refactor: complete graceful shutdown implementation and add service runner (#493)

backend/internal/utils/servicerunner_test.go

@@ -0,0 +1,125 @@
+package utils
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+// Source:
+// https://github.com/ItalyPaleAle/traefik-forward-auth/blob/v3.5.1/pkg/utils/servicerunner.go
+// Copyright (c) 2018, Thom Seddon & Contributors Copyright (c) 2023, Alessandro Segala & Contributors
+// License: MIT (https://github.com/ItalyPaleAle/traefik-forward-auth/blob/v3.5.1/LICENSE.md)
+
+func TestServiceRunner_Run(t *testing.T) {
+	t.Run("successful services", func(t *testing.T) {
+		// Create a service that just returns no error after 0.2s
+		successService := func(ctx context.Context) error {
+			time.Sleep(200 * time.Millisecond)
+			return nil
+		}
+
+		// Create a service runner with two success services
+		runner := NewServiceRunner(successService, successService)
+
+		// Run the services with a timeout to avoid hanging if something goes wrong
+		ctx, cancel := context.WithTimeout(t.Context(), 5*time.Second)
+		defer cancel()
+
+		// Run should return nil when all services succeed
+		err := runner.Run(ctx)
+		require.NoError(t, err)
+	})
+
+	t.Run("service with error", func(t *testing.T) {
+		// Create a service that returns an error
+		expectedErr := errors.New("service failed")
+		errorService := func(ctx context.Context) error {
+			return expectedErr
+		}
+
+		// Create a service runner with one error service and one success service
+		successService := func(ctx context.Context) error {
+			time.Sleep(200 * time.Millisecond)
+			return nil
+		}
+
+		runner := NewServiceRunner(errorService, successService)
+
+		// Run the services with a timeout
+		ctx, cancel := context.WithTimeout(t.Context(), 5*time.Second)
+		defer cancel()
+
+		// Run should return the error
+		err := runner.Run(ctx)
+		require.Error(t, err)
+
+		// The error should contain our expected error
+		require.ErrorIs(t, err, expectedErr)
+	})
+
+	t.Run("context canceled", func(t *testing.T) {
+		// Create a service that waits until context is canceled
+		waitingService := func(ctx context.Context) error {
+			<-ctx.Done()
+			return ctx.Err()
+		}
+
+		// Create another service that returns no error quickly
+		quickService := func(ctx context.Context) error {
+			return nil
+		}
+
+		runner := NewServiceRunner(waitingService, quickService)
+
+		// Create a context that we can cancel
+		ctx, cancel := context.WithCancel(t.Context())
+
+		// Run the runner in a goroutine
+		errCh := make(chan error)
+		go func() {
+			errCh <- runner.Run(ctx)
+		}()
+
+		// Cancel the context to trigger service shutdown
+		cancel()
+
+		// Wait for the runner to finish with a timeout
+		select {
+		case err := <-errCh:
+			require.NoError(t, err, "expected nil error (context.Canceled should be ignored)")
+		case <-time.After(5 * time.Second):
+			t.Fatal("test timed out waiting for runner to finish")
+		}
+	})
+
+	t.Run("multiple errors", func(t *testing.T) {
+		// Create two services that return different errors
+		err1 := errors.New("error 1")
+		err2 := errors.New("error 2")
+
+		service1 := func(ctx context.Context) error {
+			return err1
+		}
+		service2 := func(ctx context.Context) error {
+			return err2
+		}
+
+		runner := NewServiceRunner(service1, service2)
+
+		// Run the services
+		ctx, cancel := context.WithTimeout(t.Context(), 5*time.Second)
+		defer cancel()
+
+		// Run should join all errors
+		err := runner.Run(ctx)
+		require.Error(t, err)
+
+		// Check that both errors are included
+		require.ErrorIs(t, err, err1)
+		require.ErrorIs(t, err, err2)
+	})
+}