Parallel execution with RunnableParallel in LangChain - Mini Project: Build & Apply

Parallel execution with RunnableParallel

📖 Scenario: You are building a simple program that runs two tasks at the same time to save time. Each task is a small function that returns a message. You will use RunnableParallel from LangChain to run these tasks together.

🎯 Goal: Create two simple functions that return messages, then use RunnableParallel to run them at the same time and get both results.

📋 What You'll Learn

Create two functions called task1 and task2 that return strings

Create a RunnableParallel instance with task1 and task2

Run the parallel tasks and store the results in a variable called results

Print the results to see both outputs

💡 Why This Matters

🌍 Real World

Running multiple tasks at the same time can save time in programs that do independent work, like fetching data from different sources or processing files.

💼 Career

Understanding parallel execution is important for building efficient applications and services that handle multiple operations simultaneously.

1

Create two simple functions

Create two functions called task1 and task2. task1 should return the string 'Hello from task 1'. task2 should return the string 'Hello from task 2'.

LangChain

# Define task1 and task2 functions
# Your code here

Need a hint?

Use def to create functions and return to send back the message.

2

Import RunnableParallel and create instance

Import RunnableParallel from langchain.runnables. Then create a variable called parallel_runner and set it to RunnableParallel({"task1": task1, "task2": task2}).

LangChain

def task1(_):
    return 'Hello from task 1'

def task2(_):
    return 'Hello from task 2'

# Import RunnableParallel and create parallel_runner
# Your code here

Need a hint?

Use the import statement exactly as shown. Pass a dictionary {"task1": task1, "task2": task2} to RunnableParallel.

3

Run the parallel tasks

Use the invoke method of parallel_runner to run both tasks at the same time. Store the result in a variable called results.

LangChain

from langchain.runnables import RunnableParallel

def task1(_):
    return 'Hello from task 1'

def task2(_):
    return 'Hello from task 2'

parallel_runner = RunnableParallel({"task1": task1, "task2": task2})

# Run the parallel tasks and save results
# Your code here

Need a hint?

Call parallel_runner.invoke({}) and assign it to results.

4

Print the results

Add a line to print the results variable to see the output of both tasks.

LangChain

from langchain.runnables import RunnableParallel

def task1(_):
    return 'Hello from task 1'

def task2(_):
    return 'Hello from task 2'

parallel_runner = RunnableParallel({"task1": task1, "task2": task2})

results = parallel_runner.invoke({})

# Print the results
# Your code here

Need a hint?

Use print(results) to show the output.