Type Alias FieldMappingFn 

pub type FieldMappingFn = dyn for<'a> Fn(&'a SpanData, &'a ModelConfig) -> &'a str + Send + Sync;

Custom mapping between opentelemetry spans and datadog spans.

User can provide custom function to change the mapping. It currently supports customizing the following fields in Datadog span protocol.

field name	default value
service name	service name configuration from ModelConfig
name	opentelemetry instrumentation library name
resource	opentelemetry name

The function takes a reference to SpanData and a reference to ModelConfig as parameters. It should return a &str which will be used as the value for the field.

If no custom mapping is provided. Default mapping detailed above will be used.

For example,

use opentelemetry::global;
use opentelemetry_datadog::{ApiVersion, new_pipeline};

fn main() -> Result<(), opentelemetry_sdk::trace::TraceError> {
    let provider = new_pipeline()
        .with_service_name("my_app")
        .with_api_version(ApiVersion::Version05)
        // the custom mapping below will change the all spans' name to datadog spans
        .with_name_mapping(|span, model_config|{"datadog spans"})
        .with_agent_endpoint("http://localhost:8126")
        .install_batch()?;
    global::set_tracer_provider(provider.clone());
    let tracer = global::tracer("opentelemetry-datadog-demo");

    Ok(())
}