class ForemanRemoteExecutionCore::ScriptRunner
Constants
- EXPECTED_POWER_ACTION_MESSAGES
Attributes
execution_timeout_interval[R]
Public Class Methods
new(options)
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Calls superclass method
# File lib/foreman_remote_execution_core/script_runner.rb, line 15 def initialize(options) super() @host = options.fetch(:hostname) @script = options.fetch(:script) @ssh_user = options.fetch(:ssh_user, 'root') @ssh_port = options.fetch(:ssh_port, 22) @effective_user = options.fetch(:effective_user, nil) @effective_user_method = options.fetch(:effective_user_method, 'sudo') @host_public_key = options.fetch(:host_public_key, nil) @verify_host = options.fetch(:verify_host, nil) @execution_timeout_interval = options.fetch(:execution_timeout_interval, nil) @client_private_key_file = settings.fetch(:ssh_identity_key_file) @local_working_dir = options.fetch(:local_working_dir, settings.fetch(:local_working_dir)) @remote_working_dir = options.fetch(:remote_working_dir, settings.fetch(:remote_working_dir)) end
Public Instance Methods
close()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 110 def close @session.close if @session && !@session.closed? end
kill()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 63 def kill if @session run_sync("pkill -f #{remote_command_file('script')}") else logger.debug('connection closed') end rescue => e publish_exception('Unexpected error', e, false) end
publish_data(data, type)
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Calls superclass method
# File lib/foreman_remote_execution_core/script_runner.rb, line 114 def publish_data(data, type) super(data.force_encoding('UTF-8'), type) end
refresh()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 52 def refresh return if @session.nil? with_retries do with_disconnect_handling do @session.process(0) end end ensure check_expecting_disconnect end
start()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 32 def start remote_script = cp_script_to_remote output_path = File.join(File.dirname(remote_script), 'output') exit_code_path = File.join(File.dirname(remote_script), 'exit_code') # pipe the output to tee while capturing the exit code in a file script = " | sh <<WRAPPER | (#{su_prefix}#{remote_script} < /dev/null; echo \\$?>#{exit_code_path}) | /usr/bin/tee #{output_path} | exit \\$(cat #{exit_code_path}) | WRAPPER ".gsub(/^\s+\| /, '') logger.debug("executing script:\n#{script.lines.map { |line| " | #{line}" }.join}") run_async(script) rescue => e logger.error("error while initalizing command #{e.class} #{e.message}:\n #{e.backtrace.join("\n")}") publish_exception('Error initializing command', e) end
timeout()
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Calls superclass method
# File lib/foreman_remote_execution_core/script_runner.rb, line 73 def timeout @logger.debug('job timed out') super end
timeout_interval()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 78 def timeout_interval execution_timeout_interval end
with_disconnect_handling() { || ... }
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# File lib/foreman_remote_execution_core/script_runner.rb, line 98 def with_disconnect_handling yield rescue Net::SSH::Disconnect => e @session.shutdown! check_expecting_disconnect if @expecting_disconnect publish_exit_status(0) else publish_exception('Unexpected disconnect', e) end end
with_retries() { || ... }
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# File lib/foreman_remote_execution_core/script_runner.rb, line 82 def with_retries tries = 0 begin yield rescue => e logger.error("Unexpected error: #{e.class} #{e.message}\n #{e.backtrace.join("\n")}") tries += 1 if tries <= MAX_PROCESS_RETRIES logger.error('Retrying') retry else publish_exception('Unexpected error', e) end end end
Private Instance Methods
available_authentication_methods()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 305 def available_authentication_methods methods = %w(publickey) # Always use pubkey auth as fallback if settings[:kerberos_auth] if defined? Net::SSH::Kerberos methods << 'gssapi-with-mic' else @logger.warn('Kerberos authentication requested but not available') end end methods end
check_expecting_disconnect()
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when a remote server disconnects, it's hard to tell if it was on purpose (when calling reboot) or it's an error. When it's expected, we expect the script to produce 'restart host' as its last command output
# File lib/foreman_remote_execution_core/script_runner.rb, line 297 def check_expecting_disconnect last_output = @continuous_output.raw_outputs.find { |d| d['output_type'] == 'stdout' } return unless last_output if EXPECTED_POWER_ACTION_MESSAGES.any? { |message| last_output['output'] =~ /^#{message}/ } @expecting_disconnect = true end end
cp_script_to_remote()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 249 def cp_script_to_remote upload_data(sanitize_script(@script), remote_command_file('script'), 555) end
ensure_local_directory(path)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 240 def ensure_local_directory(path) if File.exist?(path) raise "#{path} expected to be a directory" unless File.directory?(path) else FileUtils.mkdir_p(path) end return path end
ensure_remote_directory(path)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 276 def ensure_remote_directory(path) exit_code, _output, err = run_sync("mkdir -p #{path}") if exit_code != 0 raise "Unable to create directory on remote system #{path}: exit code: #{exit_code}\n #{err}" end end
local_command_dir()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 224 def local_command_dir File.join(@local_working_dir, 'foreman-proxy', "foreman-ssh-cmd-#{@id}") end
local_command_file(filename)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 228 def local_command_file(filename) File.join(local_command_dir, filename) end
prepare_known_hosts()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 216 def prepare_known_hosts path = local_command_file('known_hosts') if @host_public_key write_command_file_locally('known_hosts', "#{@host} #{@host_public_key}") end return path end
remote_command_dir()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 232 def remote_command_dir File.join(@remote_working_dir, "foreman-ssh-cmd-#{id}") end
remote_command_file(filename)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 236 def remote_command_file(filename) File.join(remote_command_dir, filename) end
run_async(command)
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Initiates run of the remote command and yields the data when available. The yielding doesn't happen automatically, but as part of calling the `refresh` method.
# File lib/foreman_remote_execution_core/script_runner.rb, line 148 def run_async(command) raise 'Async command already in progress' if @started @started = false session.open_channel do |channel| channel.request_pty channel.on_data { |ch, data| publish_data(data, 'stdout') } channel.on_extended_data { |ch, type, data| publish_data(data, 'stderr') } # standard exit of the command channel.on_request('exit-status') { |ch, data| publish_exit_status(data.read_long) } # on signal: sending the signal value (such as 'TERM') channel.on_request('exit-signal') do |ch, data| publish_exit_status(data.read_string) ch.close # wait for the channel to finish so that we know at the end # that the session is inactive ch.wait end channel.exec(command) do |ch, success| @started = true raise('Error initializing command') unless success end end session.process(0) until @started return true end
run_sync(command, stdin = nil)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 174 def run_sync(command, stdin = nil) stdout = '' stderr = '' exit_status = nil started = false channel = session.open_channel do |ch| ch.on_data { |_, data| stdout.concat(data) } ch.on_extended_data { |_, _, data| stderr.concat(data) } ch.on_request('exit-status') { |_, data| exit_status = data.read_long } # Send data to stdin if we have some ch.send_data(stdin) unless stdin.nil? # on signal: sending the signal value (such as 'TERM') ch.on_request('exit-signal') do |_, data| exit_status = data.read_string ch.close ch.wait end ch.exec command do |_, success| raise 'could not execute command' unless success started = true end end session.process(0) until started # Closing the channel without sending any data gives us SIGPIPE channel.close unless stdin.nil? channel.wait return exit_status, stdout, stderr end
sanitize_script(script)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 283 def sanitize_script(script) script.tr("\r", '') end
session()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 120 def session @session ||= begin @logger.debug("opening session to #{@ssh_user}@#{@host}") Net::SSH.start(@host, @ssh_user, ssh_options) end end
settings()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 141 def settings ForemanRemoteExecutionCore.settings end
ssh_options()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 127 def ssh_options ssh_options = {} ssh_options[:port] = @ssh_port if @ssh_port ssh_options[:keys] = [@client_private_key_file] if @client_private_key_file ssh_options[:user_known_hosts_file] = @known_hosts_file if @known_hosts_file ssh_options[:keys_only] = true # if the host public key is contained in the known_hosts_file, # verify it, otherwise, if missing, import it and continue ssh_options[:paranoid] = true ssh_options[:auth_methods] = available_authentication_methods ssh_options[:user_known_hosts_file] = prepare_known_hosts if @host_public_key return ssh_options end
su_prefix()
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# File lib/foreman_remote_execution_core/script_runner.rb, line 204 def su_prefix return if @effective_user.nil? || @effective_user == @ssh_user case @effective_user_method when 'sudo' "sudo -n -u #{@effective_user} " when 'su' "su - #{@effective_user} -c " else raise "effective_user_method ''#{@effective_user_method}'' not supported" end end
upload_data(data, path, permissions = 555)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 253 def upload_data(data, path, permissions = 555) ensure_remote_directory File.dirname(path) # We use tee here to pipe stdin coming from ssh to a file at $path, while silencing its output # This is used to write to $path with elevated permissions, solutions using cat and output redirection # would not work, because the redirection would happen in the non-elevated shell. command = "tee '#{path}' >/dev/null && chmod '#{permissions}' '#{path}'" @logger.debug("Sending data to #{path} on remote host:\n#{data}") status, _out, err = run_sync(command, data) @logger.warn("Output on stderr while uploading #{path}:\n#{err}") unless err.empty? if status != 0 raise "Unable to upload file to #{path} on remote system: exit code: #{status}" end path end
upload_file(local_path, remote_path)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 270 def upload_file(local_path, remote_path) mode = File.stat(local_path).mode.to_s(8)[-3..-1] @logger.debug('Uploading local file: #{local_path} as #{remote_path} with #{mode} permissions') upload_data(File.read(local_path), remote_path, mode) end
write_command_file_locally(filename, content)
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# File lib/foreman_remote_execution_core/script_runner.rb, line 287 def write_command_file_locally(filename, content) path = local_command_file(filename) ensure_local_directory(File.dirname(path)) File.write(path, content) return path end