etcdctl: add --stream flag to get command

[Jefftree]

Add --stream flag. Also removes the supportsGetStream variable since e2e now supports getStream.

e2e tests now exercise the streaming path (TestKVGet) so no new tests were added.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.28%. Comparing base (3bdaa05) to head (695442b).

Files with missing lines	Patch %	Lines
etcdctl/ctlv3/command/get_command.go	0.00%	13 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
etcdctl/ctlv3/command/get_command.go	0.00% <0.00%> (ø)

... and 21 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #21747      +/-   ##
==========================================
- Coverage   70.29%   70.28%   -0.02%     
==========================================
  Files         426      426              
  Lines       35215    35227      +12     
==========================================
+ Hits        24754    24758       +4     
+ Misses       9073     9072       -1     
- Partials     1388     1397       +9     

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[Jefftree]

/retest

[Jefftree]

/assign @serathius @fuweid

[fuweid]

In pull request, we only run few set of TestKVGet - E2E_TEST_MINIMAL=true

https://github.com/kubernetes/test-infra/blob/befc6a5ebd53bbaca099ffd026b4356d29e835ca/config/jobs/etcd/etcd-presubmits.yaml#L216

If we set it to false, the cluster will be mixed with old release one. It will return error like this.

                                        match not found.  Set EXPECT_DEBUG for more info Errs: [unexpected exit code [1] after running [/home/niuhechaofan/workspace/etcd/bin/etcdctl
--endpoints=http://localhost:20000,http://localhost:20005,http://localhost:20010 get c -w json --rev=6 -w fields --keys-only --stream -w json]], last lines:
                                        Error: rpc error: code = Unimplemented desc = unknown method RangeStream for service etcdserverpb.KV
                        Test:           TestKVGet/QuorumLastVersion/Get_third_version_of_'c'_by_its_revision_--keys-only/Stream=true
                        Messages:       count not get key "c", err: match not found.  Set EXPECT_DEBUG for more info Errs: [unexpected exit code [

[serathius]

Nice catch, we run mixed version etcd clusters only in periodics.

[Jefftree]

Thanks for flagging this. My thinking is that we can fetch the server version (via client.Status) and then only proceed with rangestream on >=3.7 to handle the mixed version case.

[fuweid]

we can fetch the server version (via client.Status)

Maybe we can go with this? the clusterSupportsGetStream will go through all the members with GetStream. If old member doesn't support it, it will return false.

 func TestKVGet(t *testing.T) {
        testKVGet(t, false)
  }

  func TestKVGetStream(t *testing.T) {
        testKVGet(t, true)
  }

  func testKVGet(t *testing.T, stream bool) {
        testRunner.BeforeTest(t)
        for _, tc := range clusterTestCases() {
                t.Run(tc.name, func(t *testing.T) {
                        ctx, cancel := context.WithTimeout(t.Context(), 30*time.Second)
                        defer cancel()

                        clus := testRunner.NewCluster(ctx, t, config.WithClusterConfig(tc.config))
                        defer clus.Close()

                        if stream && !clusterSupportsGetStream(t, clus) {
                                t.Skip("RangeStream is not supported by this cluster")
                        }

                        // ...

[Jefftree]

/retest

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fuweid, Jefftree, serathius

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