Update ML models in running pipelines

Run in Google Colab View source on GitHub

This notebook demonstrates how to perform automatic model updates without stopping your Apache Beam pipeline. You can use side inputs to update your model in real time, even while the Apache Beam pipeline is running. The side input is passed in a ModelHandler configuration object. You can update the model either by leveraging one of Apache Beam's provided patterns, such as the WatchFilePattern, or by configuring a custom side input PCollection that defines the logic for the model update.

The pipeline in this notebook uses a RunInference PTransform with TensorFlow machine learning (ML) models to run inference on images. To update the model, it uses a side input PCollection that emits ModelMetadata. For more information about side inputs, see the Side inputs section in the Apache Beam Programming Guide.

This example uses WatchFilePattern as a side input. WatchFilePattern is used to watch for file updates that match the file_pattern based on timestamps. It emits the latest ModelMetadata, which is used in the RunInference PTransform to automatically update the ML model without stopping the Apache Beam pipeline.

Before you begin

Install the dependencies required to run this notebook.

To use RunInference with side inputs for automatic model updates, use Apache Beam version 2.46.0 or later.

pip install apache_beam[gcp]>=2.46.0 --quiet
pip install tensorflow --quiet
pip install tensorflow_hub --quiet

# Imports required for the notebook.
import logging
import time
from typing import Iterable
from typing import Tuple

import apache_beam as beam
from apache_beam.ml.inference.base import PredictionResult
from apache_beam.ml.inference.base import RunInference
from apache_beam.ml.inference.tensorflow_inference import TFModelHandlerTensor
from apache_beam.ml.inference.utils import WatchFilePattern
from apache_beam.options.pipeline_options import GoogleCloudOptions
from apache_beam.options.pipeline_options import PipelineOptions
from apache_beam.options.pipeline_options import SetupOptions
from apache_beam.options.pipeline_options import StandardOptions
from apache_beam.options.pipeline_options import WorkerOptions
from apache_beam.transforms.periodicsequence import PeriodicImpulse
import numpy
from PIL import Image
import tensorflow as tf



# Authenticate to your Google Cloud account.
def auth_to_colab():
  from google.colab import auth
  auth.authenticate_user()

auth_to_colab()

Configure the runner

This pipeline uses the Dataflow Runner. To run the pipeline, you need to complete the following tasks:

  • Ensure that you have all the required permissions to run the pipeline on Dataflow.
  • Configure the pipeline options for the pipeline to run on Dataflow. Make sure the pipeline is using streaming mode.

In the following code, replace BUCKET_NAME with the the name of your Cloud Storage bucket.

options = PipelineOptions()
options.view_as(StandardOptions).streaming = True

BUCKET_NAME = '<BUCKET_NAME>' # Replace with your bucket name.

# Provide required pipeline options for the Dataflow Runner.
options.view_as(StandardOptions).runner = "DataflowRunner"

# Set the project to the default project in your current Google Cloud environment.
options.view_as(GoogleCloudOptions).project = '<PROJECT_NAME>'

# Set the Google Cloud region that you want to run Dataflow in.
options.view_as(GoogleCloudOptions).region = 'us-central1'

# IMPORTANT: Replace BUCKET_NAME with the the name of your Cloud Storage bucket.
dataflow_gcs_location = "gs://%s/dataflow" % BUCKET_NAME

# The Dataflow staging location. This location is used to stage the Dataflow pipeline and the SDK binary.
options.view_as(GoogleCloudOptions).staging_location = '%s/staging' % dataflow_gcs_location


# The Dataflow staging location. This location is used to stage the Dataflow pipeline and the SDK binary.
options.view_as(GoogleCloudOptions).staging_location = '%s/staging' % dataflow_gcs_location

# The Dataflow temp location. This location is used to store temporary files or intermediate results before outputting to the sink.
options.view_as(GoogleCloudOptions).temp_location = '%s/temp' % dataflow_gcs_location

options.view_as(SetupOptions).save_main_session = True

# Launching Dataflow with only one worker might result in processing delays due to
# initial input processing. This could further postpone the side input model updates.
# To expedite the model update process, it's recommended to set num_workers>1.
# https://github.com/apache/beam/issues/28776
options.view_as(WorkerOptions).num_workers = 5

Install the tensorflow and tensorflow_hub dependencies on Dataflow. Use the requirements_file pipeline option to pass these dependencies.

# In a requirements file, define the dependencies required for the pipeline.
!printf 'tensorflow>=2.12.0\ntensorflow_hub>=0.10.0\nPillow>=9.0.0' > ./requirements.txt
# Install the pipeline dependencies on Dataflow.
options.view_as(SetupOptions).requirements_file = './requirements.txt'

Use the TensorFlow model handler

This example uses TFModelHandlerTensor as the model handler and the resnet_101 model trained on ImageNet.

For the Dataflow runner, you need to store the model in a remote location that the Apache Beam pipeline can access. For this example, download the ResNet101 model, and upload it to the Google Cloud Storage bucket.

model = tf.keras.applications.resnet.ResNet101()
model.save('resnet101_weights_tf_dim_ordering_tf_kernels.keras')
# After saving the model locally, upload the model to GCS bucket and provide that gcs bucket `URI` as `model_uri` to the `TFModelHandler`
# Replace `BUCKET_NAME` value with actual bucket name.
!gsutil cp resnet101_weights_tf_dim_ordering_tf_kernels.keras gs://<BUCKET_NAME>/dataflow/resnet101_weights_tf_dim_ordering_tf_kernels.keras



model_handler = TFModelHandlerTensor(
    model_uri=dataflow_gcs_location + "/resnet101_weights_tf_dim_ordering_tf_kernels.keras")

Preprocess images

Use preprocess_image to run the inference, read the image, and convert the image to a TensorFlow tensor.

def preprocess_image(image_name, image_dir):
  img = tf.keras.utils.get_file(image_name, image_dir + image_name)
  img = Image.open(img).resize((224, 224))
  img = numpy.array(img) / 255.0
  img_tensor = tf.cast(tf.convert_to_tensor(img[...]), dtype=tf.float32)
  return img_tensor



class PostProcessor(beam.DoFn):
  """Process the PredictionResult to get the predicted label.
  Returns predicted label.
  """
  def process(self, element: PredictionResult) -> Iterable[Tuple[str, str]]:
    predicted_class = numpy.argmax(element.inference, axis=-1)
    labels_path = tf.keras.utils.get_file(
        'ImageNetLabels.txt',
        'https://storage.googleapis.com/download.tensorflow.org/data/ImageNetLabels.txt'  # pylint: disable=line-too-long
    )
    imagenet_labels = numpy.array(open(labels_path).read().splitlines())
    predicted_class_name = imagenet_labels[predicted_class]
    yield predicted_class_name.title(), element.model_id



# Define the pipeline object.
pipeline = beam.Pipeline(options=options)

Next, review the pipeline steps and examine the code.

Pipeline steps

  1. Create a PeriodicImpulse transform, which emits output every n seconds. The PeriodicImpulse transform generates an infinite sequence of elements with a given runtime interval.

    In this example, PeriodicImpulse mimics the Pub/Sub source. Because the inputs in a streaming pipeline arrive in intervals, use PeriodicImpulse to output elements at m intervals. To learn more about PeriodicImpulse, see the PeriodicImpulse code.

start_timestamp = time.time() # start timestamp of the periodic impulse
end_timestamp = start_timestamp + 60 * 20 # end timestamp of the periodic impulse (will run for 20 minutes).
main_input_fire_interval = 60 # interval in seconds at which the main input PCollection is emitted.
side_input_fire_interval = 60 # interval in seconds at which the side input PCollection is emitted.

periodic_impulse = (
      pipeline
      | "MainInputPcoll" >> PeriodicImpulse(
          start_timestamp=start_timestamp,
          stop_timestamp=end_timestamp,
          fire_interval=main_input_fire_interval))

  1. To read and preprocess the images, use the preprocess_image function. This example uses Cat-with-beanie.jpg for all inferences.

download.png

image_data = (periodic_impulse | beam.Map(lambda x: "Cat-with-beanie.jpg")
      | "ReadImage" >> beam.Map(lambda image_name: preprocess_image(
          image_name=image_name, image_dir='https://storage.googleapis.com/apache-beam-samples/image_captioning/')))
  1. Pass the images to the RunInference PTransform. RunInference takes model_handler and model_metadata_pcoll as input parameters.
    • model_metadata_pcoll is a side input PCollection to the RunInference PTransform. This side input updates the model_uri in the model_handler while the Apache Beam pipeline runs.
    • Use WatchFilePattern as side input to watch a file_pattern matching .keras files. In this case, the file_pattern is 'gs://BUCKET_NAME/dataflow/*keras'.
# The side input used to watch for the .keras file and update the model_uri of the TFModelHandlerTensor.
file_pattern = dataflow_gcs_location + '/*.keras'
side_input_pcoll = (
      pipeline
      | "WatchFilePattern" >> WatchFilePattern(file_pattern=file_pattern,
                                                interval=side_input_fire_interval,
                                                stop_timestamp=end_timestamp))
inferences = (
      image_data
      | "ApplyWindowing" >> beam.WindowInto(beam.window.FixedWindows(10))
      | "RunInference" >> RunInference(model_handler=model_handler,
                                      model_metadata_pcoll=side_input_pcoll))
  1. Post-process the PredictionResult object. When the inference is complete, RunInference outputs a PredictionResult object that contains the fields example, inference, and model_id. The model_id field identifies the model used to run the inference. The PostProcessor returns the predicted label and the model ID used to run the inference on the predicted label.
post_processor = (
    inferences
    | "PostProcessResults" >> beam.ParDo(PostProcessor())
    | "LogResults" >> beam.Map(logging.info))

Watch for the model update

After the pipeline starts processing data, when you see output emitted from the RunInference PTransform, upload a resnet152 model saved in the .keras format to a Google Cloud Storage bucket location that matches the file_pattern you defined earlier.

model = tf.keras.applications.resnet.ResNet152()
model.save('resnet152_weights_tf_dim_ordering_tf_kernels.keras')
# Replace the `BUCKET_NAME` with the actual bucket name.
!gsutil cp resnet152_weights_tf_dim_ordering_tf_kernels.keras gs://<BUCKET_NAME>/resnet152_weights_tf_dim_ordering_tf_kernels.keras

Run the pipeline

Use the following code to run the pipeline.

# Run the pipeline.
result = pipeline.run().wait_until_finish()