ipld-eth-server/vendor/gopkg.in/DataDog/dd-trace-go.v1/ddtrace/example_test.go
2018-09-11 16:30:29 -05:00

74 lines
2.2 KiB
Go

package ddtrace_test
import (
"io/ioutil"
"log"
opentracing "github.com/opentracing/opentracing-go"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/ext"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/mocktracer"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/opentracer"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
)
// The below example illustrates a simple use case using the "tracer" package,
// our native Datadog APM tracing client integration. For thorough documentation
// and further examples, visit its own godoc page.
func Example_datadog() {
// Start the tracer and defer the Stop method.
tracer.Start(tracer.WithAgentAddr("host:port"))
defer tracer.Stop()
// Start a root span.
span := tracer.StartSpan("get.data")
defer span.Finish()
// Create a child of it, computing the time needed to read a file.
child := tracer.StartSpan("read.file", tracer.ChildOf(span.Context()))
child.SetTag(ext.ResourceName, "test.json")
// Perform an operation.
_, err := ioutil.ReadFile("~/test.json")
// We may finish the child span using the returned error. If it's
// nil, it will be disregarded.
child.Finish(tracer.WithError(err))
if err != nil {
log.Fatal(err)
}
}
// The below example illustrates how to set up an opentracing.Tracer using Datadog's
// tracer.
func Example_opentracing() {
// Start a Datadog tracer, optionally providing a set of options,
// returning an opentracing.Tracer which wraps it.
t := opentracer.New(tracer.WithAgentAddr("host:port"))
defer tracer.Stop() // important for data integrity (flushes any leftovers)
// Use it with the Opentracing API. The (already started) Datadog tracer
// may be used in parallel with the Opentracing API if desired.
opentracing.SetGlobalTracer(t)
}
// The code below illustrates a scenario of how one could use a mock tracer in tests
// to assert that spans are created correctly.
func Example_mocking() {
// Setup the test environment: start the mock tracer.
mt := mocktracer.Start()
defer mt.Stop()
// Run test code: in this example we will simply create a span to illustrate.
tracer.StartSpan("test.span").Finish()
// Assert the results: query the mock tracer for finished spans.
spans := mt.FinishedSpans()
if len(spans) != 1 {
// fail
}
if spans[0].OperationName() != "test.span" {
// fail
}
}