#!/usr/bin/php
<?php

/*
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

define('N',"\n");
define('SNAME',basename(__FILE__));
define('FNAME',preg_replace('/\.[^.]*$/','',SNAME));
define('CHILD','getinstinfo.php');
define('LIBDP','/../site/mustard/include');

require(__DIR__.LIBDP.'/ght.php');
require(__DIR__.LIBDP.'/gracetime.php');

use function mysqli_real_escape_string as myesc;

declare(ticks=1);
if (function_exists('pcntl_signal')) {
	function signalHandler($signal) {
		echo(N);
		mexit('received signal «'.$signal.'», shutting down.'.N,0,true);
	}
	pcntl_signal(SIGTERM,'signalHandler');// Termination ('kill' was called)
	pcntl_signal(SIGHUP,'signalHandler');// Terminal log-out
	pcntl_signal(SIGINT,'signalHandler');// Interrupted (Ctrl-C is pressed)
}

$msglevs=['Debug', 'Info', 'Warning', 'Error', 'None'];

$opts=[
	'gracetime'=>$gracetime,
	'poolsize'=>10,
	'peersfp'=>null,
	'dontrestore'=>false,
	'ignorelock'=>false,
	'minmsgimplev'=>1
];

$ghtsa=[[' day',' days'],[' hour',' hours'],[' minute',' minutes'],[' second',' seconds']];

$help='SYNOPSIS

 '.SNAME.' [options]

DESCRIPTION

 This script coordinates the parallel execution of a definable number of
 '.CHILD.' processes “against” all the alive instances which are already
 present in mastostart’s database, plus optionally those listed in a
 specifiable file (typically the output file from a peerscrawl.php run).

OPTIONS

 -
  Everything after a single dash will be passed to '.CHILD.' processes as is.
 -g, --gracetime <time>
  If an instance has not been responding for longer than this time, avoid
  checking it. See section «TIME SPECIFICATION» below to see how to specify
  time.
  DEFAULT: '.ght($opts['gracetime'],$ghtsa).'
 -G, --graceline
  Return the “graceline” (now - gracetime: see option above) in unix time and
  local time, then exit.
 -p, --peersfp <file>
  Defines the path to a file containing a list of instances to consider in
  addition to those which are already present in the database. Note that this
  option is ignored if the script will restore a previous unfinished session.
 -P, --poolsize <number>
  The number of slots in the processes pool, that is the number of '.CHILD.'
  processes the script will run in parallel. Note that this option is ignored
  if the script will restore a previous unfinished session.
  DEFAULT: '.$opts['poolsize'].'
 -I, --ignorelock
  Normally, if its lockfile exists, the script will exit with an error.
  If this option is set, instead, the lockfile existence will be ignored.
  Please check that the script is actually not running before using it.
 -R, --dontrestore
  If this option is set and «instances.job» and «status.job» files from
  a previous unfinished session are present in the «run» subdirectory inside
  the directory where the script resides, the script will ignore them and
  start a new session; otherwise the script will restore the previous,
  unfinished session.
 -m, --minmsgimplev <«debug»|«info»|«warning»|«error»|«none»>
  Defines the minimum “importance level” of messages to be written to the
  text user interface. There are 4 “importance levels”, in this order of
  importance: «debug», «info», «warning», «error».
  Setting this option to any of these values will write to the text user
  interface all the messages with the specified or a greater level; setting
  it to the special value «none» will completely disable messages.
  DEFAULT: '.lcfirst($msglevs[$opts['minmsgimplev']]).'
 -h, --help
  When this option is specified, the script will show this help text and exit.

TIME SPECIFICATION

 An example is better than ~5148 words :-)
 To specify 1 year, 6 months (made of 31 days), 2 weeks, 3 days, 5 hours,
 7 minutes and 12 seconds you can use «1y,6M,2w,3d,5h,7m,12s»; but you can
 also use «12s,7m,5h,3d,2w,6M,1y», or even «18M,1w,1w,2d,1d,3h,2h,7m,12s».

LICENSE

 This program comes with ABSOLUTELY NO WARRANTY; for details see the source.
 This is free software, and you are welcome to redistribute it under certain
 conditions; see <http://www.gnu.org/licenses/> for details.'.N;

$childopts='';

for ($i=1; $i<$argc; $i++) {
	if ($argv[$i]=='-') {
		if ($i<$argc-1) {
			$i++;
			while ($i<$argc) {
				$childopts.=' '.$argv[$i];
				$i++;
			}
		} else {
			eecho(2,'you have specified «-» as last argument...'.N);
		}
	} elseif ($argv[$i]=='-g' || $argv[$i]=='--gracetime') {
		if ($i+1>=$argc || ($time=parsetime($argv[$i+1]))===false)
			mexit('option «'.$argv[$i].'» requires a valid time specification as an argument (use «-h» to read help).'.N,1,false);
		$i++;
		$opts['gracetime']=$time;
	} elseif ($argv[$i]=='-G' || $argv[$i]=='--graceline') {
		$graceline=time()-$opts['gracetime'];
		echo('Graceline: '.$graceline.' ('.date('Y-m-d H:i:s',$graceline).').'.N);
		exit(0);
	} elseif ($argv[$i]=='-p' || $argv[$i]=='--peersfp') {
		if ($i+1>=$argc || !file_exists($argv[$i+1]) || !is_file($argv[$i+1]) || !is_readable($argv[$i+1]))
			mexit('option «'.$argv[$i].'» requires an existing and readable file as an argument (use «-h» to read help).'.N,1,false);
		$i++;
		$opts['peersfp']=$argv[$i];
	} elseif ($argv[$i]=='-P' || $argv[$i]=='--poolsize') {
		if ($i+1>=$argc || preg_match('/\d+/',$argv[$i+1])!==1 || $argv[$i+1]+0<1)
			mexit('option «'.$argv[$i].'» requires an integer number greater than 0 as an argument (use «-h» to read help).'.N,1,false);
		$i++;
		$opts['poolsize']=$argv[$i]+0;
	} elseif ($argv[$i]=='-R' || $argv[$i]=='--dontrestore') {
		$opts['dontrestore']=true;
	} elseif ($argv[$i]=='-I' || $argv[$i]=='--ignorelock') {
		$opts['ignorelock']=true;
	} elseif ($argv[$i]=='-m' || $argv[$i]=='--minmsgimplev') {
		if ($i+1>=$argc || !in_array(ucfirst(strtolower($argv[$i+1])),$msglevs))
			mexit('option «'.$argv[$i].'» requires a “message importance level” value as an argument (use «-h» to read help).'.N,1,false);
		$i++;
		$opts['minmsimpglev']=array_search(ucfirst(strtolower($argv[$i])),$msglevs);
	} elseif ($argv[$i]=='-h' || $argv[$i]=='--help') {
		echo($help);
		exit(0);
	} else {
		mexit('don’t know how to interpret «'.$argv[$i].'» (you can read the help text using «-h» or «--help»).'.N,1,false);
	}
}

$graceline=time()-$opts['gracetime'];

$rundirpath=__DIR__.'/run';

$lockfp=$rundirpath.'/'.FNAME.'.lock';
if (file_exists($lockfp) && !$opts['ignorelock']) {
	eecho(3,'lock file «'.$lockfp.'» exists (if you are sure '.SNAME.' is not already running you can use option «-I» to force execution).'.N);
	exit(1);
}
if (@touch($lockfp)===false) {
	eecho(3,'could not touch file «'.$lockfp.'».'.N);
	exit(1);
}

if (file_exists($rundirpath) && !is_dir($rundirpath))
	mexit('«'.$rundirpath.'» is not a directory.'.N,1,false);
elseif (file_exists($rundirpath) && (!is_readable($rundirpath) || !is_writeable($rundirpath)))
	mexit('«'.$rundirpath.'» is not readable and writeable.'.N,1,false);
elseif (!file_exists($rundirpath))
	if (@mkdir($rundirpath)===false)
		mexit('could not create directory «'.$rundirpath.'».'.N,1,false);

$instsjfp=$rundirpath.'/'.FNAME.'_instances.job';
$statusjfp=$rundirpath.'/'.FNAME.'_status.job';

(!$opts['dontrestore'] && file_exists($instsjfp) && file_exists($statusjfp)) ? $restore=true : $restore=false;

($restore) ? eecho(1,'--- restarting ---'.N) : eecho(1,'--- starting ---'.N);

if ($restore) {
	eecho(0,'looks like previous session was interrupted, trying to restore it...'.N);
	$insts=@file($instsjfp,FILE_IGNORE_NEW_LINES|FILE_SKIP_EMPTY_LINES);
	if ($insts===false) mexit('could not open file «'.$instsjfp.'» for reading.'.N,1,true);
	$cinsts=count($insts);
	eecho(1,'loaded '.$cinsts.' hostnames from previous session file.'.N);
	$buf=@file($statusjfp,FILE_IGNORE_NEW_LINES|FILE_SKIP_EMPTY_LINES);
	if ($buf===false) mexit('could not open file «'.$statusjfp.'» for reading.'.N,1,true);
	if (count($buf)<2) mexit('file «'.$statusjfp.'»: wrong format (1).'.N,1,true);
	$buf[0]=explode("\t",$buf[0]);
	if (count($buf[0])!=4 ||
		preg_match('/^\d+$/',$buf[0][0])!==1 ||
		preg_match('/^\d+$/',$buf[0][1])!==1 ||
		preg_match('/^\d+(\.\d+)?$/',$buf[0][2])!==1 ||
		preg_match('/^\d+$/',$buf[0][3])!==1)
		mexit('file «'.$statusjfp.'»: wrong format (2).'.N,1,true);
	$opts['poolsize']=$buf[0][0]+0;
	$instk=$buf[0][1]+0;
	$toff=$buf[0][2]+0;
	$done=$buf[0][3]+0;
	//eecho(0,'poolsize: '.$opts['poolsize'].'; instk: '.$instk.'; eta: '.$tet.'; done: '.$done.'.'.N);
	for ($i=1; $i<count($buf); $i++) {
		if (preg_match('/^\d+$/',$buf[$i])!==1) mexit('file «'.$statusjfp.'»: wrong format (3).'.N,1,true);
		//eecho(0,$i.': '.$buf[$i].'.'.N);
		$host=$insts[$buf[$i]+0];
		eecho(1,'bootstrapping processes pool, adding host «'.$host.'».'.N);
		$descspecs=[ 0=>['pipe','r'], 1=>['file',$rundirpath.'/'.$host.'.stdout.log','w'], 2=>['file',$rundirpath.'/'.$host.'.stderr.log','w'] ];
		$procs[]=['proc'=>proc_open(cmd($childopts,$host),$descspecs,$pipes[]), 'instk'=>$buf[$i]+0, 'host'=>$host, 'begts'=>microtime(true)];
	}
	eecho(1,'restored previous session.'.N);
} else {

	$inifp=__DIR__.'/../conf/mustard.ini';
	$iniarr=@parse_ini_file($inifp);
	if ($iniarr===false) mexit('could not open config file «'.$inifp.'»'.N,1,true);

	try { $link=@mysqli_connect($iniarr['db_host'],$iniarr['db_admin_name'],$iniarr['db_admin_password'],$iniarr['db_name'],$iniarr['db_port'],$iniarr['db_socket']); }
	catch (Exception $error) { mexit('could not connect to MySQL server: '.mysqli_connect_error().'.'.N,1,true); }
	// for php versions < 8
	if ($link===false) mexit('could not connect to MySQL server: '.mysqli_connect_error().'.'.N,1,true);
	try { $res=mysqli_set_charset($link,'utf8mb4'); }
	catch (Exception $error) { mexit('could not set «utf8mb4» charset for MySQL: '.mysqli_error($link).'.'.N,1,true); }
	// for php versions < 8
	if ($res===false) mexit('could not set MySQL charset: '.mysqli_errno($link).': '.mysqli_error($link).'.'.N,1,true);

	$insts=[];
	eecho(0,'loading instances from the database...'.N);
	$res=myq($link,'SELECT URI FROM Instances WHERE LastOkCheckTS>='.$graceline.' OR (LastOkCheckTS IS NULL AND InsertTS>='.$graceline.')',__LINE__);
	while($row=mysqli_fetch_assoc($res))
		if (!in_array($row['URI'],$insts))
			$insts[]=$row['URI'];
	eecho(1,'loaded '.count($insts).' instances which responded at least once since '.date('Y-m-d H:i:s',$graceline).' from the database.'.N);

	if (!is_null($opts['peersfp'])) {
		eecho(0,'loading “dead” instances from the database...'.N);
		$res=myq($link,'SELECT URI FROM Instances WHERE LastOkCheckTS<'.$graceline.' OR (LastOkCheckTS IS NULL AND InsertTS<'.$graceline.')',__LINE__);
		$deadinsts=[];
		while($row=mysqli_fetch_assoc($res))
			if (!in_array($row['URI'],$deadinsts))
				$deadinsts[]=$row['URI'];
		eecho(0,'loaded '.count($deadinsts).' “dead” instances from the database.'.N);
		eecho(0,'loading instances from «'.$opts['peersfp'].'»...'.N);
		$peers=@file($opts['peersfp'],FILE_IGNORE_NEW_LINES|FILE_SKIP_EMPTY_LINES);
		if ($peers===false) mexit('could not open «'.$opts['peersfp'].'» for reading.'.N,1,true);
		$i=0;
		foreach ($peers as $pdom) {
			if (!in_array($pdom,$insts)) {
				if (!in_array($pdom,$deadinsts)) {
					$i++;
					$insts[]=$pdom;
				} else {
					eecho(0,'ignoring instance «'.$pdom.'» from peers file because it’s dead.'.N);
				}
			}
		}
		eecho(1,'loaded '.$i.' more instances from «'.$opts['peersfp'].'».'.N);
		unset($deadinsts);
	}

	mysqli_close($link);
	unset($link);

	shuffle($insts);
	$cinsts=count($insts);
	eecho(1,$cinsts.' instances to be checked.'.N);

	$instsf=@fopen($instsjfp,'w');
	if ($instsf===false) mexit('could not open «'.$instsjfp.'» for writing.'.N,1,true);
	foreach ($insts as $host) fwrite($instsf,$host.N);
	fclose($instsf);

	$toff=0;
	$done=0;
	$procs=[];

	for ($instk=0; $instk<$opts['poolsize'] && $instk<$cinsts; $instk++) {
		$host=$insts[$instk];
		eecho(1,'bootstrapping processes pool, adding host «'.$host.'».'.N);
		$descspecs=[ 0=>['pipe','r'], 1=>['file',$rundirpath.'/'.$host.'.stdout.log','w'], 2=>['file',$rundirpath.'/'.$host.'.stderr.log','w'] ];
		$procs[]=['proc'=>proc_open(cmd($childopts,$host),$descspecs,$pipes[]), 'instk'=>$instk, 'host'=>$host, 'begts'=>microtime(true)];
	}
	$instk--;

}

$tini=microtime(true);
$rundone=false;
do {
	$now=microtime(true);
	$tet=$now-$tini+$toff;
	eecho(0,'[[[ CHECKING PROCESSES POOL ]]]'.N);
	$somerun=false;
	foreach ($procs as $key=>$proc) {
		if (!is_null($proc) && is_resource($proc['proc'])) {
			$pstat=proc_get_status($proc['proc']);
			if (!$pstat['running']) {
				fclose($pipes[$key][0]);
				$rv=proc_close($procs[$key]['proc']);// this always returns -1, it seems it's a php bug, anyway i'm keeping it for now to stay on the safe side (?)
				$done++;
				$out='proc slot '.$key.': finished running on «'.$proc['host'].'» after '.ght($now-$proc['begts']).' (exit code: '.$pstat['exitcode'].')';
				if ($instk<$cinsts-1) {
					$instk++;
					$host=$insts[$instk];
					$descspecs=[ 0=>['pipe','r'], 1=>['file',$rundirpath.'/'.$host.'.stdout.log','w'], 2=>['file',$rundirpath.'/'.$host.'.stderr.log','w'] ];
					$procs[$key]=['proc'=>proc_open(cmd($childopts,$host),$descspecs,$pipes[$key]), 'instk'=>$instk, 'host'=>$host, 'begts'=>$now];
					$out.='; started a new process on «'.$host.'».'.N;
				} else {
					$out.='; no more hosts to check.'.N;
					$procs[$key]=null;
				}
				eecho(1,$out);
			} else {
				eecho(0,'proc slot '.$key.': been running on «'.$proc['host'].'» for '.ght($now-$proc['begts']).'.'.N);
				$somerun=true;
			}
		}
	}
	$out=$done.'/'.$cinsts.' ('.round(100/$cinsts*$done).'%); elapsed time: '.ght($tet);
	if ($done>0) $out.='; estimated time remaining: '.ght($cinsts*$tet/$done-$tet);
	eecho(1,$out.'.'.N);
	if ($somerun) {
		writestatus($statusjfp,$opts,$instk,$tet,$done,$procs);
		sleep(1);
	} else {
		$rundone=true;
	}
} while (!$rundone);

unlink($instsjfp);
unlink($statusjfp);
unlink($lockfp);
eecho(1,'done :-)'.N);
exit(0);


// functions

function writestatus(&$statusjfp,&$opts,&$instk,&$tet,&$done,&$procs) {
	$f=@fopen($statusjfp,'w');
	if ($f===false) mexit('could not open «'.$statusjfp.'» for writing.'.N,2,true);
	fwrite($f,$opts['poolsize']."\t".$instk."\t".$tet."\t".$done.N);
	foreach ($procs as $proc)
		if (!is_null($proc))
			fwrite($f,$proc['instk'].N);
	fclose($f);
}

function cmd(&$childopts, &$host) {
	return('exec '.__DIR__.'/'.CHILD.$childopts.' '.escapeshellarg($host));
}

function eecho($lev,$msg) {
	global $opts, $msglevs;
	$time=microtime(false);
	$time=explode(' ',$time);
	$time=date('Y-m-d H:i:s',$time[1]).'.'.substr($time[0],2);
	$msg=$time.' '.$msglevs[$lev].': '.$msg;
	if ($lev>=$opts['minmsgimplev']) {
		if ($lev<2)
			echo($msg);
		else
			fwrite(STDERR,$msg);
	}
}

function myq(&$link,$query,$line) {
	try {
		$res=mysqli_query($link,$query);
	}
	catch (Exception $error) {
		mexit('query «'.$query.'» (line '.$line.') failed: '.$error->getMessage().N,3,true);
	}
	// for older php versions < 8, which seem to not catch mysql exceptions
	if ($res===false) mexit('query «'.$query.'» (line '.$line.') failed: '.mysqli_errno($link).': '.mysqli_error($link).'.'.N,3,true);
	return($res);
}

function mexit($msg,$code,$remlock) {
	global $link, $lockfp;
	if (isset($link) && $link!==false) mysqli_close($link);
	if ($remlock && isset($lockfp) && is_file($lockfp)) unlink($lockfp);
	if ($code!=0)
		eecho(3,$msg);
	else
		eecho(1,$msg);
	exit($code);
}

?>