/ 
Rex-1.13.2
River stage two • 22 direct dependents • 22 total dependents
/ rex

NAME

rex - execute tasks defined in a Rexfile

DESCRIPTION

The rex script can be used to execute tasks defined in a Rexfile from the command line.

SYNOPSIS

bash# rex -h                      # Show usage
bash# rex -T                      # List tasks
bash# rex uname                   # Run the 'uname' task
bash# rex -H server[01..10] uname # Run the 'uname' task on all the specified hosts
bash# rex -G production uname     # Run 'uname' on hosts on the 'production' hostgroup
bash# rex deploy --gracefully     # Pass '--gracefully' to the 'deploy' task

USAGE

  rex [<options>] [-H <host>] [-G <group>] <task> [<task-options>]
  rex -T[m|y|v] [<string>]

  -b     Run batch
  -e     Run the given code fragment
  -E     Execute a task on the given environment
  -G|-g  Execute a task on the given server groups
  -H     Execute a task on the given hosts (space delimited)
  -z     Execute a task on hosts from this command's output

  -K     Public key file for the ssh connection
  -P     Private key file for the ssh connection
  -p     Password for the ssh connection
  -u     Username for the ssh connection

  -d     Show debug output
  -ddd   Show more debug output (includes profiling output)
  -m     Monochrome output: no colors
  -o     Output format
  -q     Quiet mode: no log output
  -qw    Quiet mode: only output warnings and errors
  -Q     Really quiet: output nothing

  -T     List tasks
  -Ta    List all tasks, including hidden
  -Tm    List tasks in machine-readable format
  -Tv    List tasks verbosely
  -Ty    List tasks in YAML format

  -c     Turn cache ON
  -C     Turn cache OFF
  -f     Use this file instead of Rexfile
  -F     Force: disregard lock file
  -h     Display this help message
  -M     Load this module instead of Rexfile
  -O     Pass additional options, like CMDB path
  -s     Use sudo for every command
  -S     Password for sudo
  -t     Number of threads to use (aka 'parallelism' param)
  -v     Display (R)?ex version

Rexfile

When you run rex it reads the file Rexfile in the current working directory. A Rexfile consists of 2 major parts: Configuration and Task Definitions.

Configuration

Simple Authentication

user "bruce";
password "batman";
pass_auth;

Key Authentication

private_key "/path/to/your/private/key.file";
public_key "/path/to/your/public/key.file";

Define Logging

logging to_file => "rex.log";
logging to_syslog => "local0";

Group your servers

Rex gives you the ability to define groups of servers. Groups can be defined the Rexfile:

group "frontends" => "frontend01", "frontend02", "frontend03", "frontend04", "frontend[05..09]";

Groups can also be defined in a server.ini file:

[frontends]
frontend[01..04]

Other Configuration

timeout 10;    # ssh timeout
parallelism 2; # execute tasks in parallel

Defining tasks

A basic task looks like this:

 # task description
 desc "This task tells you how long since the server was rebooted";

 # task definition
 task "shortname", sub {
     say run "uptime";
 };

You can also set a default server group:

desc "This is a long description of a task";
task "shortname", group => "frontends", sub {
    say run "uptime";
};

TAB COMPLETION

Tab completion scripts are provided for Bash and Zsh in the share directory. They provide completions for the available CLI options, hosts, groups, environments and tasks.