Crate elastic_mapping 

Generate Elasticsearch mapping definitions from Rust structs and enums.

This crate provides a derive macro to automatically generate Elasticsearch mapping definitions from Rust types. It respects serde attributes and supports various Elasticsearch-specific field configurations.

Features

• Derive macro - Automatic mapping generation using #[derive(Document)]
• Serde compatibility - Respects #[serde(rename)], #[serde(rename_all)], #[serde(flatten)]
• Enum support - Handles externally tagged, internally tagged, and adjacently tagged enums
• Field annotations - Configure analyzers, keyword fields, and other Elasticsearch settings
• Optional features - Support for chrono, url, and uuid types

Quick Start

use elastic_mapping::{Document, MappingObject};

#[derive(Document)]
struct BlogPost {
    title: String,
    content: String,
    published: bool,
    views: i64,
}

fn main() {
    let mapping = BlogPost::document_mapping();
    println!("{}", serde_json::to_string_pretty(mapping.inner()).unwrap());
}

Field Annotations

Use the #[document(...)] attribute to configure Elasticsearch-specific field settings:

use elastic_mapping::Document;

#[derive(Document)]
struct Article {
    /// Configure an analyzer for text analysis
    #[document(analyzer = "english")]
    title: String,
     
    /// Add a keyword subfield that is not indexed
    #[document(keyword(index = false))]
    internal_id: String,
     
    /// Add a keyword subfield with ignore_above setting
    #[document(keyword(ignore_above = 256))]
    category: String,
}

Serde Compatibility

The macro respects common serde attributes:

use elastic_mapping::Document;
use serde::Serialize;

#[derive(Serialize, Document)]
#[serde(rename_all = "camelCase")]
struct User {
    first_name: String,      // Maps to "firstName"
    #[serde(rename = "mail")]
    email: String,            // Maps to "mail"
}

Enum Support

Different enum representations are supported:

use elastic_mapping::Document;
use serde::Serialize;

// Externally tagged (default)
#[derive(Document)]
enum Status {
    Active { since: i64 },
    Pending { until: i64 },
}

// Internally tagged
#[derive(Serialize, Document)]
#[serde(tag = "type")]
enum Message {
    Text { content: String },
    Image { url: String },
}

// Adjacently tagged
#[derive(Serialize, Document)]
#[serde(tag = "type", content = "data")]
enum Event {
    Created { id: String },
    Updated { id: String, changes: String },
}

Re-exports

pub use serde_json;

Structs

MappingDocument

A wrapper around the generated Elasticsearch mapping JSON.

Traits

MappingObject

Trait for types that can be used as Elasticsearch document mappings.

MappingType

Trait for types that can be mapped to Elasticsearch field types.

Derive Macros

Document

Derives Elasticsearch mapping generation for structs and enums.