gRPC testing causes panic

[c47gao]

Brief summary

So I was trying out the grpc testing with insecure option. And running the test causes panic

rgao@rgao-mac js % k6 run test.js

          /\      |‾‾| /‾‾/   /‾‾/   
     /\  /  \     |  |/  /   /  /    
    /  \/    \    |     (   /   ‾‾\  
   /          \   |  |\  \ |  (‾)  | 
  / __________ \  |__| \__\ \_____/ .io

  execution: local
     script: test.js
     output: -

  scenarios: (100.00%) 1 scenario, 1 max VUs, 10m30s max duration (incl. graceful stop):
           * default: 1 iterations for each of 1 VUs (maxDuration: 10m0s, gracefulStop: 30s)

ERRO[0000] panic: runtime error: invalid memory address or nil pointer dereference
goroutine 31 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:24 +0x68
go.k6.io/k6/js/common.RunWithPanicCatching.func1()
	go.k6.io/k6/js/common/util.go:102 +0x150
panic({0x101355a80, 0x101ddfb90})
	runtime/panic.go:838 +0x204
github.com/dop251/goja.AssertFunction.func1.1()
	github.com/dop251/[email protected]/runtime.go:2305 +0x84
panic({0x101355a80, 0x101ddfb90})
	runtime/panic.go:838 +0x204
github.com/dop251/goja.(*vm).try.func1()
	github.com/dop251/[email protected]/vm.go:537 +0x590
panic({0x101355a80, 0x101ddfb90})
	runtime/panic.go:838 +0x204
go.k6.io/k6/js/modules/k6/grpc.(*Client).Invoke(0x14000e0f470, {0x140001b7110, 0x2d}, {0x0, 0x0}, 0x10067bdec?)
	go.k6.io/k6/js/modules/k6/grpc/client.go:161 +0x118
reflect.Value.call({0x1013e5100?, 0x14000e0f470?, 0x1022f0108?}, {0x100ffa87d, 0x4}, {0x14001bda1e0, 0x3, 0x100c4e2a0?})
	reflect/value.go:556 +0x5e4
reflect.Value.Call({0x1013e5100?, 0x14000e0f470?, 0x1400264af90?}, {0x14001bda1e0, 0x3, 0x3})
	reflect/value.go:339 +0x98
github.com/dop251/goja.(*Runtime).wrapReflectFunc.func1({{0x1014bebb8, 0x14000e0f4a0}, {0x14000e164e0, 0x1, 0x6}})
	github.com/dop251/[email protected]/runtime.go:1891 +0x150
github.com/dop251/goja.(*vm)._nativeCall(0x14000ab0000, 0x14000f8e0a0, 0x1)
	github.com/dop251/[email protected]/vm.go:2737 +0x1f8
github.com/dop251/goja.call.exec(0xab0000?, 0x14000ab0000)
	github.com/dop251/[email protected]/vm.go:2709 +0x92c
github.com/dop251/goja.(*vm).run(0x14000ab0000)
	github.com/dop251/[email protected]/vm.go:408 +0x9c
github.com/dop251/goja.(*baseJsFuncObject)._call(0x14000e78820, {{0x1014bf408, 0x101e2f460}, {0x14002728ab0, 0x1, 0x1}}, {0x0?, 0x0}, {0x1014bebb8?, 0x14000d8c090?})
	github.com/dop251/[email protected]/func.go:193 +0x394
github.com/dop251/goja.(*arrowFuncObject).Call(0x14000dbd498?, {{0x1014bf408, 0x101e2f460}, {0x14002728ab0, 0x1, 0x1}})
	github.com/dop251/[email protected]/func.go:160 +0x4c
github.com/dop251/goja.AssertFunction.func1.2()
	github.com/dop251/[email protected]/runtime.go:2310 +0x6c
github.com/dop251/goja.(*vm).try(0x14000dbd5f8?, 0x100643aa0?)
	github.com/dop251/[email protected]/vm.go:545 +0x108
github.com/dop251/goja.AssertFunction.func1({0x1014bf408?, 0x101e2f460?}, {0x14002728ab0?, 0x1?, 0x1?})
	github.com/dop251/[email protected]/runtime.go:2309 +0xb8
go.k6.io/k6/js.(*VU).runFn.func1.1()
	go.k6.io/k6/js/runner.go:800 +0x54
go.k6.io/k6/js/eventloop.(*EventLoop).Start(0x14000d86140, 0x14000f11ef0)
	go.k6.io/k6/js/eventloop/eventloop.go:112 +0x134
go.k6.io/k6/js.(*VU).runFn.func1()
	go.k6.io/k6/js/runner.go:799 +0xe8
go.k6.io/k6/js/common.RunWithPanicCatching({0x1014bfd60?, 0x14000451650?}, 0x14000dbd898?, 0x1006060d0?)
	go.k6.io/k6/js/common/util.go:106 +0x78
go.k6.io/k6/js.(*VU).runFn(0x14000e2c820, {0x1014b7120, 0x140000dba40}, 0xe0?, 0x1400000fe48, 0x14002728aa0, {0x14002728ab0, 0x1, 0x1})
	go.k6.io/k6/js/runner.go:798 +0x208
go.k6.io/k6/js.(*ActiveVU).RunOnce(0x140000dba00)
	go.k6.io/k6/js/runner.go:750 +0x36c
go.k6.io/k6/lib/executor.getIterationRunner.func1({0x1014b71c8, 0x14000f11bc0}, {0x1014ae368?, 0x140000dba00?})
	go.k6.io/k6/lib/executor/helpers.go:144 +0x50
go.k6.io/k6/lib/executor.PerVUIterations.Run.func5({0x1014b3190, 0x14000e2c820})
	go.k6.io/k6/lib/executor/per_vu_iterations.go:243 +0x36c
created by go.k6.io/k6/lib/executor.PerVUIterations.Run
	go.k6.io/k6/lib/executor/per_vu_iterations.go:256 +0x99c

Goja stack:
native 

running (00m00.3s), 0/1 VUs, 0 complete and 1 interrupted iterations
default ✗ [======================================] 1 VUs  00m00.3s/10m0s  1/1 iters, 1 per VU
WARN[0000] No script iterations finished, consider making the test duration longer 

     data_received........: 9 B  31 B/s
     data_sent............: 42 B 146 B/s
     iteration_duration...: avg=285.6ms min=285.6ms med=285.6ms max=285.6ms p(90)=285.6ms p(95)=285.6ms
     iterations...........: 1    3.466217/s

ERRO[0000] a panic occurred during JS execution: runtime error: invalid memory address or nil pointer dereference 

k6 version

Latest (v0.39.0)

OS

mac os 12.1

Docker version and image (if applicable)

N/A

Steps to reproduce the problem

import grpc from 'k6/net/grpc';
import { check, sleep } from 'k6';

const client = new grpc.Client();
client.load([], 'greeter.proto');

export const options = {
  insecureSkipTLSVerify: true,
};

export default () => {
  client.connect('domain:port', {
    plaintext: true
  });

  const response = client.invoke('some_grpc_request');

  check(response, {
    'status is OK': (r) => r && r.status === grpc.StatusOK,
  });

  console.log(JSON.stringify(response.message));

  client.close();
  sleep(1);
};

Panic is raised during client.invoke

Expected behaviour

Test doesn't raise panic

Actual behaviour

Test raises panic

[na--]

Thanks for opening this issue! I think the problem is that you are not actually passing the second parameter to client.Invoke(), which is supposed to be the request. So we essentially get a nil but we try to marshal it to JSON and result in a panic: https://github.com/grafana/k6/blob/e09bb87277865d668586429eee97158fbbfc58e5/js/modules/k6/grpc/client.go#L161

So yeah, the script is slightly wrong, but this should certainly not cause k6 to panic, so it's a very valid bug - k6 should just throw an exception at that point. The fix is simple enough, we should just add that check (and a test), do you want to make a PR?

[c47gao]

Thank you so much for the reply. Sure i'll arrange some time adding the check, should be quite straightforward but I need some time to read thru the code

[theshashankpal]

Hi @na-- , I am a student who needs to contribute to an OpenSource project in my coursework, so I was wondering if you can assign this to me. This issue seems to be a good initiation of my journey towards contribution to FOSS projects. Can you please assign this to me?

[na--]

@c47gao, you haven't indicated that you have started work on this or that you are about to make a PR, so I don't see a reason why @theshashankpal can't work on it? @theshashankpal, I will assign it to you, in case that is a requirement for your course, but in general we don't assign issues to external contributors - you can just start working on it after a consensus is reached on how to implement something.