Nera.Lib.Elasticsearch 1.0.2

Nera.Lib.Elasticsearch

A comprehensive library for Elasticsearch integration in Nera applications, providing advanced search, filtering, pagination, and aggregation capabilities.

Overview

Nera.Lib.Elasticsearch is a powerful library that simplifies working with Elasticsearch in Nera applications. It provides a robust repository pattern implementation with support for advanced search features, including full-text search, filtering, sorting, pagination, highlighting, and aggregations.

Features

• Full CRUD Operations: Index, update, delete, and retrieve documents
• Advanced Search: Full-text search with fuzzy matching and highlighting
• Filtering: Filter by exact match, range, existence, and more
• Sorting: Sort by multiple fields with custom ordering
• Pagination: Standard and advanced pagination options
• Aggregations: Support for terms, date histogram, and range aggregations
• Geo Search: Search by geographical location and distance
• Index Management: Create, delete, and refresh indices
• Error Handling: Comprehensive error handling and logging
• IReadRepository Integration: Implements the Nera.Lib.Database IReadRepository interface

Installation

Add the Nera.Lib.Elasticsearch package to your project:

dotnet add package Nera.Lib.Elasticsearch

Usage

Basic Setup

// Register services in DI container
services.AddSingleton<ElasticsearchConfiguration>(sp => new ElasticsearchConfiguration
{
    Url = "http://localhost:9200",
    DefaultIndex = "my-index",
    EnableSsl = true,
    Username = "elastic",
    Password = "password"
});

services.AddSingleton<IElasticClient>(sp =>
{
    var config = sp.GetRequiredService<ElasticsearchConfiguration>();
    var settings = new ConnectionSettings(new Uri(config.Url))
        .DefaultIndex(config.DefaultIndex)
        .BasicAuthentication(config.Username, config.Password)
        .EnableDebugMode(config.EnableDebug)
        .RequestTimeout(TimeSpan.FromSeconds(config.TimeoutSeconds));
    
    return new ElasticClient(settings);
});

services.AddScoped<IMyEntityRepository, MyEntityRepository>();

Creating a Repository

public class MyEntityRepository : BaseElasticsearchRepository<MyEntity, Guid>
{
    public MyEntityRepository(
        IElasticClient elasticClient,
        ElasticsearchConfiguration config,
        ILogger<MyEntityRepository> logger)
        : base(elasticClient, config, logger, "my-entities")
    {
    }
    
    // Add custom repository methods here
    public async Task<List<MyEntity>> SearchByCategory(string category, CancellationToken cancellationToken = default)
    {
        var request = new ElasticsearchPaginationRequest
        {
            Page = 1,
            PageSize = 100,
            Filters = new List<FilterCondition>
            {
                new FilterCondition
                {
                    Field = "category",
                    Operator = "eq",
                    Value = category
                }
            }
        };
        
        var result = await GetPagedResultAsync(request, cancellationToken);
        return result.Items.ToList();
    }
}

Basic CRUD Operations

// Index a document
await repository.IndexAsync(entity);

// Get a document by ID
var entity = await repository.GetByIdAsync(id);

// Update a document
entity.Name = "Updated Name";
await repository.UpdateAsync(entity);

// Delete a document
await repository.DeleteAsync(id);

// Check if a document exists
bool exists = await repository.ExistsAsync(id);

Search and Pagination

// Basic search
var request = new ElasticsearchPaginationRequest
{
    Page = 1,
    PageSize = 10,
    SearchTerm = "search term",
    SortBy = "createdAt",
    SortDirection = "desc"
};

var result = await repository.GetPagedResultAsync(request);

// Advanced search with filters
var advancedRequest = new ElasticsearchPaginationRequest
{
    Page = 1,
    PageSize = 10,
    SearchTerm = "search term",
    SearchFields = new[] { "title", "description" },
    Filters = new List<FilterCondition>
    {
        new FilterCondition
        {
            Field = "category",
            Operator = "eq",
            Value = "electronics"
        },
        new FilterCondition
        {
            Field = "price",
            Operator = "gte",
            Value = 100
        }
    },
    DateRange = new DateRangeFilter
    {
        Field = "publishedDate",
        From = DateTime.UtcNow.AddMonths(-1),
        To = DateTime.UtcNow
    },
    EnableHighlighting = true,
    HighlightFields = new[] { "title", "description" },
    EnableAggregations = true,
    Aggregations = new List<AggregationDefinition>
    {
        new AggregationDefinition
        {
            Name = "categories",
            Type = "terms",
            Field = "category"
        },
        new AggregationDefinition
        {
            Name = "price_ranges",
            Type = "range",
            Field = "price"
        }
    }
};

var advancedResult = await repository.GetPagedResultAsync(advancedRequest);

Geo Search

// Search by location
var locationResult = await repository.SearchByLocationAsync(
    latitude: 40.7128,
    longitude: -74.0060,
    distanceKm: 10,
    page: 1,
    pageSize: 10);

Index Management

// Create an index with settings and mappings
await repository.CreateIndexAsync(i => i
    .Settings(s => s
        .NumberOfShards(3)
        .NumberOfReplicas(1)
        .Analysis(a => a
            .Analyzers(an => an
                .Custom("custom_analyzer", ca => ca
                    .Tokenizer("standard")
                    .Filters("lowercase", "asciifolding")
                )
            )
        )
    )
    .Map<MyEntity>(m => m
        .AutoMap()
        .Properties(p => p
            .Text(t => t.Name(n => n.Title).Analyzer("custom_analyzer"))
            .Text(t => t.Name(n => n.Description).Analyzer("custom_analyzer"))
            .Keyword(k => k.Name(n => n.Category))
            .Number(n => n.Name(n => n.Price).Type(NumberType.Double))
            .Date(d => d.Name(n => n.PublishedDate))
            .GeoPoint(g => g.Name(n => n.Location))
        )
    )
);

// Check if an index exists
bool exists = await repository.IndexExistsAsync();

// Delete an index
await repository.DeleteIndexAsync();

// Refresh an index
await repository.RefreshIndexAsync();

Advanced Usage

Custom Query Building

You can override the query building methods to customize the search behavior:

public class CustomRepository : BaseElasticsearchRepository<MyEntity, Guid>
{
    public CustomRepository(
        IElasticClient elasticClient,
        ElasticsearchConfiguration config,
        ILogger<CustomRepository> logger)
        : base(elasticClient, config, logger, "my-entities")
    {
    }
    
    protected override QueryContainer BuildQueryContainer(QueryContainerDescriptor<MyEntity> queryDescriptor, ElasticsearchPaginationRequest request)
    {
        // Custom query building logic
        var baseQuery = base.BuildQueryContainer(queryDescriptor, request);
        
        // Add additional conditions
        var customQuery = queryDescriptor.Bool(b => b
            .Must(baseQuery)
            .Filter(f => f.Term(t => t.Field("isActive").Value(true)))
        );
        
        return customQuery;
    }
}

Implementing Custom Aggregations

public async Task<Dictionary<string, int>> GetCategoryCounts(CancellationToken cancellationToken = default)
{
    var request = new ElasticsearchPaginationRequest
    {
        Page = 1,
        PageSize = 0, // We only need aggregations, not results
        EnableAggregations = true,
        Aggregations = new List<AggregationDefinition>
        {
            new AggregationDefinition
            {
                Name = "categories",
                Type = "terms",
                Field = "category"
            }
        }
    };
    
    var result = await GetPagedResultAsync(request, cancellationToken);
    
    if (result.Aggregations?.TryGetValue("categories", out var categoriesAgg) == true)
    {
        if (categoriesAgg is IEnumerable<dynamic> categories)
        {
            return categories
                .Select(c => new { Key = c.Key.ToString(), Count = (int)c.Count })
                .ToDictionary(c => c.Key, c => c.Count);
        }
    }
    
    return new Dictionary<string, int>();
}

Configuration Options

The ElasticsearchConfiguration class provides various options to configure the Elasticsearch client:

• Url: The Elasticsearch server URL
• Username: Username for authentication
• Password: Password for authentication
• DefaultIndex: Default index name
• EnableSsl: Enable SSL/TLS
• TimeoutSeconds: Request timeout in seconds
• MaxRetryAttempts: Maximum retry attempts
• RetryDelayMs: Retry delay in milliseconds
• EnableDebug: Enable debug mode
• DefaultPageSize: Default page size for pagination
• MaxPageSize: Maximum page size allowed
• AutoCreateIndex: Enable automatic index creation
• IndexSettings: Index settings for auto-created indices

Best Practices

1. Index Naming: Use a consistent naming convention for indices, such as {service}-{entity}-{environment}.
2. Mapping: Define proper mappings for your entities to ensure optimal search performance.
3. Pagination: Use reasonable page sizes (10-50) to avoid performance issues.
4. Caching: Consider caching search results for frequently used queries.
5. Error Handling: Always handle exceptions from Elasticsearch operations.
6. Logging: Enable detailed logging during development and debugging.

License

This library is part of the Nera platform and is subject to the same licensing terms as the rest of the platform.