# # Copyright (c) 2007-2008 RightScale Inc # # Permission is hereby granted, free of charge, to any person obtaining # a copy of this software and associated documentation files (the # "Software"), to deal in the Software without restriction, including # without limitation the rights to use, copy, modify, merge, publish, # distribute, sublicense, and/or sell copies of the Software, and to # permit persons to whom the Software is furnished to do so, subject to # the following conditions: # # The above copyright notice and this permission notice shall be # included in all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # require "net/https" require "uri" require "time" require "logger" module RightHttpConnection #:nodoc: end module Rightscale =begin rdoc HttpConnection maintains a persistent HTTP connection to a remote server. Each instance maintains its own unique connection to the HTTP server. HttpConnection makes a best effort to receive a proper HTTP response from the server, although it does not guarantee that this response contains a HTTP Success code. On low-level errors (TCP/IP errors) HttpConnection invokes a reconnect and retry algorithm. Note that although each HttpConnection object has its own connection to the HTTP server, error handling is shared across all connections to a server. For example, if there are three connections to www.somehttpserver.com, a timeout error on one of those connections will cause all three connections to break and reconnect. A connection will not break and reconnect, however, unless a request becomes active on it within a certain amount of time after the error (as specified by HTTP_CONNECTION_RETRY_DELAY). An idle connection will not break even if other connections to the same server experience errors. A HttpConnection will retry a request a certain number of times (as defined by HTTP_CONNNECTION_RETRY_COUNT). If all the retries fail, an exception is thrown and all HttpConnections associated with a server enter a probationary period defined by HTTP_CONNECTION_RETRY_DELAY. If the user makes a new request subsequent to entering probation, the request will fail immediately with the same exception thrown on probation entry. This is so that if the HTTP server has gone down, not every subsequent request must wait for a connect timeout before failing. After the probation period expires, the internal state of the HttpConnection is reset and subsequent requests have the full number of potential reconnects and retries available to them. =end class HttpConnection # Number of times to retry the request after encountering the first error HTTP_CONNECTION_RETRY_COUNT = 3 # Throw a Timeout::Error if a connection isn't established within this number of seconds HTTP_CONNECTION_OPEN_TIMEOUT = 5 # Throw a Timeout::Error if no data have been read on this connnection within this number of seconds HTTP_CONNECTION_READ_TIMEOUT = 120 # Length of the post-error probationary period during which all requests will fail HTTP_CONNECTION_RETRY_DELAY = 15 #-------------------- # class methods #-------------------- # @@params = {} @@params[:http_connection_retry_count] = HTTP_CONNECTION_RETRY_COUNT @@params[:http_connection_open_timeout] = HTTP_CONNECTION_OPEN_TIMEOUT @@params[:http_connection_read_timeout] = HTTP_CONNECTION_READ_TIMEOUT @@params[:http_connection_retry_delay] = HTTP_CONNECTION_RETRY_DELAY # Query the global (class-level) parameters: # # :user_agent => 'www.HostName.com' # String to report as HTTP User agent # :ca_file => 'path_to_file' # Path to a CA certification file in PEM format. The file can contain several CA certificates. If this parameter isn't set, HTTPS certs won't be verified. # :logger => Logger object # If omitted, HttpConnection logs to STDOUT # :exception => Exception to raise # The type of exception to raise # # if a request repeatedly fails. RuntimeError is raised if this parameter is omitted. # :http_connection_retry_count # by default == Rightscale::HttpConnection::HTTP_CONNECTION_RETRY_COUNT # :http_connection_open_timeout # by default == Rightscale::HttpConnection::HTTP_CONNECTION_OPEN_TIMEOUT # :http_connection_read_timeout # by default == Rightscale::HttpConnection::HTTP_CONNECTION_READ_TIMEOUT # :http_connection_retry_delay # by default == Rightscale::HttpConnection::HTTP_CONNECTION_RETRY_DELAY def self.params @@params end # Set the global (class-level) parameters def self.params=(params) @@params = params end #------------------ # instance methods #------------------ attr_accessor :http attr_accessor :server attr_accessor :params # see @@params attr_accessor :logger # Params hash: # :user_agent => 'www.HostName.com' # String to report as HTTP User agent # :ca_file => 'path_to_file' # A path of a CA certification file in PEM format. The file can contain several CA certificates. # :logger => Logger object # If omitted, HttpConnection logs to STDOUT # :exception => Exception to raise # The type of exception to raise if a request repeatedly fails. RuntimeError is raised if this parameter is omitted. # :http_connection_retry_count # by default == Rightscale::HttpConnection.params[:http_connection_retry_count] # :http_connection_open_timeout # by default == Rightscale::HttpConnection.params[:http_connection_open_timeout] # :http_connection_read_timeout # by default == Rightscale::HttpConnection.params[:http_connection_read_timeout] # :http_connection_retry_delay # by default == Rightscale::HttpConnection.params[:http_connection_retry_delay] # def initialize(params={}) @params = params @params[:http_connection_retry_count] ||= @@params[:http_connection_retry_count] @params[:http_connection_open_timeout] ||= @@params[:http_connection_open_timeout] @params[:http_connection_read_timeout] ||= @@params[:http_connection_read_timeout] @params[:http_connection_retry_delay] ||= @@params[:http_connection_retry_delay] @http = nil @server = nil @logger = get_param(:logger) || (RAILS_DEFAULT_LOGGER if defined?(RAILS_DEFAULT_LOGGER)) unless @logger @logger = Logger.new(STDOUT) @logger.level = Logger::INFO end end def get_param(name) @params[name] || @@params[name] end # Query for the maximum size (in bytes) of a single read from the underlying # socket. For bulk transfer, especially over fast links, this is value is # critical to performance. def socket_read_size? Net::BufferedIO.socket_read_size? end # Set the maximum size (in bytes) of a single read from the underlying # socket. For bulk transfer, especially over fast links, this is value is # critical to performance. def socket_read_size=(newsize) Net::BufferedIO.socket_read_size=(newsize) end # Query for the maximum size (in bytes) of a single read from local data # sources like files. This is important, for example, in a streaming PUT of a # large buffer. def local_read_size? Net::HTTPGenericRequest.local_read_size? end # Set the maximum size (in bytes) of a single read from local data # sources like files. This can be used to tune the performance of, for example, a streaming PUT of a # large buffer. def local_read_size=(newsize) Net::HTTPGenericRequest.local_read_size=(newsize) end private #-------------- # Retry state - Keep track of errors on a per-server basis #-------------- @@state = {} # retry state indexed by server: consecutive error count, error time, and error @@eof = {} # number of consecutive errors seen for server, 0 all is ok def error_count @@state[@server] ? @@state[@server][:count] : 0 end # time of last error for server, nil if all is ok def error_time @@state[@server] && @@state[@server][:time] end # message for last error for server, "" if all is ok def error_message @@state[@server] ? @@state[@server][:message] : "" end # add an error for a server def error_add(message) @@state[@server] = {:count => error_count+1, :time => Time.now, :message => message} end # reset the error state for a server (i.e. a request succeeded) def error_reset @@state.delete(@server) end # Error message stuff... def banana_message return "#{@server} temporarily unavailable: (#{error_message})" end def err_header return "#{self.class.name} :" end # Adds new EOF timestamp. # Returns the number of seconds to wait before new conection retry: # 0.5, 1, 2, 4, 8 def add_eof (@@eof[@server] ||= []).unshift Time.now 0.25 * 2 ** @@eof[@server].size end # Returns first EOF timestamp or nul if have no EOFs being tracked. def eof_time @@eof[@server] && @@eof[@server].last end # Returns true if we are receiving EOFs during last @params[:http_connection_retry_delay] seconds # and there were no successful response from server def raise_on_eof_exception? self.class.blank?(@@eof[@server]) ? false : ((Time.now.to_i-@params[:http_connection_retry_delay]) > @@eof[@server].last.to_i) end # Reset a list of EOFs for this server. # This is being called when we have got an successful response from server. def eof_reset @@eof.delete(@server) end # Detects if an object is 'streamable' - can we read from it, and can we know the size? def setup_streaming(request) if (request.body && request.body.respond_to?(:read)) body = request.body request.content_length = body.respond_to?(:lstat) ? body.lstat.size : body.size request.body_stream = request.body true end end def get_fileptr_offset(request_params) request_params[:request].body.pos rescue Exception => e # Probably caught this because the body doesn't support the pos() method, like if it is a socket. # Just return 0 and get on with life. 0 end def reset_fileptr_offset(request, offset = 0) if (request.body_stream && request.body_stream.respond_to?(:pos)) begin request.body_stream.pos = offset rescue Exception => e @logger.warn("Failed file pointer reset; aborting HTTP retries." + " -- #{err_header} #{e.inspect}") raise e end end end # Start a fresh connection. The object closes any existing connection and # opens a new one. def start(request_params) # close the previous if exists finish # create new connection @server = request_params[:server] @port = request_params[:port] @protocol = request_params[:protocol] @logger.debug("Opening new #{@protocol.upcase} connection to #@server:#@port") @http = Net::HTTP.new(@server, @port) @http.open_timeout = @params[:http_connection_open_timeout] @http.read_timeout = @params[:http_connection_read_timeout] if @protocol == 'https' verifyCallbackProc = Proc.new { |ok, x509_store_ctx| code = x509_store_ctx.error msg = x509_store_ctx.error_string #debugger @logger.warn("##### #{@server} certificate verify failed: #{msg}") unless code == 0 true } @http.use_ssl = true @http.verify_mode = OpenSSL::SSL::VERIFY_NONE # Looks like Ruby 1.9 defaults to VERIFY_PEER which doesn't work well ca_file = get_param(:ca_file) if ca_file @http.verify_mode = OpenSSL::SSL::VERIFY_PEER @http.verify_callback = verifyCallbackProc @http.ca_file = ca_file end end # open connection @http.start end public =begin rdoc Send HTTP request to server request_params hash: :server => 'www.HostName.com' # Hostname or IP address of HTTP server :port => '80' # Port of HTTP server :protocol => 'https' # http and https are supported on any port :request => 'requeststring' # Fully-formed HTTP request to make Raises RuntimeError, Interrupt, and params[:exception] (if specified in new). =end def request(request_params, &block) # We save the offset here so that if we need to retry, we can return the file pointer to its initial position mypos = get_fileptr_offset(request_params) loop do # if we are inside a delay between retries: no requests this time! if error_count > @params[:http_connection_retry_count] && error_time + @params[:http_connection_retry_delay] > Time.now # store the message (otherwise it will be lost after error_reset and # we will raise an exception with an empty text) banana_message_text = banana_message @logger.warn("#{err_header} re-raising same error: #{banana_message_text} " + "-- error count: #{error_count}, error age: #{Time.now.to_i - error_time.to_i}") exception = get_param(:exception) || RuntimeError raise exception.new(banana_message_text) end # try to connect server(if connection does not exist) and get response data begin request_params[:protocol] ||= (request_params[:port] == 443 ? 'https' : 'http') request = request_params[:request] request['User-Agent'] = get_param(:user_agent) || '' # (re)open connection to server if none exists or params has changed unless @http && @http.started? && @server == request_params[:server] && @port == request_params[:port] && @protocol == request_params[:protocol] start(request_params) end # Detect if the body is a streamable object like a file or socket. If so, stream that # bad boy. setup_streaming(request) response = @http.request(request, &block) error_reset eof_reset return response # We treat EOF errors and the timeout/network errors differently. Both # are tracked in different statistics blocks. Note below that EOF # errors will sleep for a certain (exponentially increasing) period. # Other errors don't sleep because there is already an inherent delay # in them; connect and read timeouts (for example) have already # 'slept'. It is still not clear which way we should treat errors # like RST and resolution failures. For now, there is no additional # delay for these errors although this may change in the future. # EOFError means the server closed the connection on us. rescue EOFError => e @logger.debug("#{err_header} server #{@server} closed connection") @http = nil # if we have waited long enough - raise an exception... if raise_on_eof_exception? exception = get_param(:exception) || RuntimeError @logger.warn("#{err_header} raising #{exception} due to permanent EOF being received from #{@server}, error age: #{Time.now.to_i - eof_time.to_i}") raise exception.new("Permanent EOF is being received from #{@server}.") else # ... else just sleep a bit before new retry sleep(add_eof) # We will be retrying the request, so reset the file pointer reset_fileptr_offset(request, mypos) end rescue Exception => e # See comment at bottom for the list of errors seen... @http = nil # if ctrl+c is pressed - we have to reraise exception to terminate proggy if e.is_a?(Interrupt) && !(e.is_a?(Errno::ETIMEDOUT) || e.is_a?(Timeout::Error)) @logger.debug("#{err_header} request to server #{@server} interrupted by ctrl-c") raise elsif e.is_a?(ArgumentError) && e.message.include?('wrong number of arguments (5 for 4)') # seems our net_fix patch was overriden... exception = get_param(:exception) || RuntimeError raise exception.new('incompatible Net::HTTP monkey-patch') end # oops - we got a banana: log it error_add(e.message) @logger.warn("#{err_header} request failure count: #{error_count}, exception: #{e.inspect}") # We will be retrying the request, so reset the file pointer reset_fileptr_offset(request, mypos) end end end def finish(reason = '') if @http && @http.started? reason = ", reason: '#{reason}'" unless self.class.blank?(reason) @logger.debug("Closing #{@http.use_ssl? ? 'HTTPS' : 'HTTP'} connection to #{@http.address}:#{@http.port}#{reason}") @http.finish end end def close(reason='') finish end def self.blank?(obj) case obj when NilClass, FalseClass true when TrueClass, Numeric false when Array, Hash obj.empty? when String obj.empty? || obj.strip.empty? else # "", " ", nil, [], and {} are blank if obj.respond_to?(:empty?) && obj.respond_to?(:strip) obj.empty? or obj.strip.empty? elsif obj.respond_to?(:empty?) obj.empty? else !obj end end end # Errors received during testing: # # # # # # # # # # # # # # # end end