feat: [WIP] configure klog to write to stderr to prevent JSON corruption

go.mod

@@ -5,6 +5,7 @@ go 1.23.0
 toolchain go1.23.6
 
 require (
+	github.com/go-logr/logr v1.4.2
 	github.com/google/cel-go v0.17.8
 	github.com/google/go-cmp v0.6.0
 	github.com/onsi/ginkgo/v2 v2.21.0
@@ -13,12 +14,12 @@ require (
 	github.com/spf13/cobra v1.8.1
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.9.0
+	k8s.io/klog/v2 v2.140.0
 )
 
 require (
 	github.com/antlr/antlr4/runtime/Go/antlr/v4 v4.0.0-20230305170008-8188dc5388df // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-task/slim-sprig/v3 v3.0.0 // indirect
 	github.com/google/pprof v0.0.0-20241029153458-d1b30febd7db // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect

go.sum

@@ -57,3 +57,5 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+k8s.io/klog/v2 v2.140.0 h1:Tf+J3AH7xnUzZyVVXhTgGhEKnFqye14aadWv7bzXdzc=
+k8s.io/klog/v2 v2.140.0/go.mod h1:o+/RWfJ6PwpnFn7OyAG3QnO47BFsymfEfrz6XyYSSp0=

pkg/cmd/cmd.go

@@ -1,7 +1,10 @@
 package cmd
 
 import (
+	"os"
+
 	"github.com/spf13/cobra"
+	"k8s.io/klog/v2"
 
 	"github.com/openshift-eng/openshift-tests-extension/pkg/cmd/cmdimages"
 	"github.com/openshift-eng/openshift-tests-extension/pkg/cmd/cmdinfo"
@@ -11,6 +14,26 @@ import (
 	"github.com/openshift-eng/openshift-tests-extension/pkg/extension"
 )
 
+func init() {
+	// Configure klog to write to stderr instead of stdout BEFORE any commands run.
+	// This prevents klog warnings from corrupting JSON output during test listing.
+	//
+	// Background:
+	// - The 'list tests' command outputs JSON to stdout for consumption by CI systems
+	// - klog defaults to writing to stdout, which can include warnings from imported packages
+	// - When klog warnings appear in stdout, they corrupt the JSON stream with messages like:
+	//   "W0327 12:34:56.123456 12345 warnings.go:70] deprecation warning"
+	// - This causes JSON parsers to fail with: "invalid character 'W' looking for beginning of value"
+	//
+	// Solution:
+	// - Redirect all klog output to stderr, keeping stdout clean for structured output
+	// - This is consistent with how pkg/ginkgo/util.go configures GinkgoWriter to stderr
+	// - In CI environments: stdout = structured data (JSON), stderr = logs/diagnostics
+	//
+	// See: https://github.com/openshift/cluster-authentication-operator/pull/857
+	klog.SetOutput(os.Stderr)
+}
+
 func DefaultExtensionCommands(registry *extension.Registry) []*cobra.Command {
 	return []*cobra.Command{
 		cmdrun.NewRunSuiteCommand(registry),