Keep alive configuration

[megasolis]

Hello, first of all, thanks for this amazing plugin. I have been using it for about 3 months now and it rocks!

Having said that, I have a question regarding how I can configure the time out values of the GRPC ManagedChannel used to send the GRPC requests.

• One of my use cases is to send some large requests to a GRPC service that may take more than 60 seconds to complete.
• At first, I thought on just configuring the timeout parameter of the client sampler with a proper value ~120K milliseconds
• Nevertheless, even with that configuration in place, those big requests get cancelled at around 60 seconds of start with the following Exception: Caused by: io.grpc.StatusRuntimeException: UNAVAILABLE: Network closed for unknown reason
• After doing some troubleshooting, I wrote a simple GRPC Kotlin client to try to send those same requests. The basic configuration of the ManagedChannel is as follows:

  channel = NettyChannelBuilder.forAddress(SERVICE_HOST, SERVICE_PORT)
          .useTransportSecurity()
          .sslContext(
              GrpcSslContexts.forClient().trustManager(File(CERT_PATH)).build()
          )
          .keepAliveWithoutCalls(true)
          .keepAliveTime(30, TimeUnit.SECONDS)
          .keepAliveTimeout(30, TimeUnit.SECONDS)
          .build()
      determinationAPIBlockingStub = DeterminationAPIGrpc.newBlockingStub(channel)

• As you can see, I specified keepAliveWithoutCalls as true, keepAliveTime with 30 seconds and keepAliveTimeout with 30 seconds as well
• Previous configuration allowed the channel to be "idle" for more than 60 seconds, therefore, succeeding the request call, so I think this might be the issue of the connection being closed

• Exploring the GrpcClientSampler.java class, I noticed that there is no way of specifying keep alive values when creating the channel

  public static ManagedChannel getChannel(GrpcClientSampler sampler) throws SSLException {
  Map<String, String> headerMap = createHeaderMap(sampler.getMetaData());
  
  ManagedChannelBuilder builder = NettyChannelBuilder.forAddress(sampler.getHostname(), sampler.getPort())
      .intercept(new GrpcClientInterceptor(headerMap, sampler.getTimeout()));
  
  if (!sampler.isUseSsl()) {
    builder = builder.usePlaintext();
  } else if (!StringUtils.isBlank(sampler.getCertFile())) {
    // build out a managed channel that can accept the ssl cert file
    // Get the file and verify it exists
    File certFile = new File(sampler.getCertFile());
    if (!certFile.exists()) {
      LOGGER.error("The cert file passed in does not exist at: ", sampler.getCertFile());
    }
  
    // build the client side ssl context with the cert
    SslContext sslContext = GrpcSslContexts.forClient().trustManager(certFile).build();
  
    // add the ssl context to the builder
    builder = ((NettyChannelBuilder) builder).sslContext(sslContext);
  }
  return builder.build();
  }

So, I was wondering if there is a workaround or some recommended approach on how to configure the sampler channel to use specific keep alive configuration values.

Thanks in advance.

[thoainguyen]

Workaround solution is fork this repo, change those lines of code, and rebuild the plugin :v

[megasolis]

Created a PR where I have included new code for this and other configuration properties: https://github.com/zalopay-oss/jmeter-grpc-plugin/pull/21

Thanks

[thoainguyen]

Do small things with great love!

Merged! Thank you!