Module metadata 

Metadata storage for vector annotations. Metadata storage system for EdgeVec.

This module provides a type-safe metadata storage system for attaching key-value pairs to vectors. Metadata enables filtering, sorting, and enriching vector search results with additional context.

Features

• 5 Value Types: String, Integer, Float, Boolean, StringArray
• Type-Safe: Strongly typed values with accessor methods
• Validated: Keys and values are validated against limits
• Serializable: JSON serialization with clear type tags

Quick Start

use edgevec::metadata::{MetadataValue, MetadataStore};
use edgevec::metadata::validation::validate_key_value;

// Create values using constructors
let title = MetadataValue::String("Hello World".to_string());
let count = MetadataValue::Integer(42);
let score = MetadataValue::Float(0.95);
let active = MetadataValue::Boolean(true);
let tags = MetadataValue::StringArray(vec!["rust".into(), "wasm".into()]);

// Create values using From trait
let title: MetadataValue = "Hello World".into();
let count: MetadataValue = 42i64.into();
let active: MetadataValue = true.into();

// Validate before storing
assert!(validate_key_value("title", &title).is_ok());

// Check types
assert!(title.is_string());
assert!(count.is_integer());

// Extract values
assert_eq!(title.as_string(), Some("Hello World"));
assert_eq!(count.as_integer(), Some(42));

Value Types

Type	Rust	JSON	Use Case
String	String	string	Titles, descriptions
Integer	i64	number	Counts, IDs, timestamps
Float	f64	number	Scores, weights
Boolean	bool	boolean	Flags, filters
StringArray	Vec<String>	string[]	Tags, categories

Validation Limits

Limit	Value	Description
Max keys per vector	64	Prevents memory bloat
Max key length	256 bytes	Reasonable for field names
Max string value	64KB	Prevents abuse
Max array elements	1,024	Prevents excessive arrays

JSON Serialization

Values serialize with adjacently-tagged representation:

{"type": "string", "value": "hello"}
{"type": "integer", "value": 42}
{"type": "float", "value": 2.5}
{"type": "boolean", "value": true}
{"type": "string_array", "value": ["a", "b"]}

Module Structure

• types - Core MetadataValue enum
• error - MetadataError enum
• validation - Validation constants and functions
• store - MetadataStore for CRUD operations (Day 2)

Modules

validation

Metadata validation rules and constants.

Structs

MetadataStore

Storage for vector metadata.

Enums

MetadataError

Errors that can occur during metadata operations.

MetadataValue

Supported metadata value types.

SerializationError

Errors that can occur during metadata serialization/deserialization.