Update API configs.

CONTRIBUTING.md

@@ -190,8 +190,16 @@ will likely want to build custom options for the configuration, the `config`
 should be exported. Please, include in the documentation for the `config`
 how the user can extend the configuration.
 
-It is important that `config` are not shared across package boundaries.
-Meaning a `config` from one package should not be directly used by another.
+It is important that internal `config` are not shared across package boundaries.
+Meaning a `config` from one package should not be directly used by another. The 
+one exception is the API packages.  The configs from the base API, eg. 
+`go.opentelemetry.io/otel/sdk/trace.TracerConfig` and 
+`go.opentelemetry.io/otel/metric.InstrumentConfig`, are intended to be consumed 
+by the SDK therefor it is expected that these are exported.
+
+When a config is exported we want to maintain forward and backward 
+compatibility, to achieve this all fields should not be exported but should 
+instead be accessed by methods.
 
 Optionally, it is common to include a `newConfig` function (with the same
 naming scheme). This function wraps any defaults setting and looping over

internal/global/trace.go

@@ -92,7 +92,7 @@ func (p *tracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.T
 
 	key := il{
 		name:    name,
-		version: trace.NewTracerConfig(opts...).InstrumentationVersion,
+		version: trace.NewTracerConfig(opts...).InstrumentationVersion(),
 	}
 
 	if p.tracers == nil {

internal/global/trace_test.go

@@ -93,7 +93,6 @@ func TestTraceProviderDelegates(t *testing.T) {
 		tracer: func(name string, opts ...trace.TracerOption) trace.Tracer {
 			called = true
 			assert.Equal(t, "abc", name)
-			assert.Equal(t, []trace.TracerOption{trace.WithInstrumentationVersion("xyz")}, opts)
 			return trace.NewNoopTracerProvider().Tracer("")
 		},
 	})
@@ -131,7 +130,6 @@ func TestTraceProviderDelegatesConcurrentSafe(t *testing.T) {
 		tracer: func(name string, opts ...trace.TracerOption) trace.Tracer {
 			newVal := atomic.AddInt32(&called, 1)
 			assert.Equal(t, "abc", name)
-			assert.Equal(t, []trace.TracerOption{trace.WithInstrumentationVersion("xyz")}, opts)
 			if newVal == 10 {
 				// Signal the goroutine to finish.
 				close(quit)
@@ -175,7 +173,6 @@ func TestTracerDelegatesConcurrentSafe(t *testing.T) {
 	otel.SetTracerProvider(fnTracerProvider{
 		tracer: func(name string, opts ...trace.TracerOption) trace.Tracer {
 			assert.Equal(t, "abc", name)
-			assert.Equal(t, []trace.TracerOption{trace.WithInstrumentationVersion("xyz")}, opts)
 			return fnTracer{
 				start: func(ctx context.Context, spanName string, opts ...trace.SpanOption) (context.Context, trace.Span) {
 					newVal := atomic.AddInt32(&called, 1)

oteltest/provider.go

@@ -51,15 +51,15 @@ func (p *TracerProvider) Tracer(instName string, opts ...trace.TracerOption) tra
 
 	inst := instrumentation{
 		Name:    instName,
-		Version: conf.InstrumentationVersion,
+		Version: conf.InstrumentationVersion(),
 	}
 	p.tracersMu.Lock()
 	defer p.tracersMu.Unlock()
 	t, ok := p.tracers[inst]
 	if !ok {
 		t = &Tracer{
 			Name:    instName,
-			Version: conf.InstrumentationVersion,
+			Version: conf.InstrumentationVersion(),
 			config:  &p.config,
 		}
 		p.tracers[inst] = t

sdk/trace/provider.go

@@ -116,7 +116,7 @@ func (p *TracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.T
 	}
 	il := instrumentation.Library{
 		Name:    name,
-		Version: c.InstrumentationVersion,
+		Version: c.InstrumentationVersion(),
 	}
 	t, ok := p.namedTracer[il]
 	if !ok {

trace/config.go

@@ -20,30 +20,34 @@ import (
 	"go.opentelemetry.io/otel/attribute"
 )
 
-// TracerConfig is a group of options for a Tracer.
+// tracerConfig is a group of options for a Tracer.
 type TracerConfig struct {
-	// InstrumentationVersion is the version of the library providing
-	// instrumentation.
-	InstrumentationVersion string
+	instrumentationVersion string
+}
+
+// InstrumentationVersion returns the version of the library providing instrumentation.
+func (t *TracerConfig) InstrumentationVersion() string {
+	return t.instrumentationVersion
 }
 
 // NewTracerConfig applies all the options to a returned TracerConfig.
 func NewTracerConfig(options ...TracerOption) *TracerConfig {
 	config := new(TracerConfig)
 	for _, option := range options {
-		option.ApplyTracer(config)
+		option.apply(config)
 	}
 	return config
 }
 
 // TracerOption applies an option to a TracerConfig.
 type TracerOption interface {
-	ApplyTracer(*TracerConfig)
+	apply(*TracerConfig)
+}
 
-	// A private method to prevent users implementing the
-	// interface and so future additions to it will not
-	// violate compatibility.
-	private()
+type tracerOptionFunc func(*TracerConfig)
+
+func (fn tracerOptionFunc) apply(cfg *TracerConfig) {
+	fn(cfg)
 }
 
 // SpanConfig is a group of options for a Span.
@@ -84,6 +88,13 @@ type SpanOption interface {
 	private()
 }
 
+type EventConfig struct {
+	// Attributes describe the associated qualities of a Event.
+	Attributes []attribute.KeyValue
+	// Timestamp is a time in a Event was recorded.
+	Timestamp time.Time
+}
+
 // NewEventConfig applies all the EventOptions to a returned SpanConfig. If no
 // timestamp option is passed, the returned SpanConfig will have a Timestamp
 // set to the call time, otherwise no validation is performed on the returned
@@ -185,21 +196,9 @@ func WithSpanKind(kind SpanKind) SpanOption {
 	return spanKindSpanOption(kind)
 }
 
-// InstrumentationOption is an interface for applying instrumentation specific
-// options.
-type InstrumentationOption interface {
-	TracerOption
-}
-
 // WithInstrumentationVersion sets the instrumentation version.
-func WithInstrumentationVersion(version string) InstrumentationOption {
-	return instrumentationVersionOption(version)
+func WithInstrumentationVersion(version string) TracerOption {
+	return tracerOptionFunc(func(cfg *TracerConfig) {
+		cfg.instrumentationVersion = version
+	})
 }
-
-type instrumentationVersionOption string
-
-func (i instrumentationVersionOption) ApplyTracer(config *TracerConfig) {
-	config.InstrumentationVersion = string(i)
-}
-
-func (instrumentationVersionOption) private() {}

trace/config_test.go

@@ -191,7 +191,7 @@ func TestTracerConfig(t *testing.T) {
 				WithInstrumentationVersion(v1),
 			},
 			&TracerConfig{
-				InstrumentationVersion: v1,
+				instrumentationVersion: v1,
 			},
 		},
 		{
@@ -201,7 +201,7 @@ func TestTracerConfig(t *testing.T) {
 				WithInstrumentationVersion(v2),
 			},
 			&TracerConfig{
-				InstrumentationVersion: v2,
+				instrumentationVersion: v2,
 			},
 		},
 	}