Changed: DB Params

templ/examples/counter/services/count.go

@@ -0,0 +1,84 @@
+package services
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/a-h/templ/examples/counter/db"
+	"golang.org/x/exp/slog"
+)
+
+type Counts struct {
+	Global  int
+	Session int
+}
+
+type IncrementType int
+
+const (
+	IncrementTypeUnknown IncrementType = iota
+	IncrementTypeGlobal
+	IncrementTypeSession
+)
+
+var ErrUnknownIncrementType error = errors.New("unknown increment type")
+
+func NewCount(log *slog.Logger, cs *db.CountStore) Count {
+	return Count{
+		Log:        log,
+		CountStore: cs,
+	}
+}
+
+type Count struct {
+	Log        *slog.Logger
+	CountStore *db.CountStore
+}
+
+func (cs Count) Increment(ctx context.Context, it IncrementType, sessionID string) (counts Counts, err error) {
+	// Work out which operations to do.
+	var global, session func(ctx context.Context, id string) (count int, err error)
+	switch it {
+	case IncrementTypeGlobal:
+		global = cs.CountStore.Increment
+		session = cs.CountStore.Get
+	case IncrementTypeSession:
+		global = cs.CountStore.Get
+		session = cs.CountStore.Increment
+	default:
+		return counts, ErrUnknownIncrementType
+	}
+
+	// Run the operations in parallel.
+	var wg sync.WaitGroup
+	wg.Add(2)
+	errs := make([]error, 2)
+	go func() {
+		defer wg.Done()
+		counts.Global, errs[0] = global(ctx, "global")
+	}()
+	go func() {
+		defer wg.Done()
+		counts.Session, errs[1] = session(ctx, sessionID)
+	}()
+	wg.Wait()
+
+	return counts, errors.Join(errs...)
+}
+
+func (cs Count) Get(ctx context.Context, sessionID string) (counts Counts, err error) {
+	globalAndSessionCounts, err := cs.CountStore.BatchGet(ctx, "global", sessionID)
+	if err != nil {
+		err = fmt.Errorf("countservice: failed to get counts: %w", err)
+		return
+	}
+	if len(globalAndSessionCounts) != 2 {
+		err = fmt.Errorf("countservice: unexpected counts returned, expected 2, got %d", len(globalAndSessionCounts))
+		return
+	}
+	counts.Global = globalAndSessionCounts[0]
+	counts.Session = globalAndSessionCounts[1]
+	return
+}