pocketflow/cookbook/pocketflow-streamlit-hitl/app.py

177 lines
9.0 KiB
Python

import streamlit as st
from flow import create_initial_processing_flow, create_finalization_flow
st.title("PocketFlow HITL with Streamlit")
# Initialize session state variables if they don't exist
if 'stage' not in st.session_state:
st.session_state.stage = "initial"
st.session_state.error_message = None
st.session_state.task_input = ""
# Flow-related data will be added directly as needed
print("Initialized session state.")
# --- Helper Function to Reset State ---
def reset_state():
# Keep essential Streamlit state keys if necessary, or clear selectively
keys_to_clear = [k for k in st.session_state.keys() if k not in ['stage', 'error_message', 'task_input']]
for key in keys_to_clear:
del st.session_state[key]
st.session_state.stage = "initial"
st.session_state.error_message = None
st.session_state.task_input = ""
print("Reset session state (keeping core stage/error keys).")
# --- Display Area for Shared Data (now the entire session state) ---
with st.expander("Show Session State (Shared Data)"):
# Convert to dict for clean JSON display, excluding internal Streamlit keys if desired
display_state = {k: v for k, v in st.session_state.items() if not k.startswith("_")}
st.json(display_state)
# --- Stage: Initial Input ---
st.header("1. Submit Data for Processing")
task_input_value = st.text_area(
"Enter data to process:",
value=st.session_state.task_input,
height=150,
disabled=(st.session_state.stage != "initial")
)
# Disable button if not in 'initial' stage
submit_button_disabled = (st.session_state.stage != "initial")
if st.button("Submit", disabled=submit_button_disabled):
if not submit_button_disabled: # Process click only if button was not meant to be disabled
if not task_input_value.strip():
st.error("Please enter some data to process.")
else:
print(f"Submit button clicked. Input: '{task_input_value[:50]}...'")
# Store input directly in session state
st.session_state.task_input = task_input_value
st.session_state.error_message = None
# Clear previous results if any
if "processed_output" in st.session_state: del st.session_state.processed_output
if "final_result" in st.session_state: del st.session_state.final_result
if "input_used_by_process" in st.session_state: del st.session_state.input_used_by_process
try:
with st.spinner("Processing initial task..."):
initial_flow = create_initial_processing_flow()
# Pass the entire session state as shared data
initial_flow.run(st.session_state)
# Check if processing was successful (output exists directly in session state)
if "processed_output" in st.session_state:
st.session_state.stage = "awaiting_review"
print("Initial processing complete. Moving to 'awaiting_review' stage.")
st.rerun()
else:
st.session_state.error_message = "Processing failed to produce an output."
print("Error: Processing failed, no output found.")
# Keep stage as initial to allow retry/correction
except Exception as e:
st.session_state.error_message = f"An error occurred during initial processing: {e}"
print(f"Exception during initial processing: {e}")
# Keep stage as initial
# --- Stage: Awaiting Review ---
st.header("2. Review Processed Output")
# Get processed output directly from session state
processed_output = st.session_state.get("processed_output", "No output to review yet.")
# Display placeholder if no output yet or not in review stage
output_to_display = processed_output if st.session_state.stage == "awaiting_review" else "Output will appear here after submission."
st.subheader("Output to Review:")
st.markdown(f"```\\n{str(output_to_display)}\\n```") # Display as markdown code block
col1, col2, _ = st.columns([1, 1, 5]) # Layout buttons
with col1:
# Disable button if not in 'awaiting_review' stage
approve_button_disabled = (st.session_state.stage != "awaiting_review")
if st.button("Approve", disabled=approve_button_disabled):
if not approve_button_disabled: # Process click only if button was not meant to be disabled
print("Approve button clicked.")
st.session_state.error_message = None
try:
with st.spinner("Finalizing result..."):
finalization_flow = create_finalization_flow()
# Pass the entire session state
finalization_flow.run(st.session_state)
# Check for final result directly in session state
if "final_result" in st.session_state:
st.session_state.stage = "completed"
print("Approval processed. Moving to 'completed' stage.")
st.rerun()
else:
st.session_state.error_message = "Finalization failed to produce a result."
print("Error: Finalization failed, no final_result found.")
# Stay in review stage and show error.
except Exception as e:
st.session_state.error_message = f"An error occurred during finalization: {e}"
print(f"Exception during finalization: {e}")
# Stay in review stage
st.rerun() # Rerun to show error message
with col2:
# Disable button if not in 'awaiting_review' stage
reject_button_disabled = (st.session_state.stage != "awaiting_review")
if st.button("Reject", disabled=reject_button_disabled):
if not reject_button_disabled: # Process click only if button was not meant to be disabled
print("Reject button clicked.")
st.session_state.error_message = None # Clear previous errors
# Go back to initial stage to allow modification/resubmission
st.session_state.stage = "initial"
# Keep the rejected output visible in the input field for modification
st.session_state.task_input = st.session_state.get("processed_output", st.session_state.task_input)
# Clear the processed output so it doesn't linger
if "processed_output" in st.session_state: del st.session_state.processed_output
if "final_result" in st.session_state: del st.session_state.final_result
st.info("Task rejected. Modify the input below and resubmit.")
print("Task rejected. Moving back to 'initial' stage.")
st.rerun()
# --- Stage: Completed ---
st.header("3. Task Completed")
# Get final result directly from session state
final_result = st.session_state.get("final_result", "Task not completed yet.")
# Display placeholder if not completed
result_to_display = final_result if st.session_state.stage == "completed" else "Final result will appear here upon completion."
st.subheader("Final Result:")
if st.session_state.stage == "completed":
st.success("Task approved and completed successfully!")
st.text_area("", value=str(result_to_display), height=200, disabled=True) # Always disabled for display
# Disable button if not in 'completed' or 'rejected_final' stage
start_over_button_disabled = not (st.session_state.stage == "completed" or st.session_state.stage == "rejected_final")
if st.button("Start Over", disabled=start_over_button_disabled):
if not start_over_button_disabled: # Process click only if button was not meant to be disabled
print("Start Over button clicked.")
reset_state()
st.rerun()
# --- Stage: Rejected -- (This section appears to be for a final rejected state, let's adjust for visibility)
# elif st.session_state.stage == "rejected_final": # Removed conditional rendering
# We'll integrate the display of rejection into the "Task Completed" area or manage it distinctly
# For now, this specific "rejected_final" header might be redundant if we always show "3. Task Completed" area
# And handle the message within it.
if st.session_state.stage == "rejected_final":
st.header("3. Task Rejected") # This can be shown when in this specific state.
st.error("The processed output was rejected.")
# Get rejected output directly from session state
rejected_output = st.session_state.get("processed_output", "")
if rejected_output:
st.text_area("Rejected Output:", value=str(rejected_output), height=150, disabled=True)
# The "Start Over" button for this state is handled by the one in "Task Completed" section due to shared disabling logic.
# --- Display Error Messages ---
if st.session_state.error_message:
st.error(st.session_state.error_message)
# --- Add a button to reset state anytime (for debugging) ---
# st.sidebar.button("Reset State", on_click=reset_state) # Removed sidebar