TensorFlow Serving: Update model_config (add additional models) at runtime

Question

I'm busy configuring a TensorFlow Serving client that asks a TensorFlow Serving server to produce predictions on a given input image, for a given model.

If the model being requested has not yet been served, it is downloaded from a remote URL to a folder where the server's models are located. (The client does this). At this point I need to update the model_config and trigger the server to reload it.

This functionality appears to exist (based on https://github.com/tensorflow/serving/pull/885 and https://github.com/tensorflow/serving/blob/master/tensorflow_serving/apis/model_service.proto#L22), but I can't find any documentation on how to actually use it.

I am essentially looking for a python script with which I can trigger the reload from client side (or otherwise to configure the server to listen for changes and trigger the reload itself).

Answer 1

So it took me ages of trawling through pull requests to finally find a code example for this. For the next person who has the same question as me, here is an example of how to do this. (You'll need the tensorflow_serving package for this; pip install tensorflow-serving-api).

Based on this pull request (which at the time of writing hadn't been accepted and was closed since it needed review): https://github.com/tensorflow/serving/pull/1065

from tensorflow_serving.apis import model_service_pb2_grpc
from tensorflow_serving.apis import model_management_pb2
from tensorflow_serving.config import model_server_config_pb2

import grpc

def add_model_config(host, name, base_path, model_platform):
  channel = grpc.insecure_channel(host) 
  stub = model_service_pb2_grpc.ModelServiceStub(channel)
  request = model_management_pb2.ReloadConfigRequest() 
  model_server_config = model_server_config_pb2.ModelServerConfig()

  #Create a config to add to the list of served models
  config_list = model_server_config_pb2.ModelConfigList()       
  one_config = config_list.config.add()
  one_config.name= name
  one_config.base_path=base_path
  one_config.model_platform=model_platform

  model_server_config.model_config_list.CopyFrom(config_list)

  request.config.CopyFrom(model_server_config)

  print(request.IsInitialized())
  print(request.ListFields())

  response = stub.HandleReloadConfigRequest(request,10)
  if response.status.error_code == 0:
      print("Reload sucessfully")
  else:
      print("Reload failed!")
      print(response.status.error_code)
      print(response.status.error_message)


add_model_config(host="localhost:8500", 
                    name="my_model", 
                    base_path="/models/my_model", 
                    model_platform="tensorflow")

Answer 2

Add a model to TF Serving server and to the existing config file conf_filepath: Use arguments name, base_path, model_platform for the new model. Keeps the original models intact.

Notice a small difference from @Karl 's answer - using MergeFrom instead of CopyFrom

pip install tensorflow-serving-api

import grpc
from google.protobuf import text_format
from tensorflow_serving.apis import model_service_pb2_grpc, model_management_pb2
from tensorflow_serving.config import model_server_config_pb2


def add_model_config(conf_filepath, host, name, base_path, model_platform):
    with open(conf_filepath, 'r+') as f:
        config_ini = f.read()
    channel = grpc.insecure_channel(host)
    stub = model_service_pb2_grpc.ModelServiceStub(channel)
    request = model_management_pb2.ReloadConfigRequest()
    model_server_config = model_server_config_pb2.ModelServerConfig()
    config_list = model_server_config_pb2.ModelConfigList()
    model_server_config = text_format.Parse(text=config_ini, message=model_server_config)

    # Create a config to add to the list of served models
    one_config = config_list.config.add()
    one_config.name = name
    one_config.base_path = base_path
    one_config.model_platform = model_platform

    model_server_config.model_config_list.MergeFrom(config_list)
    request.config.CopyFrom(model_server_config)

    response = stub.HandleReloadConfigRequest(request, 10)
    if response.status.error_code == 0:
        with open(conf_filepath, 'w+') as f:
            f.write(request.config.__str__())
        print("Updated TF Serving conf file")
    else:
        print("Failed to update model_config_list!")
        print(response.status.error_code)
        print(response.status.error_message)

Answer 3

While the solutions mentioned here works fine, there is one more method that you can use to hot-reload your models. You can use --model_config_file_poll_wait_seconds

As mentioned here in the documentation -

By setting the --model_config_file_poll_wait_seconds flag to instruct the server to periodically check for a new config file at --model_config_file filepath.

So, you just have to update the config file at model_config_path and tf-serving will load any new models and unload any models removed from the config file.

---

Edit 1: I looked at the source code and it seems that the flag is present from the very early version of tf-serving but there have been instances where some users were not able to use this flag (see this). So, try to use the latest version if possible.