fix(transform): don't write to out streams when nil, use updated prev…

…iew.Create

new preview create lets us make previews & still read body data downstream

go.mod

@@ -39,7 +39,7 @@ require (
 	github.com/olekukonko/tablewriter v0.0.4
 	github.com/pkg/errors v0.9.1
 	github.com/qri-io/dag v0.2.2-0.20201208212257-ae00241c4b48
-	github.com/qri-io/dataset v0.2.1-0.20210126031523-f94fd2290107
+	github.com/qri-io/dataset v0.2.1-0.20210128201320-3b1209495e96
 	github.com/qri-io/deepdiff v0.2.1-0.20200807143746-d02d9f531f5b
 	github.com/qri-io/didmod v0.0.0-20201123165422-8b2e224c993a
 	github.com/qri-io/doggos v0.1.0

lib/datasets.go

@@ -626,12 +626,12 @@ func (m *DatasetMethods) Save(p *SaveParams, res *dataset.Dataset) error {
 		// allocate an ID for the transform, for now just log the events it produces
 		runID := transform.NewRunID()
 		m.inst.bus.SubscribeID(func(ctx context.Context, e event.Event) error {
-			when := time.Unix(e.Timestamp/1000000000, e.Timestamp%1000000000)
-			log.Infof("[%s] event %s: %s", when, e.Type, e.Payload)
 			if e.Type == event.ETTransformPrint {
 				if msg, ok := e.Payload.(event.TransformMessage); ok {
-					io.WriteString(scriptOut, msg.Msg)
-					io.WriteString(scriptOut, "\n")
+					if p.ScriptOutput != nil {
+						io.WriteString(scriptOut, msg.Msg)
+						io.WriteString(scriptOut, "\n")
+					}
 				}
 			}
 			return nil

lib/transform.go

@@ -91,8 +91,10 @@ func (m *TransformMethods) Apply(p *ApplyParams, res *ApplyResult) error {
 		log.Debugw("apply transform event", "type", e.Type, "payload", e.Payload)
 		if e.Type == event.ETTransformPrint {
 			if msg, ok := e.Payload.(event.TransformMessage); ok {
-				io.WriteString(p.ScriptOutput, msg.Msg)
-				io.WriteString(p.ScriptOutput, "\n")
+				if p.ScriptOutput != nil {
+					io.WriteString(p.ScriptOutput, msg.Msg)
+					io.WriteString(p.ScriptOutput, "\n")
+				}
 			}
 		}
 		return nil

remote/browse.go

@@ -115,7 +115,7 @@ func (rp LocalPreviews) Preview(ctx context.Context, _, refStr string) (*dataset
 		return nil, err
 	}
 
-	return preview.CreatePreview(ctx, ds)
+	return preview.Create(ctx, ds)
 }
 
 // PreviewComponent gets a component for a reference & component name

transform/startf/exec_step.go

@@ -170,7 +170,7 @@ func (r *StepRunner) callTransformFunc(ctx context.Context, thread *starlark.Thr
 	}
 
 	if r.eventsCh != nil {
-		pview, err := preview.CreatePreview(ctx, ds)
+		pview, err := preview.Create(ctx, ds)
 		if err != nil {
 			return err
 		}