Cross-posts happened to other thread.
   This looks useful:
   [1]https://github.com/google/sentencepiece/blob/master/python/README.md
   #training-without-local-filesystem
import urllib.request
import io
import sentencepiece as spm

# Loads model from URL as iterator and stores the model to BytesIO.
model = io.BytesIO()
with urllib.request.urlopen(
    '[2]https://raw.githubusercontent.com/google/sentencepiece/master/data/botch
an.txt'
) as response:
  spm.SentencePieceTrainer.train(
      sentence_iterator=response, model_writer=model, vocab_size=1000)

# Serialize the model as file.
# with open('out.model', 'wb') as f:
#   f.write(model.getvalue())

# Directly load the model from serialized model.
sp = spm.SentencePieceProcessor(model_proto=model.getvalue())
print(sp.encode('this is test'))

References

   1. https://github.com/google/sentencepiece/blob/master/python/README.md#training-without-local-filesystem
   2. https://raw.githubusercontent.com/google/sentencepiece/master/data/botchan.txt