libdd-trace-stats

Compute aggregated statistics from distributed tracing spans with time-bucketed concentration.

Overview

libdd-trace-stats provides utilities for computing trace statistics by aggregating spans into time-based buckets with support for DDSketch distributions.

Features

• Span Concentration: Aggregate spans into time buckets
• DDSketch Integration: Use DDSketch for latency distribution metrics
• Peer Tags: Support for peer service aggregation
• Span Filtering: Filter spans by top-level, measured, or span.kind
• Time Bucketing: Configurable bucket sizes for aggregation
• Statistics Export: Generate statistics payloads for Datadog backend

Span Concentrator

The SpanConcentrator is the core component that aggregates spans into statistics:

Aggregation

Spans are aggregated into time buckets based on their end time. Within each bucket, spans are further aggregated by:

• Service name
• Resource name
• Operation name
• Span type
• HTTP status code
• Peer tags (if enabled)

Span Eligibility

Only certain spans are aggregated:

• Root spans
• Top-level spans
• Measured spans
• Spans with eligible span.kind values

Flushing

When flushed, the concentrator keeps the most recent buckets and returns older buckets as statistics.

Example Usage

use libdd_trace_stats::span_concentrator::SpanConcentrator;
use std::time::{Duration, SystemTime};

// Create a concentrator
let mut concentrator = SpanConcentrator::new(
    Duration::from_secs(10), // 10 second buckets
    SystemTime::now(),
    vec!["client".to_string(), "server".to_string()], // eligible span kinds
    vec!["peer.service".to_string()], // peer tag keys
);

// Add spans
// concentrator.add_span(&span);

// Flush statistics
// let stats = concentrator.flush(false);