Kafka.ipynb is broken in colab.

[MarkDaoust]

Using tensorflow_io 0.17

The kafka.ipynb notebook fails in this block:

thread = threading.Thread(target=write_to_kafka_after_sleep,
                          args=("susy-train", zip(x_train, y_train)))
thread.daemon = True
thread.start()

for mini_ds in online_train_ds:
  mini_ds = mini_ds.shuffle(buffer_size=32)
  mini_ds = mini_ds.map(decode_kafka_online_item)
  mini_ds = mini_ds.batch(32)
  model.fit(mini_ds, epochs=3)

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-28-5ff39e4e4280> in <module>()
      8   mini_ds = mini_ds.map(decode_kafka_online_item)
      9   mini_ds = mini_ds.batch(32)
---> 10   model.fit(mini_ds, epochs=3)

/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py in fit(self, x, y, batch_size, epochs, verbose, callbacks, validation_split, validation_data, shuffle, class_weight, sample_weight, initial_epoch, steps_per_epoch, validation_steps, validation_batch_size, validation_freq, max_queue_size, workers, use_multiprocessing)
   1108 
   1109         if logs is None:
-> 1110           raise ValueError('Expect x to be a non-empty array or dataset.')
   1111         epoch_logs = copy.copy(logs)
   1112 

ValueError: Expect x to be a non-empty array or dataset.

[kvignesh1420]

@MarkDaoust the online-training variant might not be stable in Colab env. I will fix this.

[kvignesh1420]

closing the issue as #1274 has been merged.