Fix Go SDK cron inputs (#2481)

* cron input in Go SDK

* add example

sdks/go/examples/cron/main.go

@@ -40,6 +40,9 @@ func main() {
 		}, nil
 	},
 		hatchet.WithWorkflowCron("0 2 * * *"),
+		hatchet.WithWorkflowCronInput(CronInput{
+			Timestamp: time.Now().Format(time.RFC3339),
+		}),
 		hatchet.WithWorkflowDescription("Daily cleanup and maintenance tasks"),
 	)
 	// !!

sdks/go/internal/declaration.go

@@ -119,6 +119,7 @@ type workflowDeclarationImpl[I any, O any] struct {
 	Description    *string
 	OnEvents       []string
 	OnCron         []string
+	CronInput      *string
 	Concurrency    []types.Concurrency
 	OnFailureTask  *task.OnFailureTaskDeclaration[I]
 	StickyStrategy *types.StickyStrategy
@@ -179,6 +180,7 @@ func NewWorkflowDeclaration[I any, O any](opts create.WorkflowCreateOpts[I], v0
 		name:        workflowName,
 		OnEvents:    onEvents,
 		OnCron:      opts.OnCron,
+		CronInput:   opts.CronInput,
 		Concurrency: opts.Concurrency,
 		// OnFailureTask:    opts.OnFailureTask, // TODO: add this back in
 		StickyStrategy:   opts.StickyStrategy,
@@ -588,6 +590,7 @@ func (w *workflowDeclarationImpl[I, O]) Dump() (*contracts.CreateWorkflowVersion
 		Name:            w.name,
 		EventTriggers:   w.OnEvents,
 		CronTriggers:    w.OnCron,
+		CronInput:       w.CronInput,
 		DefaultPriority: w.DefaultPriority,
 	}
 

sdks/go/workflow.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"reflect"
 	"sync"
 	"time"
@@ -116,6 +117,7 @@ type workflowConfig struct {
 	taskDefaults    *create.TaskDefaults
 	defaultPriority *RunPriority
 	stickyStrategy  *types.StickyStrategy
+	cronInput       *string
 }
 
 // WithWorkflowCron configures the workflow to run on a cron schedule.
@@ -126,6 +128,24 @@ func WithWorkflowCron(cronExpressions ...string) WorkflowOption {
 	}
 }
 
+// WithWorkflowCronInput sets the input for cron workflows.
+func WithWorkflowCronInput(input any) WorkflowOption {
+	return func(config *workflowConfig) {
+		inputJSON := "{}"
+
+		if input != nil {
+			bytes, err := json.Marshal(input)
+			if err != nil {
+				panic(fmt.Errorf("could not marshal cron input: %w", err))
+			}
+
+			inputJSON = string(bytes)
+		}
+
+		config.cronInput = &inputJSON
+	}
+}
+
 // WithWorkflowEvents configures the workflow to trigger on specific events.
 func WithWorkflowEvents(events ...string) WorkflowOption {
 	return func(config *workflowConfig) {
@@ -183,12 +203,18 @@ func newWorkflow(name string, v0Client v0Client.Client, options ...WorkflowOptio
 		opt(config)
 	}
 
+	if len(config.onCron) > 0 && config.cronInput == nil {
+		emptyJSON := "{}"
+		config.cronInput = &emptyJSON
+	}
+
 	createOpts := create.WorkflowCreateOpts[any]{
 		Name:           name,
 		Version:        config.version,
 		Description:    config.description,
 		OnEvents:       config.onEvents,
 		OnCron:         config.onCron,
+		CronInput:      config.cronInput,
 		Concurrency:    config.concurrency,
 		TaskDefaults:   config.taskDefaults,
 		StickyStrategy: config.stickyStrategy,