GRPC assertion failure when subscribing to streams

Not exactly sure what is causing this error, it seems to be pretty sporadic and only happen after running a few iterations of testing.

Assertion failed: stream->dep_prev (../deps/nghttp2/lib/nghttp2_stream.c: nghttp2_stream_dep_remove: 777)

It seems that this test is able to reproduce it most of the time with the added loop:

describe('Eventstore GRPC Client', () => {
  let client: EventStoreDBClient

  beforeAll(() => {
    client = new EventStoreDBClient(
      {
        endpoint: {
          address: process.env.ES_HOSTNAME ?? 'eventstore',
          port: parseInt(process.env.ES_GRPC_PORT ?? '2113'),
        },
      },
      { insecure: true },
      {
        username: process.env.ES_USERNAME!,
        password: process.env.ES_PASSWORD!,
      },
    )
  })

  it('can subscribe to a stream', async () => {
    jest.setTimeout(10000)

    for (let j = 0; j < 10; ++j) {
      const stream = `test_${uuidv4().replace(/\-/g, '')}`
      const events = []
      for (let i = 0; i < 10; ++i) {
        events.push(
          jsonEvent({
            type: 'test-event',
            id: uuidv4(),
            data: {
              a: i,
            },
          }),
        )
      }

      const appendRes = await client.appendToStream(stream, events.slice(0, 3), {
        expectedRevision: NO_STREAM,
      })

      const received: ResolvedEvent[] = []
      const sub = client.subscribeToStream(stream, {
        fromRevision: START,
      })
      sub.on('error', (err) => console.log(err, err?.message))
      sub.on('close', () => console.log('subscription stopped'))
      sub.on('data', (evt) => {
        console.log(`received event ${events.length}`)
        received.push(evt)
      })
      while (received.length < 3) await forMs(10)
      await client.appendToStream(stream, events.slice(3, 10), {
        expectedRevision: appendRes.nextExpectedRevision,
      })
      while (received.length < 10) await forMs(10)
      expect(received.map((e) => e.event?.id)).toStrictEqual(events.map((e) => e.id))
      await sub.unsubscribe()
    }
  })
})

This is my eventstore configuration (from docker compose) for testing

  eventstore:
    image: eventstore/eventstore:20.10.0-bionic
    environment:
      EVENTSTORE_START_STANDARD_PROJECTIONS: 'true'
      EVENTSTORE_INSECURE: 'true'
      EVENTSTORE_RUN_PROJECTIONS: 'All'

This was tested with Alpha 13.

[George-Payne]

Hi guys,

Thanks for the further details. Turns out I needed to increase the number of loops to see the error, though it seems to only happen occasionally, so may have just been increasing the chances of me hitting it.

The cause of the error looks to be https://github.com/grpc/grpc-node/issues/1652, that (one more issue down the chain), points towards it being caused by a bug in node itself.

In #129, I’ve added your reproduction as a test case and applied the workaround provided in the issue.

[dkvasnicka]

Awesome, thanks for the quick turnaround!