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# You may distribute under the terms of either the GNU General Public License
# or the Artistic License (the same terms as Perl itself)
#
# (C) Paul Evans, 2020 -- leonerd@leonerd.org.uk
package Metrics::Any::Adapter::File 0.10;
use v5.14;
use warnings;
use Carp;
=head1 NAME
C<Metrics::Any::Adapter::File> - write metrics to a file
=head1 SYNOPSIS
use Metrics::Any::Adapter 'File', path => "metrics.log";
=head1 DESCRIPTION
This L<Metrics::Any> adapter type writes observations of metric values into a
file. This may be helpful while debugging or otherwise testing code that
reports metrics.
For example, by setting the C<METRICS_ANY_ADAPTER> environment variable to
configure the adapter, a metric log will be written as a side-effect of
running a unit test:
$ METRICS_ANY_ADAPTER=File:path=metrics.log perl -Mblib t/01test.t
The generated file can then be inspected to see what metric values were
reported while the program was running.
In particular, specifying the file F</dev/null> allows the full metrics
generation path to be tested with the code under test seeing a "real" adapter
even though the output goes nowhere.
$ METRICS_ANY_ADAPTER=File:path=/dev/null ./Build test
Distribution and timing metrics are tracked with a running total and count of
observations.
This adapter type does not support batch mode reporting.
=head1 ARGUMENTS
The following additional arguments are recognised
=head2 path
The path to the file to write to.
=cut
my %metrics;
sub new
{
my $class = shift;
my %args = @_;
my $fh;
if( $args{fh} ) {
# fh isn't documented but useful for unit testing
$fh = $args{fh};
}
elsif( $args{path} ) {
open $fh, ">>", $args{path} or die "Cannot open $args{path} for writing - $!\n";
}
else {
croak "Require a 'path' argument";
}
$fh->autoflush;
return bless {
__fh => $fh,
}, $class;
}
sub _make
{
my $self = shift;
my ( $type, $handle, %args ) = @_;
my $name = $args{name};
$name = join "_", @$name if ref $name eq "ARRAY";
$self->{$handle} = {
type => $type,
name => $name,
labels => $args{labels},
};
}
sub _key
{
my $self = shift;
my ( $handle, $suffix, @labelvalues ) = @_;
my $meta = $self->{$handle};
my $key = $meta->{name};
$key .= $suffix if defined $suffix;
if( my $labels = $meta->{labels} ) {
$key .= " $labels->[$_]:$labelvalues[$_]" for 0 .. $#$labels;
}
return $key;
}
sub make_counter { shift->_make( counter => @_ ) }
sub inc_counter_by
{
my $self = shift;
my ( $handle, $amount, @labelvalues ) = @_;
my $fh = $self->{__fh};
my $key = $self->_key( $handle, undef, @labelvalues );
my $current = $metrics{$key} += $amount;
printf $fh "METRIC COUNTER %s %+g => %g\n",
$key, $amount, $current;
}
sub make_distribution { shift->_make( distribution => @_ ) }
sub report_distribution
{
my $self = shift;
my ( $handle, $amount, @labelvalues ) = @_;
my $fh = $self->{__fh};
my $count = $metrics{ $self->_key( $handle, "_count", @labelvalues ) } += 1;
my $total = $metrics{ $self->_key( $handle, "_total", @labelvalues ) } += $amount;
printf $fh "METRIC DISTRIBUTION %s +%g => %g/%d [avg=%g]\n",
$self->_key( $handle, undef, @labelvalues ), $amount, $total, $count, $total/$count;
}
sub make_gauge { shift->_make( gauge => @_ ) }
sub inc_gauge_by
{
my $self = shift;
my ( $handle, $amount, @labelvalues ) = @_;
my $fh = $self->{__fh};
my $key = $self->_key( $handle, undef, @labelvalues );
my $current = $metrics{$key} += $amount;
printf $fh "METRIC GAUGE %s %+g => %g\n",
$key, $amount, $current;
}
sub set_gauge_to
{
my $self = shift;
my ( $handle, $amount, @labelvalues ) = @_;
my $fh = $self->{__fh};
my $key = $self->_key( $handle, undef, @labelvalues );
my $current = $metrics{$key} = $amount;
printf $fh "METRIC GAUGE %s => %g\n",
$key, $current;
}
sub make_timer { shift->_make( timer => @_ ) }
sub report_timer
{
my $self = shift;
my ( $handle, $duration, @labelvalues ) = @_;
my $fh = $self->{__fh};
my $count = $metrics{ $self->_key( $handle, "_count", @labelvalues ) } += 1;
my $total = $metrics{ $self->_key( $handle, "_total", @labelvalues ) } += $duration;
printf $fh "METRIC TIMER %s +%.3g => %.3g/%d [avg=%g]\n",
$self->_key( $handle, undef, @labelvalues ), $duration, $total, $count, $total/$count;
}
=head1 AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
=cut
0x55AA;
|
