fix configuration key name

Signed-off-by: Valery Piashchynski <piashchynski.valery@gmail.com>

go.sum

@@ -150,7 +150,6 @@ github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5m
 github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+HVt/4epWDjd4=
 github.com/gorilla/sessions v1.2.1/go.mod h1:dk2InVEVJ0sfLlnXv9EAgkf6ecYs/i80K/zI+bUmuGM=
-github.com/grpc-ecosystem/grpc-gateway v1.16.0 h1:gmcG1KaJ57LophUzW0Hy8NmPhnMZb4M0+kPpLofRdBo=
 github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0/go.mod h1:hgWBS7lorOAVIJEQMi4ZsPv9hVvWI6+ch50m39Pf2Ks=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.10.0 h1:ESEyqQqXXFIcImj/BE8oKEX37Zsuceb2cZI+EL/zNCY=

plugin.go

@@ -2,7 +2,6 @@ package otel
 
 import (
 	"context"
-	"fmt"
 	"net/http"
 	"os"
 	"runtime"
@@ -27,7 +26,8 @@ import (
 )
 
 const (
-	name string = "otel"
+	name             string = "otel"
+	configurationKey        = "http.otel"
 )
 
 type Plugin struct {
@@ -41,12 +41,12 @@ type Plugin struct {
 func (p *Plugin) Init(cfg config.Configurer, log *zap.Logger) error {
 	const op = errors.Op("otel_plugin_init")
 
-	if !cfg.Has(name) {
+	// name -> http.otel
+	if !cfg.Has(configurationKey) {
 		return errors.E(errors.Disabled)
 	}
 
-	// name -> http.otel
-	err := cfg.UnmarshalKey(fmt.Sprintf("%s.%s", "http", name), &p.cfg)
+	err := cfg.UnmarshalKey(configurationKey, &p.cfg)
 	if err != nil {
 		return errors.E(op, err)
 	}