Struct RequestIdGenerator 

pub struct RequestIdGenerator;

Request ID generator for distributed tracing and request correlation.

This generator implements the MakeRequestId trait from tower-http to either:

1. Preserve an existing x-request-id header from the incoming request, or
2. Generate a new UUIDv7 if no request ID is present

Using UUIDv7 provides several benefits:

• Time-ordered: IDs are sortable by creation time
• Unique: Collision-resistant across distributed systems
• Traceable: Can correlate requests across multiple services

Request ID Flow

Client Request
    │
    ├─ Has x-request-id header? ─> Preserve it
    │
    └─ No header? ─> Generate new UUIDv7

Examples

use axum_conf::RequestIdGenerator;
use tower_http::request_id::SetRequestIdLayer;

// Add to your Axum router
let layer = SetRequestIdLayer::x_request_id(RequestIdGenerator);

Use Cases

• Distributed Tracing: Track a request across multiple microservices
• Debugging: Correlate logs from different components of a request
• Auditing: Track the lifecycle of a request for compliance
• Monitoring: Measure end-to-end request latency

Trait Implementations

impl Clone for RequestIdGenerator

fn clone(&self) -> RequestIdGenerator

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RequestIdGenerator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl MakeRequestId for RequestIdGenerator

fn make_request_id<B>(&mut self, req: &Request<B>) -> Option<RequestId>

Generates or extracts a request ID from an HTTP request.

If the request already has an x-request-id header, that value is preserved. Otherwise, a new UUIDv7 is generated with high-precision timestamp context.

Arguments

• req - The HTTP request to process

Returns

An Option<RequestId> containing either the existing or newly generated ID. Returns None only if UUID generation or header value creation fails (which is extremely rare in practice).

impl Copy for RequestIdGenerator