Rex::Commands::Run - Execute a remote command
With this module you can run a command.
my $output = run 'ls -l'; sudo 'id';
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.
$command
$?
run 'uptime'; my $output = run 'uptime'; my @output_lines = run 'uptime';
It supports optional callbacks as subroutine reference, which will receive the command's output sent to STDOUT and STDERR.
STDOUT
STDERR
run 'uptime', sub { my ( $stdout, $stderr ) = @_; my $server = Rex::get_current_connection()->{server}; say "[$server] $stdout\n"; };
It also takes further options in a form of a hash. Supported options are:
Sets the working directory of the executed command to $path.
$path
Executes the command only if $condition_command returns success.
$condition_command
Executes the command if $condition_command returns failure.
Queues the command to be executed later upon notification.
Sets environment variables for the given command.
Sets the timeout for the command to be run.
Die if the command returns with an exit code indicating failure. It can be set globally via the exec_autodie feature flag.
If present, Rex will execute $command_to_run, and treat the first arugment as an identifier for the given run() block (e.g. to be triggered with notify).
$command_to_run
run()
Tries to create $file_to_create upon execution, and skips execution if the file already exists.
$file_to_create
Calls $callback subroutine reference for each line of the command's output, passing the line as an argument.
$callback
End execution early as soon as $pattern is detected in the command's output.
$pattern
Examples:
If you only want to run a command if another command succeeds or fails, use the only_if or unless options.
only_if
unless
run 'some-command', only_if => 'pgrep httpd'; # only run if httpd is running run 'some-other-command', unless => 'pgrep httpd'; # only run if httpd is _not_ running
If you want to set custom environment variables you can do it like this:
run 'my_command', env => { env_var_1 => 'the value for 1', env_var_2 => 'the value for 2', };
If you want to end the command upon receiving a certain output:
run 'my_command', end_if_matched => qr{$pattern};
This form will execute $command with the given $arguments pass as an array reference. All arguments will be quoted by Rex with Net::OpenSSH::ShellQuoter-quoter()> according to the managed host's shell.
$arguments
Net::OpenSSH::ShellQuoter-
run 'ls', [ '-l', '-t', '-r', '-a' ]; run 'ls', [ '/tmp', '-l' ], auto_die => TRUE;
If you only want to run a command in certain cases, you can queue the command and notify it to trigger its execution.
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
This function checks if a command is available in the path. It accepts a list of commands, and returns the full path to the first command found.
task 'uptime', sub { if ( my $cmd = can_run( 'uptime', 'downtime' ) ) { say run $cmd; } };
Run a single command, a code block, or all commands with sudo. You need perl to be available on the remote systems to use sudo.
sudo
Depending on your remote sudo configuration, you may need to define a sudo password with sudo_password first:
sudo_password 'my_sudo_password'; # hardcoding
Or alternatively, since Rexfile is plain perl, you can read the password from terminal at the start:
use Term::ReadKey; print 'I need sudo password: '; ReadMode('noecho'); sudo_password ReadLine(0); ReadMode('restore');
Similarly, it is also possible to read it from a secret file, database, etc.
You can turn sudo on globally with:
sudo TRUE; # run _everything_ with sudo
To run only a specific command with sudo, use :
say sudo 'id'; # passing a remote command directly say sudo { command => 'id' }; # passing anonymous hashref say sudo { command => 'id', user => 'different' }; # run a single command with sudo as different user
To run multiple commands with sudo, either use an anonymous code reference directly:
sudo sub { service 'nginx' => 'restart'; say run 'id'; };
or pass it via command (optionally along a different user):
command
sudo { command => sub { say run 'id'; say run 'pwd', cwd => '/home/different'; }, user => 'different', };
Note that some users receive the error sudo: sorry, you must have a tty to run sudo. In this case you have to disable requiretty for this user. You can do this in your sudoers file with the following code:
sudo: sorry, you must have a tty to run sudo
requiretty
Defaults:$username !requiretty
To install Rex, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Rex
CPAN shell
perl -MCPAN -e shell install Rex
For more information on module installation, please visit the detailed CPAN module installation guide.