PACT.Net Cannot assign requested address - docker

Question

I am currently trying to run my pact.net example tests in a docker container , however I am getting the following error:
Starting test execution, please wait...
pact-consumer-tests | [xUnit.net 00:00:19.9436627]
pact_consumer.tests.AddConsumerTest.Add_customer [FAIL]
pact-consumer-tests | Failed
pact_consumer.tests.AddConsumerTest.Add_customer
pact-consumer-tests | Error Message:
pact-consumer-tests | System.AggregateException : One or more errors
occurred. (One or more errors occurred. (Cannot assign requested
address)) (The following constructor parameters did not have matching
fixture data: ConsumerApiPact data)
pact-consumer-tests | ---- System.AggregateException : One or more
errors occurred. (Cannot assign requested address)
pact-consumer-tests | -------- System.Net.Http.HttpRequestException :
Cannot assign requested address
pact-consumer-tests | ------------ System.Net.Sockets.SocketException
: Cannot assign requested address
pact-consumer-tests | ---- The following constructor parameters did
not have matching fixture data: ConsumerApiPact data
pact-consumer-tests | Stack Trace:
pact-consumer-tests |
pact-consumer-tests | ----- Inner Stack Trace #1
(System.AggregateException) -----
pact-consumer-tests | at
PactNet.Mocks.MockHttpService.Host.RubyHttpHost.Start() in
C:\projects\pact-
net\PactNet\Mocks\MockHttpService\Host\RubyHttpHost.cs:line 65
pact-consumer-tests | at PactNet.PactBuilder.MockService(Int32
port, JsonSerializerSettings jsonSerializerSettings, Boolean enableSsl,
IPAddress host) in C:\projects\pact-net\PactNet\PactBuilder.cs:line 82
pact-consumer-tests | at
pact_consumer.tests.context.ConsumerApiPact..ctor() in /app/pact-
consumer.tests/context/ConsumerApiPact.cs:line 27
pact-consumer-tests | ----- Inner Stack Trace -----
pact-consumer-tests | at
System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port,
CancellationToken cancellationToken)
....
Whatever I send into the framework for the Host IPAddress.Any AND IpAddress.Loopback but I still seem to get this issue?
Am I missing something? Its running in a docker container with no other service running..
I can run this on OSX using dotnet test and all is well.
Many thanks in advance
Richard

Answer 1

System.Net.Sockets.SocketException : Cannot assign requested address definitely looks like the system is unable to bind to a port - are you sure that port is available on the host (not just the Docker container)?

Answer 2

I have had the same error but in c#. The same technique could be used on the ruby problem. I into the issue with a dotnet application running in a docker container. The quick answer is that it's probably trying to connect to something and nothing is listening or it cant get to it, so you'll need to enable some networking hooks in the docker line. For the remainder part of this answer, I'll show how I came to that conclusion. I'm running EchoBot which I downloaded from Github:
https://github.com/microsoft/BotBuilder-Samples/tree/master/samples/csharp_dotnetcore/02.echo-bot
First we build that into a container and deploy it and try to use it from the bot emulator to reproduce the error. The emulator is running on my desktop and connects to the bot over port 3978.
Start a echobot container and use it from the emulator to see the original error:
$ docker run --rm -it --entrypoint=bash -p 3978:3978 myImage
# dotnet EchoBot1.dll
...
info: Microsoft.Bot.Builder.Integration.AspNet.Core.BotFrameworkHttpAdapter[0]
Sending activity. ReplyToId: adfa9af0-5f17-11ea-8765-033688f22eac
fail: Microsoft.Bot.Builder.Integration.AspNet.Core.BotFrameworkHttpAdapter[0]
[OnTurnError] unhandled error : Cannot assign requested address
System.Net.Http.HttpRequestException: Cannot assign requested address ---> System.Net.Sockets.SocketException: Cannot assign requested address
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
You can see that there is a socket exception with the cannot assign socket error. We can remove docker from the equation to see if the error changes.
Remove docker from the picture to see the error
$ dotnet run
...
info: Microsoft.Bot.Builder.Integration.AspNet.Core.BotFrameworkHttpAdapter[0]
Sending activity. ReplyToId: 3a427871-5f18-11ea-8765-033688f22eac
fail: Microsoft.Bot.Builder.Integration.AspNet.Core.BotFrameworkHttpAdapter[0]
[OnTurnError] unhandled error : Connection refused
System.Net.Http.HttpRequestException: Connection refused ---> System.Net.Sockets.SocketException: Connection refused
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
You can see that the error is really a Connection Refused when the same code runs outside of docker. So what can we do to see where its connecting to? if you're on linux you can run tcpdump or wireshark on windows.
Capture the network packets to see if there is an outbound connection
$tcpdump -ilo -n -v | tee tcpdump-output
...
19:38:45.336179 IP (tos 0x0, ttl 64, id 12504, offset 0, flags [DF], proto TCP (6), length 60)
127.0.0.1.46215 > 127.0.0.1.52148: Flags [S], cksum 0xfe30 (incorrect -> 0xea5f), seq 549373294, win 65495, options [mss 65495,sackOK,TS val 3769835141 ecr 0,nop,wscale 7], length 0
There is going to be a lot of junk in there, so I tee the output to a file and then use an editor to remove thee lines that are distracting (like DNS queries) but you can see that something is trying to connect over to port 52148.
It turns out that the local emulator is listening on the same port so I need to connect that port over to my desktop where the emulator is running. There are many ways to do this, but I prefer the older SSH way which is convenient.
Hook up a listening tunnel
$ ssh nmishr#104.xxx.xxx.xxx -R 52148:localhost:52148
Once I hooked up the listener on my local host machine to be listening we need to enable the docker container to talk to the host machine and the error goes away:
Run docker with --network=host
$ docker run --rm -it --entrypoint=bash --network=host myImage
# dotnet EchoBot1.dll
...
info: Microsoft.Bot.Builder.Integration.AspNet.Core.BotFrameworkHttpAdapter[0]
Sending activity. ReplyToId: c321ebb1-5f1a-11ea-8765-033688f22eac
info: Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker[2]
Executed action method EchoBot1.Controllers.BotController.PostAsync (EchoBot1), returned result Microsoft.AspNetCore.Mvc.EmptyResult in 518.6485ms.
info: Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker[2]
Executed action EchoBot1.Controllers.BotController.PostAsync (EchoBot1) in 550.6136ms
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
Request finished in 687.9129ms 200