[
https://issues.apache.org/jira/browse/BEAM-9615?focusedWorklogId=565609&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-565609
]
ASF GitHub Bot logged work on BEAM-9615:
----------------------------------------
Author: ASF GitHub Bot
Created on: 13/Mar/21 04:33
Start Date: 13/Mar/21 04:33
Worklog Time Spent: 10m
Work Description: youngoli commented on a change in pull request #14192:
URL: https://github.com/apache/beam/pull/14192#discussion_r593553104
##########
File path: sdks/go/pkg/beam/core/runtime/graphx/schema/schema.go
##########
@@ -280,82 +301,194 @@ func (r *Registry) FromType(ot reflect.Type)
(*pipepb.Schema, error) {
return r.fromType(ot)
}
+func (r *Registry) logicalTypeToFieldType(t reflect.Type) (*pipepb.FieldType,
string, error) {
+ // Check if a logical type was registered that matches this struct type
directly
+ // and if so, extract the schema from it for use.
+ if lID, ok := r.logicalTypeIdentifiers[t]; ok {
+ lt := r.logicalTypes[lID]
+ ftype, err := r.reflectTypeToFieldType(lt.StorageType())
+ if err != nil {
+ return nil, "", errors.Wrapf(err, "unable to convert
LogicalType[%v]'s storage type %v for Go type of %v to a schema", lID,
lt.StorageType(), lt.GoType())
+ }
+ return ftype, lID, nil
+ }
+ for _, lti := range r.logicalTypeInterfaces {
+ if !t.Implements(lti) {
+ continue
+ }
+ p := r.logicalTypeProviders[lti]
+ st, err := p(t)
+ if err != nil {
+ return nil, "", errors.Wrapf(err, "unable to convert
LogicalType[%v] using provider for %v schema field", t, lti)
+ }
+ if st == nil {
+ continue
+ }
+ ftype, err := r.reflectTypeToFieldType(st)
+ if err != nil {
+ return nil, "", errors.Wrapf(err, "unable to convert
LogicalType[%v]'s storage type %v for Go type of %v to a schema", "interface",
st, t)
+ }
+ return ftype, t.String(), nil
+ }
+ return nil, "", nil
+}
+
func (r *Registry) fromType(ot reflect.Type) (*pipepb.Schema, error) {
- if reflectx.SkipPtr(ot).Kind() != reflect.Struct {
- return nil, errors.Errorf("cannot convert %v to schema.
FromType only converts structs to schemas", ot)
+ if schm, ok := r.typeToSchema[ot]; ok {
+ return schm, nil
}
- schm, err := r.structToSchema(ot)
+ ftype, lID, err := r.logicalTypeToFieldType(ot)
if err != nil {
return nil, err
}
- if ot.Kind() == reflect.Ptr {
- schm.Options = append(schm.Options, &pipepb.Option{
- Name: optGoNillable,
- })
+ if ftype != nil {
Review comment:
I notice the beginning of `structToSchema` is very similar to this
section of `fromType`, and it gets called right after this section anyway. Is
there a reason this needs to be here instead of just calling `structToSchema`
right away? (If so it might be good to leave a comment explaining it)
##########
File path: sdks/go/pkg/beam/core/graph/coder/row_decoder.go
##########
@@ -114,16 +114,38 @@ func (b *RowDecoderBuilder) decoderForType(t
reflect.Type) (func(io.Reader) (int
// decoderForStructReflect returns a reflection based decoder function for the
// given struct type.
func (b *RowDecoderBuilder) decoderForStructReflect(t reflect.Type)
(func(reflect.Value, io.Reader) error, error) {
-
var coder typeDecoderReflect
coder.typ = t
for i := 0; i < t.NumField(); i++ {
i := i // avoid alias issues in the closures.
sf := t.Field(i)
isUnexported := sf.PkgPath != ""
- if isUnexported {
+ if sf.Anonymous {
+ ft := sf.Type
+ if ft.Kind() == reflect.Ptr {
+ // If a struct embeds a pointer to an
unexported type,
+ // it is not possible to set a newly allocated
value
+ // since the field is unexported.
+ //
+ // See https://golang.org/issue/21357
+ //
+ // Since the values are created by this package
reflectively,
+ // there's no work around like pre-allocating
the field
+ // manually.
+ if isUnexported {
Review comment:
Does `isUnexported` describe whether the field itself is unexported? Or
whether the type of the field is unexported? I thought it was the first, but
based on this line and the comment you added at line 144, it's actually the
second one. Is that right?
##########
File path: sdks/go/pkg/beam/core/runtime/graphx/schema/schema.go
##########
@@ -280,82 +301,194 @@ func (r *Registry) FromType(ot reflect.Type)
(*pipepb.Schema, error) {
return r.fromType(ot)
}
+func (r *Registry) logicalTypeToFieldType(t reflect.Type) (*pipepb.FieldType,
string, error) {
+ // Check if a logical type was registered that matches this struct type
directly
+ // and if so, extract the schema from it for use.
+ if lID, ok := r.logicalTypeIdentifiers[t]; ok {
+ lt := r.logicalTypes[lID]
+ ftype, err := r.reflectTypeToFieldType(lt.StorageType())
+ if err != nil {
+ return nil, "", errors.Wrapf(err, "unable to convert
LogicalType[%v]'s storage type %v for Go type of %v to a schema", lID,
lt.StorageType(), lt.GoType())
+ }
+ return ftype, lID, nil
+ }
+ for _, lti := range r.logicalTypeInterfaces {
+ if !t.Implements(lti) {
+ continue
+ }
+ p := r.logicalTypeProviders[lti]
+ st, err := p(t)
+ if err != nil {
+ return nil, "", errors.Wrapf(err, "unable to convert
LogicalType[%v] using provider for %v schema field", t, lti)
+ }
+ if st == nil {
+ continue
+ }
+ ftype, err := r.reflectTypeToFieldType(st)
+ if err != nil {
+ return nil, "", errors.Wrapf(err, "unable to convert
LogicalType[%v]'s storage type %v for Go type of %v to a schema", "interface",
st, t)
+ }
+ return ftype, t.String(), nil
+ }
+ return nil, "", nil
+}
+
func (r *Registry) fromType(ot reflect.Type) (*pipepb.Schema, error) {
- if reflectx.SkipPtr(ot).Kind() != reflect.Struct {
- return nil, errors.Errorf("cannot convert %v to schema.
FromType only converts structs to schemas", ot)
+ if schm, ok := r.typeToSchema[ot]; ok {
+ return schm, nil
}
- schm, err := r.structToSchema(ot)
+ ftype, lID, err := r.logicalTypeToFieldType(ot)
if err != nil {
return nil, err
}
- if ot.Kind() == reflect.Ptr {
- schm.Options = append(schm.Options, &pipepb.Option{
- Name: optGoNillable,
- })
+ if ftype != nil {
+ schm := ftype.GetRowType().GetSchema()
+ schm = proto.Clone(schm).(*pipepb.Schema)
+ if ot.Kind() == reflect.Ptr {
+ schm.Options = append(schm.Options, &pipepb.Option{
+ Name: optGoNillable,
+ })
+ }
+ if lID != "" {
+ schm.Options = append(schm.Options, logicalOption(lID))
+ }
+ schm.Id = r.getNextID()
+ r.typeToSchema[ot] = schm
+ r.idToType[schm.GetId()] = ot
+ return schm, nil
}
- return schm, nil
+
+ t := reflectx.SkipPtr(ot)
+
+ schm, err := r.structToSchema(t)
+ if err != nil {
+ return nil, err
+ }
+ // Cache the pointer type here with it's own id.
+ pt := reflect.PtrTo(t)
+ schm = proto.Clone(schm).(*pipepb.Schema)
+ schm.Id = r.getNextID()
+ schm.Options = append(schm.Options, &pipepb.Option{
+ Name: optGoNillable,
+ })
+ r.idToType[schm.GetId()] = pt
+ r.typeToSchema[pt] = schm
+
+ // Return whatever the original type was.
+ return r.typeToSchema[ot], nil
Review comment:
After reading a little further down here, I think I might be missing
some implicit assumption here. Is everything after line 360 assuming that if
the type wasn't found above in either `typeToSchema` or
`logicalTypeToFieldType` then it must be a pointer type? Because we return the
original type, but it wouldn't be present in that map unless `ot` and `pt`
matched, right?
Edit: Or maybe this works here because we called `structToSchema` on the
non-pointer version, and then also added the pointer version, so one or the
other is guaranteed to be present? That seems worth adding a comment too. Like:
```
// Both pointer and non-pointer variants of the original type are
registered, so we can return whatever the original type was.
```
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Issue Time Tracking
-------------------
Worklog Id: (was: 565609)
Time Spent: 24h 10m (was: 24h)
> [Go SDK] Beam Schemas
> ---------------------
>
> Key: BEAM-9615
> URL: https://issues.apache.org/jira/browse/BEAM-9615
> Project: Beam
> Issue Type: New Feature
> Components: sdk-go
> Reporter: Robert Burke
> Assignee: Robert Burke
> Priority: P2
> Time Spent: 24h 10m
> Remaining Estimate: 0h
>
> Schema support is required for advanced cross language features in Beam, and
> has the opportunity to replace the current default JSON encoding of elements.
> Some quick notes, though a better fleshed out doc with details will be
> forthcoming:
> * All base coders should be implemented, and listed as coder capabilities. I
> think only stringutf8 is missing presently.
> * Should support fairly arbitrary user types, seamlessly. That is, users
> should be able to rely on it "just working" if their type is compatible.
> * Should support schema metadata tagging.
> In particular, one breaking shift in the default will be to explicitly fail
> pipelines if elements have unexported fields, when no other custom coder has
> been added. This has been a source of errors/dropped data/keys and a simply
> warning at construction time won't cut it. However, we could provide a manual
> "use beam schemas, but ignore unexported fields" registration as a work
> around.
> Edit: Doc is now at https://s.apache.org/beam-go-schemas
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