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main.go
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main.go
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// Copyright 2018 Google LLC
//
// 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 (
"context"
"fmt"
"net/http"
"os"
"time"
"cloud.google.com/go/profiler"
"github.com/gorilla/mux"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
"go.opentelemetry.io/otel/propagation"
sdktrace "go.opentelemetry.io/otel/sdk/trace"
"google.golang.org/grpc"
)
const (
port = "8080"
defaultCurrency = "USD"
cookieMaxAge = 60 * 60 * 48
cookiePrefix = "shop_"
cookieSessionID = cookiePrefix + "session-id"
cookieCurrency = cookiePrefix + "currency"
)
var (
whitelistedCurrencies = map[string]bool{
"USD": true,
"EUR": true,
"CAD": true,
"JPY": true,
"GBP": true,
"TRY": true,
}
baseUrl = ""
)
type ctxKeySessionID struct{}
type frontendServer struct {
productCatalogSvcAddr string
productCatalogSvcConn *grpc.ClientConn
currencySvcAddr string
currencySvcConn *grpc.ClientConn
cartSvcAddr string
cartSvcConn *grpc.ClientConn
recommendationSvcAddr string
recommendationSvcConn *grpc.ClientConn
checkoutSvcAddr string
checkoutSvcConn *grpc.ClientConn
shippingSvcAddr string
shippingSvcConn *grpc.ClientConn
adSvcAddr string
adSvcConn *grpc.ClientConn
collectorAddr string
collectorConn *grpc.ClientConn
shoppingAssistantSvcAddr string
}
func main() {
ctx := context.Background()
log := logrus.New()
log.Level = logrus.DebugLevel
log.Formatter = &logrus.JSONFormatter{
FieldMap: logrus.FieldMap{
logrus.FieldKeyTime: "timestamp",
logrus.FieldKeyLevel: "severity",
logrus.FieldKeyMsg: "message",
},
TimestampFormat: time.RFC3339Nano,
}
log.Out = os.Stdout
svc := new(frontendServer)
otel.SetTextMapPropagator(
propagation.NewCompositeTextMapPropagator(
propagation.TraceContext{}, propagation.Baggage{}))
baseUrl = os.Getenv("BASE_URL")
if os.Getenv("ENABLE_TRACING") == "1" {
log.Info("Tracing enabled.")
initTracing(log, ctx, svc)
} else {
log.Info("Tracing disabled.")
}
if os.Getenv("ENABLE_PROFILER") == "1" {
log.Info("Profiling enabled.")
go initProfiling(log, "frontend", "1.0.0")
} else {
log.Info("Profiling disabled.")
}
srvPort := port
if os.Getenv("PORT") != "" {
srvPort = os.Getenv("PORT")
}
addr := os.Getenv("LISTEN_ADDR")
mustMapEnv(&svc.productCatalogSvcAddr, "PRODUCT_CATALOG_SERVICE_ADDR")
mustMapEnv(&svc.currencySvcAddr, "CURRENCY_SERVICE_ADDR")
mustMapEnv(&svc.cartSvcAddr, "CART_SERVICE_ADDR")
mustMapEnv(&svc.recommendationSvcAddr, "RECOMMENDATION_SERVICE_ADDR")
mustMapEnv(&svc.checkoutSvcAddr, "CHECKOUT_SERVICE_ADDR")
mustMapEnv(&svc.shippingSvcAddr, "SHIPPING_SERVICE_ADDR")
mustMapEnv(&svc.adSvcAddr, "AD_SERVICE_ADDR")
mustMapEnv(&svc.shoppingAssistantSvcAddr, "SHOPPING_ASSISTANT_SERVICE_ADDR")
mustConnGRPC(ctx, &svc.currencySvcConn, svc.currencySvcAddr)
mustConnGRPC(ctx, &svc.productCatalogSvcConn, svc.productCatalogSvcAddr)
mustConnGRPC(ctx, &svc.cartSvcConn, svc.cartSvcAddr)
mustConnGRPC(ctx, &svc.recommendationSvcConn, svc.recommendationSvcAddr)
mustConnGRPC(ctx, &svc.shippingSvcConn, svc.shippingSvcAddr)
mustConnGRPC(ctx, &svc.checkoutSvcConn, svc.checkoutSvcAddr)
mustConnGRPC(ctx, &svc.adSvcConn, svc.adSvcAddr)
r := mux.NewRouter()
r.HandleFunc(baseUrl + "/", svc.homeHandler).Methods(http.MethodGet, http.MethodHead)
r.HandleFunc(baseUrl + "/product/{id}", svc.productHandler).Methods(http.MethodGet, http.MethodHead)
r.HandleFunc(baseUrl + "/cart", svc.viewCartHandler).Methods(http.MethodGet, http.MethodHead)
r.HandleFunc(baseUrl + "/cart", svc.addToCartHandler).Methods(http.MethodPost)
r.HandleFunc(baseUrl + "/cart/empty", svc.emptyCartHandler).Methods(http.MethodPost)
r.HandleFunc(baseUrl + "/setCurrency", svc.setCurrencyHandler).Methods(http.MethodPost)
r.HandleFunc(baseUrl + "/logout", svc.logoutHandler).Methods(http.MethodGet)
r.HandleFunc(baseUrl + "/cart/checkout", svc.placeOrderHandler).Methods(http.MethodPost)
r.HandleFunc(baseUrl + "/assistant", svc.assistantHandler).Methods(http.MethodGet)
r.PathPrefix(baseUrl + "/static/").Handler(http.StripPrefix(baseUrl + "/static/", http.FileServer(http.Dir("./static/"))))
r.HandleFunc(baseUrl + "/robots.txt", func(w http.ResponseWriter, _ *http.Request) { fmt.Fprint(w, "User-agent: *\nDisallow: /") })
r.HandleFunc(baseUrl + "/_healthz", func(w http.ResponseWriter, _ *http.Request) { fmt.Fprint(w, "ok") })
r.HandleFunc(baseUrl + "/product-meta/{ids}", svc.getProductByID).Methods(http.MethodGet)
r.HandleFunc(baseUrl + "/bot", svc.chatBotHandler).Methods(http.MethodPost)
var handler http.Handler = r
handler = &logHandler{log: log, next: handler} // add logging
handler = ensureSessionID(handler) // add session ID
handler = otelhttp.NewHandler(handler, "frontend") // add OTel tracing
log.Infof("starting server on " + addr + ":" + srvPort)
log.Fatal(http.ListenAndServe(addr+":"+srvPort, handler))
}
func initStats(log logrus.FieldLogger) {
// TODO(arbrown) Implement OpenTelemtry stats
}
func initTracing(log logrus.FieldLogger, ctx context.Context, svc *frontendServer) (*sdktrace.TracerProvider, error) {
mustMapEnv(&svc.collectorAddr, "COLLECTOR_SERVICE_ADDR")
mustConnGRPC(ctx, &svc.collectorConn, svc.collectorAddr)
exporter, err := otlptracegrpc.New(
ctx,
otlptracegrpc.WithGRPCConn(svc.collectorConn))
if err != nil {
log.Warnf("warn: Failed to create trace exporter: %v", err)
}
tp := sdktrace.NewTracerProvider(
sdktrace.WithBatcher(exporter),
sdktrace.WithSampler(sdktrace.AlwaysSample()))
otel.SetTracerProvider(tp)
return tp, err
}
func initProfiling(log logrus.FieldLogger, service, version string) {
// TODO(ahmetb) this method is duplicated in other microservices using Go
// since they are not sharing packages.
for i := 1; i <= 3; i++ {
log = log.WithField("retry", i)
if err := profiler.Start(profiler.Config{
Service: service,
ServiceVersion: version,
// ProjectID must be set if not running on GCP.
// ProjectID: "my-project",
}); err != nil {
log.Warnf("warn: failed to start profiler: %+v", err)
} else {
log.Info("started Stackdriver profiler")
return
}
d := time.Second * 10 * time.Duration(i)
log.Debugf("sleeping %v to retry initializing Stackdriver profiler", d)
time.Sleep(d)
}
log.Warn("warning: could not initialize Stackdriver profiler after retrying, giving up")
}
func mustMapEnv(target *string, envKey string) {
v := os.Getenv(envKey)
if v == "" {
panic(fmt.Sprintf("environment variable %q not set", envKey))
}
*target = v
}
func mustConnGRPC(ctx context.Context, conn **grpc.ClientConn, addr string) {
var err error
ctx, cancel := context.WithTimeout(ctx, time.Second*3)
defer cancel()
*conn, err = grpc.DialContext(ctx, addr,
grpc.WithInsecure(),
grpc.WithUnaryInterceptor(otelgrpc.UnaryClientInterceptor()),
grpc.WithStreamInterceptor(otelgrpc.StreamClientInterceptor()))
if err != nil {
panic(errors.Wrapf(err, "grpc: failed to connect %s", addr))
}
}