Update provider to use AlwaysSampler instead of ProbabilitySampler (#506)

* update provider to use AlwaysSampler instead of ProbabilitySampler

* remove unused defaultSamplingProbability constant

* fix broken tests

* update failure message in test

* fix test description

Co-authored-by: Rahul Patel <rghetia@yahoo.com>

Author: rghetia

sdk/trace/provider.go

@@ -65,7 +65,7 @@ func NewProvider(opts ...ProviderOption) (*Provider, error) {
 		namedTracer: make(map[string]*tracer),
 	}
 	tp.config.Store(&Config{
-		DefaultSampler:       ProbabilitySampler(defaultSamplingProbability),
+		DefaultSampler:       AlwaysSample(),
 		IDGenerator:          defIDGenerator(),
 		MaxAttributesPerSpan: DefaultMaxAttributesPerSpan,
 		MaxEventsPerSpan:     DefaultMaxEventsPerSpan,

sdk/trace/sampling.go

@@ -20,8 +20,6 @@ import (
 	"go.opentelemetry.io/otel/api/core"
 )
 
-const defaultSamplingProbability = 1e-4
-
 // Sampler decides whether a trace should be sampled and exported.
 type Sampler func(SamplingParameters) SamplingDecision
 

sdk/trace/trace_test.go

@@ -128,12 +128,12 @@ func TestSetName(t *testing.T) {
 	}
 }
 
-func TestRecordingIsOff(t *testing.T) {
+func TestRecordingIsOn(t *testing.T) {
 	tp, _ := NewProvider()
-	_, span := tp.Tracer("Recording off").Start(context.Background(), "StartSpan")
+	_, span := tp.Tracer("Recording on").Start(context.Background(), "StartSpan")
 	defer span.End()
-	if span.IsRecording() == true {
-		t.Error("new span is recording events")
+	if span.IsRecording() == false {
+		t.Error("new span is not recording events")
 	}
 }
 
@@ -218,7 +218,7 @@ func TestStartSpanWithParent(t *testing.T) {
 	sc1 := core.SpanContext{
 		TraceID:    tid,
 		SpanID:     sid,
-		TraceFlags: 0x0,
+		TraceFlags: 0x1,
 	}
 	_, s1 := tr.Start(apitrace.ContextWithRemoteSpanContext(ctx, sc1), "span1-unsampled-parent1")
 	if err := checkChild(sc1, s1); err != nil {