Exports the Trackable object obj to SavedModel format.

Used in the notebooks

Used in the guide Used in the tutorials

Example usage:

class Adder(tf.Module):

  @tf.function(input_signature=[tf.TensorSpec(shape=None, dtype=tf.float32)])
  def add(self, x):
    return x + x + 1.

to_export = Adder(), '/tmp/adder')

The resulting SavedModel is then servable with an input named "x", its value having any shape and dtype float32.

The optional signatures argument controls which methods in obj will be available to programs which consume SavedModels, for example, serving APIs. Python functions may be decorated with @tf.function(input_signature=...) and passed as signatures directly, or lazily with a call to get_concrete_function on the method decorated with @tf.function.

If the signatures argument is omitted, obj will be searched for @tf.function-decorated methods. If exactly one @tf.function is found, that method will be used as the default signature for the SavedModel. This behavior is expected to change in the future, when a corresponding tf.saved_model.load symbol is added. At that point signatures will be completely optional, and any @tf.function attached to obj or its dependencies will be exported for use with load.

When invoking a signature in an exported SavedModel, Tensor arguments are identified by name. These names will come from the Python function's argument names by default. They may be overridden by specifying a name=... argument in the corresponding tf.TensorSpec object. Explicit naming is required if multiple Tensors are passed through a single argument to the Python function.

The outputs of functions used as signatures must either be flat lists, in which case outputs will be numbered, or a dictionary mapping string keys to Tensor, in which case the keys will be used to name outputs.

Signatures are available in objects returned by tf.saved_model.load as a .signatures attribute. This is a reserved attribute: on an object with a custom .signatures attribute will raise an exception.

Since tf.keras.Model objects are also Trackable, this function can be used to export Keras models. For example, exporting with a signature specified:

class Model(tf.keras.Model):

  @tf.function(input_signature=[tf.TensorSpec(shape=[None], dtype=tf.string)])
  def serve(self, serialized):

m = Model(), '/tmp/saved_model/')

Exporting from a function without a fixed signature: