implement grpc gateway and addl handler support

pkg/app/monitor.go

@@ -0,0 +1,72 @@
+package app
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+)
+
+// Watches contexts and channels for the
+// app to be finished and calls shutdown once
+// the app is done
+func (a *App) monitor() {
+	select {
+	case <-a.AppContext.Done():
+		a.l.Warn().Str("reason", a.AppContext.Err().Error()).
+			Msg("shutting down on context done")
+	case <-a.HTTP.HTTPDone: // TODO: return error on this channel
+		a.l.Warn().Msg("shutting down early on http server done")
+	case err := <-a.GRPC.GRPCDone:
+		a.l.Warn().Err(err).Msg("shutting down early on grpc server done")
+	}
+
+	a.Shutdown()     // Run through all shutdown funcs
+	a.appDone <- nil // Notify app
+}
+
+// Typically invoked when AppContext is done
+// or Server has exited. Not intended to be called
+// manually
+func (a *App) Shutdown() {
+	now := time.Now()
+
+	doneCtx, cncl := context.WithTimeout(context.Background(), 15*time.Second)
+	defer func() {
+		if doneCtx.Err() == context.DeadlineExceeded {
+			a.l.Err(doneCtx.Err()).
+				Dur("shutdownTime", time.Since(now)).
+				Msg("app shutdown aborted")
+		} else {
+			a.l.Info().
+				Int("shutdownFuncsCalled", len(a.shutdownFuncs)).
+				Dur("shutdownTime", time.Since(now)).
+				Msg("app shutdown normally")
+		}
+		cncl()
+	}()
+
+	doneCtx, span := a.tracer.Start(doneCtx, "shutdown")
+	defer span.End()
+
+	span.SetAttributes(attribute.Int("shutdown.funcs", len(a.shutdownFuncs)))
+
+	var wg sync.WaitGroup
+	wg.Add(len(a.shutdownFuncs))
+
+	for _, f := range a.shutdownFuncs {
+		go func() {
+			defer wg.Done()
+			err := f(doneCtx)
+			if err != nil {
+				span.SetStatus(codes.Error, "shutdown failed")
+				span.RecordError(err)
+				a.l.Err(err).Send()
+			}
+		}()
+	}
+
+	wg.Wait()
+}