1. Build a basic chatbot using Gemini 2.0 flash

.env.template

@@ -0,0 +1 @@
+GOOGLE_API_KEY=your_google_api_key_here

.gitignore

@@ -136,6 +136,7 @@ venv/
 ENV/
 env.bak/
 venv.bak/
+Scripts/
 
 # Spyder project settings
 .spyderproject

Include/site/python3.13/greenlet/greenlet.h

@@ -0,0 +1,164 @@
+/* -*- indent-tabs-mode: nil; tab-width: 4; -*- */
+
+/* Greenlet object interface */
+
+#ifndef Py_GREENLETOBJECT_H
+#define Py_GREENLETOBJECT_H
+
+
+#include <Python.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This is deprecated and undocumented. It does not change. */
+#define GREENLET_VERSION "1.0.0"
+
+#ifndef GREENLET_MODULE
+#define implementation_ptr_t void*
+#endif
+
+typedef struct _greenlet {
+    PyObject_HEAD
+    PyObject* weakreflist;
+    PyObject* dict;
+    implementation_ptr_t pimpl;
+} PyGreenlet;
+
+#define PyGreenlet_Check(op) (op && PyObject_TypeCheck(op, &PyGreenlet_Type))
+
+
+/* C API functions */
+
+/* Total number of symbols that are exported */
+#define PyGreenlet_API_pointers 12
+
+#define PyGreenlet_Type_NUM 0
+#define PyExc_GreenletError_NUM 1
+#define PyExc_GreenletExit_NUM 2
+
+#define PyGreenlet_New_NUM 3
+#define PyGreenlet_GetCurrent_NUM 4
+#define PyGreenlet_Throw_NUM 5
+#define PyGreenlet_Switch_NUM 6
+#define PyGreenlet_SetParent_NUM 7
+
+#define PyGreenlet_MAIN_NUM 8
+#define PyGreenlet_STARTED_NUM 9
+#define PyGreenlet_ACTIVE_NUM 10
+#define PyGreenlet_GET_PARENT_NUM 11
+
+#ifndef GREENLET_MODULE
+/* This section is used by modules that uses the greenlet C API */
+static void** _PyGreenlet_API = NULL;
+
+#    define PyGreenlet_Type \
+        (*(PyTypeObject*)_PyGreenlet_API[PyGreenlet_Type_NUM])
+
+#    define PyExc_GreenletError \
+        ((PyObject*)_PyGreenlet_API[PyExc_GreenletError_NUM])
+
+#    define PyExc_GreenletExit \
+        ((PyObject*)_PyGreenlet_API[PyExc_GreenletExit_NUM])
+
+/*
+ * PyGreenlet_New(PyObject *args)
+ *
+ * greenlet.greenlet(run, parent=None)
+ */
+#    define PyGreenlet_New                                        \
+        (*(PyGreenlet * (*)(PyObject * run, PyGreenlet * parent)) \
+             _PyGreenlet_API[PyGreenlet_New_NUM])
+
+/*
+ * PyGreenlet_GetCurrent(void)
+ *
+ * greenlet.getcurrent()
+ */
+#    define PyGreenlet_GetCurrent \
+        (*(PyGreenlet * (*)(void)) _PyGreenlet_API[PyGreenlet_GetCurrent_NUM])
+
+/*
+ * PyGreenlet_Throw(
+ *         PyGreenlet *greenlet,
+ *         PyObject *typ,
+ *         PyObject *val,
+ *         PyObject *tb)
+ *
+ * g.throw(...)
+ */
+#    define PyGreenlet_Throw                 \
+        (*(PyObject * (*)(PyGreenlet * self, \
+                          PyObject * typ,    \
+                          PyObject * val,    \
+                          PyObject * tb))    \
+             _PyGreenlet_API[PyGreenlet_Throw_NUM])
+
+/*
+ * PyGreenlet_Switch(PyGreenlet *greenlet, PyObject *args)
+ *
+ * g.switch(*args, **kwargs)
+ */
+#    define PyGreenlet_Switch                                              \
+        (*(PyObject *                                                      \
+           (*)(PyGreenlet * greenlet, PyObject * args, PyObject * kwargs)) \
+             _PyGreenlet_API[PyGreenlet_Switch_NUM])
+
+/*
+ * PyGreenlet_SetParent(PyObject *greenlet, PyObject *new_parent)
+ *
+ * g.parent = new_parent
+ */
+#    define PyGreenlet_SetParent                                 \
+        (*(int (*)(PyGreenlet * greenlet, PyGreenlet * nparent)) \
+             _PyGreenlet_API[PyGreenlet_SetParent_NUM])
+
+/*
+ * PyGreenlet_GetParent(PyObject* greenlet)
+ *
+ * return greenlet.parent;
+ *
+ * This could return NULL even if there is no exception active.
+ * If it does not return NULL, you are responsible for decrementing the
+ * reference count.
+ */
+#     define PyGreenlet_GetParent                                    \
+    (*(PyGreenlet* (*)(PyGreenlet*))                                 \
+     _PyGreenlet_API[PyGreenlet_GET_PARENT_NUM])
+
+/*
+ * deprecated, undocumented alias.
+ */
+#     define PyGreenlet_GET_PARENT PyGreenlet_GetParent
+
+#     define PyGreenlet_MAIN                                         \
+    (*(int (*)(PyGreenlet*))                                         \
+     _PyGreenlet_API[PyGreenlet_MAIN_NUM])
+
+#     define PyGreenlet_STARTED                                      \
+    (*(int (*)(PyGreenlet*))                                         \
+     _PyGreenlet_API[PyGreenlet_STARTED_NUM])
+
+#     define PyGreenlet_ACTIVE                                       \
+    (*(int (*)(PyGreenlet*))                                         \
+     _PyGreenlet_API[PyGreenlet_ACTIVE_NUM])
+
+
+
+
+/* Macro that imports greenlet and initializes C API */
+/* NOTE: This has actually moved to ``greenlet._greenlet._C_API``, but we
+   keep the older definition to be sure older code that might have a copy of
+   the header still works. */
+#    define PyGreenlet_Import()                                               \
+        {                                                                     \
+            _PyGreenlet_API = (void**)PyCapsule_Import("greenlet._C_API", 0); \
+        }
+
+#endif /* GREENLET_MODULE */
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_GREENLETOBJECT_H */

README.md

@@ -1,3 +1,11 @@
-# test_langgraph
+# Test of LangGraph
 
-First test of LangGraph
+First test of LangGraph following the documentation
+
+Step 1 : follow the LangGraph tutorial "Build a custom workflow"
+Step 2 : use the base to create a different custom workflow
+
+To use, install all dependancies : requirements.txt
+Add your Google Gemini API key in .env
+Run : python -m main
+Exit with "quit", "exit", "q"

main.py

@@ -0,0 +1,35 @@
+# from src.graph_builder import build_graph
+from src.graph_builder import graph_builder
+from src.nodes import chatbot
+from langgraph.graph import START, END
+
+
+# The first argument is the unique node name
+# The second argument is the function or object that will be called whenever
+# the node is used.
+
+if __name__ == "__main__":
+    graph_builder.add_node("chatbot", chatbot)
+    graph_builder.add_edge(START, "chatbot")
+    graph_builder.add_edge("chatbot", END)
+    graph = graph_builder.compile()
+
+    def stream_graph_updates(user_input: str):
+        for event in graph.stream({"messages": [{"role": "user", "content": user_input}]}):
+            for value in event.values():
+                print("Assistant:", value["messages"][-1].content)
+
+
+    while True:
+        try:
+            user_input = input("User: ")
+            if user_input.lower() in ["quit", "exit", "q"]:
+                print("Goodbye!")
+                break
+            stream_graph_updates(user_input)
+        except:
+            # fallback if input() is not available
+            user_input = "What do you know about LangGraph?"
+            print("User: " + user_input)
+            stream_graph_updates(user_input)
+            break

pyvenv.cfg

@@ -0,0 +1,5 @@
+home = C:\Users\julie\AppData\Local\Programs\Python\Python313
+include-system-site-packages = false
+version = 3.13.0
+executable = C:\Users\julie\AppData\Local\Programs\Python\Python313\python.exe
+command = C:\Users\julie\AppData\Local\Programs\Python\Python313\python.exe -m venv C:\Users\julie\projects\test_langgraph

src/graph_builder.py

@@ -0,0 +1,32 @@
+# Defines and builds the StateGraph 
+
+from typing import Annotated
+
+from typing_extensions import TypedDict
+
+from langgraph.graph import StateGraph, START, END
+from langgraph.graph.message import add_messages
+
+
+class State(TypedDict):
+    # Messages have the type "list". The `add_messages` function
+    # in the annotation defines how this state key should be updated
+    # (in this case, it appends messages to the list, rather than overwriting them)
+    messages: Annotated[list, add_messages]
+
+
+graph_builder = StateGraph(State)
+
+
+
+
+
+# from langgraph import Graph
+# from src.nodes import CustomNode
+
+# def build_graph():
+#     graph = Graph()
+#     # Add nodes and edges here
+#     node = CustomNode()
+#     graph.add_node(node)
+#     return graph

src/nodes.py

@@ -0,0 +1,21 @@
+import os
+from dotenv import load_dotenv
+from langchain.chat_models import init_chat_model
+from langgraph.graph import StateGraph
+from src.graph_builder import State
+
+load_dotenv()
+
+#os.environ["GOOGLE_API_KEY"] = "..."
+
+llm = init_chat_model("google_genai:gemini-2.0-flash")
+
+def chatbot(state: State):
+    return {"messages": [llm.invoke(state["messages"])]}
+
+
+# class CustomNode:
+#     def __init__(self):
+#         pass
+#     def run(self):
+#         print("Custom node running")

src/utils.py

@@ -0,0 +1 @@
+# Utility functions for LangGraph project

tests/test_graph.py

@@ -0,0 +1,10 @@
+import unittest
+from src.graph_builder import build_graph
+
+class TestGraph(unittest.TestCase):
+    def test_graph_runs(self):
+        graph = build_graph()
+        self.assertIsNotNone(graph)
+
+if __name__ == "__main__":
+    unittest.main()