add influxdb command

package Travelynx::Command::influxdb;

# Copyright (C) 2022 Daniel Friesel

#

# SPDX-License-Identifier: AGPL-3.0-or-later

use Mojo::Base 'Mojolicious::Command';

use DateTime;

has description => 'Generate statistics for InfluxDB';

has usage => sub { shift->extract_usage };

sub query_to_influx {

	my ( $label, $value ) = @_;

	if ( defined $value ) {

		return sprintf( '%s=%f', $label, $value );

	}

	return;

}

sub run {

	my ($self) = @_;

	my $db = $self->app->pg->db;

	my $now    = DateTime->now( time_zone => 'Europe/Berlin' );

	my $active = $now->clone->subtract( months => 1 );

	my $checkin_window_query

	  = qq{select count(*) as count from journeys where checkin_time > to_timestamp(?);};

	# DateTime's  math does not like time zones: When subtracting 7 days from

	# sun 2am and the previous sunday was the switch from CET to CEST (i.e.,

	# the switch to daylight saving time), the resulting datetime is invalid.

	# This is a fatal error. We avoid this edge case by performing date math

	# on the epoch timestamp, which does not know or care about time zones and

	# daylight saving time.

	my $one_day   = 24 * 60 * 60;

	my $one_week  = 7 * $one_day;

	my $one_month = 30 * $one_day;

	my @out;

	push(

		@out,

		query_to_influx(

			'pending_user_count',

			$db->select( 'users', 'count(*) as count', { status => 0 } )

			  ->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'reg_user_count',

			$db->select( 'users', 'count(*) as count', { status => 1 } )

			  ->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'active_user_count',

			$db->select(

				'users',

				'count(*) as count',

				{

					status    => 1,

					last_seen => { '>', $active }

				}

			)->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'checked_in_count',

			$db->select( 'in_transit', 'count(*) as count' )->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'checkins_24h_count',

			$db->query( $checkin_window_query, $now->epoch - $one_day )

			  ->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'checkins_7d_count',

			$db->query( $checkin_window_query, $now->epoch - $one_week )

			  ->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'checkins_30d_count',

			$db->query( $checkin_window_query, $now->epoch - $one_month )

			  ->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'polyline_count',

			$db->select( 'polylines', 'count(*) as count' )->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'traewelling_pull_count',

			$db->select(

				'traewelling',

				'count(*) as count',

				{ pull_sync => 1 }

			)->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'traewelling_push_count',

			$db->select(

				'traewelling',

				'count(*) as count',

				{ push_sync => 1 }

			)->hash->{count}

		)

	);

	push(

		@out,

		query_to_influx(

			'polyline_ratio',

			$db->query(

'select (select count(polyline_id) from journeys)::float / (select count(*) from polylines) as ratio'

			)->hash->{ratio}

		)

	);

	say join( ',', @out );

	return;

}

1;

__END__

=head1 SYNOPSIS

  Usage: index.pl influx

  Write statistics for InfluxDB to stdout