server.go

// Copyright Ravil Galaktionov
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
	"log"
	"net/http"
	"os"

	"github.com/99designs/gqlgen/graphql/handler"
	"github.com/99designs/gqlgen/graphql/playground"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
	"go.opentelemetry.io/otel/propagation"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"

	"github.com/ravilushqa/otelgqlgen"
	"github.com/ravilushqa/otelgqlgen/example/graph"
	"github.com/ravilushqa/otelgqlgen/example/graph/generated"
)

const defaultPort = "8080"

var tracer = otel.Tracer("gqlgen-server")

func main() {
	port := os.Getenv("PORT")
	if port == "" {
		port = defaultPort
	}

	initTracer()

	srv := handler.NewDefaultServer(generated.NewExecutableSchema(generated.Config{Resolvers: &graph.Resolver{Tracer: tracer}}))
	srv.Use(otelgqlgen.Middleware())

	http.Handle("/", playground.Handler("GraphQL playground", "/query"))
	http.Handle("/query", srv)

	log.Printf("connect to http://localhost:%s/ for GraphQL playground", port)
	log.Fatal(http.ListenAndServe(":"+port, nil))
}

func initTracer() {
	traceExporter, err := stdouttrace.New(
		stdouttrace.WithPrettyPrint(),
	)
	if err != nil {
		log.Fatalf("failed to initialize stdouttrace export pipeline: %v", err)
	}

	tp := sdktrace.NewTracerProvider(
		sdktrace.WithSampler(sdktrace.AlwaysSample()),
		sdktrace.WithSyncer(traceExporter),
	)

	otel.SetTracerProvider(tp)
	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
}