Handle openai change of api base for just embeddings (zilliztech#495)

gptcache/embedding/openai.py

@@ -27,13 +27,19 @@ class OpenAI(BaseEmbedding):
             embed = encoder.to_embeddings(test_sentence)
     """
 
-    def __init__(self, model: str = "text-embedding-ada-002", api_key: str = None):
+    def __init__(self, model: str = "text-embedding-ada-002", api_key: str = None, api_base: str = None):
         if not api_key:
             if openai.api_key:
                 api_key = openai.api_key
             else:
                 api_key = os.getenv("OPENAI_API_KEY")
+        if not api_base:
+            if openai.api_base:
+                api_base = openai.api_base
+            else:
+                api_base = os.getenv("OPENAI_API_BASE")
         openai.api_key = api_key
+        self.api_base = api_base  # don't override all of openai as we may just want to override for say embeddings
         self.model = model
         if model in self.dim_dict():
             self.__dimension = self.dim_dict()[model]
@@ -48,7 +54,7 @@ def to_embeddings(self, data, **_):
 
         :return: a text embedding in shape of (dim,).
         """
-        sentence_embeddings = openai.Embedding.create(model=self.model, input=data)
+        sentence_embeddings = openai.Embedding.create(model=self.model, input=data, api_base=self.api_base)
         return np.array(sentence_embeddings["data"][0]["embedding"]).astype("float32")
 
     @property