Execute.pm 14282 2010-07-26 00:12:54Z David $
#
#   Copyright (c) 2007, Tim Bunce, Ireland
#
#   You may distribute under the terms of either the GNU General Public
#   License or the Artistic License, as specified in the Perl README file.

use strict;
use warnings;

use Carp;

use DBI qw(dbi_time);
use DBI::Gofer::Request;
use DBI::Gofer::Response;

use base qw(DBI::Util::_accessor);

our $VERSION = "0.014283";

our @all_dbh_methods = sort map { keys %$_ } $DBI::DBI_methods{db}, $DBI::DBI_methods{common};
our %all_dbh_methods = map { $_ => (DBD::_::db->can($_)||undef) } @all_dbh_methods;

our $local_log = $ENV{DBI_GOFER_LOCAL_LOG}; # do extra logging to stderr

our $current_dbh;   # the dbh we're using for this request


# set trace for server-side gofer
# Could use DBI_TRACE env var when it's an unrelated separate process
# but using DBI_GOFER_TRACE makes testing easier for subprocesses (eg stream)
DBI->trace(split /=/, $ENV{DBI_GOFER_TRACE}, 2) if $ENV{DBI_GOFER_TRACE};


# define valid configuration attributes (args to new())
# the values here indicate the basic type of values allowed
my %configuration_attributes = (
    gofer_execute_class => 1,
    default_connect_dsn => 1,
    forced_connect_dsn  => 1,
    default_connect_attributes => {},
    forced_connect_attributes  => {},
    track_recent => 1,
    check_request_sub => sub {},
    check_response_sub => sub {},
    forced_single_resultset => 1,
    max_cached_dbh_per_drh => 1,
    max_cached_sth_per_dbh => 1,
    forced_response_attributes => {},
    forced_gofer_random => 1,
    stats => {},
);

__PACKAGE__->mk_accessors(
    keys %configuration_attributes
);



sub new {
    my ($self, $args) = @_;
    $args->{default_connect_attributes} ||= {};
    $args->{forced_connect_attributes}  ||= {};
    $args->{max_cached_sth_per_dbh}     ||= 1000;
    $args->{stats} ||= {};
    return $self->SUPER::new($args);
}


sub valid_configuration_attributes {
    my $self = shift;
    return { %configuration_attributes };
}


my %extra_attr = (
    # Only referenced if the driver doesn't support private_attribute_info method.
    # What driver-specific attributes should be returned for the driver being used?
    # keyed by $dbh->{Driver}{Name}
    # XXX for sth should split into attr specific to resultsets (where NUM_OF_FIELDS > 0) and others
    # which would reduce processing/traffic for non-select statements
    mysql  => {
        dbh => [qw(
            mysql_errno mysql_error mysql_hostinfo mysql_info mysql_insertid
            mysql_protoinfo mysql_serverinfo mysql_stat mysql_thread_id
        )],
        sth => [qw(
            mysql_is_blob mysql_is_key mysql_is_num mysql_is_pri_key mysql_is_auto_increment
            mysql_length mysql_max_length mysql_table mysql_type mysql_type_name mysql_insertid
        )],
        # XXX this dbh_after_sth stuff is a temporary, but important, hack.
        # should be done via hash instead of arrays where the hash value contains
        # flags that can indicate which attributes need to be handled in this way
        dbh_after_sth => [qw(
            mysql_insertid
        )],
    },
    Pg  => {
        dbh => [qw(
            pg_protocol pg_lib_version pg_server_version
            pg_db pg_host pg_port pg_default_port
            pg_options pg_pid
        )],
        sth => [qw(
            pg_size pg_type pg_oid_status pg_cmd_status
        )],
    },
    Sybase => {
        dbh => [qw(
            syb_dynamic_supported syb_oc_version syb_server_version syb_server_version_string
        )],
        sth => [qw(
            syb_types syb_proc_status syb_result_type
        )],
    },
    SQLite => {
        dbh => [qw(
            sqlite_version
        )],
        sth => [qw(
        )],
    },
    ExampleP => {
        dbh => [qw(
            examplep_private_dbh_attrib
        )],
        sth => [qw(
            examplep_private_sth_attrib
        )],
        dbh_after_sth => [qw(
            examplep_insertid
        )],
    },
);


sub _connect {
    my ($self, $request) = @_;

    my $stats = $self->{stats};

    # discard CachedKids from time to time
    if (++$stats->{_requests_served} % 1000 == 0 # XXX config?
        and my $max_cached_dbh_per_drh = $self->{max_cached_dbh_per_drh}
    ) {
        my %drivers = DBI->installed_drivers();
        while ( my ($driver, $drh) = each %drivers ) {
            next unless my $CK = $drh->{CachedKids};
            next unless keys %$CK > $max_cached_dbh_per_drh;
            next if $driver eq 'Gofer'; # ie transport=null when testing
            DBI->trace_msg(sprintf "Clearing %d cached dbh from $driver",
                scalar keys %$CK, $self->{max_cached_dbh_per_drh});
            $_->{Active} && $_->disconnect for values %$CK;
            %$CK = ();
        }
    }

    # local $ENV{...} can leak, so only do it if required
    local $ENV{DBI_AUTOPROXY} if $ENV{DBI_AUTOPROXY};

    my ($connect_method, $dsn, $username, $password, $attr) = @{ $request->dbh_connect_call };
    $connect_method ||= 'connect_cached';
    $stats->{method_calls_dbh}->{$connect_method}++;

    # delete attributes we don't want to affect the server-side
    # (Could just do this on client-side and trust the client. DoS?)
    delete @{$attr}{qw(Profile InactiveDestroy AutoInactiveDestroy HandleError HandleSetErr TraceLevel Taint TaintIn TaintOut)};

    $dsn = $self->forced_connect_dsn || $dsn || $self->default_connect_dsn
        or die "No forced_connect_dsn, requested dsn, or default_connect_dsn for request";

    my $random = $self->{forced_gofer_random} || $ENV{DBI_GOFER_RANDOM} || '';

    my $connect_attr = {

        # the configured default attributes, if any
        %{ $self->default_connect_attributes },

        # pass username and password as attributes
        # then they can be overridden by forced_connect_attributes
        Username => $username,
        Password => $password,

        # the requested attributes
        %$attr,

        # force some attributes the way we'd like them
        PrintWarn  => $local_log,
        PrintError => $local_log,

        # the configured default attributes, if any
        %{ $self->forced_connect_attributes },

        # RaiseError must be enabled
        RaiseError => 1,

        # reset Executed flag (of the cached handle) so we can use it to tell
        # if errors happened before the main part of the request was executed
        Executed => 0,

        # ensure this connect_cached doesn't have the same args as the client
        # because that causes subtle issues if in the same process (ie transport=null)
        # include pid to avoid problems with forking (ie null transport in mod_perl)
        # include gofer-random to avoid random behaviour leaking to other handles
        dbi_go_execute_unique => join("|", __PACKAGE__, $$, $random),
    };

    # XXX implement our own private connect_cached method? (with rate-limited ping)
    my $dbh = DBI->$connect_method($dsn, undef, undef, $connect_attr);

    $dbh->{ShowErrorStatement} = 1 if $local_log;

    # XXX should probably just be a Callbacks => arg to connect_cached
    # with a cache of pre-built callback hooks (memoized, without $self)
    if (my $random = $self->{forced_gofer_random} || $ENV{DBI_GOFER_RANDOM}) {
        $self->_install_rand_callbacks($dbh, $random);
    }

    my $CK = $dbh->{CachedKids};
    if ($CK && keys %$CK > $self->{max_cached_sth_per_dbh}) {
        %$CK = (); #  clear all statement handles
    }

    #$dbh->trace(0);
    $current_dbh = $dbh;
    return $dbh;
}


sub reset_dbh {
    my ($self, $dbh) = @_;
    $dbh->set_err(undef, undef); # clear any error state
}


sub new_response_with_err {
    my ($self, $rv, $eval_error, $dbh) = @_;
    # this is the usual way to create a response for both success and failure
    # capture err+errstr etc and merge in $eval_error ($@)

    my ($err, $errstr, $state) = ($DBI::err, $DBI::errstr, $DBI::state);

    if ($eval_error) {
        $err ||= $DBI::stderr || 1; # ensure err is true
        if ($errstr) {
            $eval_error =~ s/(?: : \s)? \Q$errstr//x if $errstr;
            chomp $errstr;
            $errstr .= "; $eval_error";
        }
        else {
            $errstr = $eval_error;
        }
    }
    chomp $errstr if $errstr;

    my $flags;
    # (XXX if we ever add transaction support then we'll need to take extra
    # steps because the commit/rollback would reset Executed before we get here)
    $flags |= GOf_RESPONSE_EXECUTED if $dbh && $dbh->{Executed};

    my $response = DBI::Gofer::Response->new({
        rv     => $rv,
        err    => $err,
        errstr => $errstr,
        state  => $state,
        flags  => $flags,
    });

    return $response;
}


sub execute_request {
    my ($self, $request) = @_;
    # should never throw an exception

    DBI->trace_msg("-----> execute_request\n");

    my @warnings;
    local $SIG{__WARN__} = sub {
        push @warnings, @_;
        warn @_ if $local_log;
    };

    my $response = eval {

        if (my $check_request_sub = $self->check_request_sub) {
            $request = $check_request_sub->($request, $self)
                or die "check_request_sub failed";
        }

        my $version = $request->version || 0;
        die ref($request)." version $version is not supported"
            if $version < 0.009116 or $version >= 1;

        ($request->is_sth_request)
            ? $self->execute_sth_request($request)
            : $self->execute_dbh_request($request);
    };
    $response ||= $self->new_response_with_err(undef, $@, $current_dbh);

    if (my $check_response_sub = $self->check_response_sub) {
        # not protected with an eval so it can choose to throw an exception
        my $new = $check_response_sub->($response, $self, $request);
        $response = $new if ref $new;
    }

    undef $current_dbh;

    $response->warnings(\@warnings) if @warnings;
    DBI->trace_msg("<----- execute_request\n");
    return $response;
}


sub execute_dbh_request {
    my ($self, $request) = @_;
    my $stats = $self->{stats};

    my $dbh;
    my $rv_ref = eval {
        $dbh = $self->_connect($request);
        my $args = $request->dbh_method_call; # [ wantarray, 'method_name', @args ]
        my $wantarray = shift @$args;
        my $meth      = shift @$args;
        $stats->{method_calls_dbh}->{$meth}++;
        my @rv = ($wantarray)
            ?        $dbh->$meth(@$args)
            : scalar $dbh->$meth(@$args);
        \@rv;
    } || [];
    my $response = $self->new_response_with_err($rv_ref, $@, $dbh);

    return $response if not $dbh;

    # does this request also want any dbh attributes returned?
    if (my $dbh_attributes = $request->dbh_attributes) {
        $response->dbh_attributes( $self->gather_dbh_attributes($dbh, $dbh_attributes) );
    }

    if ($rv_ref and my $lid_args = $request->dbh_last_insert_id_args) {
        $stats->{method_calls_dbh}->{last_insert_id}++;
        my $id = $dbh->last_insert_id( @$lid_args );
        $response->last_insert_id( $id );
    }

    if ($rv_ref and UNIVERSAL::isa($rv_ref->[0],'DBI::st')) {
        # dbh_method_call was probably a metadata method like table_info
        # that returns a statement handle, so turn the $sth into resultset
        my $sth = $rv_ref->[0];
        $response->sth_resultsets( $self->gather_sth_resultsets($sth, $request, $response) );
        $response->rv("(sth)"); # don't try to return actual sth
    }

    # we're finished with this dbh for this request
    $self->reset_dbh($dbh);

    return $response;
}


sub gather_dbh_attributes {
    my ($self, $dbh, $dbh_attributes) = @_;
    my @req_attr_names = @$dbh_attributes;
    if ($req_attr_names[0] eq '*') { # auto include std + private
        shift @req_attr_names;
        push @req_attr_names, @{ $self->_std_response_attribute_names($dbh) };
    }
    my %dbh_attr_values;
    @dbh_attr_values{@req_attr_names} = $dbh->FETCH_many(@req_attr_names);

    # XXX piggyback installed_methods onto dbh_attributes for now
    $dbh_attr_values{dbi_installed_methods} = { DBI->installed_methods };

    # XXX piggyback default_methods onto dbh_attributes for now
    $dbh_attr_values{dbi_default_methods} = _get_default_methods($dbh);

    return \%dbh_attr_values;
}


sub _std_response_attribute_names {
    my ($self, $h) = @_;
    $h = tied(%$h) || $h; # switch to inner handle

    # cache the private_attribute_info data for each handle
    # XXX might be better to cache it in the executor
    # as it's unlikely to change
    # or perhaps at least cache it in the dbh even for sth
    # as the sth are typically very short lived

    my ($dbh, $h_type, $driver_name, @attr_names);

    if ($dbh = $h->{Database}) {    # is an sth

        # does the dbh already have the answer cached?
        return $dbh->{private_gofer_std_attr_names_sth} if $dbh->{private_gofer_std_attr_names_sth};

        ($h_type, $driver_name) = ('sth', $dbh->{Driver}{Name});
        push @attr_names, qw(NUM_OF_PARAMS NUM_OF_FIELDS NAME TYPE NULLABLE PRECISION SCALE);
    }
    else {                          # is a dbh
        return $h->{private_gofer_std_attr_names_dbh} if $h->{private_gofer_std_attr_names_dbh};

        ($h_type, $driver_name, $dbh) = ('dbh', $h->{Driver}{Name}, $h);
        # explicitly add these because drivers may have different defaults
        # add Name so the client gets the real Name of the connection
        push @attr_names, qw(ChopBlanks LongReadLen LongTruncOk ReadOnly Name);
    }

    if (my $pai = $h->private_attribute_info) {
        push @attr_names, keys %$pai;
    }
    else {
        push @attr_names, @{ $extra_attr{ $driver_name }{$h_type} || []};
    }
    if (my $fra = $self->{forced_response_attributes}) {
        push @attr_names, @{ $fra->{ $driver_name }{$h_type} || []}
    }
    $dbh->trace_msg("_std_response_attribute_names for $driver_name $h_type: @attr_names\n");

    # cache into the dbh even for sth, as the dbh is usually longer lived
    return $dbh->{"private_gofer_std_attr_names_$h_type"} = \@attr_names;
}


sub execute_sth_request {
    my ($self, $request) = @_;
    my $dbh;
    my $sth;
    my $last_insert_id;
    my $stats = $self->{stats};

    my $rv = eval {
        $dbh = $self->_connect($request);

        my $args = $request->dbh_method_call; # [ wantarray, 'method_name', @args ]
        shift @$args; # discard wantarray
        my $meth = shift @$args;
        $stats->{method_calls_sth}->{$meth}++;
        $sth = $dbh->$meth(@$args);
        my $last = '(sth)'; # a true value (don't try to return actual sth)

        # execute methods on the sth, e.g., bind_param & execute
        if (my $calls = $request->sth_method_calls) {
            for my $meth_call (@$calls) {
                my $method = shift @$meth_call;
                $stats->{method_calls_sth}->{$method}++;
                $last = $sth->$method(@$meth_call);
            }
        }

        if (my $lid_args = $request->dbh_last_insert_id_args) {
            $stats->{method_calls_sth}->{last_insert_id}++;
            $last_insert_id = $dbh->last_insert_id( @$lid_args );
        }

        $last;
    };
    my $response = $self->new_response_with_err($rv, $@, $dbh);

    return $response if not $dbh;

    $response->last_insert_id( $last_insert_id )
        if defined $last_insert_id;

    # even if the eval failed we still want to try to gather attribute values
    # (XXX would be nice to be able to support streaming of results.
    # which would reduce memory usage and latency for large results)
    if ($sth) {
        $response->sth_resultsets( $self->gather_sth_resultsets($sth, $request, $response) );
        $sth->finish;
    }

    # does this request also want any dbh attributes returned?
    my $dbh_attr_set;
    if (my $dbh_attributes = $request->dbh_attributes) {
        $dbh_attr_set = $self->gather_dbh_attributes($dbh, $dbh_attributes);
    }
    # XXX needs to be integrated with private_attribute_info() etc
    if (my $dbh_attr = $extra_attr{$dbh->{Driver}{Name}}{dbh_after_sth}) {
        @{$dbh_attr_set}{@$dbh_attr} = $dbh->FETCH_many(@$dbh_attr);
    }
    $response->dbh_attributes($dbh_attr_set) if $dbh_attr_set && %$dbh_attr_set;

    $self->reset_dbh($dbh);

    return $response;
}


sub gather_sth_resultsets {
    my ($self, $sth, $request, $response) = @_;
    my $resultsets = eval {

        my $attr_names = $self->_std_response_attribute_names($sth);
        my $sth_attr = {};
        $sth_attr->{$_} = 1 for @$attr_names;

        # let the client add/remove sth attributes
        if (my $sth_result_attr = $request->sth_result_attr) {
            $sth_attr->{$_} = $sth_result_attr->{$_}
                for keys %$sth_result_attr;
        }
        my @sth_attr = grep { $sth_attr->{$_} } keys %$sth_attr;

        my $row_count = 0;
        my $rs_list = [];
        while (1) {
            my $rs = $self->fetch_result_set($sth, \@sth_attr);
            push @$rs_list, $rs;
            if (my $rows = $rs->{rowset}) {
                $row_count += @$rows;
            }
            last if $self->{forced_single_resultset};
            last if !($sth->more_results || $sth->{syb_more_results});
         }

        my $stats = $self->{stats};
        $stats->{rows_returned_total} += $row_count;
        $stats->{rows_returned_max} = $row_count
            if $row_count > ($stats->{rows_returned_max}||0);

        $rs_list;
    };
    $response->add_err(1, $@) if $@;
    return $resultsets;
}


sub fetch_result_set {
    my ($self, $sth, $sth_attr) = @_;
    my %meta;
    eval {
        @meta{ @$sth_attr } = $sth->FETCH_many(@$sth_attr);
        # we assume @$sth_attr contains NUM_OF_FIELDS
        $meta{rowset}       = $sth->fetchall_arrayref()
            if (($meta{NUM_OF_FIELDS}||0) > 0); # is SELECT
        # the fetchall_arrayref may fail with a 'not executed' kind of error
        # because gather_sth_resultsets/fetch_result_set are called even if
        # execute() failed, or even if there was no execute() call at all.
        # The corresponding error goes into the resultset err, not the top-level
        # response err, so in most cases this resultset err is never noticed.
    };
    if ($@) {
        chomp $@;
        $meta{err}    = $DBI::err    || 1;
        $meta{errstr} = $DBI::errstr || $@;
        $meta{state}  = $DBI::state;
    }
    return \%meta;
}


sub _get_default_methods {
    my ($dbh) = @_;
    # returns a ref to a hash of dbh method names for methods which the driver
    # hasn't overridden i.e., quote(). These don't need to be forwarded via gofer.
    my $ImplementorClass = $dbh->{ImplementorClass} or die;
    my %default_methods;
    for my $method (@all_dbh_methods) {
        my $dbi_sub = $all_dbh_methods{$method}       || 42;
        my $imp_sub = $ImplementorClass->can($method) || 42;
        next if $imp_sub != $dbi_sub;
        #warn("default $method\n");
        $default_methods{$method} = 1;
    }
    return \%default_methods;
}


# XXX would be nice to make this a generic DBI module
sub _install_rand_callbacks {
    my ($self, $dbh, $dbi_gofer_random) = @_;

    my $callbacks = $dbh->{Callbacks} || {};
    my $prev      = $dbh->{private_gofer_rand_fail_callbacks} || {};

    # return if we've already setup this handle with callbacks for these specs
    return if (($callbacks->{_dbi_gofer_random_spec}||'') eq $dbi_gofer_random);
    #warn "$dbh # $callbacks->{_dbi_gofer_random_spec}";
    $callbacks->{_dbi_gofer_random_spec} = $dbi_gofer_random;

    my ($fail_percent, $fail_err, $delay_percent, $delay_duration, %spec_part, @spec_note);
    my @specs = split /,/, $dbi_gofer_random;
    for my $spec (@specs) {
        if ($spec =~ m/^fail=(-?[.\d]+)%?$/) {
            $fail_percent = $1;
            $spec_part{fail} = $spec;
            next;
        }
        if ($spec =~ m/^err=(-?\d+)$/) {
            $fail_err = $1;
            $spec_part{err} = $spec;
            next;
        }
        if ($spec =~ m/^delay([.\d]+)=(-?[.\d]+)%?$/) {
            $delay_duration = $1;
            $delay_percent  = $2;
            $spec_part{delay} = $spec;
            next;
        }
        elsif ($spec !~ m/^(\w+|\*)$/) {
            warn "Ignored DBI_GOFER_RANDOM item '$spec' which isn't a config or a dbh method name";
            next;
        }

        my $method = $spec;
        if ($callbacks->{$method} && $prev->{$method} && $callbacks->{$method} != $prev->{$method}) {
            warn "Callback for $method method already installed so DBI_GOFER_RANDOM callback not installed\n";
            next;
        }
        unless (defined $fail_percent or defined $delay_percent) {
            warn "Ignored DBI_GOFER_RANDOM item '$spec' because not preceded by 'fail=N' and/or 'delayN=N'";
            next;
        }

        push @spec_note, join(",", values(%spec_part), $method);
        $callbacks->{$method} = $self->_mk_rand_callback($method, $fail_percent, $delay_percent, $delay_duration, $fail_err);
    }
    warn "DBI_GOFER_RANDOM failures/delays enabled: @spec_note\n"
        if @spec_note;
    $dbh->{Callbacks} = $callbacks;
    $dbh->{private_gofer_rand_fail_callbacks} = $callbacks;
}

my %_mk_rand_callback_seqn;

sub _mk_rand_callback {
    my ($self, $method, $fail_percent, $delay_percent, $delay_duration, $fail_err) = @_;
    my ($fail_modrate, $delay_modrate);
    $fail_percent  ||= 0;  $fail_modrate  = int(1/(-$fail_percent )*100) if $fail_percent;
    $delay_percent ||= 0;  $delay_modrate = int(1/(-$delay_percent)*100) if $delay_percent;
    # note that $method may be "*" but that's not recommended or documented or wise
    return sub {
        my ($h) = @_;
        my $seqn = ++$_mk_rand_callback_seqn{$method};
        my $delay = ($delay_percent > 0) ? rand(100) < $delay_percent :
                    ($delay_percent < 0) ? !($seqn % $delay_modrate): 0;
        my $fail  = ($fail_percent  > 0) ? rand(100) < $fail_percent  :
                    ($fail_percent  < 0) ? !($seqn % $fail_modrate) : 0;
        #no warnings 'uninitialized';
        #warn "_mk_rand_callback($fail_percent:$fail_modrate, $delay_percent:$delay_modrate): seqn=$seqn fail=$fail delay=$delay";
        if ($delay) {
            my $msg = "DBI_GOFER_RANDOM delaying execution of $method() by $delay_duration seconds\n";
            # Note what's happening in a trace message. If the delay percent is an even
            # number then use warn() instead so it's sent back to the client.
            ($delay_percent % 2 == 1) ? warn($msg) : $h->trace_msg($msg);
            select undef, undef, undef, $delay_duration; # allows floating point value
        }
        if ($fail) {
            undef $_; # tell DBI to not call the method
            # the "induced by DBI_GOFER_RANDOM" is special and must be included in errstr
            # as it's checked for in a few places, such as the gofer retry logic
            return $h->set_err($fail_err || $DBI::stderr,
                "fake error from $method method induced by DBI_GOFER_RANDOM env var ($fail_percent%)");
        }
        return;
    }
}


sub update_stats {
    my ($self,
        $request, $response,
        $frozen_request, $frozen_response,
        $time_received,
        $store_meta, $other_meta,
    ) = @_;

    # should always have a response object here
    carp("No response object provided") unless $request;

    my $stats = $self->{stats};
    $stats->{frozen_request_max_bytes} = length($frozen_request)
        if $frozen_request
        && length($frozen_request)  > ($stats->{frozen_request_max_bytes}||0);
    $stats->{frozen_response_max_bytes} = length($frozen_response)
        if $frozen_response
        && length($frozen_response) > ($stats->{frozen_response_max_bytes}||0);

    my $recent;
    if (my $track_recent = $self->{track_recent}) {
        $recent = {
            request  => $frozen_request,
            response => $frozen_response,
            time_received => $time_received,
            duration => dbi_time()-$time_received,
            # for any other info
            ($store_meta) ? (meta => $store_meta) : (),
        };
        $recent->{request_object} = $request
            if !$frozen_request && $request;
        $recent->{response_object} = $response
            if !$frozen_response;
        my @queues =  ($stats->{recent_requests} ||= []);
        push @queues, ($stats->{recent_errors}   ||= [])
            if !$response or $response->err;
        for my $queue (@queues) {
            push @$queue, $recent;
            shift @$queue if @$queue > $track_recent;
        }
    }
    return $recent;
}


1;
__END__