Tensorflow: How do I convert a EagerTensor into a numpy array?

There is a .numpy() function which you can use, alternatively you could also do numpy.array(y). For example:

import tensorflow as tf
import numpy as np

tf.enable_eager_execution()

x = tf.constant([1., 2.])
print(type(x))            # <type 'EagerTensor'>
print(type(x.numpy()))    # <type 'numpy.ndarray'>
print(type(np.array(x)))  # <type 'numpy.ndarray'>

See the section in the eager execution guide.