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Bootstrap strategies

Bootstrap strategies control how Elasticsearch infrastructure (templates, policies, endpoints) is created before ingestion begins.

Your channel needs Elasticsearch infrastructure to exist before it can write data: component templates define your mappings and settings, index templates tie them together, and optional ILM policies or lifecycle configurations manage data retention. Bootstrap strategies create all of this automatically so you don't have to manage it manually.

The easiest way to create bootstrap strategies is through the BootstrapStrategies factory:

// Data stream (component + data stream templates)
BootstrapStrategies.DataStream()

// Data stream with retention
BootstrapStrategies.DataStream("30d")

// Data stream with ILM
BootstrapStrategies.DataStreamWithIlm("my-policy", hotMaxAge: "7d", deleteMinAge: "90d")

// Index (component + index templates)
BootstrapStrategies.Index()

// Index with ILM
BootstrapStrategies.IndexWithIlm("my-policy", hotMaxAge: "30d", deleteMinAge: "180d")

// No-op (wired streams)
BootstrapStrategies.None()

Pass the result to an IngestStrategies factory method:

var strategy = IngestStrategies.DataStream<LogEntry>(context,
    BootstrapStrategies.DataStreamWithIlm("logs-policy", hotMaxAge: "7d", deleteMinAge: "90d"));
var options = new IngestChannelOptions<LogEntry>(transport, strategy, context);

The IBootstrapStrategy interface orchestrates an ordered list of IBootstrapStep instances:

public interface IBootstrapStrategy
{
    IReadOnlyList<IBootstrapStep> Steps { get; }
    Task<bool> BootstrapAsync(BootstrapContext context, CancellationToken ctx = default);
    bool Bootstrap(BootstrapContext context);
}

The built-in implementation runs steps sequentially, stopping on the first failure:

var strategy = new DefaultBootstrapStrategy(
    new ComponentTemplateStep(),
    new DataStreamTemplateStep()
);

Each step implements IBootstrapStep and performs a single bootstrap action:

Step Purpose
ComponentTemplateStep Creates settings and mappings component templates
IndexTemplateStep Creates an index template (without data stream)
DataStreamTemplateStep Creates an index template with "data_stream": {}
InferenceEndpointStep Creates ELSER inference endpoints
IlmPolicyStep Creates an ILM policy (skipped on serverless)
DataStreamLifecycleStep Configures data stream lifecycle retention
NoopBootstrapStep No-op step for wired streams

The BootstrapMethod enum controls error handling:

Method Behavior
None Skip bootstrap entirely
Silent Return false on failure, don't throw
Failure Throw an exception on failure

Steps run in the order they're provided. Common orderings:

Data stream with ILM:

new DefaultBootstrapStrategy(
    new IlmPolicyStep("my-policy", hotMaxAge: "30d", deleteMinAge: "90d"),
    new ComponentTemplateStep(),
    new DataStreamTemplateStep()
);

Data stream with lifecycle (serverless-compatible):

new DefaultBootstrapStrategy(
    new ComponentTemplateStep(),
    new DataStreamLifecycleStep("30d"),
    new DataStreamTemplateStep()
);

Semantic index:

new DefaultBootstrapStrategy(
    new InferenceEndpointStep("my-elser"),
    new ComponentTemplateStep(),
    new IndexTemplateStep()
);

IndexTemplateStep and DataStreamTemplateStep check if the existing template's _meta.hash matches the current channel hash. If it matches, the template PUT is skipped, avoiding unnecessary API calls.