Performance: Redundant Hash Calculations

[kitzy]

Performance Inefficiency

Location: Lines 743-750 in FleetImporter/FleetImporter.py

Issue: Downloads entire file from S3 just to calculate SHA256 hash - wasteful for large packages.

if package_was_uploaded:
    hash_sha256 = self._calculate_file_sha256(pkg_path)
else:
    hash_sha256 = self._calculate_s3_file_sha256(aws_s3_bucket, s3_key)

Impact:

• Unnecessary network bandwidth usage
• Slower execution for large packages
• Increased AWS data transfer costs

Current Implementation:
The _calculate_s3_file_sha256 method downloads the entire file just to hash it.

Recommended Fix:

1. Store SHA256 hash as S3 object metadata during upload
2. Retrieve hash from metadata instead of downloading file
3. Use S3 ETag for verification (multipart uploads are different)

# During upload
s3_client.put_object(
    Bucket=bucket,
    Key=s3_key,
    Body=file_data,
    Metadata={
        'sha256': calculated_hash
    }
)

# During retrieval
head_response = s3_client.head_object(Bucket=bucket, Key=s3_key)
hash_sha256 = head_response['Metadata'].get('sha256')

Priority: Low-Medium - Optimization opportunity