Initial commit

main.go

@@ -0,0 +1,145 @@
+// This template contains a simple
+// app with OTEL bootstrap that will create an
+// HTTP server configured by environment that exports
+// spans and metrics to an OTEL collector if configured
+// to do so. Will also stand up a prometheus metrics
+// endpoint.
+//
+// Configuration and logger stored in context
+// Reference implementation of the provided packages
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/rs/zerolog"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/app"
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/otel"
+
+	"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/config"
+	"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/demo"
+	"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/service"
+)
+
+const (
+	terminationGracePeriod = 30 * time.Second
+	appName                = "demo-app"
+)
+
+var (
+	// TODO: Register your service.AppService implementers here
+	// This should be the only change necessary here
+	// NOTE: At least one service needs to add a dial option
+	// for transport credentials, otherwise you will have to do it here
+	appServices = []service.AppService{
+		&demo.DemoService{},
+	}
+
+	flagSchema bool
+)
+
+func main() {
+	ctx, cncl := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
+	defer cncl()
+
+	// Load configuration and setup logging. The go-app framework
+	// will handle loading config and environment into our demo
+	// app config struct which embeds app.AooConfig
+	ctx, serviceConfig := app.MustLoadConfigInto(ctx, &config.ServiceConfig{})
+
+	// Print schema if that's all we have to do
+	if flagSchema {
+		printSchema()
+		os.Exit(0)
+	}
+
+	// Prepare app
+	app := &app.App{
+		AppContext: ctx,
+	}
+	app.InitOTEL()
+
+	tracer := otel.GetTracer(ctx, appName)
+	ctx, span := tracer.Start(ctx, appName+".startup", trace.WithAttributes(
+		attribute.Int("appServices", len(appServices)),
+	))
+
+	log := zerolog.Ctx(ctx)
+	log.Debug().Any("mergedConfig", serviceConfig).Msg("App configuration prepared")
+
+	// Prepare services
+	var err error
+	sdFuncs := make([]service.ShutdownFunc, len(appServices))
+	for i, svc := range appServices {
+		sdFuncs[i], err = svc.Init(ctx, serviceConfig)
+		if err != nil {
+			span.RecordError(err)
+			span.SetStatus(codes.Error, err.Error())
+			log.Fatal().Err(err).Send()
+		}
+	}
+	span.AddEvent("app services initialized")
+
+	// Merge all service implementations and add to app
+	grpcSvcs, httpSvcs := service.MergeServices(ctx, appServices...)
+	app.GRPC = grpcSvcs
+	app.HTTP = httpSvcs
+
+	span.SetAttributes(
+		attribute.Int("grpcServices", len(app.GRPC.Services)),
+		attribute.Int("httpServices", len(app.HTTP.Funcs)+len(app.HTTP.Handlers)),
+	)
+
+	// Launch app
+	app.MustRun()
+
+	span.AddEvent("app started")
+	span.SetStatus(codes.Ok, "")
+	span.End()
+
+	// Wait for app to complete and then perform internal shutdown
+	<-app.Done()
+
+	log.Info().Int("numServices", len(appServices)).Msg("shutting down app services")
+
+	sdCtx, cncl := context.WithTimeout(context.Background(), terminationGracePeriod)
+	defer cncl()
+
+	// Call registered shutdown funcs from all services
+	var sdWg sync.WaitGroup
+	for _, sdFunc := range sdFuncs {
+		sdWg.Add(1)
+		go func() {
+			defer sdWg.Done()
+			svcName, err := sdFunc(sdCtx)
+			log.Err(err).Str("service", svcName).Msg("terminated")
+		}()
+	}
+	sdWg.Wait()
+}
+
+// flag.Parse will be called by go-app
+func init() {
+	flag.BoolVar(&flagSchema, "schema", false, "generate json schema and exit")
+}
+
+func printSchema() {
+	bytes, err := app.CustomSchema(&config.ServiceConfig{})
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(string(bytes))
+	os.Exit(0)
+}