API: Add allowed_tokens support

This is the opposite of banned tokens. Exllama specific implementation
of #181.

Signed-off-by: kingbri <bdashore3@proton.me>

backends/exllamav2/model.py

@@ -1099,6 +1099,11 @@ class ExllamaV2Container:
         if banned_tokens:
             gen_settings.disallow_tokens(self.tokenizer, banned_tokens)
 
+        # Set allowed tokens
+        allowed_tokens = unwrap(kwargs.get("allowed_tokens"), [])
+        if allowed_tokens:
+            gen_settings.allow_tokens(self.tokenizer, allowed_tokens)
+
         # Set logit bias
         if logit_bias:
             # Create a vocab tensor if it doesn't exist for token biasing
@@ -1167,7 +1172,7 @@ class ExllamaV2Container:
         log_prompt(
             f"{self.tokenizer.bos_token if add_bos_token else ''}{prompt}",
             request_id,
-            negative_prompt
+            negative_prompt,
         )
 
         # Create and add a new job
@@ -1313,6 +1318,7 @@ class ExllamaV2Container:
                 logprobs=request_logprobs,
                 stop_conditions=stop_conditions,
                 banned_tokens=banned_tokens,
+                allowed_tokens=allowed_tokens,
                 banned_strings=banned_strings,
                 logit_bias=logit_bias,
                 filters=grammar_handler.filters,

common/sampling.py

@@ -50,6 +50,13 @@ class BaseSamplerRequest(BaseModel):
         examples=[[128, 330]],
     )
 
+    allowed_tokens: Optional[Union[List[int], str]] = Field(
+        default_factory=lambda: get_default_sampler_value("allowed_tokens", []),
+        validation_alias=AliasChoices("allowed_tokens", "allowed_token_ids"),
+        description="Aliases: allowed_token_ids",
+        examples=[[128, 330]],
+    )
+
     token_healing: Optional[bool] = Field(
         default_factory=lambda: get_default_sampler_value("token_healing", False)
     )
@@ -287,12 +294,17 @@ class BaseSamplerRequest(BaseModel):
         if self.banned_strings and isinstance(self.banned_strings, str):
             self.banned_strings = [self.banned_strings]
 
-        # Convert string banned tokens to an integer list
+        # Convert string banned and allowed tokens to an integer list
         if self.banned_tokens and isinstance(self.banned_tokens, str):
             self.banned_tokens = [
                 int(x) for x in self.banned_tokens.split(",") if x.isdigit()
             ]
 
+        if self.allowed_tokens and isinstance(self.allowed_tokens, str):
+            self.allowed_tokens = [
+                int(x) for x in self.allowed_tokens.split(",") if x.isdigit()
+            ]
+
         gen_params = {
             "max_tokens": self.max_tokens,
             "min_tokens": self.min_tokens,
@@ -305,6 +317,7 @@ class BaseSamplerRequest(BaseModel):
             "token_healing": self.token_healing,
             "logit_bias": self.logit_bias,
             "banned_tokens": self.banned_tokens,
+            "allowed_tokens": self.allowed_tokens,
             "temperature": self.temperature,
             "temperature_last": self.temperature_last,
             "min_temp": self.min_temp,

sampler_overrides/sample_preset.yml

@@ -126,6 +126,10 @@ banned_tokens:
   override: []
   force: false
   additive: false
+allowed_tokens:
+  override: []
+  force: false
+  additive: false
 
 # MARK: CFG scale
 cfg_scale: