TypeError: channelCredentials._equals is not a function

[davemason-ladbible]

This issue occurs on versions 1.1.2 and later.

When attempting to publish a message to the emulator, I'm getting the following error:

TypeError: channelCredentials._equals is not a function

Function to re-create error:

const pub = async (topicName, data) => {
  const options = {
    keyFilename,
    projectId
  };
  if (process.env.NODE_ENV === 'development' || process.env.NODE_ENV === 'test') {
    options.apiEndpoint = 'emulator:8085';
  }
  const pubsub = new PubSub(options);
  const stringifiedData = JSON.stringify(data);
  const dataBuffer = await Buffer.from(stringifiedData);

  const topic = `projects/${projectId}/topics/${topicName}`;

  return pubsub
    .topic(topic)
    .publish(dataBuffer)
    .then((response) => {
      logger.info('Message published.', response);
      return {
        success: true
      };
    })
    .catch((error) => {
      logger.error('Failed to publish topic', error);
      return {
        success: false
      };
    });
};

Dockerfile of emulator:

FROM google/cloud-sdk:alpine

LABEL maintainer="LADbible Group"

RUN apk --update add openjdk7-jre
RUN gcloud components install --quiet beta pubsub-emulator
RUN gcloud components update
RUN mkdir -p /var/pubsub

VOLUME /var/pubsub

EXPOSE 8085

CMD [ "gcloud", "beta", "emulators", "pubsub", "start", "--data-dir=/var/pubsub", "--host-port=0.0.0.0:8085", "--log-http", "--verbosity=debug", "--user-output-enabled" ]

Environment details

• OS: alpine
• Node.js version: 10.15.0
• npm version: 6.5.0
• @google-cloud/pubsub version: 1.1.2+

[callmehiphop]

@davemason-ladbible thanks for the write up! Any chance you could provide us with a stack trace?

[davemason-ladbible]

@callmehiphop Sure, here you are:

TypeError: channelCredentials._equals is not a function
          at SubchannelPool.getOrCreateSubchannel (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/subchannel-pool.ts:132:32)
          at Object.createSubchannel (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/channel.ts:139:36)
          at Object.createSubchannel (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/resolving-load-balancer.ts:249:42)
          at subchannels.latestAddressList.map.address (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/load-balancer-pick-first.ts:336:33)
          at Array.map (<anonymous>)
          at PickFirstLoadBalancer.connectToAddressList (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/load-balancer-pick-first.ts:335:47)
          at PickFirstLoadBalancer.updateAddressList (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/load-balancer-pick-first.ts:386:12)
          at Object.onSuccessfulResolution (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/resolving-load-balancer.ts:210:34)
          at pendingResultPromise.then (/app/node_modules/google-gax/node_modules/@grpc/grpc-js/src/resolver-dns.ts:269:25)

[callmehiphop]

Interesting, @murgatroid99 any thoughts on this?

[murgatroid99]

My best guess from that error is that a Client or Channel is being created with a bad channelCredentials argument. It could be some other kind of object, or a ChannelCredentials object from the grpc library or an older version of @grpc/grpc-js. I don't immediately see anything in that code that would cause that.

[kbariotis]

Found the same when attempting to connect to the emulator. Latest version of both the emulator and this library.

[willianw]

Found the same when attempting to create a new subscription wihtin the emulator. Topic creation is ok. Versions:

• @google-cloud/[email protected]
• [email protected]
• [email protected]
• [email protected]

[feywind]

I'm going to put this on my list of stuff to retry shortly. I suspect some changes have happened to the emulator itself, because some of the problems I've tried to reproduce weren't happening for me. Also grpc-js has changed a lot. I see that some are using gRPC C++, though, so grpc-js updates wouldn't help with that.

[meredithslota]

@feywind If the issue isn't resolved with the new version of grpc-js (and it's still an issue with the emulator) let's kick it to @kamalaboulhosn for guidance on ownership.

[feywind]

I finally got a chance to try this out myself. I did have to make a few tweaks to make it works, so maybe this will help.

This is my Dockerfile, based on the original, but with an updated openjdk:

FROM google/cloud-sdk:alpine

RUN apk --update add openjdk11-jre-headless
RUN gcloud components install --quiet beta pubsub-emulator
RUN gcloud components update
RUN mkdir -p /var/pubsub

VOLUME /var/pubsub

EXPOSE 8085

CMD [ "gcloud", "beta", "emulators", "pubsub", "start", "--data-dir=/var/pubsub", "--host-port=0.0.0.0:8085", "--log-http", "--verbosity=debug", "--user-output-enabled" ]

This fixed a Java exception in the emulator for not finding the Duration class.

This is the sample code:

const PubSub = require('@google-cloud/pubsub').PubSub;

const pub = async (topicName, data) => {
  const options = {
    projectId: 'testproject',
    apiEndpoint: 'localhost:8085'
  };
  const pubsub = new PubSub(options);
  const stringifiedData = JSON.stringify(data);
  const dataBuffer = await Buffer.from(stringifiedData);

  const topicId = `projects/${options.projectId}/topics/${topicName}`;

  const topic = pubsub.topic(topicId);
  const exists = await topic.exists();
  if (!exists[0]) {
    await topic.create();
    console.log('created topic');
  }

  let sub = pubsub.subscription('testsub');
  const subExists = await sub.exists();
  if (!subExists[0]) {
    await topic.createSubscription('testsub');
    console.log('created sub');
    sub = topic.subscription('testsub');
  }

  const receivePromise = new Promise(r => {
    sub.on('message', message => {
      console.log('Message received', message.data.toString());
      message.ack();
      r();
    });
  });

  const response = await topic.publish(dataBuffer);
  console.log('Message published', response);

  await receivePromise;
};

pub('testtopic2', { test: 'test' }).then(() => {
  console.log('Exiting');
  process.exit(0);
}).catch(e => {
  console.error('Error', e);
});

This is the package.json:

{
    "name": "example",
    "version": "1.0.0",
    "description": "",
    "dependencies": {
        "@google-cloud/pubsub": "^2.0.0"
    }
}

And I'm getting this output:

Message published 4
Message received {"test":"test"}
Exiting

So I think this has been fixed by subsequent grpc updates or other changes. @willianw Your subscriber issue might be fixed by updating the JDK in the Docker image?

Please feel free to re-open if there are still problems!