mirror of
https://github.com/langchain-ai/langgraph.git
synced 2026-09-28 04:25:08 +02:00
x
This commit is contained in:
@@ -451,25 +451,54 @@ Read [this how-to](https://langchain-ai.github.io/langgraph/how-tos/recursion-li
|
||||
|
||||
## Breakpoints
|
||||
|
||||
It can often be useful to set breakpoints before or after certain nodes execute. This can be used to wait for human approval before continuing. These can be set when you ["compile" a graph](#compiling-your-graph). You can set breakpoints either _before_ a node executes (using `interrupt_before`) or after a node executes (using `interrupt_after`.)
|
||||
Breakpoints enable **human-in-the-loop** workflows by **pausing** graph execution to allow for human review before continuing.
|
||||
|
||||
You **MUST** use a [checkpointer](./persistence.md) when using breakpoints. This is because your graph needs to be able to resume execution.
|
||||
You **MUST** use a [checkpointer](./persistence.md) when using breakpoints as breakpoints require the ability to save the state of the graph at the time of pausing.
|
||||
|
||||
In order to resume execution, you can just invoke your graph with `None` as the input.
|
||||
There are two types of breakpoints:
|
||||
|
||||
1. **Static breakpoints**: Pause the graph **before** or **after** a node executes.
|
||||
2. **Dynamic breakpoints**: Pause the graph from **inside** a node.
|
||||
|
||||
### Static Breakpoints
|
||||
|
||||
To set static breakpoints, specify the `interrupt_before` and/or `interrupt_after` key when [compiling your graph](#compiling-your-graph).
|
||||
|
||||
```python
|
||||
# Initial run of graph
|
||||
graph.invoke(inputs, config=config)
|
||||
|
||||
# Let's assume it hit a breakpoint somewhere, you can then resume by passing in None
|
||||
graph.invoke(None, config=config)
|
||||
graph = graph_builder.compile(
|
||||
interrupt_before=["node_a"],
|
||||
interrupt_after=["node_b", "node_c"],
|
||||
checkpointer=..., # Required
|
||||
)
|
||||
```
|
||||
|
||||
See [this guide](../how-tos/human_in_the_loop/breakpoints.ipynb) for a full walkthrough of how to add breakpoints.
|
||||
When using sub-graphs, specify the `interrupt_before` and `interrupt_after` values when compiling the subgraph.
|
||||
|
||||
### Dynamic Breakpoints
|
||||
### Dynamic Breakpoints
|
||||
|
||||
It may be helpful to **dynamically** interrupt the graph from inside a given node based on some condition. In `LangGraph` you can do so by using `NodeInterrupt` -- a special exception that can be raised from inside a node.
|
||||
There are two ways to interrupt the graph dynamically:
|
||||
|
||||
1. `interrupt` **function (recommended)**: Interrupts the graph within a node and surfaces a value to the client as part of the interrupt information.
|
||||
2. `NodeInterrupt` exception: An older, less flexible method for interrupting.
|
||||
|
||||
#### `interrupt`
|
||||
|
||||
```python
|
||||
from langgraph.types import interrupt
|
||||
|
||||
def node(state: State):
|
||||
...
|
||||
client_value = interrupt(
|
||||
# This value will be sent to the client.
|
||||
# It can be any JSON serializable value.
|
||||
{"key": "value"}
|
||||
)
|
||||
...
|
||||
```
|
||||
|
||||
#### `NodeInterrupt`
|
||||
|
||||
Throw a `NodeInterrupt` exception to interrupt the graph.
|
||||
|
||||
```python
|
||||
def my_node(state: State) -> State:
|
||||
@@ -479,6 +508,46 @@ def my_node(state: State) -> State:
|
||||
return state
|
||||
```
|
||||
|
||||
### Resuming
|
||||
|
||||
When a breakpoint is hit, graph execution will pause.
|
||||
|
||||
=== "Command"
|
||||
|
||||
Resume execution using the new `Command` primitive.
|
||||
|
||||
```python
|
||||
graph.invoke(inputs, config=config) # This will pause at the breakpoint
|
||||
...
|
||||
# Do something (e.g., get human input)
|
||||
...
|
||||
graph.invoke(
|
||||
Command(
|
||||
# Use `resume` to pass a value to the `interrupt`.
|
||||
resume=resume,
|
||||
# For other kinds of breakpoints, use `update` to update the state.
|
||||
update=update,
|
||||
),
|
||||
config=config
|
||||
)
|
||||
```
|
||||
|
||||
=== "Without the Command Primitive"
|
||||
|
||||
Resume execution without the `Command` primitive (older versions of LangGraph).
|
||||
|
||||
```python
|
||||
graph.invoke(inputs, config=config) # This will pause at the breakpoint
|
||||
...
|
||||
# Do something (e.g., get human input)
|
||||
...
|
||||
|
||||
graph.update_state(update, config=config)
|
||||
graph.invoke(None, config=config)
|
||||
```
|
||||
|
||||
See [this guide](../how-tos/human_in_the_loop/breakpoints.ipynb) for a full walkthrough of how to add breakpoints.
|
||||
|
||||
## Subgraphs
|
||||
|
||||
A subgraph is a [graph](#graphs) that is used as a [node](#nodes) in another graph. This is nothing more than the age-old concept of encapsulation, applied to LangGraph. Some reasons for using subgraphs are:
|
||||
|
||||
Reference in New Issue
Block a user