add prompt

Signed-off-by: junjie.jiang <junjie.jiang@zilliz.com>

README.md

@@ -1,2 +1,56 @@
-# template
+# question-answer
 
+<br />
+
+
+
+## Desription
+
+Prompt Template.
+
+
+<br />
+
+
+
+## Code Example
+
+### Example
+
+
+```python
+
+from towhee import ops, pipe
+import requests
+
+towhee_docs = requests.get('https://raw.githubusercontent.com/towhee-io/towhee/main/README.md').context
+
+temp = """{question}
+
+input:
+{context}
+"""
+
+p = (
+    pipe.input('question', 'doc', 'history')
+    .map(('question', 'doc', 'history'), 'prompt', ops.prompt.template(temp))
+    .map('prompt', 'answer', ops.LLM.OpenAI())
+    .output('answer')
+)
+
+an1 = p('Tell me something about Towhee', towhee_docs, []).get()[0]
+
+an2 = p('Give an example', towhee_docs, [('Tell me something about Towhee', an1)]).get()[0]
+
+```
+
+## Factory Constructor
+
+Create the operator via the following factory method:
+
+***ops.prompt.template(temp)***
+
+<br />
+
+
+**Returns:** *List[Dict]*

__init__.py

@@ -0,0 +1,4 @@
+from .template_prompt import TemplatePrompt
+
+def question_answer(temp: str):
+    return TemplatePrompt(temp)

template_prompt.py

@@ -0,0 +1,21 @@
+from typing import List, Tuple, Dict, Optional
+
+from towhee.operator import PyOperator
+
+
+class TemplatePrompt(PyOperator):
+    def __init__(self, temp: str):
+        super().__init__()
+        self._template = temp
+
+    def __call__(self, **kwargs) -> List[Dict[str, str]]:
+        history = kwargs.get('history', [])
+        prompt_str = self._template.format(**kwargs)
+        ret = [{'question': prompt_str}]
+        if not isinstance(history, list):
+            return ret
+        else:
+            history_data = []
+            for item in history:
+                history_data.append({'question': item[0], 'answer': item[1]})
+            return history_data + ret