mirror of
https://github.com/percona/percona-toolkit.git
synced 2025-09-28 00:21:56 +00:00
Large refactoring of pt-agent to make the initial start up experience more reliable, i.e. just run and wait till a good config makes everything else work.
This commit is contained in:
Daniel Nichter
182
lib/Daemon.pm
182
lib/Daemon.pm
@@ -31,47 +31,24 @@ use Fcntl qw(:DEFAULT);
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sub new {
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my ($class, %args) = @_;
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my $self = {
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log_file => $args{log_file},
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pid_file => $args{pid_file},
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daemonize => $args{daemonize},
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log_file => $args{log_file},
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pid_file => $args{pid_file},
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daemonize => $args{daemonize},
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force_log_file => $args{force_log_file},
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};
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return bless $self, $class;
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}
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sub run {
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my ($self, %args) = @_;
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my $pid ||= $PID;
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my $pid_file ||= $self->{pid_file};
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my $log_file ||= $self->{log_file};
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my ($self) = @_;
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if ( $self->{daemonize} ) {
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$self->_daemonize(
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pid => $pid,
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pid_file => $pid_file,
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log_file => $log_file,
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);
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}
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elsif ( $pid_file ) {
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$self->_make_pid_file(
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pid => $pid,
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pid_file => $pid_file,
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);
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$self->{pid_file_owner} = $pid;
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}
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else {
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PTDEBUG && _d('Neither --daemonize nor --pid was specified');
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}
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# Just for brevity:
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my $daemonize = $self->{daemonize};
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my $pid_file = $self->{pid_file};
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my $log_file = $self->{log_file};
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my $force_log_file = $self->{force_log_file};
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return;
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}
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sub _daemonize {
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my ($self, %args) = @_;
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my $pid = $args{pid};
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my $pid_file = $args{pid_file};
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my $log_file = $args{log_file};
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PTDEBUG && _d('Daemonizing');
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PTDEBUG && _d('Starting daemon');
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# First obtain the pid file or die trying. NOTE: we're still the parent
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# so the pid file will contain the parent's pid at first. This is done
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@@ -82,93 +59,90 @@ sub _daemonize {
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if ( $pid_file ) {
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eval {
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$self->_make_pid_file(
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pid => $pid, # parent's pid
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pid => $PID, # parent's pid
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pid_file => $pid_file,
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);
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};
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if ( $EVAL_ERROR ) {
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die "Cannot daemonize: $EVAL_ERROR\n";
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die "$EVAL_ERROR\n" if $EVAL_ERROR;
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if ( !$daemonize ) {
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# We're not going to daemonize, so mark the pid file as owned
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# by the parent. Otherwise, daemonize/fork and the child will
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# take ownership.
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$self->{pid_file_owner} = $PID; # parent's pid
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}
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}
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# Fork, exit parent, continue as child process.
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defined (my $child_pid = fork())
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or die "Cannot fork: $OS_ERROR";
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if ( $child_pid ) {
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# I'm the parent.
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PTDEBUG && _d('Forked child', $child_pid);
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exit 0;
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if ( $daemonize ) {
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defined (my $child_pid = fork()) or die "Cannot fork: $OS_ERROR";
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if ( $child_pid ) {
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# I'm the parent.
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PTDEBUG && _d('Forked child', $child_pid);
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exit 0;
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}
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# I'm the child.
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POSIX::setsid() or die "Cannot start a new session: $OS_ERROR";
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chdir '/' or die "Cannot chdir to /: $OS_ERROR";
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# Now update the pid file to contain the child's pid.
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if ( $pid_file ) {
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$self->_update_pid_file(
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pid => $PID, # child's pid
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pid_file => $pid_file,
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);
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$self->{pid_file_owner} = $PID;
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}
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}
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# I'm the child. First, open the log file, if any. Do this first
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# so that all daemon/child output goes there.
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# We used to only reopen STDIN to /dev/null if it's a tty because
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# otherwise it may be a pipe, in which case we didn't want to break
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# it. However, Perl -t is not reliable. This is true and false on
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# various boxes even when the same code is ran, or it depends on if
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# the code is ran via cron, Jenkins, etc. Since there should be no
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# sane reason to `foo | pt-tool --daemonize` for a tool that reads
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# STDIN, we now just always close STDIN.
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PTDEBUG && _d('Redirecting STDIN to /dev/null');
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close STDIN;
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open STDIN, '/dev/null'
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or die "Cannot reopen STDIN to /dev/null: $OS_ERROR";
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if ( $log_file ) {
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PTDEBUG && _d('Redirecting STDOUT and STDERR to', $log_file);
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close STDOUT;
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open STDOUT, '>>', $log_file
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or die "Cannot open log file $log_file: $OS_ERROR";
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# If we don't close STDERR explicitly, then prove Daemon.t fails
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# because STDERR gets written before STDOUT even though we print
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# to STDOUT first in the tests. I don't know why, but it's probably
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# best that we just explicitly close all fds before reopening them.
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close STDERR;
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open STDERR, ">&STDOUT"
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or die "Cannot dupe STDERR to STDOUT: $OS_ERROR";
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}
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else {
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if ( -t STDOUT ) {
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PTDEBUG && _d('No log file and STDOUT is a terminal;',
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'redirecting to /dev/null');
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if ( $daemonize || $force_log_file ) {
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# We used to only reopen STDIN to /dev/null if it's a tty because
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# otherwise it may be a pipe, in which case we didn't want to break
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# it. However, Perl -t is not reliable. This is true and false on
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# various boxes even when the same code is ran, or it depends on if
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# the code is ran via cron, Jenkins, etc. Since there should be no
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# sane reason to `foo | pt-tool --daemonize` for a tool that reads
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# STDIN, we now just always close STDIN.
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PTDEBUG && _d('Redirecting STDIN to /dev/null');
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close STDIN;
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open STDIN, '/dev/null'
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or die "Cannot reopen STDIN to /dev/null: $OS_ERROR";
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if ( $log_file ) {
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PTDEBUG && _d('Redirecting STDOUT and STDERR to', $log_file);
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close STDOUT;
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open STDOUT, '>', '/dev/null'
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or die "Cannot reopen STDOUT to /dev/null: $OS_ERROR";
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}
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if ( -t STDERR ) {
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PTDEBUG && _d('No log file and STDERR is a terminal;',
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'redirecting to /dev/null');
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open STDOUT, '>>', $log_file
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or die "Cannot open log file $log_file: $OS_ERROR";
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# If we don't close STDERR explicitly, then prove Daemon.t fails
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# because STDERR gets written before STDOUT even though we print
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# to STDOUT first in the tests. I don't know why, but it's probably
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# best that we just explicitly close all fds before reopening them.
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close STDERR;
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open STDERR, '>', '/dev/null'
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or die "Cannot reopen STDERR to /dev/null: $OS_ERROR";
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open STDERR, ">&STDOUT"
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or die "Cannot dupe STDERR to STDOUT: $OS_ERROR";
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}
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else {
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if ( -t STDOUT ) {
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PTDEBUG && _d('No log file and STDOUT is a terminal;',
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'redirecting to /dev/null');
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close STDOUT;
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open STDOUT, '>', '/dev/null'
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or die "Cannot reopen STDOUT to /dev/null: $OS_ERROR";
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}
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if ( -t STDERR ) {
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PTDEBUG && _d('No log file and STDERR is a terminal;',
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'redirecting to /dev/null');
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close STDERR;
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open STDERR, '>', '/dev/null'
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or die "Cannot reopen STDERR to /dev/null: $OS_ERROR";
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}
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}
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}
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# XXX: I don't think we need this?
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# $OUTPUT_AUTOFLUSH = 1;
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PTDEBUG && _d('I am child', $PID);
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# Now update the pid file to contain the correct pid, i.e. the child's pid.
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if ( $pid_file ) {
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$self->_update_pid_file(
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pid => $PID, # child's pid
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pid_file => $pid_file,
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);
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$self->{pid_file_owner} = $PID;
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}
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# Last: other misc daemon stuff.
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POSIX::setsid() or die "Cannot start a new session: $OS_ERROR";
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chdir '/' or die "Cannot chdir to /: $OS_ERROR";
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# We're not fully daemonized.
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PTDEBUG && _d('Daemon running');
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return;
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}
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# Call this for non-daemonized scripts to make a PID file.
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sub _make_pid_file {
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my ($self, %args) = @_;
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