feat(configwatcher): add write-through methods (SetString/Bool/Int/Float)

Closes #17

Author: zeevdr

sdk/configwatcher/write.go

@@ -0,0 +1,70 @@
+package configwatcher
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/opendecree/decree/sdk/configclient"
+)
+
+// SetString writes a string value to the server and optimistically updates the
+// local cached value for any registered watcher on the same field path.
+func (w *Watcher) SetString(ctx context.Context, fieldPath, value string, opts ...WriteOption) error {
+	return w.set(ctx, fieldPath, configclient.StringVal(value), opts)
+}
+
+// SetBool writes a bool value to the server and optimistically updates the
+// local cached value for any registered watcher on the same field path.
+func (w *Watcher) SetBool(ctx context.Context, fieldPath string, value bool, opts ...WriteOption) error {
+	return w.set(ctx, fieldPath, configclient.BoolVal(value), opts)
+}
+
+// SetInt writes an int64 value to the server and optimistically updates the
+// local cached value for any registered watcher on the same field path.
+func (w *Watcher) SetInt(ctx context.Context, fieldPath string, value int64, opts ...WriteOption) error {
+	return w.set(ctx, fieldPath, configclient.IntVal(value), opts)
+}
+
+// SetFloat writes a float64 value to the server and optimistically updates the
+// local cached value for any registered watcher on the same field path.
+func (w *Watcher) SetFloat(ctx context.Context, fieldPath string, value float64, opts ...WriteOption) error {
+	return w.set(ctx, fieldPath, configclient.FloatVal(value), opts)
+}
+
+// WriteOption configures a write-through operation.
+type WriteOption func(*configclient.SetFieldRequest)
+
+// WithDescription sets the change description on the write.
+func WithDescription(desc string) WriteOption {
+	return func(req *configclient.SetFieldRequest) { req.Description = desc }
+}
+
+// WithExpectedChecksum adds an optimistic-concurrency guard to the write.
+func WithExpectedChecksum(cs string) WriteOption {
+	return func(req *configclient.SetFieldRequest) { req.ExpectedChecksum = &cs }
+}
+
+func (w *Watcher) set(ctx context.Context, fieldPath string, tv *configclient.TypedValue, opts []WriteOption) error {
+	req := &configclient.SetFieldRequest{
+		TenantID:  w.tenantID,
+		FieldPath: fieldPath,
+		Value:     tv,
+	}
+	for _, o := range opts {
+		o(req)
+	}
+
+	_, err := w.transport.SetField(ctx, req)
+	if err != nil {
+		return fmt.Errorf("configwatcher: set %s: %w", fieldPath, err)
+	}
+
+	// Optimistically update the local value if this field is registered.
+	w.mu.RLock()
+	entry, ok := w.fields[fieldPath]
+	w.mu.RUnlock()
+	if ok && entry.typedUpdate != nil {
+		entry.typedUpdate(tv)
+	}
+	return nil
+}

sdk/configwatcher/write_test.go

@@ -0,0 +1,129 @@
+package configwatcher
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/opendecree/decree/sdk/configclient"
+)
+
+type writeTransport struct {
+	mockTransport
+	setFieldFn func(ctx context.Context, req *configclient.SetFieldRequest) (*configclient.SetFieldResponse, error)
+}
+
+func (t *writeTransport) SetField(ctx context.Context, req *configclient.SetFieldRequest) (*configclient.SetFieldResponse, error) {
+	return t.setFieldFn(ctx, req)
+}
+
+func TestSetString_WritesAndUpdatesLocal(t *testing.T) {
+	var written *configclient.SetFieldRequest
+	tr := &writeTransport{
+		mockTransport: mockTransport{
+			getConfigFn: func(_ context.Context, _ *configclient.GetConfigRequest) (*configclient.GetConfigResponse, error) {
+				return &configclient.GetConfigResponse{
+					Values: []configclient.ConfigValue{{FieldPath: "app.env", Value: configclient.StringVal("staging")}},
+				}, nil
+			},
+			subscribeFn: func(ctx context.Context, _ *configclient.SubscribeRequest) (configclient.Subscription, error) {
+				return newMockSubscription(ctx), nil
+			},
+		},
+		setFieldFn: func(_ context.Context, req *configclient.SetFieldRequest) (*configclient.SetFieldResponse, error) {
+			written = req
+			return &configclient.SetFieldResponse{}, nil
+		},
+	}
+
+	w := New(tr, "tenant1")
+	val, err := w.String("app.env", "default")
+	if err != nil {
+		t.Fatalf("String: %v", err)
+	}
+	if err := w.Start(context.Background()); err != nil {
+		t.Fatalf("Start: %v", err)
+	}
+	defer w.Close()
+
+	if err := w.SetString(context.Background(), "app.env", "production"); err != nil {
+		t.Fatalf("SetString: %v", err)
+	}
+
+	// Server was called with correct params.
+	if written == nil || written.FieldPath != "app.env" {
+		t.Errorf("SetField not called with expected field path, got %+v", written)
+	}
+	sv, _ := written.Value.StringValue()
+	if sv != "production" {
+		t.Errorf("SetField value = %q, want %q", sv, "production")
+	}
+
+	// Optimistic local update applied.
+	if got := val.Get(); got != "production" {
+		t.Errorf("local value = %q, want %q", got, "production")
+	}
+}
+
+func TestSetString_TransportError(t *testing.T) {
+	tr := &writeTransport{
+		mockTransport: mockTransport{
+			getConfigFn: func(_ context.Context, _ *configclient.GetConfigRequest) (*configclient.GetConfigResponse, error) {
+				return &configclient.GetConfigResponse{}, nil
+			},
+			subscribeFn: func(ctx context.Context, _ *configclient.SubscribeRequest) (configclient.Subscription, error) {
+				return newMockSubscription(ctx), nil
+			},
+		},
+		setFieldFn: func(_ context.Context, _ *configclient.SetFieldRequest) (*configclient.SetFieldResponse, error) {
+			return nil, errors.New("server error")
+		},
+	}
+
+	w := New(tr, "tenant1")
+	if err := w.Start(context.Background()); err != nil {
+		t.Fatalf("Start: %v", err)
+	}
+	defer w.Close()
+
+	err := w.SetString(context.Background(), "app.env", "production")
+	if err == nil {
+		t.Error("expected error from transport, got nil")
+	}
+}
+
+func TestSetBool_WriteThroughOptions(t *testing.T) {
+	var req *configclient.SetFieldRequest
+	tr := &writeTransport{
+		mockTransport: mockTransport{
+			getConfigFn: func(_ context.Context, _ *configclient.GetConfigRequest) (*configclient.GetConfigResponse, error) {
+				return &configclient.GetConfigResponse{}, nil
+			},
+			subscribeFn: func(ctx context.Context, _ *configclient.SubscribeRequest) (configclient.Subscription, error) {
+				return newMockSubscription(ctx), nil
+			},
+		},
+		setFieldFn: func(_ context.Context, r *configclient.SetFieldRequest) (*configclient.SetFieldResponse, error) {
+			req = r
+			return &configclient.SetFieldResponse{}, nil
+		},
+	}
+	w := New(tr, "tenant1")
+	if err := w.Start(context.Background()); err != nil {
+		t.Fatalf("Start: %v", err)
+	}
+	defer w.Close()
+
+	if err := w.SetBool(context.Background(), "app.debug", true,
+		WithDescription("enable debug"),
+		WithExpectedChecksum("abc123"),
+	); err != nil {
+		t.Fatalf("SetBool: %v", err)
+	}
+	if req.Description != "enable debug" {
+		t.Errorf("Description = %q, want %q", req.Description, "enable debug")
+	}
+	if req.ExpectedChecksum == nil || *req.ExpectedChecksum != "abc123" {
+		t.Errorf("ExpectedChecksum = %v, want abc123", req.ExpectedChecksum)
+	}
+}