Feat/environment variables in workflow (#6515)

Co-authored-by: JzoNg <jzongcode@gmail.com>

api/core/workflow/utils/variable_template_parser.py

@@ -3,12 +3,46 @@ from collections.abc import Mapping
 from typing import Any
 
 from core.workflow.entities.variable_entities import VariableSelector
+from core.workflow.entities.variable_pool import VariablePool
 
-REGEX = re.compile(r"\{\{(#[a-zA-Z0-9_]{1,50}(\.[a-zA-Z_][a-zA-Z0-9_]{0,29}){1,10}#)\}\}")
+REGEX = re.compile(r'\{\{(#[a-zA-Z0-9_]{1,50}(\.[a-zA-Z_][a-zA-Z0-9_]{0,29}){1,10}#)\}\}')
+
+
+def parse_mixed_template(*, template: str, variable_pool: VariablePool) -> str:
+    """
+    This is an alternative to the VariableTemplateParser class,
+    offering the same functionality but with better readability and ease of use.
+    """
+    variable_keys = [match[0] for match in re.findall(REGEX, template)]
+    variable_keys = list(set(variable_keys))
+
+    # This key_selector is a tuple of (key, selector) where selector is a list of keys
+    # e.g. ('#node_id.query.name#', ['node_id', 'query', 'name'])
+    key_selectors = filter(
+        lambda t: len(t[1]) >= 2,
+        ((key, selector.replace('#', '').split('.')) for key, selector in zip(variable_keys, variable_keys)),
+    )
+    inputs = {key: variable_pool.get_any(selector) for key, selector in key_selectors}
+
+    def replacer(match):
+        key = match.group(1)
+        # return original matched string if key not found
+        value = inputs.get(key, match.group(0))
+        if value is None:
+            value = ''
+        value = str(value)
+        # remove template variables if required
+        return re.sub(REGEX, r'{\1}', value)
+
+    result = re.sub(REGEX, replacer, template)
+    result = re.sub(r'<\|.*?\|>', '', result)
+    return result
 
 
 class VariableTemplateParser:
     """
+    !NOTE: Consider to use the new `segments` module instead of this class.
+
     A class for parsing and manipulating template variables in a string.
 
     Rules:
@@ -72,14 +106,11 @@ class VariableTemplateParser:
             if len(split_result) < 2:
                 continue
 
-            variable_selectors.append(VariableSelector(
-                variable=variable_key,
-                value_selector=split_result
-            ))
+            variable_selectors.append(VariableSelector(variable=variable_key, value_selector=split_result))
 
         return variable_selectors
 
-    def format(self, inputs: Mapping[str, Any], remove_template_variables: bool = True) -> str:
+    def format(self, inputs: Mapping[str, Any]) -> str:
         """
         Formats the template string by replacing the template variables with their corresponding values.
 
@@ -90,6 +121,7 @@ class VariableTemplateParser:
         Returns:
             The formatted string with template variables replaced by their values.
         """
+
         def replacer(match):
             key = match.group(1)
             value = inputs.get(key, match.group(0))  # return original matched string if key not found
@@ -99,11 +131,9 @@ class VariableTemplateParser:
             # convert the value to string
             if isinstance(value, list | dict | bool | int | float):
                 value = str(value)
-                
+
             # remove template variables if required
-            if remove_template_variables:
-                return VariableTemplateParser.remove_template_variables(value)
-            return value
+            return VariableTemplateParser.remove_template_variables(value)
 
         prompt = re.sub(REGEX, replacer, self.template)
         return re.sub(r'<\|.*?\|>', '', prompt)