Mapping context and strategy resolution

The target-specific attributes -- [Index<T>], [DataStream<T>], and [WiredStream<T>] -- on your mapping context drive everything the channel does: what kind of Elasticsearch target to create, which templates to put in place, how to format bulk operations, and how to manage aliases. This page is the complete reference for how attribute parameters map to channel behavior.

[ElasticsearchMappingContext]
[Index<Product>(Name = "products")]
public static partial class MyContext;
		

This targets an index named products. The source generator produces MyContext.Product.Context -- an ElasticsearchTypeContext containing mappings JSON, settings, and accessor delegates.

Each Elasticsearch target type has its own attribute with properties that make sense for that target:

// Index -- mutable documents, upserts, aliases
[Index<Product>(Name = "products")]

// Index with templated name -- resolved at runtime
[Index<Product>(NameTemplate = "products-{env}")]

// Data stream -- append-only, automatic rollover
[DataStream<LogEntry>(Type = "logs", Dataset = "myapp")]

// Wired stream -- serverless managed, no local bootstrap
[WiredStream<LogEntry>(Type = "logs", Dataset = "myapp")]
		

Attributes on your document class further refine the resolved strategy:

[Index<T>] supports the following properties:

[Index<Product>(
    Name = "products",
    WriteAlias = "products-write",
    ReadAlias = "products-search",
    DatePattern = "yyyy.MM.dd.HHmmss",
    Shards = 3,
    Replicas = 2,
    RefreshInterval = "5s",
    Dynamic = false
)]
		

1. Fixed index name
2. Write alias for zero-downtime rotation
3. Search alias spanning all indices
4. Time-stamped index names

SearchPattern is no longer a manual parameter. When DatePattern is set, the search pattern is auto-derived as "{writeTarget}-*". When DatePattern is not set, no search pattern is generated.

Use NameTemplate for index names that depend on runtime parameters:

[Index<KnowledgeArticle>(
    NameTemplate = "docs-{searchType}-{env}",
    DatePattern = "yyyy.MM.dd.HHmmss"
)]
		

This generates CreateContext(string searchType, string? env = null) instead of a static Context property. The {env}, {environment}, and {namespace} placeholders are optional and resolve from environment variables when omitted.

See templated index names for the full reference.

[DataStream<T>] controls the data stream naming convention {type}-{dataset}-{namespace}:

[DataStream<LogEntry>(
    Type = "logs",
    Dataset = "myapp",
    Namespace = "production",
    DataStreamMode = DataStreamMode.Tsdb
)]
		

1. Required: logs, metrics, traces, etc.
2. Required: source identifier
3. Optional: defaults from environment variables
4. Optional: Default, LogsDb, or Tsdb

Data stream name: {type}-{dataset}-{namespace} (e.g. logs-myapp-production)

[WiredStream<T>] is similar to [DataStream<T>] but bootstrap is fully managed by Elasticsearch:

[WiredStream<LogEntry>(
    Type = "logs",
    Dataset = "myapp"
)]
		

Use Variant to define multiple index configurations for the same document type:

[ElasticsearchMappingContext]
[Index<Article>(
    Name = "articles-lexical",
    WriteAlias = "articles-lexical",
    ReadAlias = "articles-lexical-search",
    DatePattern = "yyyy.MM.dd.HHmmss"
)]
[Index<Article>(
    Name = "articles-semantic",
    Variant = "Semantic",
    WriteAlias = "articles-semantic",
    ReadAlias = "articles-semantic-search",
    DatePattern = "yyyy.MM.dd.HHmmss"
)]
public static partial class ArticleContext;
		

This generates:

• ArticleContext.Article.Context (lexical, default variant)
• ArticleContext.ArticleSemantic.Context (semantic variant)

Use variants with IncrementalSyncOrchestrator to coordinate multiple indices over the same data. See semantic enrichment for an end-to-end example.

When the auto-resolved strategy isn't enough, use the IngestStrategies and BootstrapStrategies factory methods:

// Add 30-day retention to a data stream
var strategy = IngestStrategies.DataStream<LogEntry>(context, "30d");
var options = new IngestChannelOptions<LogEntry>(transport, strategy, context);

// Add ILM to an index
var strategy = IngestStrategies.Index<Product>(context,
    BootstrapStrategies.IndexWithIlm("products-policy"));
var options = new IngestChannelOptions<Product>(transport, strategy, context);
		

See strategies for the complete factory method reference.