Rename plugin directory to instrumentation (#779)

* Rename plugin directory to instrumentation

As per https://github.com/open-telemetry/opentelemetry-specification/pull/539

* Update package paths

* Fix tracer names in othttp instrumentation

example/grpc/client/main.go

@@ -23,7 +23,7 @@ import (
 	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/example/grpc/api"
 	"go.opentelemetry.io/otel/example/grpc/config"
-	"go.opentelemetry.io/otel/plugin/grpctrace"
+	"go.opentelemetry.io/otel/instrumentation/grpctrace"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/metadata"

example/grpc/server/main.go

@@ -25,7 +25,7 @@ import (
 	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/example/grpc/api"
 	"go.opentelemetry.io/otel/example/grpc/config"
-	"go.opentelemetry.io/otel/plugin/grpctrace"
+	"go.opentelemetry.io/otel/instrumentation/grpctrace"
 
 	"google.golang.org/grpc"
 )

example/http/client/client.go

@@ -29,7 +29,7 @@ import (
 	"go.opentelemetry.io/otel/api/correlation"
 	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/exporters/trace/stdout"
-	"go.opentelemetry.io/otel/plugin/httptrace"
+	"go.opentelemetry.io/otel/instrumentation/httptrace"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 )
 

example/http/server/server.go

@@ -23,7 +23,7 @@ import (
 	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/api/trace"
 	"go.opentelemetry.io/otel/exporters/trace/stdout"
-	"go.opentelemetry.io/otel/plugin/httptrace"
+	"go.opentelemetry.io/otel/instrumentation/httptrace"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 )
 

instrumentation/httptrace/clienttrace.go

@@ -67,7 +67,7 @@ func NewClientTrace(ctx context.Context) *httptrace.ClientTrace {
 		activeHooks: make(map[string]context.Context),
 	}
 
-	ct.tr = global.Tracer("go.opentelemetry.io/otel/plugin/httptrace")
+	ct.tr = global.Tracer("go.opentelemetry.io/otel/instrumentation/httptrace")
 
 	return &httptrace.ClientTrace{
 		GetConn:              ct.getConn,

instrumentation/httptrace/clienttrace_test.go

@@ -25,7 +25,7 @@ import (
 
 	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/api/kv"
-	"go.opentelemetry.io/otel/plugin/httptrace"
+	"go.opentelemetry.io/otel/instrumentation/httptrace"
 	export "go.opentelemetry.io/otel/sdk/export/trace"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 )

instrumentation/othttp/filters/filters.go

@@ -20,7 +20,7 @@ import (
 	"net/http"
 	"strings"
 
-	"go.opentelemetry.io/otel/plugin/othttp"
+	"go.opentelemetry.io/otel/instrumentation/othttp"
 )
 
 // Any takes a list of Filters and returns a Filter that

instrumentation/othttp/filters/filters_test.go

@@ -19,7 +19,7 @@ import (
 	"net/url"
 	"testing"
 
-	"go.opentelemetry.io/otel/plugin/othttp"
+	"go.opentelemetry.io/otel/instrumentation/othttp"
 )
 
 type scenario struct {

instrumentation/othttp/filters/header_go14.go

@@ -20,7 +20,7 @@ import (
 	"net/http"
 	"strings"
 
-	"go.opentelemetry.io/otel/plugin/othttp"
+	"go.opentelemetry.io/otel/instrumentation/othttp"
 )
 
 // Header returns a Filter that returns true if the request

instrumentation/othttp/filters/header_nongo14.go

@@ -21,7 +21,7 @@ import (
 	"net/textproto"
 	"strings"
 
-	"go.opentelemetry.io/otel/plugin/othttp"
+	"go.opentelemetry.io/otel/instrumentation/othttp"
 )
 
 // Header returns a Filter that returns true if the request

instrumentation/othttp/handler.go

@@ -57,7 +57,7 @@ func NewHandler(handler http.Handler, operation string, opts ...Option) http.Han
 	}
 
 	defaultOpts := []Option{
-		WithTracer(global.Tracer("go.opentelemetry.io/plugin/othttp")),
+		WithTracer(global.Tracer("go.opentelemetry.io/otel/instrumentation/othttp")),
 		WithPropagators(global.Propagators()),
 		WithSpanOptions(trace.WithSpanKind(trace.SpanKindServer)),
 		WithSpanNameFormatter(defaultHandlerFormatter),

instrumentation/othttp/handler_example_test.go

@@ -27,7 +27,7 @@ import (
 	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/api/trace"
 	"go.opentelemetry.io/otel/exporters/trace/stdout"
-	"go.opentelemetry.io/otel/plugin/othttp"
+	"go.opentelemetry.io/otel/instrumentation/othttp"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 )
 

instrumentation/othttp/transport.go

@@ -49,7 +49,7 @@ func NewTransport(base http.RoundTripper, opts ...Option) *Transport {
 	}
 
 	defaultOpts := []Option{
-		WithTracer(global.Tracer("go.opentelemetry.io/plugin/othttp")),
+		WithTracer(global.Tracer("go.opentelemetry.io/otel/instrumentation/othttp")),
 		WithPropagators(global.Propagators()),
 		WithSpanOptions(trace.WithSpanKind(trace.SpanKindClient)),
 		WithSpanNameFormatter(defaultTransportFormatter),