Support llama3 tokenizer (#67)

* Support llama3 tokenizer

* Add tiktoken to requirements

* Add blobfile to requirements

* Fix unit tests

* Fix linting issues

* Fix pytype errors

* Move llama3 tokenizer to third_party directory

* Fix pytype error

* Update pytype command

Author: bhavya01

.github/workflows/unit_tests.yaml

@@ -50,7 +50,7 @@ jobs:
         pip install -r benchmarks/requirements.in
     - name: Typecheck the code with pytype
       run: |
-        pytype --jobs auto --disable import-error --disable module-attr jetstream/ benchmarks/
+        pytype --jobs auto --disable=import-error,module-attr jetstream/ benchmarks/
     - name: Analysing the code with pylint
       run: |
         pylint jetstream/ benchmarks/

jetstream/engine/token_utils.py

@@ -27,6 +27,7 @@
 from jetstream.engine import mock_utils
 from jetstream.engine import tokenizer_api
 from jetstream.engine import tokenizer_pb2
+from jetstream.third_party.llama3 import llama3_tokenizer
 
 # ResultToken class to store tokens ids.
 ResultTokens = Any
@@ -40,9 +41,10 @@ def take_nearest_length(lengths: list[int], length: int) -> int:
   return lengths[pos]
 
 
-def tokenize_and_pad(
-    s: str,
-    vocab: Vocabulary,
+def pad_tokens(
+    tokens: np.ndarray,
+    bos_id: int,
+    pad_id: int,
     is_bos: bool = True,
     prefill_lengths: Optional[List[int]] = None,
     max_prefill_length: Optional[int] = None,
@@ -84,14 +86,13 @@ def tokenize_and_pad(
     ] + [
         max_prefill_length,
     ]
-  tokens = np.array(vocab.encode_tf(s))  # [Length]
   # Add a beginning of sequence token if this is the beginning.
   if is_bos:
     tokens = np.concatenate(
         [
             np.array(
                 [
-                    vocab.bos_id,
+                    bos_id,
                 ]
             ),
             tokens,
@@ -101,13 +102,12 @@ def tokenize_and_pad(
   true_length = tokens.shape[-1]
   padded_length = take_nearest_length(prefill_lengths, true_length)
   padding = padded_length - true_length
-  assert vocab.pad_id == 0, "Further logic required if pad_id not 0."
   if padding < 0:
     logging.warning("Provided sequence longer than available.")
     # Take the last N tokens if we have too many.
     padded_tokens = tokens[-padded_length:]
   else:
-    padded_tokens = np.pad(tokens, (0, padding))
+    padded_tokens = np.pad(tokens, (0, padding), constant_values=(pad_id,))
   if jax_padding:
     padded_tokens = jnp.array(padded_tokens)
   return padded_tokens, true_length
@@ -117,7 +117,8 @@ def process_result_tokens(
     slot: int,
     slot_max_length: int,
     result_tokens: ResultTokens,
-    vocab: Vocabulary,
+    eos_id: int,
+    pad_id: int,
     complete: np.ndarray,
     debug: bool = False,
 ) -> Tuple[List[List[int]], np.ndarray]:
@@ -128,7 +129,8 @@ def process_result_tokens(
     slot: The slot at which to draw tokens from.
     slot_max_length: Max length for a sample in the slot.
     result_tokens: The tokens to access by slot.
-    vocab: For the detokenizer.
+    eos_id: Id for EOS token.
+    pad_id: Id for pad token.
     complete: Array representing the completion status of each sample in the
       slot.
     debug: Whether to log step by step detokenisation.
@@ -143,7 +145,7 @@ def process_result_tokens(
   slot_valid = slot_data.valid
   slot_lengths = slot_data.lengths
   samples, speculations = slot_tokens.shape
-  stop_tokens = [vocab.eos_id, vocab.pad_id]
+  stop_tokens = [eos_id, pad_id]
   # Stop anything which has reached it's max length.
   complete = complete | (slot_lengths > slot_max_length)
   if debug:
@@ -212,11 +214,9 @@ def encode(
       self, s: str, **kwargs
   ) -> Tuple[Union[jax.Array, np.ndarray], int]:
     """Tokenize a string.
-
     Args:
         s: String to tokenize.
         **kwargs: Additional keyword arguments
-
     Returns:
         tokens: Tokenized into integers.
         true_length: Actual length of the non-padded sequence
@@ -225,13 +225,18 @@ def encode(
     is_bos = kwargs.pop("is_bos", True)
     prefill_lengths = kwargs.pop("prefill_lengths", None)
     max_prefill_length = kwargs.pop("max_prefill_length", None)
+    jax_padding = kwargs.pop("jax_padding", True)
+
+    tokens = np.array(self.vocab.encode_tf(s))
 
-    tokens, true_length = tokenize_and_pad(
-        s,
-        self.vocab,
+    tokens, true_length = pad_tokens(
+        tokens,
+        self.bos_id,
+        self.pad_id,
         is_bos=is_bos,
         prefill_lengths=prefill_lengths,
         max_prefill_length=max_prefill_length,
+        jax_padding=jax_padding,
     )
     return tokens, true_length
 
@@ -245,15 +250,13 @@ def decode(
   ) -> Tuple[List[List[int]], np.ndarray]:
     """Processes a result tokens into a list of strings, handling multiple
     samples.
-
     Args:
       slot: The slot at which to draw tokens from.
       slot_max_length: Max length for a sample in the slot.
       result_tokens: The tokens to access by slot.
       complete: Array representing the completion status of each sample in the
         slot.
       kwargs: Additional keyword arguments.
-
     Returns:
       sample_return: List of strings, one per sample.
       complete: Updated complete.
@@ -263,12 +266,22 @@ def decode(
         slot=slot,
         slot_max_length=slot_max_length,
         result_tokens=result_tokens,
-        vocab=self.vocab,
+        eos_id=self.eos_id,
+        pad_id=self.pad_id,
         complete=complete,
         debug=debug,
     )
     return results, complete
 
+  def decode_str(self, token_ids: list[int]) -> str:
+    """Processess input token ids to generate a string.
+    Args:
+      token_ids: List of token ids.
+    Returns:
+      str: String generated from the token ids.
+    """
+    return self.vocab.tokenizer.decode(token_ids)
+
   @property
   def pad_id(self) -> int:
     """ID of the pad token."""
@@ -278,3 +291,102 @@ def pad_id(self) -> int:
   def eos_id(self) -> int:
     """ID of EOS token."""
     return self.vocab.eos_id
+
+  @property
+  def bos_id(self) -> int:
+    """ID of the BOS token."""
+    return self.vocab.bos_id
+
+
+class TikToken(tokenizer_api.Tokenizer):
+  """Tokenizer to convert strings to token ids and vice-versa."""
+
+  def __init__(self, metadata: tokenizer_pb2.TokenizerParameters):
+    self.tokenizer = llama3_tokenizer.Tokenizer(metadata.path)
+
+  def encode(
+      self, s: str, **kwargs
+  ) -> Tuple[Union[jax.Array, np.ndarray], int]:
+    """Tokenize a string.
+    Args:
+        s: String to tokenize.
+        **kwargs: Additional keyword arguments
+    Returns:
+        tokens: Tokenized into integers.
+        true_length: Actual length of the non-padded sequence
+          if padding is used.
+    """
+    is_bos = kwargs.pop("is_bos", True)
+    prefill_lengths = kwargs.pop("prefill_lengths", None)
+    max_prefill_length = kwargs.pop("max_prefill_length", None)
+    jax_padding = kwargs.pop("jax_padding", True)
+
+    tokens = np.array(self.tokenizer.encode(s, bos=False, eos=False))
+
+    tokens, true_length = pad_tokens(
+        tokens,
+        self.bos_id,
+        self.pad_id,
+        is_bos=is_bos,
+        prefill_lengths=prefill_lengths,
+        max_prefill_length=max_prefill_length,
+        jax_padding=jax_padding,
+    )
+    return tokens, true_length
+
+  def decode(
+      self,
+      slot: int,
+      slot_max_length: int,
+      result_tokens: ResultTokens,
+      complete: np.ndarray,
+      **kwargs,
+  ) -> Tuple[List[List[int]], np.ndarray]:
+    """Processes a result tokens into a list of strings, handling multiple
+    samples.
+    Args:
+      slot: The slot at which to draw tokens from.
+      slot_max_length: Max length for a sample in the slot.
+      result_tokens: The tokens to access by slot.
+      complete: Array representing the completion status of each sample in the
+        slot.
+      kwargs: Additional keyword arguments.
+    Returns:
+      sample_return: List of strings, one per sample.
+      complete: Updated complete.
+    """
+    debug = kwargs.pop("debug", False)
+    results, complete = process_result_tokens(
+        slot=slot,
+        slot_max_length=slot_max_length,
+        result_tokens=result_tokens,
+        eos_id=self.eos_id,
+        pad_id=self.pad_id,
+        complete=complete,
+        debug=debug,
+    )
+    return results, complete
+
+  def decode_str(self, token_ids: list[int]) -> str:
+    """Processess input token ids to generate a string.
+    Args:
+      token_ids: List of token ids.
+    Returns:
+      str: String generated from the token ids.
+    """
+    return self.tokenizer.decode(token_ids)
+
+  @property
+  def pad_id(self) -> int:
+    """ID of the pad token."""
+    return self.tokenizer.pad_id
+
+  @property
+  def eos_id(self) -> int:
+    """ID of EOS token."""
+    return self.tokenizer.eos_id
+
+  @property
+  def bos_id(self) -> int:
+    """ID of the BOS token."""
+    return self.tokenizer.bos_id

jetstream/engine/tokenizer_api.py

@@ -32,11 +32,9 @@ def encode(
       self, s: str, **kwargs
   ) -> Tuple[Union[jax.Array, np.ndarray], int]:
     """Tokenize a string.
-
     Args:
         s: String to tokenize.
         **kwargs: Additional keyword arguments
-
     Returns:
         tokens: Tokenized into integers.
         true_length: Actual length of the non-padded sequence
@@ -54,20 +52,26 @@ def decode(
   ) -> Tuple[list[list[int]], np.ndarray]:
     """Processes a result tokens into a list of token ids, handling multiple
     samples.
-
     Args:
       slot: The slot at which to draw tokens from.
       slot_max_length: Max length for a sample in the slot.
       result_tokens: The tokens to access by slot.
       complete: Array representing the completion status of each sample in the
         slot.
       **kwards: Additional keyword arguments.
-
     Returns:
-      sample_return: List of strings, one per sample.
+      sample_return: List of token_ids, one per sample.
       complete: Updated complete.
     """
-    # TODO(bbahl): Add an option to return str from decode.
+
+  @abc.abstractmethod
+  def decode_str(self, token_ids: list[int]) -> str:
+    """Processess input token ids to generate a string.
+    Args:
+      token_ids: List of token ids.
+    Returns:
+      str: String generated from the token ids.
+    """
 
   @property
   @abc.abstractmethod
@@ -78,3 +82,8 @@ def pad_id(self) -> int:
   @abc.abstractmethod
   def eos_id(self) -> int:
     """ID of EOS token."""
+
+  @property
+  @abc.abstractmethod
+  def bos_id(self) -> int:
+    """ID of BOS token."""

jetstream/tests/engine/test_mock_engine.py

@@ -52,8 +52,8 @@ def _prefill(self):
     # A 2 will be pre-pended as 'bos' token from the vocab.
     text = "AB"
     metadata = engine.get_tokenizer()
-    vocab = token_utils.load_vocab(metadata.path, metadata.extra_ids)
-    tokens, true_length = token_utils.tokenize_and_pad(text, vocab, is_bos=True)
+    tokenizer = engine.build_tokenizer(metadata)
+    tokens, true_length = tokenizer.encode(text, is_bos=True)
     prefill_result = engine.prefill(
         params=params, padded_tokens=tokens, true_length=3
     )
@@ -65,10 +65,8 @@ def _prefill_np(self):
     # A 2 will be pre-pended as 'bos' token from the vocab.
     text = "AB"
     metadata = engine.get_tokenizer()
-    vocab = token_utils.load_vocab(metadata.path, metadata.extra_ids)
-    tokens, true_length = token_utils.tokenize_and_pad(
-        text, vocab, is_bos=True, jax_padding=False
-    )
+    tokenizer = engine.build_tokenizer(metadata)
+    tokens, true_length = tokenizer.encode(text, is_bos=True, jax_padding=False)
     prefill_result = engine.prefill(
         params=params, padded_tokens=tokens, true_length=3
     )