adding pg support for external message persistance

src/backend/langflow/config.yaml

@@ -69,6 +69,7 @@ memories:
   - ConversationBufferMemory
   - ConversationSummaryMemory
   - ConversationKGMemory
+  - PostgresChatMessageHistory
 prompts:
   - PromptTemplate
   - FewShotPromptTemplate

src/backend/langflow/custom/customs.py

@@ -21,6 +21,9 @@ CUSTOM_NODES = {
     "utilities": {
         "SQLDatabase": frontend_node.agents.SQLDatabaseNode(),
     },
+    "memories": {
+        "PostgresChatMessageHistory": frontend_node.memories.PostgresChatMessageHistoryFrontendNode(),
+    },
     "chains": {
         "SeriesCharacterChain": frontend_node.chains.SeriesCharacterChainNode(),
         "TimeTravelGuideChain": frontend_node.chains.TimeTravelGuideChainNode(),

src/backend/langflow/interface/initialize/loading.py

@@ -225,6 +225,7 @@ def load_agent_executor(agent_class: type[agent_module.Agent], params, **kwargs)
     """Load agent executor from agent class, tools and chain"""
     allowed_tools: Sequence[BaseTool] = params.get("allowed_tools", [])
     llm_chain = params["llm_chain"]
+    memory = params["memory"]
     # if allowed_tools is not a list or set, make it a list
     if not isinstance(allowed_tools, (list, set)) and isinstance(
         allowed_tools, BaseTool
@@ -237,6 +238,7 @@ def load_agent_executor(agent_class: type[agent_module.Agent], params, **kwargs)
     return AgentExecutor.from_agent_and_tools(
         agent=agent,
         tools=allowed_tools,
+        memory=memory,
         **kwargs,
     )
 

src/backend/langflow/template/frontend_node/memories.py

@@ -2,6 +2,7 @@ from typing import Optional
 
 from langflow.template.field.base import TemplateField
 from langflow.template.frontend_node.base import FrontendNode
+from langflow.template.template.base import Template
 
 
 class MemoryFrontendNode(FrontendNode):
@@ -64,3 +65,42 @@ class MemoryFrontendNode(FrontendNode):
             field.value = ""
         if field.name == "memory_key":
             field.value = "chat_history"
+
+
+class PostgresChatMessageHistoryFrontendNode(MemoryFrontendNode):
+    name: str = "PostgresChatMessageHistory"
+    template: Template = Template(
+        type_name="PostgresChatMessageHistory",
+        fields=[
+            TemplateField(
+                field_type="str",
+                required=True,
+                placeholder="",
+                is_list=False,
+                show=True,
+                multiline=False,
+                name="session_id",
+            ),
+            TemplateField(
+                field_type="str",
+                required=True,
+                show=True,
+                name="connection_string",
+            ),
+            TemplateField(
+                field_type="str",
+                required=True,
+                placeholder="",
+                is_list=False,
+                show=True,
+                multiline=False,
+                value="message_store",
+                name="table_name",
+            ),
+        ],
+    )
+    description: str = "Memory store with Postgres"
+    base_classes: list[str] = [
+        "PostgresChatMessageHistory",
+        "BaseChatMessageHistory"
+    ]