Distributed Config API

The DistributedConfig struct controls how the logger behaves in a distributed system, defining service identity and trace propagation rules.

Fields

enabled: bool

Enable distributed context features. When true, distributed fields (like service name, region) are automatically attached to logs. Default: false

Service Identity

service_name: ?[]const u8

Name of the service or application (e.g., "auth-service", "payment-api"). Default: null

service_version: ?[]const u8

Semantic version of the running artifact (e.g., "1.0.2", "v2.0.0-rc1"). Default: null

environment: ?[]const u8

Deployment environment (e.g., "production", "staging", "development"). Default: null

datacenter: ?[]const u8

Datacenter or Availability Zone identifier (e.g., "us-east-1a", "eu-west-2"). Default: null

region: ?[]const u8

Cloud region identifier (e.g., "us-east-1"). Default: null

instance_id: ?[]const u8

Unique identifier for the specific instance (e.g., Kubernetes Pod ID, EC2 Instance ID, container ID). Default: null

Trace Propagation

trace_header: []const u8

HTTP header name used for propagating Trace IDs. Default: "X-Trace-ID"

span_header: []const u8

HTTP header name used for propagating Span IDs. Default: "X-Span-ID"

parent_header: []const u8

HTTP header name used for propagating Parent Span IDs. Default: "X-Parent-ID"

baggage_header: []const u8

HTTP header name for Baggage/Correlation Context. Default: "Correlation-Context"

trace_sampling_rate: f64

Sampling probablity for distributed traces (0.0 to 1.0). Default: 1.0 (100% sampling)

Callbacks

on_trace_created: ?*const fn (trace_id: []const u8) void

Optional callback invoked whenever logger.setTraceContext is called. Default: null

on_span_created: ?*const fn (span_id: []const u8, name: []const u8) void

Optional callback invoked whenever logger.startSpan is called. Default: null

Usage

var config = logly.Config.default();
config.distributed = .{
    .enabled = true,
    .service_name = "payment-service",
    .environment = "production",
    .region = "us-east-1",
    .trace_header = "b3-traceid", // Support B3 propagation headers
    .span_header = "b3-spanid",
};