S3 Service

The S3 Service provides a centralised interface for all Amazon S3 operations within the Digital Landscape backend. It implements a singleton pattern to ensure consistent S3 client instances and provides methods for common S3 operations.

Overview

The service manages three different S3 buckets: - Main bucket - Primary application data storage - TAT bucket - Technology Assessment Tool data - Copilot bucket - GitHub Copilot metrics and data

Configuration

The service automatically configures S3 clients based on environment variables:

const mainBucket = process.env.S3_BUCKET_NAME;
const tatBucket = process.env.S3_BUCKET_NAME_TAT;
const copilotBucket = process.env.S3_BUCKET_NAME_COPILOT;

Methods

getObject(bucket, key)

Retrieves an object from the specified S3 bucket.

Parameters: - bucket (string) - The S3 bucket name - key (string) - The object key/path

Returns: Promise resolving to the object data

Example:

const s3Service = require('./s3Service');
const data = await s3Service.getObject('my-bucket', 'data/file.json');

putObject(bucket, key, body, contentType = 'application/json')

Stores an object in the specified S3 bucket.

Parameters: - bucket (string) - The S3 bucket name - key (string) - The object key/path - body (any) - The object data to store - contentType (string, optional) - MIME type (default: 'application/json')

Returns: Promise resolving to the put operation result

Example:

const result = await s3Service.putObject(
  'my-bucket', 
  'data/file.json', 
  { message: 'Hello World' }
);

getObjectViaSignedUrl(bucket, key, expiresIn = 3600)

Generates a presigned URL for accessing an S3 object.

Parameters: - bucket (string) - The S3 bucket name - key (string) - The object key/path - expiresIn (number, optional) - URL expiration time in seconds (default: 3600)

Returns: Promise resolving to the signed URL

Example:

const signedUrl = await s3Service.getObjectViaSignedUrl(
  'my-bucket', 
  'private/file.pdf', 
  7200
);

Bucket Configuration Methods

getMainBucket()

Returns the main application bucket name.

getTatBucket()

Returns the TAT (Technology Assessment Tool) bucket name.

getCopilotBucket()

Returns the Copilot metrics bucket name.

Error Handling

The service includes comprehensive error handling:

• Logs all S3 operations and errors using the application logger
• Throws descriptive errors for failed operations
• Handles AWS SDK errors appropriately

Usage Example

const s3Service = require('../services/s3Service');

// Get project data
try {
  const projectData = await s3Service.getObject(
    s3Service.getMainBucket(), 
    'projects/data.json'
  );
  console.log('Project data retrieved successfully');
} catch (error) {
  console.error('Failed to retrieve project data:', error);
}

// Store updated data
try {
  await s3Service.putObject(
    s3Service.getMainBucket(),
    'projects/updated-data.json',
    { projects: updatedProjects }
  );
  console.log('Data stored successfully');
} catch (error) {
  console.error('Failed to store data:', error);
}

Implementation Notes

• Uses singleton pattern to maintain single S3 client instances
• Automatically stringifies JSON data for storage
• Provides consistent error logging across all operations
• Supports multiple bucket configurations for different data types