WARN TCPServer Error: Address already in use - bind(2) in linux EC2 and Heroku servers - ruby

Question

[2013-01-29 09:17:50] INFO WEBrick 1.3.1
[2013-01-29 09:17:50] INFO ruby 1.8.7 (2012-10-12) [i386-linux]
[2013-01-29 09:17:50] WARN TCPServer Error: Address already in use - bind(2)
[2013-01-29 09:17:50] INFO WEBrick::HTTPServer#start: pid=4107 port=8080
When I run the file attached below in linux I get the error described. I tried all possible command and strategies online to listen to processes (including rogue) and kill them. I did this in lots of ports. No luck.
As soon as I run the script in Mac OS and it works. Nevertheless I have to mount it on a server and clients have to communicate with it. It happens on every instance of amazon ec2 and on heroku. I have seen this error one too many times and spend many hours trying to fix it. I configured the security group of ec2 instances and still did not work. I am beyond desperate. At this point I have to think that the problem must be WEBrick itself or something in my code.
require 'webrick'
require 'uri'
require 'net/http'
$own_address = 8080
class AuctionInfo
# The representation is a hash mapping item names to [highest_bidder, highest_bid, end_time]
def initialize
#data = {}
end
def new_item(item, endTime)
#data[item] = ["UNKNOWN", 0, endTime]
end
def bid(item, bid, client)
if #data.has_key?(item)
endTime = #data[item][2]
if #data[item][1].to_i < bid.to_i and Time.new.to_i < endTime.to_i
#data[item] = [client, bid, endTime]
end
end
end
def get_status(item)
if #data.has_key?(item)
return #data[item][0]
end
end
def winner(item)
if #data.has_key?(item)
if #data[item][2].to_i + 1 <= Time.new.to_i
return #data[item][0]
else return "UNKNOWN"
end
end
end
def reset
#data = {}
end
def has_item(item)
return #data.has_key?(item)
end
def get_data
return {}.replace(#data)
end
end
class StartAuctionServlet < WEBrick::HTTPServlet::AbstractServlet
def initialize(server, data)
#data = data
end
def do_POST(request, response)
if request.query['name'] and request.query['end_time']
#data.new_item(request.query['name'], request.query['end_time'].to_i)
end
response.status = 200
end
alias_method :do_GET, :do_POST
end
class BidServlet < WEBrick::HTTPServlet::AbstractServlet
def initialize(server, data)
#data = data
end
def do_POST(request, response)
if request.query['name'] and request.query['client'] and request.query['bid']
#data.bid(request.query['name'], request.query['bid'].to_i, request.query['client'])
end
response.status = 200
end
alias_method :do_GET, :do_POST
end
class StatusServlet < WEBrick::HTTPServlet::AbstractServlet
def initialize(server, data)
#data = data
end
def do_GET(request, response)
if request.query['name']
response.body = #data.get_status(request.query['name'])
end
response.status = 200
end
alias_method :do_POST, :do_GET
end
class WinnerServlet < WEBrick::HTTPServlet::AbstractServlet
def initialize(server, data)
#data = data
end
def do_GET(request, response)
if request.query['name']
response.body = #data.winner(request.query['name'])
end
response.status = 200
end
alias_method :do_POST, :do_GET
end
class ResetServlet < WEBrick::HTTPServlet::AbstractServlet
def initialize(server, data)
#data = data
end
def do_POST(request, response)
#data.reset
response.status = 200
end
alias_method :do_GET, :do_POST
end
class RandomServlet < WEBrick::HTTPServlet::AbstractServlet
def initialize(server, data)
#data = data
end
def do_GET(request, response)
response.status = 200
response.body = #data.get_data.to_s
end
alias_method :do_POST, :do_GET
end
data = AuctionInfo.new
server = WEBrick::HTTPServer.new(:Port => $own_address)
server.mount '/start_auction', StartAuctionServlet, data
server.mount '/bid', BidServlet, data
server.mount '/status', StatusServlet, data
server.mount '/winner', WinnerServlet, data
server.mount '/rst', ResetServlet, data
server.mount '/', RandomServlet, data
trap("INT") { server.shutdown }
server.start

Answer 1

Have you checked whether the linux server is running apache, tomcat, trinidad or any other web server? Odds are one of them is already running on port 8080 on the server.
lsof is a useful command. Try lsof | grep 8080 and see whether anything shows up