Module: Net::SSH::Multi::SessionActions

Defined in:
lib/cute/net-ssh.rb

Instance Method Summary collapse

Instance Method Details

#exec!(command, &block) ⇒ Hash

Monkey patch that adds the exec! method. It executes a command on multiple hosts capturing their associated output (stdout, stderr and status). It blocks until the command finishes returning the resulting output as a Hash. It uses a logger for debugging purposes.

Example

session.exec!("date") #=> {"node3"=>{:stdout=>"Wed Mar 11 12:38:11 UTC 2015", :status=>0},
                      #    "node1"=>{:stdout=>"Wed Mar 11 12:38:11 UTC 2015", :status=>0}, ...}

session.exec!("cmd") #=> {"node4"=>{:stderr=>"bash: cmd: command not found", :status=>127},
                     #    "node3"=>{:stderr=>"bash: cmd: command not found", :status=>127}, ...}

Returns:

  • (Hash) —

    result Hash stdout, stderr and status of executed commands

See Also:



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# File 'lib/cute/net-ssh.rb', line 97

def exec!(command, &block)

  Multi.logger.debug "SSH execution: #{command}"
  results = {}

  main =open_channel do |channel|
    channel.exec(command) do |ch, success|
      raise "could not execute command: #{command.inspect} (#{ch[:host]})" unless success
      Multi.logger.debug("Executing #{command} on [#{ch.connection.host}]")

      results[ch.connection.host] ||= {}

      channel.on_data do |c, data|
        if block
          block.call(c, :stdout, data)
        else
          results[c.connection.host][:stdout] ||= ""
          results[c.connection.host][:stdout] += data.strip
          Multi.logger.debug("[#{c.connection.host}] #{data.strip}")
        end
      end
      channel.on_extended_data do |c, _type, data|
        if block
          block.call(c, :stderr, data)
        else
          results[c.connection.host][:stderr] ||= ""
          results[c.connection.host][:stderr] += data.strip
          Multi.logger.debug("[#{c.connection.host}] #{data.strip}")
        end
      end
      channel.on_request("exit-status") do |c, data|
        c[:exit_status] = data.read_long
        results[c.connection.host][:status] = c[:exit_status]
        if c[:exit_status] != 0
          Multi.logger.info("execution of '#{command}' on #{c.connection.host}
                          failed with return status #{c[:exit_status]}")
          if results[c.connection.host][:stdout]
            Multi.logger.info("--- stdout dump ---")
            Multi.logger.info(results[c.connection.host][:stdout])
          end

          if  results[c.connection.host][:stderr]
            Multi.logger.info("--stderr dump ---")
            Multi.logger.info(results[c.connection.host][:stderr])
          end
        end
      end
      # need to decide severity level if the command fails
    end
  end
  main.wait # we have to wait the channel otherwise we will have void results
  return results
end