class ManageIQ::SSH::Util
Utility wrapper around the net-ssh library.
Constants
- VERSION
The version of the manageiq-ssh-util library
Attributes
The name of the host provided to the constructor.
The options hash passed to the constructor.
The exit status of the ssh command.
The username passed to the constructor.
Public Class Methods
Create and return a ManageIQ::SSH::Util
object. A host, user and password must be specified.
The options
param may contain options that are passed directly to the Net::SSH constructor. By default the :non_interactive option is set to true (meaning it will fail instead of prompting for a password), the :verbose level is set to :warn, and the :use_agent option is set to false.
The :logger option is not set by default. If you do set it, you should NOT use an existing logger, but instead use a separate custom log. If the log already exists, then the option is effectively ignored. Some additional logging will be written to the global ManageIQ
log in debug mode.
The following local options are also supported:
:passwordless_sudo - If set to true, then it is assumed that the sudo command does not require a password, and 'sudo' will automatically be prepended to your command. For sudo that requires a password, set the :su_user and :su_password options instead.
:remember_host - Setting this to true will cause a HostKeyMismatch error to be rescued and retried once after recording the host and key in the known hosts file. By default this is false.
:su_user - If set, ssh commands for that object will be executed via sudo. Do not use if :passwordless_sudo is set to true.
:su_password - When used in conjunction with :su_user, the password sent to the command prompt when asked for as the result of using the su command. Do not use if :passwordless_sudo is set to true.
# File lib/manageiq/ssh/util.rb, line 55 def initialize(host, user, password = nil, options = {}) @host = host @user = user @password = password @options = { :remember_host => false, :verbose => :warn, :non_interactive => true, :use_agent => false }.merge(options) @options[:password] = password if password # Pull our custom keys out of the hash because the SSH initializer will complain @remember_host = @options.delete(:remember_host) @su_user = @options.delete(:su_user) @su_password = @options.delete(:su_password) @passwordless_sudo = @options.delete(:passwordless_sudo) # Obsolete, delete if passed in @options.delete(:authentication_prompt_delay) end
Shortcut method that creates and yields a ManageIQ::SSH::Util
object, with the host
, remote_user
and remote_password
options passed in as the first three params to the constructor, while the su_user
and su_password
parameters automatically set the corresponding :su_user and :su_password options. The remaining options are passed normally.
This method is functionally identical to the following code, except that it yields itself (and nil).
ManageIQ::SSH::Util.new(host, remote_user, remote_password, {:su_user => su_user, :su_password => su_password})
# File lib/manageiq/ssh/util.rb, line 346 def self.shell_with_su(host, remote_user, remote_password, su_user, su_password, options = {}) options[:su_user], options[:su_password] = su_user, su_password ssu = new(host, remote_user, remote_password, options) yield(ssu, nil) end
Public Instance Methods
Execute the remote cmd
via ssh. This is automatically handled via channels on the ssh session so that various states can be checked, stored and logged independently and asynchronously.
If the :passwordless_sudo option was set to true in the constructor then the cmd
will automatically be prepended with “sudo”.
If specified, the data collection will stop the first time a done_string
argument is encountered at the end of a line. In practice you would typically specify a newline character.
If present, the stdin
argument will be sent to the underlying command as input for those commands that expect it, e.g. tee.
If a signal is received, the command returns any sort of non-zero error status, or if any stderr output is encountered then an exception is raised.
# File lib/manageiq/ssh/util.rb, line 137 def exec(cmd, done_string = nil, stdin = nil) error_buffer = "" output_buffer = "" status = 0 signal = nil header = "#{self.class}##{__method__}" # If passwordless sudo is true then prepend every command with 'sudo'. cmd = 'sudo ' + cmd if @passwordless_sudo run_session do |ssh| ssh.open_channel do |channel| channel.exec(cmd) do |chan, success| raise "#{header} - Could not execute command #{cmd}" unless success $log&.debug("#{header} - Command: #{cmd} started.") if stdin.present? chan.send_data(stdin) chan.eof! end channel.on_data do |_channel, data| $log&.debug("#{header} - STDOUT: #{data}") output_buffer << data data.each_line { |l| return output_buffer if done_string == l.chomp } unless done_string.nil? end channel.on_extended_data do |_channel, _type, data| $log&.debug("#{header} - STDERR: #{data}") error_buffer << data end channel.on_request('exit-status') do |_channel, data| status = data.read_long || 0 $log&.debug("#{header} - STATUS: #{status}") end channel.on_request('exit-signal') do |_channel, data| signal = data.read_string $log&.debug("#{header} - SIGNAL: #{signal}") end channel.on_eof do |_channel| $log&.debug("#{header} - EOF RECEIVED") end channel.on_close do |_channel| $log&.debug("#{header} - Command: #{cmd}, exit status: #{status}") if signal.present? || status.nonzero? || error_buffer.present? raise "#{header} - Command '#{cmd}' exited with signal #{signal}" if signal.present? raise "#{header} - Command '#{cmd}' exited with status #{status}" if status.nonzero? raise "#{header} - Command '#{cmd}' failed: #{error_buffer}" end return output_buffer end end # exec end # open_channel ssh.loop end # run_session end
Returns whether or not the remote filename
exists.
# File lib/manageiq/ssh/util.rb, line 394 def file_exists?(filename) shell_exec("test -f #{filename}") rescue false else true end
Copies the remote file_path
to a local temporary file, and then yields or returns a filehandle to the local temporary file.
# File lib/manageiq/ssh/util.rb, line 377 def file_open(file_path, perm = 'r') if block_given? Tempfile.open('miqscvmm') do |tf| tf.close get_file(file_path, tf.path) File.open(tf.path, perm) { |f| yield(f) } end else tf = Tempfile.open('miqscvmm') tf.close get_file(file_path, tf.path) File.open(tf.path, perm) end end
Download the contents of the remote from
file to the local to
file. Some messages will be written to the global ManageIQ
log in debug mode.
Note that the returned data is normally a Net::SFTP::Operations::Download object. If you want to store the file contents in memory, pass an IO object as the second argument.
# File lib/manageiq/ssh/util.rb, line 94 def get_file(from, to) run_session do |ssh| $log&.debug("#{self.class}##{__method__} - Copying file #{host}:#{from} to #{to}.") data = ssh.sftp.download!(from, to) $log&.debug("#{self.class}##{__method__} - Copying of #{host}:#{from} to #{to}, complete.") return data end end
Upload the contents of local file to
to remote location path
. You may use the specified content
instead of the content of the local file.
At least one of the content
or path
parameters must be specified or an error is raised.
# File lib/manageiq/ssh/util.rb, line 109 def put_file(to, content = nil, path = nil) raise ArgumentError, "Need to provide either content or path" if content.nil? && path.nil? run_session do |ssh| content ||= IO.binread(path) $log&.debug("#{self.class}##{__method__} - Copying file to #{@host}:#{to}.") ssh.sftp.file.open(to, 'wb') { |f| f.write(content) } $log&.debug("#{self.class}##{__method__} - Copying of file to #{@host}:#{to}, complete.") end end
Returns a boolean value indicating whether or not the remember_host
option is set. This tells Net::SSH to record the host and key in the known hosts file, so that subsequent connections will remember them.
# File lib/manageiq/ssh/util.rb, line 83 def remember_host? !!@remember_host end
This method creates and yields an ssh object. If the :remember_host option was set to true, it will record this host and key in the known hosts file and retry once.
# File lib/manageiq/ssh/util.rb, line 406 def run_session first_try = true begin Net::SSH.start(@host, @user, @options) do |ssh| yield(ssh) end rescue Net::SSH::HostKeyMismatch => err if remember_host? && first_try # Save fingerprint and try again first_try = false err.remember_host! retry else # Re-raise error raise err end end end
Executes the provided cmd
using the exec or suexec method, depending on whether or not the :su_user option is set. The done_string
and stdin
arguments are passed along to the appropriate method as well.
In the case of suexec, escape characters are automatically removed from the final output.
# File lib/manageiq/ssh/util.rb, line 363 def shell_exec(cmd, done_string = nil, _shell = nil, stdin = nil) return exec(cmd, done_string, stdin) if @su_user.nil? ret = suexec(cmd, done_string, stdin) # Remove escape character from the end of the line ret.sub!(/\e$/, '') ret end
Execute the remote cmd
via ssh. This is nearly identical to the exec method, and is used only if the :su_user and :su_password options are set in the constructor.
The difference between this method and the exec method are primarily in the underlying handling of the sudo user and sudo password parameters, i.e creating a PTY session and dealing with prompts. From the perspective of an end user they are essentially identical.
# File lib/manageiq/ssh/util.rb, line 208 def suexec(cmd_str, done_string = nil, stdin = nil) error_buffer = "" output_buffer = "" prompt = "" cmd_rx = "" status = 0 signal = nil state = :initial header = "#{self.class}##{__method__}" run_session do |ssh| temp_cmd_file(cmd_str) do |cmd| ssh.open_channel do |channel| # now we request a "pty" (i.e. interactive) session so we can send data back and forth if needed. # it WILL NOT WORK without this, and it has to be done before any call to exec. channel.request_pty(:chars_wide => 256) do |_channel, success| raise "Could not obtain pty (i.e. an interactive ssh session)" unless success end channel.on_data do |channel, data| $log&.debug("#{header} - state: [#{state.inspect}] STDOUT: [#{data.hex_dump.chomp}]") if state == :prompt # Detect the common prompts # someuser@somehost ... $ rootuser@somehost ... # [someuser@somehost ...] $ [rootuser@somehost ...] # prompt = data if data =~ /^\[*[\w\-\.]+@[\w\-\.]+.+\]*[\#\$]\s*$/ output_buffer << data unless done_string.nil? data.each_line { |l| return output_buffer if done_string == l.chomp } end if output_buffer[-prompt.length, prompt.length] == prompt return output_buffer[0..(output_buffer.length - prompt.length)] end end if state == :command_sent cmd_rx << data state = :prompt if cmd_rx == "#{cmd}\r\n" end if state == :password_sent prompt << data.lstrip if data.strip =~ /\#/ $log&.debug("#{header} - Superuser Prompt detected: sending command #{cmd}") channel.send_data("#{cmd}\n") state = :command_sent end end if state == :initial prompt << data.lstrip if data.strip =~ /[Pp]assword:/ prompt = "" $log&.debug("#{header} - Password Prompt detected: sending su password") channel.send_data("#{@su_password}\n") state = :password_sent end end end channel.on_extended_data do |_channel, _type, data| $log&.debug("#{header} - STDERR: #{data}") error_buffer << data end channel.on_request('exit-status') do |_channel, data| status = data.read_long $log&.debug("#{header} - STATUS: #{status}") end channel.on_request('exit-signal') do |_channel, data| signal = data.read_string $log&.debug("#{header} - SIGNAL: #{signal}") end channel.on_eof do |_channel| $log&.debug("#{header} - EOF RECEIVED") end channel.on_close do |_channel| error_buffer << prompt if [:initial, :password_sent].include?(state) $log&.debug("#{header} - Command: #{cmd}, exit status: #{status}") raise "#{header} - Command #{cmd}, exited with signal #{signal}" unless signal.nil? unless status.zero? raise "#{header} - Command #{cmd}, exited with status #{status}" if error_buffer.empty? raise "#{header} - Command #{cmd} failed: #{error_buffer}, status: #{status}" end return output_buffer end $log&.debug("#{header} - Command: [#{cmd_str}] started.") su_command = @su_user == 'root' ? "su -l\n" : "su -l #{@su_user}\n" channel.exec(su_command) do |chan, success| raise "#{header} - Could not execute command #{cmd}" unless success if stdin.present? chan.send_data(stdin) chan.eof! end end end end ssh.loop end end
Creates a local temporary file under /var/tmp with cmd
as its contents. The tempfile name is the name of the command with “miq-” prepended and “.sh” appended to the end.
The end result is a string meant to be run via the suexec method. For example:
“chmod 700 /var/tmp/miq-foo.sh; /var/tmp/miq-foo.sh; rm -f /var/tmp/miq-foo.sh
# File lib/manageiq/ssh/util.rb, line 322 def temp_cmd_file(cmd) temp_remote_script = Tempfile.new(["miq-", ".sh"], "/var/tmp") temp_file = temp_remote_script.path begin temp_remote_script.write(cmd) temp_remote_script.close remote_cmd = "chmod 700 #{temp_file}; #{temp_file}; rm -f #{temp_file}" yield(remote_cmd) ensure temp_remote_script.close! end end