Module: Teleport::Util

Extended by:
Util
Included in:
Infer, Infer::Apt, Install, Main, Util
Defined in:
lib/teleport/util.rb

Overview

Helper module for executing commands and printing stuff out.

The general idea is to only print commands that are actually interesting. For example, mkdir_if_necessary won’t print anything if the directory already exists. That way we can scan teleport output and see what changes were made without getting lost in repetitive commands that had no actual effect.

Defined Under Namespace

Classes: RunError

Constant Summary collapse

RESET = 
"\e[0m"
RED = 
"\e[1;37;41m"
GREEN = 
"\e[1;37;42m"
YELLOW = 
"\e[1;37;43m"
BLUE = 
"\e[1;37;44m"
MAGENTA = 
"\e[1;37;45m"
CYAN = 
"\e[1;37;46m"

Instance Method Summary collapse

Instance Method Details

A nice printout in green.



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# File 'lib/teleport/util.rb', line 253

def banner(s, color = GREEN)
  s = "#{s} ".ljust(72, " ")      
  $stderr.write "#{color}[#{Time.new.strftime('%H:%M:%S')}] #{s}#{RESET}\n"
  $stderr.flush
end

#chmod(file, mode) ⇒ Object

Chmod file to a new mode.



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# File 'lib/teleport/util.rb', line 212

def chmod(file, mode)
  if File.stat(file).mode != mode
    FileUtils.chmod(mode, file, :verbose => verbose?)      
  end
end

#chown(file, user) ⇒ Object

Chown file to be owned by user.



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# File 'lib/teleport/util.rb', line 200

def chown(file, user)
  user = user.to_s
  # who is the current owner?
  @uids ||= {}
  @uids[user] ||= Etc.getpwnam(user).uid
  uid = @uids[user]
  if File.stat(file).uid != uid
    run "chown #{user}:#{user} '#{file}'"        
  end
end

#copy_metadata(src, dst) ⇒ Object

Copy perms and timestamps from src file to dst.



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# File 'lib/teleport/util.rb', line 151

def copy_metadata(src, dst)
  stat = File.stat(src)
  File.chmod(stat.mode, dst)
  File.utime(stat.atime, stat.mtime, dst)
end

#copy_perms(src, dst) ⇒ Object

Copy perms from src file to dst.



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# File 'lib/teleport/util.rb', line 145

def copy_perms(src, dst)
  stat = File.stat(src)
  File.chmod(stat.mode, dst)
end

#cp(src, dst, owner = nil, mode = nil) ⇒ Object

Copy file or dir from src to dst. Optionally, set the mode and owner of dst.



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# File 'lib/teleport/util.rb', line 159

def cp(src, dst, owner = nil, mode = nil)
  FileUtils.cp_r(src, dst, :preserve => true, :verbose => verbose?)
  if owner && !File.symlink?(dst)      
    chown(dst, owner) 
  end
  if mode
    chmod(dst, mode)
  end
end

#cp_if_necessary(src, dst, owner = nil, mode = nil) ⇒ Object

Copy file or dir from src to dst, but ONLY if dst doesn’t exist or has different contents than src. Optionally, set the mode and owner of dst.



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# File 'lib/teleport/util.rb', line 179

def cp_if_necessary(src, dst, owner = nil, mode = nil)
  if !File.exists?(dst) || different?(src, dst)
    cp(src, dst, owner, mode)
    true
  end
end

#cp_with_mkdir(src, dst, owner = nil, mode = nil) ⇒ Object

Copy file or dir from src to dst, but create the dst directory first if necessary. Optionally, set the mode and owner of dst.



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# File 'lib/teleport/util.rb', line 171

def cp_with_mkdir(src, dst, owner = nil, mode = nil)
  mkdir_if_necessary(File.dirname(dst))
  cp(src, dst, owner, mode)
end

#different?(a, b) ⇒ Boolean

Are two files different?

Returns:

  • (Boolean) 


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# File 'lib/teleport/util.rb', line 140

def different?(a, b)
  !FileUtils.compare_file(a, b)
end

#fails?(command) ⇒ Boolean

Run a command, return true if it fails.

Returns:

  • (Boolean) 


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# File 'lib/teleport/util.rb', line 105

def fails?(command)
  !succeeds?(command)
end

#fatal(msg) ⇒ Object

Print a fatal error in red, then exit.



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# File 'lib/teleport/util.rb', line 265

def fatal(msg)
  banner(msg, RED)
  exit(1)
end

#gem_if_necessary(gem) ⇒ Object

Install gem if necessary.



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# File 'lib/teleport/util.rb', line 289

def gem_if_necessary(gem)
  grep = args = nil
  if gem =~ /(.*)-(\d+\.\d+\.\d+)$/
    gem, version = $1, $2
    grep = "^#{gem}.*#{version}"
    args = " --version #{version}"
  else
    grep = "^#{gem}"
  end
  if fails?("gem list #{gem} | grep '#{grep}'")
    banner "#{gem}..."
    run "gem install #{gem} #{args} --no-rdoc --no-ri"
    return true
  end
  false
end

#gem_version(name) ⇒ Object

Returns the newest currently installed version of the named gem or false if the gem is not installed



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# File 'lib/teleport/util.rb', line 308

def gem_version(name)
  spec_out = `gem specification #{name} 2> /dev/null`
  if !spec_out.empty?
    spec = Gem::Specification.from_yaml(spec_out)
    spec.version
  end
end

#ln(src, dst) ⇒ Object

Create a symlink from src to dst.



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# File 'lib/teleport/util.rb', line 232

def ln(src, dst)
  FileUtils.ln_sf(src, dst, :verbose => verbose?)
end

#ln_if_necessary(src, dst) ⇒ Object

Create a symlink from src to dst, but only if it hasn’t already been created.



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# File 'lib/teleport/util.rb', line 238

def ln_if_necessary(src, dst)
  ln = false
  if !File.symlink?(dst)
    ln = true
  elsif File.readlink(dst) != src
    rm(dst)
    ln = true
  end
  if ln
    ln(src, dst)
    true
  end
end

#md5sum(path) ⇒ Object

Calculate the md5 checksum for a file



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# File 'lib/teleport/util.rb', line 333

def md5sum(path)
  digest, buf = Digest::MD5.new, ""
  File.open(path) do |f|
    while f.read(4096, buf)
      digest.update(buf)
    end
  end
  digest.hexdigest
end

#mkdir(dir, owner = nil, mode = nil) ⇒ Object

Like mkdir -p. Optionally, set the owner and mode.



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# File 'lib/teleport/util.rb', line 121

def mkdir(dir, owner = nil, mode = nil)
  FileUtils.mkdir_p(dir, :verbose => verbose?)
  chmod(dir, mode) if mode
  chown(dir, owner) if owner
end

#mkdir_if_necessary(dir, owner = nil, mode = nil) ⇒ Object

mkdir only if the directory doesn’t already exist. Optionally, set the owner and mode.



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# File 'lib/teleport/util.rb', line 129

def mkdir_if_necessary(dir, owner = nil, mode = nil)
  mkdir(dir, owner, mode) if !(File.exists?(dir) || File.symlink?(dir))
end

#mv(src, dst) ⇒ Object

Move src to dst. Because this uses FileUtils, it works even if dst is on a different partition.



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# File 'lib/teleport/util.rb', line 188

def mv(src, dst)
  FileUtils.mv(src, dst, :verbose => verbose?)
end

#mv_with_mkdir(src, dst) ⇒ Object

Move src to dst, but create the dst directory first if necessary.



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# File 'lib/teleport/util.rb', line 194

def mv_with_mkdir(src, dst)
  mkdir_if_necessary(File.dirname(dst))
  mv(src, dst)
end

#package_if_necessary(pkg) ⇒ Object

Install pkg if necessary.



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# File 'lib/teleport/util.rb', line 281

def package_if_necessary(pkg)
  if !package_is_installed?(pkg)
    banner "#{pkg}..."
    run "apt-get -y install #{pkg}"
  end
end

#package_is_installed?(pkg) ⇒ Boolean

Returns true if the pkg is installed.

Returns:

  • (Boolean) 


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# File 'lib/teleport/util.rb', line 276

def package_is_installed?(pkg)
  succeeds?("dpkg-query -f='${Status}' -W #{pkg} 2>&1 | grep 'install ok installed'")    
end

#process_by_pid?(pidfile) ⇒ Boolean

Returns true if the pidfile exists and that process id exists as well.

Returns:

  • (Boolean) 


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# File 'lib/teleport/util.rb', line 318

def process_by_pid?(pidfile)
  begin
    if File.exists?(pidfile)
      pid = File.read(pidfile).to_i
      if pid != 0
        Process.kill(0, pid)
        return true
      end
    end
  rescue Errno::ENOENT, Errno::ESRCH
  end
  false
end

#rm(file) ⇒ Object

rm a file



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# File 'lib/teleport/util.rb', line 219

def rm(file)
  FileUtils.rm(file, :force => true, :verbose => verbose?)
end

#rm_and_mkdir(dir) ⇒ Object

rm a dir and recreate it.



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# File 'lib/teleport/util.rb', line 134

def rm_and_mkdir(dir)
  raise "don't do this" if dir == ""
  run "rm -rf #{dir} && mkdir -p #{dir}"
end

#rm_if_necessary(file) ⇒ Object

rm a file, but only if it exists.



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# File 'lib/teleport/util.rb', line 224

def rm_if_necessary(file)
  if File.exists?(file)
    rm(file)
    true
  end
end

#run(command, args = nil) ⇒ Object

Run a command, raise an error upon failure. Output goes to $stdout/$stderr.



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# File 'lib/teleport/util.rb', line 40

def run(command, args = nil)
  line = nil
  if args
    args = args.map(&:to_s)
    line = "#{command} #{args.join(" ")}"
    vputs line
    system(command, *args)
  else
    line = command
    vputs line
    system(command)
  end
  if $? != 0
    if $?.termsig == Signal.list["INT"]
      raise "#{line} interrupted"
    end
    raise RunError, "#{line} failed : #{$?.to_i / 256}"
  end
end

#run_capture(command, *args) ⇒ Object

Run a command, raise an error upon failure. The output is captured as a string and returned.



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# File 'lib/teleport/util.rb', line 62

def run_capture(command, *args)
  if !args.empty?
    args = args.flatten.map { |i| shell_escape(i) }.join(" ")
    command = "#{command} #{args}"
  end
  result = `#{command}`
  if $? != 0
    if $?.termsig == Signal.list["INT"]
      raise "#{command} interrupted"
    end
    raise RunError, "#{command} failed : #{$?.to_i / 256} #{result.inspect}"
  end
  result
end

#run_capture_lines(command, *args) ⇒ Object

Run a command and split the result into lines, raise an error upon failure. The output is captured as an array of strings and returned.



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# File 'lib/teleport/util.rb', line 80

def run_capture_lines(command, *args)
  run_capture(command, args).split("\n")
end

#run_quietly(command, *args) ⇒ Object

Run a command but don’t send any output to $stdout/$stderr.



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# File 'lib/teleport/util.rb', line 85

def run_quietly(command, *args)
  if !args.empty?
    args = args.flatten.map { |i| shell_escape(i) }.join(" ")
    command = "#{command} #{args}"
  end
  run("#{command} > /dev/null 2> /dev/null")
end

#run_verbose! ⇒ Object

Make all commands echo before running.



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# File 'lib/teleport/util.rb', line 34

def run_verbose!
  @run_verbose = true
end

#shell(commands) ⇒ Object

Run one or several commands, separate by newlines.



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# File 'lib/teleport/util.rb', line 94

def shell(commands)
  commands.split("\n").each { |i| run(i) }
end

#shell_escape(s) ⇒ Object

Escape some text for the shell and enclose it in single quotes if necessary.



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# File 'lib/teleport/util.rb', line 111

def shell_escape(s)
  s = s.to_s
  if s !~ /^[0-9A-Za-z+,.\/:=@_-]+$/
    s = s.gsub("'") { "'\\''" }
    s = "'#{s}'"
  end
  s
end

#succeeds?(command) ⇒ Boolean

Run a command, return true if it succeeds.

Returns:

  • (Boolean) 


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# File 'lib/teleport/util.rb', line 99

def succeeds?(command)
  system("#{command} > /dev/null 2> /dev/null")
  $? == 0
end

#warning(msg) ⇒ Object

Print a warning in yellow.



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# File 'lib/teleport/util.rb', line 260

def warning(msg)
  banner("Warning: #{msg}", YELLOW)
end

#whoami ⇒ Object

Who owns this process?



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# File 'lib/teleport/util.rb', line 271

def whoami
  @whoami ||= Etc.getpwuid(Process.uid).name
end