Use panics for serialisation errors

context.go

@@ -48,7 +48,7 @@ type Context interface {
 	Awakeable(options ...options.AwakeableOption) Awakeable
 	// ResolveAwakeable allows an awakeable (not necessarily from this service) to be
 	// resolved with a particular value.
-	ResolveAwakeable(id string, value any, options ...options.ResolveAwakeableOption) error
+	ResolveAwakeable(id string, value any, options ...options.ResolveAwakeableOption)
 	// ResolveAwakeable allows an awakeable (not necessarily from this service) to be
 	// rejected with a particular error.
 	RejectAwakeable(id string, reason error)
@@ -81,11 +81,11 @@ type Awakeable interface {
 // CallClient represents all the different ways you can invoke a particular service/key/method tuple.
 type CallClient interface {
 	// RequestFuture makes a call and returns a handle on a future response
-	RequestFuture(input any) (ResponseFuture, error)
+	RequestFuture(input any) ResponseFuture
 	// Request makes a call and blocks on getting the response which is stored in output
 	Request(input any, output any) error
 	// Send makes a one-way call which is executed in the background
-	Send(input any, delay time.Duration) error
+	Send(input any, delay time.Duration)
 }
 
 // ResponseFuture is a handle on a potentially not-yet completed outbound call.
@@ -166,9 +166,9 @@ type ObjectSharedContext interface {
 // KeyValueReader is the set of read-only methods which can be used in all Virtual Object handlers.
 type KeyValueReader interface {
 	// Get gets value associated with key and stores it in value
-	// If key does not exist, this function returns ErrKeyNotFound
+	// If key does not exist, this function returns false
 	// Note: Use GetAs generic helper function to avoid passing in a value pointer
-	Get(key string, value any, options ...options.GetOption) error
+	Get(key string, value any, options ...options.GetOption) bool
 	// Keys returns a list of all associated key
 	Keys() []string
 	// Key retrieves the key for this virtual object invocation. This is a no-op and is
@@ -179,7 +179,7 @@ type KeyValueReader interface {
 // KeyValueWriter is the set of mutating methods which can be used in exclusive-mode Virtual Object handlers.
 type KeyValueWriter interface {
 	// Set sets a value against a key, using the provided codec (defaults to JSON)
-	Set(key string, value any, options ...options.SetOption) error
+	Set(key string, value any, options ...options.SetOption)
 	// Clear deletes a key
 	Clear(key string)
 	// ClearAll drops all stored state associated with key

examples/codegen/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"log/slog"
 	"os"
@@ -34,49 +33,31 @@ type counter struct {
 }
 
 func (c counter) Add(ctx restate.ObjectContext, req *helloworld.AddRequest) (*helloworld.GetResponse, error) {
-	count, err := restate.GetAs[int64](ctx, "counter")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return nil, err
-	}
+	count, _ := restate.GetAs[int64](ctx, "counter")
 
-	watchers, err := restate.GetAs[[]string](ctx, "watchers")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return nil, err
-	}
+	watchers, _ := restate.GetAs[[]string](ctx, "watchers")
 
 	count += req.Delta
-	if err := ctx.Set("counter", count); err != nil {
-		return nil, err
-	}
+	ctx.Set("counter", count)
 
 	for _, awakeableID := range watchers {
-		if err := ctx.ResolveAwakeable(awakeableID, count); err != nil {
-			return nil, err
-		}
+		ctx.ResolveAwakeable(awakeableID, count)
 	}
 	ctx.Clear("watchers")
 
 	return &helloworld.GetResponse{Value: count}, nil
 }
 
 func (c counter) Get(ctx restate.ObjectSharedContext, _ *helloworld.GetRequest) (*helloworld.GetResponse, error) {
-	count, err := restate.GetAs[int64](ctx, "counter")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return nil, err
-	}
+	count, _ := restate.GetAs[int64](ctx, "counter")
 
 	return &helloworld.GetResponse{Value: count}, nil
 }
 
 func (c counter) AddWatcher(ctx restate.ObjectContext, req *helloworld.AddWatcherRequest) (*helloworld.AddWatcherResponse, error) {
-	watchers, err := restate.GetAs[[]string](ctx, "watchers")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return nil, err
-	}
+	watchers, _ := restate.GetAs[[]string](ctx, "watchers")
 	watchers = append(watchers, req.AwakeableId)
-	if err := ctx.Set("watchers", watchers); err != nil {
-		return nil, err
-	}
+	ctx.Set("watchers", watchers)
 	return &helloworld.AddWatcherResponse{}, nil
 }
 

examples/ticketreservation/ticket_service.go

@@ -1,8 +1,6 @@
 package main
 
 import (
-	"errors"
-
 	restate "github.com/restatedev/sdk-go"
 )
 
@@ -21,13 +19,11 @@ type ticketService struct{}
 func (t *ticketService) ServiceName() string { return TicketServiceName }
 
 func (t *ticketService) Reserve(ctx restate.ObjectContext, _ restate.Void) (bool, error) {
-	status, err := restate.GetAs[TicketStatus](ctx, "status")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return false, err
-	}
+	status, _ := restate.GetAs[TicketStatus](ctx, "status")
 
 	if status == TicketAvailable {
-		return true, ctx.Set("status", TicketReserved)
+		ctx.Set("status", TicketReserved)
+		return true, nil
 	}
 
 	return false, nil
@@ -36,11 +32,8 @@ func (t *ticketService) Reserve(ctx restate.ObjectContext, _ restate.Void) (bool
 func (t *ticketService) Unreserve(ctx restate.ObjectContext, _ restate.Void) (void restate.Void, err error) {
 	ticketId := ctx.Key()
 	ctx.Log().Info("un-reserving ticket", "ticket", ticketId)
-	status, err := restate.GetAs[TicketStatus](ctx, "status")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return void, err
-	}
 
+	status, _ := restate.GetAs[TicketStatus](ctx, "status")
 	if status != TicketSold {
 		ctx.Clear("status")
 		return void, nil
@@ -53,13 +46,10 @@ func (t *ticketService) MarkAsSold(ctx restate.ObjectContext, _ restate.Void) (v
 	ticketId := ctx.Key()
 	ctx.Log().Info("mark ticket as sold", "ticket", ticketId)
 
-	status, err := restate.GetAs[TicketStatus](ctx, "status")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return void, err
-	}
-
+	status, _ := restate.GetAs[TicketStatus](ctx, "status")
 	if status == TicketReserved {
-		return void, ctx.Set("status", TicketSold)
+		ctx.Set("status", TicketSold)
+		return void, nil
 	}
 
 	return void, nil
@@ -69,10 +59,6 @@ func (t *ticketService) Status(ctx restate.ObjectSharedContext, _ restate.Void)
 	ticketId := ctx.Key()
 	ctx.Log().Info("mark ticket as sold", "ticket", ticketId)
 
-	status, err := restate.GetAs[TicketStatus](ctx, "status")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return status, err
-	}
-
+	status, _ := restate.GetAs[TicketStatus](ctx, "status")
 	return status, nil
 }

examples/ticketreservation/user_session.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"errors"
 	"slices"
 	"time"
 
@@ -29,30 +28,17 @@ func (u *userSession) AddTicket(ctx restate.ObjectContext, ticketId string) (boo
 	}
 
 	// add ticket to list of tickets
-	tickets, err := restate.GetAs[[]string](ctx, "tickets")
-
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return false, err
-	}
-
+	tickets, _ := restate.GetAs[[]string](ctx, "tickets")
 	tickets = append(tickets, ticketId)
 
-	if err := ctx.Set("tickets", tickets); err != nil {
-		return false, err
-	}
-
-	if err := ctx.Object(UserSessionServiceName, userId, "ExpireTicket").Send(ticketId, 15*time.Minute); err != nil {
-		return false, err
-	}
+	ctx.Set("tickets", tickets)
+	ctx.Object(UserSessionServiceName, userId, "ExpireTicket").Send(ticketId, 15*time.Minute)
 
 	return true, nil
 }
 
 func (u *userSession) ExpireTicket(ctx restate.ObjectContext, ticketId string) (void restate.Void, err error) {
-	tickets, err := restate.GetAs[[]string](ctx, "tickets")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return void, err
-	}
+	tickets, _ := restate.GetAs[[]string](ctx, "tickets")
 
 	deleted := false
 	tickets = slices.DeleteFunc(tickets, func(ticket string) bool {
@@ -66,19 +52,15 @@ func (u *userSession) ExpireTicket(ctx restate.ObjectContext, ticketId string) (
 		return void, nil
 	}
 
-	if err := ctx.Set("tickets", tickets); err != nil {
-		return void, err
-	}
+	ctx.Set("tickets", tickets)
+	ctx.Object(TicketServiceName, ticketId, "Unreserve").Send(nil, 0)
 
-	return void, ctx.Object(TicketServiceName, ticketId, "Unreserve").Send(nil, 0)
+	return void, nil
 }
 
 func (u *userSession) Checkout(ctx restate.ObjectContext, _ restate.Void) (bool, error) {
 	userId := ctx.Key()
-	tickets, err := restate.GetAs[[]string](ctx, "tickets")
-	if err != nil && !errors.Is(err, restate.ErrKeyNotFound) {
-		return false, err
-	}
+	tickets, _ := restate.GetAs[[]string](ctx, "tickets")
 
 	ctx.Log().Info("tickets in basket", "tickets", tickets)
 
@@ -88,11 +70,8 @@ func (u *userSession) Checkout(ctx restate.ObjectContext, _ restate.Void) (bool,
 
 	timeout := ctx.After(time.Minute)
 
-	request, err := restate.CallAs[PaymentResponse](ctx.Object(CheckoutServiceName, "", "Payment")).
+	request := restate.CallAs[PaymentResponse](ctx.Object(CheckoutServiceName, "", "Payment")).
 		RequestFuture(PaymentRequest{UserID: userId, Tickets: tickets})
-	if err != nil {
-		return false, err
-	}
 
 	// race between the request and the timeout
 	switch ctx.Select(timeout, request).Select() {
@@ -113,9 +92,7 @@ func (u *userSession) Checkout(ctx restate.ObjectContext, _ restate.Void) (bool,
 
 	for _, ticket := range tickets {
 		call := ctx.Object(TicketServiceName, ticket, "MarkAsSold")
-		if err := call.Send(nil, 0); err != nil {
-			return false, err
-		}
+		call.Send(nil, 0)
 	}
 
 	ctx.Clear("tickets")

facilitators.go

@@ -7,9 +7,9 @@ import (
 )
 
 // GetAs get the value for a key, returning a typed response instead of accepting a pointer.
-// If there is no associated value with key, [ErrKeyNotFound] is returned
-func GetAs[T any](ctx ObjectSharedContext, key string, options ...options.GetOption) (output T, err error) {
-	err = ctx.Get(key, &output, options...)
+// If there is no associated value with key, the zero value of T and false is returned
+func GetAs[T any](ctx ObjectSharedContext, key string, options ...options.GetOption) (output T, ok bool) {
+	ok = ctx.Get(key, &output, options...)
 	return
 }
 
@@ -51,11 +51,11 @@ func AwakeableAs[T any](ctx Context, options ...options.AwakeableOption) TypedAw
 // TypedCallClient is an extension of [CallClient] which deals in typed values
 type TypedCallClient[I any, O any] interface {
 	// RequestFuture makes a call and returns a handle on a future response
-	RequestFuture(input I) (TypedResponseFuture[O], error)
+	RequestFuture(input I) TypedResponseFuture[O]
 	// Request makes a call and blocks on getting the response
 	Request(input I) (O, error)
 	// Send makes a one-way call which is executed in the background
-	Send(input I, delay time.Duration) error
+	Send(input I, delay time.Duration)
 }
 
 type typedCallClient[I any, O any] struct {
@@ -70,24 +70,16 @@ func NewTypedCallClient[I any, O any](client CallClient) TypedCallClient[I, O] {
 }
 
 func (t typedCallClient[I, O]) Request(input I) (output O, err error) {
-	fut, err := t.inner.RequestFuture(input)
-	if err != nil {
-		return output, err
-	}
-	err = fut.Response(&output)
+	err = t.inner.RequestFuture(input).Response(&output)
 	return
 }
 
-func (t typedCallClient[I, O]) RequestFuture(input I) (TypedResponseFuture[O], error) {
-	fut, err := t.inner.RequestFuture(input)
-	if err != nil {
-		return nil, err
-	}
-	return typedResponseFuture[O]{fut}, nil
+func (t typedCallClient[I, O]) RequestFuture(input I) TypedResponseFuture[O] {
+	return typedResponseFuture[O]{t.inner.RequestFuture(input)}
 }
 
-func (t typedCallClient[I, O]) Send(input I, delay time.Duration) error {
-	return t.inner.Send(input, delay)
+func (t typedCallClient[I, O]) Send(input I, delay time.Duration) {
+	t.inner.Send(input, delay)
 }
 
 // TypedResponseFuture is an extension of [ResponseFuture] which returns typed responses instead of accepting a pointer

handler.go

@@ -82,7 +82,8 @@ func (h *serviceHandler[I, O]) Call(ctx Context, bytes []byte) ([]byte, error) {
 
 	bytes, err = encoding.Marshal(h.options.Codec, output)
 	if err != nil {
-		return nil, TerminalError(fmt.Errorf("failed to serialize output: %w", err))
+		// we don't use a terminal error here as this is hot-fixable by changing the return type
+		return nil, fmt.Errorf("failed to serialize output: %w", err)
 	}
 
 	return bytes, nil
@@ -170,7 +171,8 @@ func (h *objectHandler[I, O]) Call(ctx ObjectContext, bytes []byte) ([]byte, err
 
 	bytes, err = encoding.Marshal(h.options.Codec, output)
 	if err != nil {
-		return nil, TerminalError(fmt.Errorf("failed to serialize output: %w", err))
+		// we don't use a terminal error here as this is hot-fixable by changing the return type
+		return nil, fmt.Errorf("failed to serialize output: %w", err)
 	}
 
 	return bytes, nil