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https://issues.apache.org/jira/browse/BEAM-7726?focusedWorklogId=279101&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-279101
]
ASF GitHub Bot logged work on BEAM-7726:
----------------------------------------
Author: ASF GitHub Bot
Created on: 18/Jul/19 16:10
Start Date: 18/Jul/19 16:10
Worklog Time Spent: 10m
Work Description: lostluck commented on pull request #9080: [BEAM-7726]
Implement State Backed Iterables in Go SDK
URL: https://github.com/apache/beam/pull/9080#discussion_r305001696
##########
File path: sdks/go/pkg/beam/core/runtime/exec/datasource.go
##########
@@ -262,3 +282,60 @@ func (n *DataSource) Split(splits []int64, frac float32)
(int64, error) {
// return an error.
return 0, fmt.Errorf("failed to split at requested splits: {%v},
DataSource at index: %v", splits, c)
}
+
+type concatReStream struct {
+ first, next ReStream
+}
+
+func (c *concatReStream) Open() (Stream, error) {
+ firstStream, err := c.first.Open()
+ if err != nil {
+ return nil, err
+ }
+ return &concatStream{first: firstStream, nextStream: c.next}, nil
+}
+
+type concatStream struct {
+ first Stream
+ nextStream ReStream
+}
+
+// Close nils the stream.
+func (s *concatStream) Close() error {
+ if s.first == nil {
+ return nil
+ }
+ defer func() {
+ s.first = nil
+ s.nextStream = nil
+ }()
+ return s.first.Close()
+}
+
+func (s *concatStream) Read() (*FullValue, error) {
+ if s.first == nil { // When the stream is closed.
+ return nil, io.EOF
+ }
+ fv, err := s.first.Read()
+ if err == nil {
+ return fv, nil
+ }
+ if err == io.EOF {
+ if err := s.first.Close(); err != nil {
+ s.nextStream = nil
+ return nil, err
+ }
+ if s.nextStream == nil {
+ s.first = nil
+ return nil, io.EOF
+ }
+ s.first, err = s.nextStream.Open()
Review comment:
That's right. For this use of concatStream, that's exactly what's happening.
concatReStream and concatStream are general though, so any two re-streams can
be concatenated together (including nested concat streams)
The continuations from statemgr.go took me a moment too, but fortunately
that code is already nicely written.
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Issue Time Tracking
-------------------
Worklog Id: (was: 279101)
Time Spent: 2h 10m (was: 2h)
> [Go SDK] State Backed Iterables
> -------------------------------
>
> Key: BEAM-7726
> URL: https://issues.apache.org/jira/browse/BEAM-7726
> Project: Beam
> Issue Type: Improvement
> Components: sdk-go
> Affects Versions: Not applicable
> Reporter: Robert Burke
> Assignee: Robert Burke
> Priority: Major
> Fix For: Not applicable
>
> Time Spent: 2h 10m
> Remaining Estimate: 0h
>
> The Go SDK should support the State backed iterables protocol per the proto.
> [https://github.com/apache/beam/blob/master/model/pipeline/src/main/proto/beam_runner_api.proto#L644]
>
> Primary case is for iterables after CoGBKs.
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