PremAI

PremAI is a unified platform that lets you build powerful production-ready GenAI-powered applications with the least effort so that you can focus more on user experience and overall growth.

ChatPremAI

This example goes over how to use LangChain to interact with different chat models with ChatPremAI

Installation and setup

We start by installing langchain and premai-sdk. You can type the following command to install:

pip install premai langchain

Before proceeding further, please make sure that you have made an account on PremAI and already started a project. If not, then here's how you can start for free:

1. Sign in to PremAI, if you are coming for the first time and create your API key here.

2. Go to app.premai.io and this will take you to the project's dashboard.

3. Create a project and this will generate a project-id (written as ID). This ID will help you to interact with your deployed application.

4. Head over to LaunchPad (the one with 🚀 icon). And there deploy your model of choice. Your default model will be gpt-4. You can also set and fix different generation parameters (like max-tokens, temperature, etc) and also pre-set your system prompt.

Congratulations on creating your first deployed application on PremAI 🎉 Now we can use langchain to interact with our application.

from langchain_core.messages import HumanMessage, SystemMessage
from langchain_community.chat_models import ChatPremAI

API Reference:

• HumanMessage
• SystemMessage
• ChatPremAI

Setup ChatPrem instance in LangChain

Once we import our required modules, let's set up our client. For now, let's assume that our project_id is 8. But make sure you use your project-id, otherwise, it will throw an error.

To use langchain with prem, you do not need to pass any model name or set any parameters with our chat client. All of those will use the default model name and parameters of the LaunchPad model.

NOTE: If you change the model_name or any other parameter like temperature while setting the client, it will override existing default configurations.

import os
import getpass

if "PREMAI_API_KEY" not in os.environ:
    os.environ["PREMAI_API_KEY"] = getpass.getpass("PremAI API Key:")

chat = ChatPremAI(project_id=8)

Calling the Model

Now you are all set. We can now start by interacting with our application. ChatPremAI supports two methods invoke (which is the same as generate) and stream.

The first one will give us a static result. Whereas the second one will stream tokens one by one. Here's how you can generate chat-like completions.

Generation

human_message = HumanMessage(content="Who are you?")

chat.invoke([human_message])

The above looks interesting, right? I set my default launchpad system-prompt as: Always sound like a pirate You can also, override the default system prompt if you need to. Here's how you can do it.

system_message = SystemMessage(content="You are a friendly assistant.")
human_message = HumanMessage(content="Who are you?")

chat.invoke([system_message, human_message])

You can also change generation parameters while calling the model. Here's how you can do that:

chat.invoke(
    [system_message, human_message],
    temperature = 0.7, max_tokens = 20, top_p = 0.95
)

Important notes:

Before proceeding further, please note that the current version of ChatPrem does not support parameters: n and stop are not supported.

We will provide support for those two above parameters in later versions.

Streaming

And finally, here's how you do token streaming for dynamic chat-like applications.

import sys

for chunk in chat.stream("hello how are you"):
    sys.stdout.write(chunk.content)
    sys.stdout.flush()

Similar to above, if you want to override the system-prompt and the generation parameters, here's how you can do it.

import sys

for chunk in chat.stream(
    "hello how are you",
    system_prompt = "You are an helpful assistant", temperature = 0.7, max_tokens = 20
):
    sys.stdout.write(chunk.content)
    sys.stdout.flush()

Embedding

In this section, we are going to discuss how we can get access to different embedding models using PremEmbeddings. Let's start by doing some imports and defining our embedding object

from langchain_community.embeddings import PremEmbeddings

Once we import our required modules, let's set up our client. For now, let's assume that our project_id is 8. But make sure you use your project-id, otherwise, it will throw an error.

import os
import getpass

if os.environ.get("PREMAI_API_KEY") is None:
    os.environ["PREMAI_API_KEY"] = getpass.getpass("PremAI API Key:")

# Define a model as a required parameter here since there is no default embedding model

model = "text-embedding-3-large"
embedder = PremEmbeddings(project_id=8, model=model)

We have defined our embedding model. We support a lot of embedding models. Here is a table that shows the number of embedding models we support.

Provider	Slug	Context Tokens
cohere	embed-english-v3.0	N/A
openai	text-embedding-3-small	8191
openai	text-embedding-3-large	8191
openai	text-embedding-ada-002	8191
replicate	replicate/all-mpnet-base-v2	N/A
together	togethercomputer/Llama-2-7B-32K-Instruct	N/A
mistralai	mistral-embed	4096

To change the model, you simply need to copy the slug and access your embedding model. Now let's start using our embedding model with a single query followed by multiple queries (which is also called as a document)

query = "Hello, this is a test query"
query_result = embedder.embed_query(query)

# Let's print the first five elements of the query embedding vector

print(query_result[:5])

Finally, let's embed a document

documents = [
    "This is document1",
    "This is document2",
    "This is document3"
]

doc_result = embedder.embed_documents(documents)

# Similar to the previous result, let's print the first five element
# of the first document vector

print(doc_result[0][:5])