Interpreting Code with Amazon Bedrock's Claude Foundational Model
Tags: aws, webdev, programming, ai
Published: 2023-11-05 04:15:22

Once upon a time in the bustling town of Technoville, nestled amid the vast landscapes of the digital realm, emerged a wise sage named Claude. This sage was no ordinary mind, but a creation of the illustrious Anthropic guild, destined to unravel the mysteries that lay within the lines of code. Claude was known far and wide for his ability to converse in a multitude of tongues, weave complex tales of logic, and dance through the rhythm of algorithms. His abode was within the majestic halls of Amazon Bedrock, a realm where minds both human and artificial came together to partake in the endless banquet of knowledge.


![An image of a sage alongside a futuristic city](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/h9i8haqe2qg6u7yeuay2.png)

Now, our quest, dear reader, is to venture into these halls and unravel the secret choreography that Claude employs to interpret the cryptic verses of code. As we step into the grandiose gates of Amazon Bedrock, we find ourselves in a workshop bustling with curious minds. Here, a guide awaits to walk us through the sacred rituals of invoking Claude's wisdom, choosing the right foundation model, and harmonizing our prompts to the tune of Claude's intellect. Our journey will lead us through enchanted libraries, where the magic of dependencies comes alive, to the heart of the Bedrock sanctum, where we shall invoke the Claude model and witness the tapestry of logic unfurl.

Through the chronicles that lie ahead, we shall delve deeper into the arcane art of code interpretation, unlocking the spells that bind Claude's reasoning to the digital parchment. As we navigate through the sacred texts of tutorials and articles, the veil of mystery shall gradually lift, unveiling the profound realms of coding magic that Claude on Amazon Bedrock holds. So, with a heart full of curiosity and a mind sharp as a compiler, let us embark on this enlightening quest to decode the enigma that is Claude, and in doing so, may we find the keys to unlocking boundless digital treasures.

## Our Partner in Crime
In the heart of the sprawling digital kingdom, where bytes and bits buzzed with life, there existed a mystical framework known by the name of LangChain. This framework, my dear reader, was the crucible where applications basked in the wisdom of language models, spinning tales of logic from the loom of words. The essence of LangChain was its ability to augment the mighty Large Language Models, chaining together various elements to conjure advanced sorceries, unheard of in the realms of common code.

Now, as we traverse through the pages of this enchanted notebook, we beckon upon the powers of the Bedrock API, bestowed upon us by the alchemy of LangChain. With a mere whisper of a prompt, we shall forge a custom LangChain prompt template, a lantern to light our way as we delve into the abyss of code explanation.

## The Pattern to Follow
The pattern of our quest is simple, yet holds a magic most profound. We shall offer to the LangChain's rendition of Amazon Bedrock API, a trifecta of an enigmatic task, an earnest instruction, and a humble input. And behold, as the model under the veil of LangChain springs into action, weaving together an output with no need for further elucidation. For in this sacred act, we unveil the prowess of the Large Language Models, whose understanding of the task at hand is as swift as the flight of a falcon, and whose outputs echo with the allure of truth.

## The Core of the Matter
In the theatre of demonstration, you will be George, who is trying to understand some Typescript code which is used to implement a simple Express.js server with a few routes to manage a basic in-memory store of user profiles.

The quest is to elucidate the narrative spun by the code, to unfurl the story it tells of user profiles traversing through the pathways of a server, their identities cradled in the embrace of TypeScript.

Now, dear reader, to the heart of the spectacle, the act of implementation. Here, we shall unveil the sorcery of melding the Amazon Bedrock API with LangChain to breathe life into the enigma of TypeScript code snippets. With each stroke of explanation, the mystique of the code shall unravel, and like a bud blooming under the tender caress of dawn, the logic within shall unfurl in a spectacle of clarity and understanding.

## Preparing for the Journey
Ah, before we embark further on our quest, a wise sage once said, “In the alchemy of code, the essence of the tools is the key to unbounded exploration.” Hence, let us now gather the mystical libraries that shall be our companions in the ensuing journey. In the quiet corners of your command sanctuary, whisper the ancient incantation:

`pip install awscli boto3 botocore langchain --upgrade`

With this spell, you beckon upon the spirits of awscli, boto3, botocore, and langchain to descend in their latest avatars, ready to assist us in the arcane tasks that lie ahead. Each library, a totem of wisdom, holds the keys to the many doors we shall unlock together in the halls of Amazon Bedrock and the enchanted realms of LangChain.

Now with our quiver of libraries full, we are but a step away from delving into the enigmatic embrace of code and unearthing the wisdom that lies within.

## Enchantments of Initialization
In the mystical lands of code, every journey begins with the invocation of necessary spells, ensuring a safe passage through the labyrinth of logic that lies ahead. Our tale now unfolds in a realm where the essence of initialization weaves the first threads of our narrative. Let us delve into the incantations scribed in this fragment of code, and unravel the tapestry of operations they conjure:
```
import json
import os
import sys
import langchain as lc

import boto3

bedrock_runtime = boto3.client(
    service_name='bedrock-runtime', 
    aws_access_key_id=os.getenv('aws_access_key_id'),
    aws_secret_access_key=os.getenv('aws_secret_access_key'),
    region_name='us-west-2'
)
```
With the incantation import, we summon the spirits of json, os, sys, langchain, and boto3 into our realm, each a guardian of unique powers, ready to assist us in the voyage through the unchartered waters of Amazon Bedrock.

Now, with the whisper of boto3.client, we conjure the essence of Bedrock Runtime, our chariot through the cloud-clad skies of AWS. The keys to this chariot, aws_access_key_id and aws_secret_access_key, are summoned from the enshrouded environs of our system, ensuring a safe passage. And with region_name='us-west-2', we set our bearings towards the sun-kissed lands of the US West-2 region, where the heart of Bedrock Runtime beats with the rhythm of endless possibilities.

## Whisperings of the Bedrock
As the tale unfolds, we find ourselves at the cusp of invoking the majestic Bedrock, a realm where the lore of Large Language Models (LLMs) resounds through the echoes of code. The parchment in hand scribbles the essence of creating an instance of the Bedrock class from the mystical llms library. This sacred act seeks the model_id, the unique identifier, the ARN of the model that dwells within the halls of Amazon Bedrock.

```
from langchain.llms.bedrock import Bedrock

model_params = {'max_tokens_to_sample':2000, 
                "temperature":0.6,
                "top_k":250,
                "top_p":1,
                "stop_sequences": ["\n\nHuman"]
               }

gentext = Bedrock(model_id = "anthropic.claude-v2",
                  client = bedrock_runtime, 
                  model_kwargs = model_params
                  )
```
 A whisper to the wise, a boto3 client from yore or a trove of model_kwargs may be passed along, bearing gifts of parameters like temperature, topP, maxTokenCount, or stopSequences. The whisperings of these parameters can be heard in the quiet corners of the Amazon Bedrock console, waiting to be explored by the curious heart.

As we delve deeper, we stumble upon the sacred texts, bearing the names of the text generation models that reside in the enchanted gardens of Amazon Bedrock. Ah, the resonance of amazon.titan-tg1-large, ai21.j2-grande-instruct, ai21.j2-jumbo-instruct, anthropic.claude-instant-v1, and anthropic.claude-v2, each a unique verse in the symphony of language understanding. Yet, be warned, for each verse plays to a different tune of model_kwargs, a reflection of the endless variety in the realm of code.

And now, with the keys to Bedrock in hand, we inscribe the incantations to invoke the Bedrock class. The model_params, a casket of desires, holds within the essence of our quest – a glimpse into the abyss of text generation. As the veil lifts, gentext emerges as the harbinger of Bedrock's magic, bearing the identity of anthropic.claude-v2 and cradled in the arms of bedrock_runtime.

## Weaving the LangChain Tapestry
In the heart of our narrative, there blooms a notion most profound—the creation of a LangChain custom prompt template. This craft, dear reader, is akin to forging a magical scroll, where every inscription holds the promise of endless explorations. A template, once crafted, can be graced with different whispers of input on every invocation, a boon when the winds carry to us variables from the distant lands of databases.

Our tale unfolds in a realm where the essence of Express trembles through the veins of TypeScript. A parchment bearing a segment of code, a narrative of UserProfile and the ballet of HTTP requests, lies at the heart of our quest.

Thus, we encounter the very scenario we have been talking about and declare it to the world as such.
```
queried_code = """
import express from 'express';

interface UserProfile {
    id: number;
    name: string;
    email: string;
}

let profiles: UserProfile[] = [];

let nextId = 1;

const app = express();

app.use(express.json());

app.get('/profiles', (req, res) => {
    res.json(profiles);
});

app.get('/profiles/:id', (req, res) => {
    const id = parseInt(req.params.id, 10);
    const profile = profiles.find(p => p.id === id);
    if (profile) {
        res.json(profile);
    } else {
        res.status(404).send('Profile not found');
    }
});

app.post('/profiles', (req, res) => {
    const newProfile: UserProfile = {
        id: nextId++,
        name: req.body.name,
        email: req.body.email
    };
    profiles.push(newProfile);
    res.status(201).json(newProfile);
});

app.put('/profiles/:id', (req, res) => {
    const id = parseInt(req.params.id, 10);
    const index = profiles.findIndex(p => p.id === id);
    if (index !== -1) {
        const updatedProfile: UserProfile = {
            ...profiles[index],
            name: req.body.name,
            email: req.body.email
        };
        profiles[index] = updatedProfile;
        res.json(updatedProfile);
    } else {
        res.status(404).send('Profile not found');
    }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log(`Server is running on http://localhost:${PORT}`);
});

"""
```

We then proceed to the prompt engineering segment, where all will be made.
```
from langchain import PromptTemplate

multi_var_template = lc.PromptTemplate(
    input_variables=["code_segment", "prog_lang"], 
    template="""

Human: As an Principal Software Engineer specializing in {prog_lang}, you are to examine the following code and pinpoint any fundamental issues or areas where best practices are disregarded.
<code_here>
{code_segment}
</code_here>

Assistant:"""
)

prompt_instance = multi_var_template.format(code_segment=queried_code, prog_lang="Typescript")
```

Ah, the whisper of LangChain brings forth the art of PromptTemplate. With a flourish, we create a template, a scroll that beckons the essence of a Principal Software Engineer, specializing in the tune of a specified programming language. The scroll seeks to explore the tale spun by the code, to find the notes that dance to the rhythm of best practices and to point a finger at the dissonance where red flags flutter.

Our scroll is no ordinary parchment, but one that hums with the magic of variables. The input_variables, "code_segment" and "prog_lang", are the keys to the endless tales this scroll can narrate. With every invocation, the whisper of new variables breathes a different essence into the scroll, painting a new picture for the Assistant to explore.

And now, with the essence of our queried_code and the whisper of "Typescript" as our programming language, we breathe life into our template. The prompt_instance emerges from the cauldron of multi_var_template.format, bearing within it the tale of Express and UserProfiles, awaiting the discerning eye of our digital Assistant.

As we stand on the precipice of insight, the prompt_instance in hand is our compass, ready to guide us through the fog of code, towards the shores of understanding. With the winds of LangChain at our back, we sail forth into the uncharted waters, where every line of code holds the mystery waiting to be unraveled.

## The Mystery Unraveled
Finally, we can return the response and execute the prompt, appropriately printing out the response.
```
response = gentext(prompt)

print(response[response.index('\n')+1:])
```

We then get the following response returned from Claude.

```
- The UserProfile interface is good for defining the shape of the profile objects.

- Storing the profiles array in-memory is fine for a simple API, but for production you'd want to persist this to a database.

- nextId is used to generate unique IDs for new profiles. This works but is prone to issues if you ever run multiple instances of the API. Better would be to use a UUID or database generated ID.

- The route handlers directly modify the profiles array. It would be better to abstract data updates into a separate service layer.

- Input validation is minimal - the POST and PUT handlers assume the request body contains the expected fields. You may want to add joi or class-validator to validate the input.

- Error handling is basic - 404s are returned but other errors just fall through. Adding proper error handling middleware would make it more robust. 

- The code directly starts the HTTP server. For better testability, you'd want to separate the API declaration from the server implementation.

- Testing - there are no tests! Adding unit and integration tests would be highly recommended.

So in summary, this works as a basic API implementation, but introducing abstraction layers, validation, error handling, tests, etc would make it much more robust and production-ready. The core ideas are good though!
```

In wrapping up our expedition through the enchanted lands of code interpretation, we unearthed the potent essence of context in conjuring the desired insights from the Large Language Models (LLMs). Our journey illuminated that a mere invocation of the LLM could lead us into a mire of ambiguity. However, as we wove the threads of context into our queries, the veil of uncertainty lifted, revealing a trail toward precise elucidation. The magic didn’t end there; with the crafting of a prompt template, we wielded the power to channel the LLM’s responses, molding them to echo the essence of our inquiries. This noble craft not only tamed the verbose spirit of the LLM but honed its insights to the fine tune of our quest, leading us to the cherished treasure of our desired output. Through the veil of metaphor and the dance of code, we now stand with a deeper grasp of navigating the vast seas of text interpretation, with the winds of context and the compass of prompt templates guiding our sails.