[THRIFT-4312] Erlang client cannot connect to Python server: exception error: econnrefused

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.10.0
• Fix Version/s: 0.11.0
• Component/s: Erlang - Library, Python - Library, Tutorial
• Labels: Connection Erlang Python Tutorial

Environment

Windows 10
Erlang OTP 20
Python 3.6.2

• Assignee: James E. King III
• Reporter: Walter Weinmann
• Created: 05/Sep/17 07:34
• Updated: 14/Dec/17 13:55
• Resolved: 21/Sep/17 14:09

Description

Connecting the Erlang client with the Python server gives connection error:

Erlang client:

– the examples are taken from the Apache Thrift tutorials —

-module(client).

-include("calculator_thrift.hrl").

-export([t/0]).

p(X) ->
io:format("~p~n", [X]),
ok.

t() ->
Port = 9090,

Unknown macro: {ok, Client0}

= thrift_client_util:new("localhost",
Port,
calculator_thrift,
[]),

{Client1, {ok, ok}} = thrift_client:call(Client0, ping, []),
io:format("ping~n", []),

{Client2, {ok, Sum}} = thrift_client:call(Client1, add, [1, 1]),
io:format("1+1=~p~n", [Sum]),

{Client3, {ok, Sum1}} = thrift_client:call(Client2, add, [1, 4]),
io:format("1+4=~p~n", [Sum1]),

Work = #'Work'

Unknown macro: {op=?TUTORIAL_OPERATION_SUBTRACT, num1=15, num2=10}

,
{Client4, {ok, Diff}} = thrift_client:call(Client3, calculate, [1, Work]),
io:format("15-10=~p~n", [Diff]),

{Client5, {ok, Log}} = thrift_client:call(Client4, getStruct, [1]),
io:format("Log: ~p~n", [Log]),

Client6 =
try
Work1 = #'Work'

Unknown macro: {op=?TUTORIAL_OPERATION_DIVIDE, num1=1, num2=0}

,
{ClientS1, {ok, _Quot}} = thrift_client:call(Client5, calculate, [2, Work1]),

io:format("LAME: exception handling is broken~n", []),
ClientS1
catch
throw:

Unknown macro: {ClientS2, Z}

->
io:format("Got exception where expecting - the " ++
"following is NOT a problem!!!~n"),
p(Z),
ClientS2
end,

{Client7, {ok, ok}} = thrift_client:call(Client6, zip, []),
io:format("zip~n", []),

{_Client8, ok} = thrift_client:close(Client7),
ok.

Python server:

#!/usr/bin/env python

from tutorial import Calculator
from tutorial.ttypes import InvalidOperation, Operation

from shared.ttypes import SharedStruct

from thrift.transport import TSocket
from thrift.transport import TTransport
from thrift.protocol import TBinaryProtocol
from thrift.server import TServer

class CalculatorHandler:
def _init_(self):
self.log = {}

def ping(self):
print('ping()')

def add(self, n1, n2):
print('add(%d,%d)' % (n1, n2))
return n1 + n2

def calculate(self, logid, work):
print('calculate(%d, %r)' % (logid, work))

if work.op == Operation.ADD:
val = work.num1 + work.num2
elif work.op == Operation.SUBTRACT:
val = work.num1 - work.num2
elif work.op == Operation.MULTIPLY:
val = work.num1 * work.num2
elif work.op == Operation.DIVIDE:
if work.num2 == 0:
x = InvalidOperation()
x.whatOp = work.op
x.why = 'Cannot divide by 0'
raise x
val = work.num1 / work.num2
else:
x = InvalidOperation()
x.whatOp = work.op
x.why = 'Invalid operation'
raise x

log = SharedStruct()
log.key = logid
log.value = '%d' % (val)
self.log[logid] = log

return val

def getStruct(self, key):
print('getStruct(%d)' % (key))
return self.log[key]

def zip(self):
print('zip()')

if _name_ == '_main_':
handler = CalculatorHandler()
processor = Calculator.Processor(handler)
transport = TSocket.TServerSocket(port=9090)
tfactory = TTransport.TBufferedTransportFactory()
pfactory = TBinaryProtocol.TBinaryProtocolFactory()

server = TServer.TSimpleServer(processor, transport, tfactory, pfactory)

1. You could do one of these for a multithreaded server
2. server = TServer.TThreadedServer(
3. processor, transport, tfactory, pfactory)
4. server = TServer.TThreadPoolServer(
5. processor, transport, tfactory, pfactory)

print('Starting the server...')
server.serve()
print('done.')

Runtime protocol:

EBIN Path : D:\SoftDevelopment\Projects\erlang-and-thrift_idea\erlang-and-thrift_build\default\lib\erlang_and_thrift\ebin D:\SoftDevelopment\Projects\erlang-and-thrift_idea\erlang-and-thrift_build\default\lib\jsx\ebin D:\SoftDevelopment\Projects\erlang-and-thrift_idea\erlang-and-thrift_build\default\lib\thrift\ebin
------------------------------------------
Eshell V9.0 (abort with ^G)
1> client:t().

• • exception error: no match of right hand side value
    Unknown macro: {error,econnrefused}

    in function client:t/0 (d:/SoftDevelopment/Projects/erlang-and-thrift_idea/erlang-and-thrift/_build/default/lib/erlang_and_thrift/src/client.erl, line 33)
    2> Terminate batch job (Y/N)? y

D:\SoftDevelopment\Projects\erlang-and-thrift_idea\erlang-and-thrift>tcping64 localhost 9090

Probing ::1:9090/tcp - Port is open - time=0.580ms
Probing ::1:9090/tcp - Port is open - time=0.622ms
Probing ::1:9090/tcp - Port is open - time=1.038ms
Probing ::1:9090/tcp - Port is open - time=1.050ms

Ping statistics for ::1:9090
4 probes sent.
4 successful, 0 failed.
Approximate trip times in milli-seconds:
Minimum = 0.580ms, Maximum = 1.050ms, Average = 0.822ms

Issue Links

• links to: GitHub Pull Request #1365