[
https://issues.apache.org/jira/browse/BEAM-9746?focusedWorklogId=422403&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-422403
]
ASF GitHub Bot logged work on BEAM-9746:
----------------------------------------
Author: ASF GitHub Bot
Created on: 14/Apr/20 22:51
Start Date: 14/Apr/20 22:51
Worklog Time Spent: 10m
Work Description: lostluck commented on pull request #11413: [BEAM-9746]
check for 0 length copies from state
URL: https://github.com/apache/beam/pull/11413#discussion_r408481474
##########
File path: sdks/go/pkg/beam/core/runtime/harness/statemgr_test.go
##########
@@ -258,6 +260,166 @@ func TestStateChannel(t *testing.T) {
}
}
+// TestStateKeyReader validates ordinary Read cases
+func TestStateKeyReader(t *testing.T) {
+ const readLen = 4
+ tests := []struct {
+ name string
+ buflens []int // sizes of the buffers received on the state
channel.
+ numReads int
+ closed bool // tries to read from closed reader
+ noGet bool // tries to read from nil get response reader
+ }{
+ {
+ name: "emptyData",
+ buflens: []int{-1},
+ numReads: 1,
+ }, {
+ name: "singleBufferSingleRead",
+ buflens: []int{readLen},
+ numReads: 2,
+ }, {
+ name: "singleBufferMultipleReads",
+ buflens: []int{2 * readLen},
+ numReads: 3,
+ }, {
+ name: "singleBufferShortRead",
+ buflens: []int{readLen - 1},
+ numReads: 2,
+ }, {
+ name: "multiBuffer",
+ buflens: []int{readLen, readLen},
+ numReads: 3,
+ }, {
+ name: "multiBuffer-short-reads",
+ buflens: []int{readLen - 1, readLen - 1, readLen - 2},
+ numReads: 4,
+ }, {
+ name: "emptyDataFirst", // Shouldn't happen, but
not unreasonable to handle.
+ buflens: []int{-1, readLen, readLen},
+ numReads: 4,
+ }, {
+ name: "emptyDataMid", // Shouldn't happen, but not
unreasonable to handle.
+ buflens: []int{readLen, readLen, -1, readLen},
+ numReads: 5,
+ }, {
+ name: "emptyDataLast", // Shouldn't happen, but not
unreasonable to handle.
+ buflens: []int{readLen, readLen, -1},
+ numReads: 3,
+ }, {
+ name: "emptyDataLast-short",
+ buflens: []int{3*readLen - 2, -1},
+ numReads: 4,
+ }, {
+ name: "closed",
+ buflens: []int{-1, -1},
+ numReads: 1,
+ closed: true,
+ }, {
+ name: "noGet",
+ buflens: []int{-1},
+ numReads: 1,
+ noGet: true,
+ },
+ }
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ ctx, cancelFn :=
context.WithCancel(context.Background())
+ ch := &StateChannel{
+ id: "test",
+ requests: make(chan *fnpb.StateRequest),
+ responses: make(map[string]chan<-
*fnpb.StateResponse),
+ cancelFn: cancelFn,
+ DoneCh: ctx.Done(),
+ }
+
+ // Handle the channel behavior asynchronously.
+ go func() {
+ if test.noGet {
+ req := <-ch.requests
+ ch.responses[req.Id] <-
&fnpb.StateResponse{
+ Id: req.Id,
+ }
+ return
+ }
+ for i, buflen := range test.buflens {
+ var buf []byte
+ if buflen >= 0 {
+ buf = bytes.Repeat([]byte{42},
buflen)
+ }
+ token := []byte(fmt.Sprint(i))
+ if i+1 == len(test.buflens) {
+ // On the last request response
pair, send no token.
+ token = nil
+ }
+ req := <-ch.requests
+
+ ch.responses[req.Id] <-
&fnpb.StateResponse{
+ Id: req.Id,
+ Response:
&fnpb.StateResponse_Get{
+ Get:
&fnpb.StateGetResponse{
+
ContinuationToken: token,
+ Data:
buf,
+ },
+ },
+ }
+ }
+ }()
+
+ r := stateKeyReader{
+ ch: ch,
+ }
+
+ if test.closed {
+ err := r.Close()
+ if err != nil {
+ t.Errorf("unexpected error on Close(),
got %v", err)
+ }
+ }
+
+ var totalBytes int
+ for _, l := range test.buflens {
+ if l > 0 {
+ totalBytes += l
+ }
+ }
+ var finalerr error
+ var count, reads int
+
+ // Read all the bytes.
+ for count <= totalBytes {
+ reads++
+ b := make([]byte, readLen) // io.Read is keyed
off of length, not capacity.
+ n, err := r.Read(b)
+ if err != nil {
+ finalerr = err
+ break
+ }
+ count += n
+ // Special check to avoid spurious zero
elements.
+ if count == totalBytes && n == 0 {
+ t.Error("expected byte count read, last
read is 0, but no EOF")
+ }
+ }
+ if got, want := reads, test.numReads; got != want {
+ t.Errorf("read %d times, want %d", got, want)
+ }
+ if got, want := count, totalBytes; got != want {
+ t.Errorf("read %v bytes, want %v", got, want)
+ }
+ if test.closed {
+ if got, want := finalerr, errors.New("side
input closed"); !contains(got, want) {
Review comment:
Ack. Not an unreasonable position. I just know I stopped making the trivial
but easy to overlook mistakes when I started using this pattern.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
Issue Time Tracking
-------------------
Worklog Id: (was: 422403)
Time Spent: 2h 20m (was: 2h 10m)
> [Go SDK] Empty side inputs causing spurious zero elements
> ---------------------------------------------------------
>
> Key: BEAM-9746
> URL: https://issues.apache.org/jira/browse/BEAM-9746
> Project: Beam
> Issue Type: Improvement
> Components: sdk-go
> Reporter: Robert Burke
> Assignee: Robert Burke
> Priority: Major
> Time Spent: 2h 20m
> Remaining Estimate: 0h
>
> A user discovered that empty side inputs would spuriously provide a single
> zero element.
> The error was narrowed down to the Go SDK's state manager code copying the
> stateGetResponse data wasn't checking that the original data source even had
> any bytes in it, leading it in particular to interpret length prefixed data
> as having 0 length, which would cause zero value elements to be generated.
> Notably, this caused empty strings.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
