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Hosting your own models

TensorFlow Hub provides an open repository of trained models at thub.dev. The tensorflow_hub library can load models from this repository and other HTTP based repositories of machine learning models. In particular the protocol allows to use the URL identifying the model both for the documentation of the model and the endpoint to fetch the model.

If you are interested in hosting your own repository of models that are loadable with the tensorflow_hub library, your HTTP distribution service should follow the following protocol.

Protocol

When a URL such as https://example.com/model is used to identify a model to load or instantiate, the model resolver will attempt to download a compressed tarball from the URL after appending a query parameter ?tf-hub-format=compressed.

The query param is to be interpreted as a comma separated list of the model formats that the client is interested in. For now only the "compressed" format is defined.

The compressed format indicates that the client expects a tar.gz archive with the model contents. The root of the archive is the root of the model directory and should contain a SavedModel, as in this example:

# Create a compressed model from a SavedModel directory.
$ tar -cz -f model.tar.gz --owner=0 --group=0 -C /tmp/export-model/ .

# Inspect files inside a compressed model
$ tar -tf model.tar.gz
./
./variables/
./variables/variables.data-00000-of-00001
./variables/variables.index
./assets/
./saved_model.pb

Tarballs for use with the deprecated hub.Module() API from TF1 will also contain a ./tfhub_module.pb file. The hub.load() API for TF2 SavedModels ignores such a file.

The tensorflow_hub library expects that model URLs are versioned and that the model content of a given version is immutable, so that it can be cached indefinitely.