Add basic bash completion script and framework for others

README.md

@@ -88,6 +88,22 @@ Here are the keys that vmfloaty currently supports:
 - url
   + String
 
+### Tab Completion
+
+There is a basic completion script for Bash (and possibly other shells) included with the gem in the [extras/completions](https://github.com/briancain/vmfloaty/blob/master/extras/completions) folder. To activate, that file simply needs to be sourced somehow in your shell profile.
+
+For convenience, the path to the completion script for the currently active version of the gem can be found with the `floaty completion` subcommand. This makes it easy to add the completion script to your profile like so:
+
+```bash
+source $(floaty completion --shell bash)
+```
+
+If you are running on macOS and use Homebrew's `bash-completion` formula, you can symlink the script to `/usr/local/etc/bash_completion.d/floaty` and it will be sourced automatically:
+
+```bash
+ln -s $(floaty completion --shell bash) /usr/local/etc/bash_completion.d/floaty
+```
+
 ## vmpooler API
 
 This cli tool uses the [vmpooler API](https://github.com/puppetlabs/vmpooler/blob/master/API.md).

extras/completions/floaty.bash

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+_vmfloaty()
+{
+  local cur prev subcommands template_subcommands hostname_subcommands
+  COMPREPLY=()
+  cur="${COMP_WORDS[COMP_CWORD]}"
+  prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+  subcommands="delete get help list modify query revert snapshot ssh status summary token"
+  template_subcommands="get ssh"
+  hostname_subcommands="delete modify query revert snapshot"
+
+  if [[ $cur == -* ]] ; then
+    # TODO: option completion
+    COMPREPLY=()
+  elif [[ $template_subcommands =~ (^| )$prev($| ) ]] ; then
+    if [[ -z "$_vmfloaty_avail_templates" ]] ; then
+      _vmfloaty_avail_templates=$(floaty list 2>/dev/null)
+    fi
+
+    COMPREPLY=( $(compgen -W "${_vmfloaty_avail_templates}" -- "${cur}") )
+  elif [[ $hostname_subcommands =~ (^| )$prev($| ) ]] ; then
+    _vmfloaty_active_hostnames=$(floaty list --active 2>/dev/null | grep '^-' | cut -d' ' -f2)
+    COMPREPLY=( $(compgen -W "${_vmfloaty_active_hostnames}" -- "${cur}") )
+  else
+    COMPREPLY=( $(compgen -W "${subcommands}" -- "${cur}") )
+  fi
+}
+complete -F _vmfloaty floaty

lib/vmfloaty.rb

@@ -562,6 +562,32 @@ class Vmfloaty
       end
     end
 
+    command :completion do |c|
+      c.syntax = 'floaty completion [options]'
+      c.summary = 'Outputs path to completion script'
+      c.description = Utils.strip_heredoc(<<-EOF)
+        Outputs path to a completion script for the specified shell (or 'bash' if not specified). This makes it easy to add the completion script to your profile:
+
+          source $(floaty completion --shell bash)
+
+        This subcommand will exit non-zero with an error message if no completion script is available for the requested shell.
+      EOF
+      c.example 'Gets path to bash tab completion script', 'floaty completion --shell bash'
+      c.option '--shell STRING', String, 'Shell to request completion script for'
+      c.action do |args, options|
+        shell = (options.shell || 'bash').downcase.strip
+        completion_file = File.expand_path(File.join('..', '..', 'extras', 'completions', "floaty.#{shell}"), __FILE__)
+
+        if File.exist?(completion_file)
+          puts completion_file
+          exit 0
+        else
+          STDERR.puts "Could not find completion file for '#{shell}': No such file #{completion_file}"
+          exit 1
+        end
+      end
+    end
+
     run!
   end
 end

lib/vmfloaty/utils.rb

@@ -113,4 +113,12 @@ class Utils
     puts
     puts message.colorize(status['status']['ok'] ? :default : :red)
   end
+
+  # Adapted from ActiveSupport
+  def self.strip_heredoc(str)
+    min_indent = str.scan(/^[ \t]*(?=\S)/).min
+    min_indent_size = min_indent.nil? ? 0 : min_indent.size
+
+    str.gsub(/^[ \t]{#{min_indent_size}}/, '')
+  end
 end

vmfloaty.gemspec

@@ -12,7 +12,7 @@ Gem::Specification.new do |s|
   s.summary = 'CLI application to interface with vmpooler'
 
   s.executables = ['floaty']
-  s.files = Dir['LICENSE', 'README.md', 'lib/**/*']
+  s.files = Dir['LICENSE', 'README.md', 'lib/**/*', 'extras/**/*']
   s.test_files = Dir['spec/**/*']
   s.require_path = 'lib'