import (
    "net/http"
    zhttp "github.com/openzipkin/zipkin-go/middleware/http"
)

func MyRequestSampler(r *http.Request) *bool {
    switch r.URL.Path {
    case "/health":
        return zhttp.Discard() // not interested in tracing health checks
    case "/important/path":
        return zhttp.Sample() // trace this regardless of upstream decision
    }

    return nil // path didn't match so keep upstream decision as is
}