Documentation
¶
Overview ¶
Package apmot provides an Elastic APM implementation of the OpenTracing API.
Things not implemented by this tracer:
- binary propagation format
- baggage
- logging
TODO(axw)
- update spanContext to stop storing objects once we have completed support for distributed tracing; we should only store trace context
- investigate injecting native APM transactions/spans as the parent when starting an OT span. This probably requires extending the OT API.
Example ¶
tracer, apmtracer, recorder := newTestTracer()
defer apmtracer.Close()
opentracing.SetGlobalTracer(tracer)
defer opentracing.SetGlobalTracer(nil)
parent := opentracing.StartSpan("Parent")
for i := 0; i < 5; i++ {
id := fmt.Sprintf("span_%d", i)
parent.LogEvent(fmt.Sprintf("Starting %s", id))
child := opentracing.StartSpan(id, opentracing.ChildOf(parent.Context()))
time.Sleep(10 * time.Millisecond)
child.Finish()
}
parent.LogEvent("A Log")
parent.Finish()
apmtracer.Flush(nil)
payloads := recorder.Payloads()
if len(payloads) != 1 {
panic(fmt.Errorf("expected 1 payload, got %d", len(payloads)))
}
transactions := payloads[0].Transactions()
if len(transactions) != 1 {
panic(fmt.Errorf("expected 1 transaction, got %d", len(transactions)))
}
transaction := transactions[0]
fmt.Printf("transaction: %s/%s\n", transaction.Name, transaction.Type)
fmt.Println("spans:")
for _, span := range transaction.Spans {
fmt.Printf(" - %s/%s\n", span.Name, span.Type)
}
Output: transaction: Parent/unknown spans: - span_0/unknown - span_1/unknown - span_2/unknown - span_3/unknown - span_4/unknown
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Option ¶
type Option func(*otTracer)
Option sets options for the OpenTracing Tracer implementation.
func WithTracer ¶
func WithTracer(t *elasticapm.Tracer) Option
WithTracer returns an Option which sets t as the underlying elasticapm.Tracer for constructing an OpenTracing Tracer.
Notes ¶
Bugs ¶
spanContext must not hold onto any transaction or span objects, as an opentracing.SpanContext may outlive the span to which it relates. To fix this, we need spans at the top level, and a means of creating them from a TraceContext.
In most cases this is *probably* OK, because a child-of relation means that the parent span cannot be ended before the child. However, there's no guarantee that the ordering of operations on the OpenTracing API follows the ordering of the events exactly (e.g. you could complete the entire business transaction before emitting events, and then emit events for the transaction and then its spans.)
Source Files