There are many instances were you want to provide human oversight of the agents work. This lesson builds on what we looked at in Lesson 4.
As a graph is executed a snapshot of the state is stored in the memory:
|
v
---
|0,3|<-------
--- | Memory
| | ---------
v | | State 3 |
/ \ | ---------
< 1 > | | State 2 |
\ / | ---------
/ V \ | | State 1 |
/ \ | ---------
--- --- | | State 0 |
| | | 2 |----- ---------
--- --- |
V
StateSnapshot: { AgentState, useful_things}
|
V
{..., thread, thread_ts, ...}
| |
V |
config = {configurable: {thread_id: '1', V
thread_ts: '1ef17b36-ed06-6185-8001-15cf75dea535'}};
The thread and the thread_ts (the threads UID) can be used to access the states:
config = {configurable: {thread_id: '1'}}; ---------
| | State 3 |
V ---------
graph.getState({..., thread, ...}); Returns 'current state'
We can also get an iterator over all of the previous states:
---------
graph.getStateHistory({..., thread, ...}); | State 3 |
--------- |
--------- |
Returns an iterator over --------- |
all StateSnapshots ---------
Using the iterator allows us to get individual snapshots with their UIDs thread_ts we can then use this to replay from a previous point:
graph.invoke(null, {..., thread, thread_ts, ...}); ---------
graph.stream(null, {..., thread, thread_ts, ...}); | State n |
---------
Run with state n as the
starting point, Time Travel
If we do the above with out the thread_ts identifier we will use the current state as the starting point:
graph.invoke(null, {..., thread, ...}); ---------
graph.stream(null, {..., thread, ...}); | State 3 |
---------
Uses the current state
as the starting point
We can also use the thread_ts to access a previous state, we can then modify it and add the modified state back on the memory stack making it the current state:
---------
graph.getState({..., thread, thread_ts, ...}); | State 1 |
---------
|
V
---------
modify it | State m |
---------
|
V
---------
graph.updateState(thread, state_m.values); | State 4 |
---------
graph.invoke(null, {..., thread, ...}); Runs state 4 as the current state.