Class: Beaker::SshConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/beaker/ssh_connection.rb

Constant Summary collapse

SUPPORTED_CONNECTION_METHODS = 
%i[ip vmhostname hostname]
RETRYABLE_EXCEPTIONS = 
[
  SocketError,
  Timeout::Error,
  Errno::ETIMEDOUT,
  Errno::EHOSTDOWN,
  Errno::EHOSTUNREACH,
  Errno::ECONNREFUSED,
  Errno::ECONNRESET,
  Errno::ENETUNREACH,
  Net::SSH::Exception,
  Net::SSH::Disconnect,
  Net::SSH::AuthenticationFailed,
  Net::SSH::ChannelRequestFailed,
  Net::SSH::ChannelOpenFailed,
  IOError,
]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name_hash, user = nil, ssh_opts = {}, options = {}) ⇒ SshConnection

Returns a new instance of SshConnection.



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# File 'lib/beaker/ssh_connection.rb', line 28

def initialize name_hash, user = nil, ssh_opts = {}, options = {}
  @vmhostname = name_hash[:vmhostname]
  @ip = name_hash[:ip]
  @hostname = name_hash[:hostname]
  @user = user
  @ssh_opts = ssh_opts
  @logger = options[:logger]
  @options = options
  @ssh_connection_preference = @options[:ssh_connection_preference]
end

Instance Attribute Details

#hostname ⇒ Object

Returns the value of attribute hostname.



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# File 'lib/beaker/ssh_connection.rb', line 7

def hostname
  @hostname
end

#ip ⇒ Object

Returns the value of attribute ip.



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# File 'lib/beaker/ssh_connection.rb', line 7

def ip
  @ip
end

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/beaker/ssh_connection.rb', line 7

def logger
  @logger
end

#ssh_connection_preference ⇒ Object

Returns the value of attribute ssh_connection_preference.



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# File 'lib/beaker/ssh_connection.rb', line 7

def ssh_connection_preference
  @ssh_connection_preference
end

#vmhostname ⇒ Object

Returns the value of attribute vmhostname.



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# File 'lib/beaker/ssh_connection.rb', line 7

def vmhostname
  @vmhostname
end

Class Method Details

.connect(name_hash, user = 'root', ssh_opts = {}, options = {}) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 39

def self.connect name_hash, user = 'root', ssh_opts = {}, options = {}
  connection = new name_hash, user, ssh_opts, options
  connection.connect
  connection
end

Instance Method Details

#close ⇒ Object

closes this SshConnection



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# File 'lib/beaker/ssh_connection.rb', line 131

def close
  begin
    if @ssh and not @ssh.closed?
      @ssh.close
    else
      @logger.warn("ssh.close: connection is already closed, no action needed")
    end
  rescue *RETRYABLE_EXCEPTIONS => e
    @logger.warn "Attemped ssh.close, (caught #{e.class.name} - #{e.message})."
  rescue => e
    @logger.warn "ssh.close threw unexpected Error: #{e.class.name} - #{e.message}.  Shutting down, and re-raising error below"
    @ssh.shutdown!
    raise e
  ensure
    @ssh = nil
    @logger.debug("ssh connection to #{@hostname} has been terminated")
  end
end

#connect(options = {}) ⇒ Object

Connect to the host, creating a new connection if required

Parameters:

  • options (Hash{Symbol=>String}) (defaults to: {}) —

    Options hash to control method conditionals

Options Hash (options):



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# File 'lib/beaker/ssh_connection.rb', line 108

def connect options = {}
  # Try three ways to connect to host (vmhostname, ip, hostname)
  # Try each method in turn until we succeed
  methods = @ssh_connection_preference.dup
  while (not @ssh) && (not methods.empty?)
    if instance_variable_get(:"@#{methods[0]}").nil?
      @logger.warn "Skipping #{methods[0]} method to ssh to host as its value is not set. Refer to https://github.com/puppetlabs/beaker/tree/master/docs/how_to/ssh_connection_preference.md to remove this warning"
    elsif SUPPORTED_CONNECTION_METHODS.include?(methods[0])
      @ssh = connect_block(instance_variable_get(:"@#{methods[0]}"), @user, @ssh_opts, options)
    else
      @logger.warn "Beaker does not support #{methods[0]} to SSH to host, trying next available method."
      @ssh_connection_preference.delete(methods[0])
    end
    methods.shift
  end
  unless @ssh
    @logger.error "Failed to connect to #{@hostname}, attempted #{@ssh_connection_preference.join(', ')}"
    raise RuntimeError, "Cannot connect to #{@hostname}"
  end
  @ssh
end

#connect_block(host, user, ssh_opts, options) ⇒ Net::SSH::Connection::Session

Note:

For more information about Net::SSH library, check out these docs:

Setup and return the ssh connection object

Parameters:

  • host (String) —

    hostname of the machine to connect to

  • user (String) —

    username to login to the host as

  • ssh_opts (Hash{Symbol=>String}) —

    Options hash passed directly to Net::SSH.start method

  • options (Hash{Symbol=>String}) —

    Options hash to control method conditionals

Options Hash (options):

  • :max_connection_tries (Integer) —

    Limit the number of connection start tries to this number (default: 11)

  • :silent (Boolean) —

    Stops logging attempt failure messages if set to true (default: true)

Returns:

  • (Net::SSH::Connection::Session) —

    session returned from Net::SSH.start method



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# File 'lib/beaker/ssh_connection.rb', line 62

def connect_block host, user, ssh_opts, options
  try = 1
  last_wait = 2
  wait = 3
  max_connection_tries = options[:max_connection_tries] || 11
  begin
    @logger.debug "Attempting ssh connection to #{host}, user: #{user}, opts: #{ssh_opts}"

    # Work around net-ssh 6+ incompatibilities
    if ssh_opts.include?(:strict_host_key_checking) && (Net::SSH::Version::CURRENT.major > 5)
      strict_host_key_checking = ssh_opts.delete(:strict_host_key_checking)

      unless ssh_opts[:verify_host_key].is_a?(Symbol)
        ssh_opts[:verify_host_key] ||= strict_host_key_checking ? :always : :never
      end
    end

    # Beaker stringifies options when storing them in a config file.
    # net-ssh raises a fatal error if it does not get a symbol.
    if ssh_opts[:verify_host_key].is_a?(String)
      ssh_opts[:verify_host_key] = ssh_opts[:verify_host_key].to_sym
    end

    Net::SSH.start(host, user, ssh_opts)
  rescue *RETRYABLE_EXCEPTIONS => e
    if try <= max_connection_tries
      @logger.warn "Try #{try} -- Host #{host} unreachable: #{e.class.name} - #{e.message}" unless options[:silent]
      @logger.warn "Trying again in #{wait} seconds" unless options[:silent]

      sleep wait
      (last_wait, wait) = wait, last_wait + wait
      try += 1

      retry
    else
      @logger.warn "Failed to connect to #{host}, after #{try} attempts" unless options[:silent]
      nil
    end
  end
end

#execute(command, options = {}, stdout_callback = nil, stderr_callback = stdout_callback) ⇒ Object

Execute a command on a host, ensuring a connection exists first

Parameters:

  • options (Hash{Symbol=>String}) (defaults to: {}) —

    Options hash to control method conditionals

Options Hash (options):



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# File 'lib/beaker/ssh_connection.rb', line 240

def execute command, options = {}, stdout_callback = nil,
            stderr_callback = stdout_callback
  # ensure that we have a current connection object
  connect(options)
  try_to_execute(command, options, stdout_callback, stderr_callback)
end

#process_stdin_for(channel, stdin) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 282

def process_stdin_for channel, stdin
  # queue stdin data, force it to packets, and signal eof: this
  # triggers action in many remote commands, notably including
  # 'puppet apply'.  It must be sent at some point before the rest
  # of the action.
  channel.send_data stdin.to_s
  channel.process
  channel.eof!
end

#register_exit_code_for(channel, output) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 276

def register_exit_code_for channel, output
  channel.on_request("exit-status") do |_ch, data|
    output.exit_code = data.read_long
  end
end

#register_stderr_for(channel, output, callback = nil) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 266

def register_stderr_for channel, output, callback = nil
  channel.on_extended_data do |_ch, type, data|
    if type == 1
      callback[data] if callback
      output.stderr << data
      output.output << data
    end
  end
end

#register_stdout_for(channel, output, callback = nil) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 258

def register_stdout_for channel, output, callback = nil
  channel.on_data do |_ch, data|
    callback[data] if callback
    output.stdout << data
    output.output << data
  end
end

#request_terminal_for(channel, command) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 247

def request_terminal_for channel, command
  channel.request_pty do |_ch, success|
    if success
      @logger.debug "Allocated a PTY on #{@hostname} for #{command.inspect}"
    else
      raise Net::SSH::Exception.new("FAILED: could not allocate a pty when requested on " +
        "#{@hostname} for #{command.inspect}")
    end
  end
end

#scp_from(source, target, options = {}) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 324

def scp_from source, target, options = {}
  local_opts = options.dup
  local_opts[:recursive] = true if local_opts[:recursive].nil?
  local_opts[:chunk_size] ||= 16384

  result = Result.new(@hostname, [source, target])
  result.stdout = "\n"

  begin
    # This is probably windows with an environment variable so we need to
    # expand it.
    source = self.execute(%{echo "#{source}"}).output.strip.delete('"') if source.include?('%')

    @ssh.scp.download! source, target, local_opts do |_ch, name, sent, total|
      result.stdout << (format("\tcopying %s: %10d/%d\n", name, sent, total))
    end
  rescue => e
    logger.warn "#{e.class} error in scp'ing. Forcing the connection to close, which should " <<
                "raise an error."
    close
  end

  # Setting these values allows reporting via result.log(test_name)
  result.stdout << "  SCP'ed file #{@hostname}:#{source} to #{target}"

  # Net::Scp always returns 0, so just set the return code to 0.
  result.exit_code = 0

  result.finalize!
  result
end

#scp_to(source, target, options = {}) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 292

def scp_to source, target, options = {}
  local_opts = options.dup
  local_opts[:recursive] = File.directory?(source) if local_opts[:recursive].nil?
  local_opts[:chunk_size] ||= 16384

  result = Result.new(@hostname, [source, target])
  result.stdout = "\n"

  begin
    # This is probably windows with an environment variable so we need to
    # expand it.
    target = self.execute(%{echo "#{target}"}).output.strip.delete('"') if target.include?('%')

    @ssh.scp.upload! source, target, local_opts do |_ch, name, sent, total|
      result.stdout << (format("\tcopying %s: %10d/%d\n", name, sent, total))
    end
  rescue => e
    logger.warn "#{e.class} error in scp'ing. Forcing the connection to close, which should " <<
                "raise an error."
    close
  end

  # Setting these values allows reporting via result.log(test_name)
  result.stdout << "  SCP'ed file #{source} to #{@hostname}:#{target}"

  # Net::Scp always returns 0, so just set the return code to 0.
  result.exit_code = 0

  result.finalize!
  return result
end

#try_to_execute(command, options = {}, stdout_callback = nil, stderr_callback = stdout_callback) ⇒ Object 



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# File 'lib/beaker/ssh_connection.rb', line 203

def try_to_execute command, options = {}, stdout_callback = nil, stderr_callback = stdout_callback
  result = Result.new(@hostname, command)

  @ssh.open_channel do |channel|
    request_terminal_for(channel, command) if options[:pty]

    channel.exec(command) do |terminal, success|
      raise Net::SSH::Exception.new("FAILED: to execute command on a new channel on #{@hostname}") unless success

      register_stdout_for terminal, result, stdout_callback
      register_stderr_for terminal, result, stderr_callback
      register_exit_code_for terminal, result

      process_stdin_for(terminal, options[:stdin]) if options[:stdin]
    end
  end

  # Process SSH activity until we stop doing that - which is when our
  # channel is finished with...
  begin
    @ssh.loop
  rescue *RETRYABLE_EXCEPTIONS => e
    # this would indicate that the connection failed post execution, since the channel exec was successful
    @logger.warn "ssh channel on #{@hostname} received exception post command execution #{e.class.name} - #{e.message}"
    close
  end

  result.finalize!
  @logger.last_result = result
  result
end

#wait_for_connection_failure(options = {}, stdout_callback = nil, stderr_callback = stdout_callback) ⇒ Boolean

Wait for the ssh connection to fail, returns true on connection failure and false otherwise

Parameters:

  • options (Hash{Symbol=>String}) (defaults to: {}) —

    Options hash to control method conditionals

  • stdout_callback (IO) (defaults to: nil) —

    An IO stream to send connection stdout to, defaults to nil

  • stderr_callback (IO) (defaults to: stdout_callback) —

    An IO stream to send connection stderr to, defaults to nil

Options Hash (options):

  • :pty (Boolean) —

    Should we request a terminal when attempting to send a command over this connection?

  • :stdin (String) —

    Any input to be sent along with the command

Returns:

  • (Boolean) —

    true if connection failed, false otherwise



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# File 'lib/beaker/ssh_connection.rb', line 158

def wait_for_connection_failure options = {}, stdout_callback = nil, stderr_callback = stdout_callback
  try = 1
  last_wait = 2
  wait = 3
  command = 'echo echo' # can be run on all platforms (I'm looking at you, windows)
  while try < 11
    result = Result.new(@hostname, command)
    begin
      @logger.notify "Waiting for connection failure on #{@hostname} (attempt #{try}, try again in #{wait} second(s))"
      @logger.debug("\n#{@hostname} #{Time.new.strftime('%H:%M:%S')}$ #{command}")
      @ssh.open_channel do |channel|
        request_terminal_for(channel, command) if options[:pty]

        channel.exec(command) do |terminal, success|
          raise Net::SSH::Exception.new("FAILED: to execute command on a new channel on #{@hostname}") unless success

          register_stdout_for terminal, result, stdout_callback
          register_stderr_for terminal, result, stderr_callback
          register_exit_code_for terminal, result

          process_stdin_for(terminal, options[:stdin]) if options[:stdin]
        end
      end
      loop_tries = 0
      # loop is actually loop_forever, so let it try 3 times and then quit instead of endless blocking
      @ssh.loop { loop_tries += 1; loop_tries < 4 }
    rescue *RETRYABLE_EXCEPTIONS => e
      @logger.debug "Connection on #{@hostname} failed as expected (#{e.class.name} - #{e.message})"
      close # this connection is bad, shut it down
      return true
    end
    slept = 0
    stdout_callback.call("sleep #{wait} second(s): ")
    while slept < wait
      sleep slept
      stdout_callback.call('.')
      slept += 1
    end
    stdout_callback.call("\n")
    (last_wait, wait) = wait, last_wait + wait
    try += 1
  end
  false
end