NAME

Rex::Commands::Run - Execute a remote command

DESCRIPTION

With this module you can run a command.

SYNOPSIS

my $output = run "ls -l";
sudo "id";

EXPORTED FUNCTIONS

run($command [, $callback])

run($command_description, command => $command, %options)

This function will execute the given command and returns the output. In scalar context it returns the raw output as is, and in list context it returns the list of output lines. The exit value of the command is stored in the $? variable.

task "uptime", "server01", sub {
  say run "uptime";
  run "uptime", sub {
    my ($stdout, $stderr) = @_;
    my $server = Rex::get_current_connection()->{server};
    say "[$server] $stdout\n";
  };
};

Supported options are:

cwd           => $path
  sets the working directory of the executed command to $path
only_if       => $condition_command
  executes the command only if $condition_command completes successfully
unless        => $condition_command
  executes the command unless $condition_command completes successfully
only_notified => TRUE
  queues the command, to be executed upon notification (see below)
env           => { var1 => $value1, ..., varN => $valueN }
  sets environment variables in the environment of the command
timeout       => value
  sets the timeout for the command to be run
auto_die      => TRUE
  die if the command returns with a non-zero exit code
  it can be set globally via the exec_autodie feature flag
command       => $command_to_run
  if set, run tries to execute the specified command and the first argument
  becomes an identifier for the run block (e.g. to be triggered with notify)
creates       => $file_to_create
  tries to create $file_to_create upon execution
  skips execution if the file already exists

Examples:

If you only want to run a command in special cases, you can queue the command and notify it when you want to run it.

task "prepare", sub {
  run "extract-something",
    command     => "tar -C /foo -xzf /tmp/foo.tgz",
    only_notified => TRUE;

  # some code ...

  notify "run", "extract-something";  # now the command gets executed
};

If you only want to run a command if another command succeeds or fails, you can use only_if or unless option.

run "some-command",
  only_if => "ps -ef | grep -q httpd";   # only run if httpd is running

run "some-other-command",
  unless => "ps -ef | grep -q httpd";    # only run if httpd is not running

If you want to set custom environment variables you can do it like this:

run "my_command",

   env => {
    env_var_1 => "the value for 1",
    env_var_2 => "the value for 2",
  };

If you want to end the command upon receiving a certain output: run "my_command", end_if_matched => qr/PATTERN/;

can_run($command)

This function checks if a command is in the path or is available. You can specify multiple commands, the first command found will be returned.

task "uptime", sub {
  if( my $cmd = can_run("uptime", "downtime") ) {
    say run $cmd;
  }
};

sudo

Run a single command, a code block, or all commands with sudo. You need perl to be available on the remote systems to use sudo.

Depending on your remote sudo configuration, you may need to define a sudo password with sudo_password first:

sudo_password 'my_sudo_password'; # hardcoding

Or alternatively, since Rexfile is plain perl, you can read the password from terminal at the start:

use Term::ReadKey;

print 'I need sudo password: ';
ReadMode('noecho');
sudo_password ReadLine(0);
ReadMode('restore');

Similarly, it is also possible to read it from a secret file, database, etc.

You can turn sudo on globally with:

sudo TRUE; # run _everything_ with sudo

To run only a specific command with sudo, use :

say sudo 'id';                # passing a remote command directly
say sudo { command => 'id' }; # passing anonymous hashref

say sudo { command => 'id', user => 'different' }; # run a single command with sudo as different user

# running a single command with sudo as different user, and `cd` to another directory too
say sudo { command => 'id', user => 'different', cwd => '/home/different' };

Passing an anonymous coderef to sudo allows for running the commands in the sub with sudo:

sudo sub {
    service 'nginx' => 'restart';
    say run 'id';
};

cpanm Rex

perl -MCPAN -e shell
install Rex