feat: add backward-compatible Specs field to LoadProfile

Add Specs []LoadProfileSpec field alongside existing Spec field to enable
time-series replay support in future. Update all code to use GetSpecs()
accessor method for unified access to both old and new formats.

Changes:
- Add Specs field with omitempty tags to LoadProfile struct
- Add GetSpecs() method to handle both single Spec and Specs formats
- Update LoadProfile.Validate() to validate all specs
- Update runner, runkperf bench, and warmup commands to use GetSpecs()
- Maintain backward compatibility with existing configs

All existing configs with 'spec:' continue to work unchanged. New configs
can use 'specs:' array format. No functional changes in this commit.

Author: JasonXuDeveloper

api/types/load_traffic.go

@@ -6,6 +6,7 @@ package types
 import (
 	"encoding/json"
 	"fmt"
+	"reflect"
 	"strings"
 
 	apitypes "k8s.io/apimachinery/pkg/types"
@@ -37,8 +38,29 @@ type LoadProfile struct {
 	Version int `json:"version" yaml:"version"`
 	// Description is a string value to describe this object.
 	Description string `json:"description,omitempty" yaml:"description"`
-	// Spec defines behavior of load profile.
-	Spec LoadProfileSpec `json:"spec" yaml:"spec"`
+	// Spec defines behavior of load profile (deprecated, use Specs for single or multiple specs).
+	Spec LoadProfileSpec `json:"spec,omitempty" yaml:"spec,omitempty"`
+	// Specs defines behaviors of load profile for time-series replay support.
+	Specs []LoadProfileSpec `json:"specs,omitempty" yaml:"specs,omitempty"`
+}
+
+// GetSpecs returns specs as a slice, handling both old and new format.
+// If Specs is set, returns it. Otherwise, returns Spec as a single-element slice.
+func (lp *LoadProfile) GetSpecs() []LoadProfileSpec {
+	if len(lp.Specs) > 0 {
+		return lp.Specs
+	}
+	// Fallback to old single Spec field
+	return []LoadProfileSpec{lp.Spec}
+}
+
+// SetFirstSpec updates the first spec, handling both old and new format.
+func (lp *LoadProfile) SetFirstSpec(spec LoadProfileSpec) {
+	if len(lp.Specs) > 0 {
+		lp.Specs[0] = spec
+	} else {
+		lp.Spec = spec
+	}
 }
 
 // LoadProfileSpec defines the load traffic for traget resource.
@@ -198,7 +220,21 @@ func (lp LoadProfile) Validate() error {
 	if lp.Version != 1 {
 		return fmt.Errorf("version should be 1")
 	}
-	return lp.Spec.Validate()
+
+	// Validate that at least one format is provided
+	if len(lp.Specs) == 0 && reflect.DeepEqual(lp.Spec, LoadProfileSpec{}) {
+		return fmt.Errorf("either 'spec' or 'specs' must be provided")
+	}
+
+	// Validate all specs
+	specs := lp.GetSpecs()
+	for i, spec := range specs {
+		if err := spec.Validate(); err != nil {
+			return fmt.Errorf("spec[%d]: %w", i, err)
+		}
+	}
+
+	return nil
 }
 
 // Validate verifies fields of LoadProfileSpec.

cmd/kperf/commands/runner/runner.go

@@ -103,19 +103,20 @@ var runCommand = cli.Command{
 			return err
 		}
 
-		clientNum := profileCfg.Spec.Conns
+		specs := profileCfg.GetSpecs()
+		clientNum := specs[0].Conns
 		restClis, err := request.NewClients(kubeCfgPath,
 			clientNum,
 			request.WithClientUserAgentOpt(cliCtx.String("user-agent")),
-			request.WithClientQPSOpt(profileCfg.Spec.Rate),
-			request.WithClientContentTypeOpt(profileCfg.Spec.ContentType),
-			request.WithClientDisableHTTP2Opt(profileCfg.Spec.DisableHTTP2),
+			request.WithClientQPSOpt(specs[0].Rate),
+			request.WithClientContentTypeOpt(specs[0].ContentType),
+			request.WithClientDisableHTTP2Opt(specs[0].DisableHTTP2),
 		)
 		if err != nil {
 			return err
 		}
 
-		stats, err := request.Schedule(context.TODO(), &profileCfg.Spec, restClis)
+		stats, err := request.Schedule(context.TODO(), &specs[0], restClis)
 		if err != nil {
 			return err
 		}
@@ -165,40 +166,44 @@ func loadConfig(cliCtx *cli.Context) (*types.LoadProfile, error) {
 		return nil, fmt.Errorf("failed to unmarshal %s from yaml format: %w", cfgPath, err)
 	}
 
+	specs := profileCfg.GetSpecs()
 	// override value by flags
 	if v := "rate"; cliCtx.IsSet(v) {
-		profileCfg.Spec.Rate = cliCtx.Float64(v)
+		specs[0].Rate = cliCtx.Float64(v)
 	}
-	if v := "conns"; cliCtx.IsSet(v) || profileCfg.Spec.Conns == 0 {
-		profileCfg.Spec.Conns = cliCtx.Int(v)
+	if v := "conns"; cliCtx.IsSet(v) || specs[0].Conns == 0 {
+		specs[0].Conns = cliCtx.Int(v)
 	}
-	if v := "client"; cliCtx.IsSet(v) || profileCfg.Spec.Client == 0 {
-		profileCfg.Spec.Client = cliCtx.Int(v)
+	if v := "client"; cliCtx.IsSet(v) || specs[0].Client == 0 {
+		specs[0].Client = cliCtx.Int(v)
 	}
 	if v := "total"; cliCtx.IsSet(v) {
-		profileCfg.Spec.Total = cliCtx.Int(v)
+		specs[0].Total = cliCtx.Int(v)
 	}
 	if v := "duration"; cliCtx.IsSet(v) {
-		profileCfg.Spec.Duration = cliCtx.Int(v)
+		specs[0].Duration = cliCtx.Int(v)
 	}
-	if profileCfg.Spec.Total > 0 && profileCfg.Spec.Duration > 0 {
-		klog.Warningf("both total:%v and duration:%v are set, duration will be ignored\n", profileCfg.Spec.Total, profileCfg.Spec.Duration)
-		profileCfg.Spec.Duration = 0
+	if specs[0].Total > 0 && specs[0].Duration > 0 {
+		klog.Warningf("both total:%v and duration:%v are set, duration will be ignored\n", specs[0].Total, specs[0].Duration)
+		specs[0].Duration = 0
 	}
-	if profileCfg.Spec.Total == 0 && profileCfg.Spec.Duration == 0 {
+	if specs[0].Total == 0 && specs[0].Duration == 0 {
 		// Use default total value
-		profileCfg.Spec.Total = cliCtx.Int("total")
+		specs[0].Total = cliCtx.Int("total")
 	}
-	if v := "content-type"; cliCtx.IsSet(v) || profileCfg.Spec.ContentType == "" {
-		profileCfg.Spec.ContentType = types.ContentType(cliCtx.String(v))
+	if v := "content-type"; cliCtx.IsSet(v) || specs[0].ContentType == "" {
+		specs[0].ContentType = types.ContentType(cliCtx.String(v))
 	}
 	if v := "disable-http2"; cliCtx.IsSet(v) {
-		profileCfg.Spec.DisableHTTP2 = cliCtx.Bool(v)
+		specs[0].DisableHTTP2 = cliCtx.Bool(v)
 	}
 	if v := "max-retries"; cliCtx.IsSet(v) {
-		profileCfg.Spec.MaxRetries = cliCtx.Int(v)
+		specs[0].MaxRetries = cliCtx.Int(v)
 	}
 
+	// Update profileCfg with modified specs
+	profileCfg.SetFirstSpec(specs[0])
+
 	if err := profileCfg.Validate(); err != nil {
 		return nil, err
 	}

contrib/cmd/runkperf/commands/bench/utils.go

@@ -151,9 +151,10 @@ func newLoadProfileFromEmbed(cliCtx *cli.Context, name string) (_name string, _s
 				return fmt.Errorf("invalid total-requests value: %v", reqs)
 			}
 			reqsTime := cliCtx.Int("duration")
+			specs := spec.Profile.GetSpecs()
 			if !cliCtx.IsSet("total") && reqsTime > 0 {
 				reqs = 0
-				spec.Profile.Spec.Duration = reqsTime
+				specs[0].Duration = reqsTime
 			}
 
 			rgAffinity := cliCtx.GlobalString("rg-affinity")
@@ -163,10 +164,14 @@ func newLoadProfileFromEmbed(cliCtx *cli.Context, name string) (_name string, _s
 			}
 
 			if reqs != 0 {
-				spec.Profile.Spec.Total = reqs
+				specs[0].Total = reqs
 			}
 			spec.NodeAffinity = affinityLabels
-			spec.Profile.Spec.ContentType = types.ContentType(cliCtx.String("content-type"))
+			specs[0].ContentType = types.ContentType(cliCtx.String("content-type"))
+
+			// Update profile with modified specs
+			spec.Profile.SetFirstSpec(specs[0])
+
 			data, _ := yaml.Marshal(spec)
 
 			// Tweak the load profile for read-update case
@@ -202,7 +207,8 @@ func tweakReadUpdateProfile(cliCtx *cli.Context, spec *types.RunnerGroupSpec) er
 	configmapTotal := cliCtx.Int("read-update-configmap-total")
 
 	if namePattern != "" || ratio != 0 || namespace != "" || configmapTotal > 0 {
-		for _, r := range spec.Profile.Spec.Requests {
+		specs := spec.Profile.GetSpecs()
+		for _, r := range specs[0].Requests {
 			if r.Patch != nil {
 				if namePattern != "" {
 					r.Patch.Name = fmt.Sprintf("runkperf-cm-%s", namePattern)

contrib/cmd/runkperf/commands/warmup/command.go

@@ -102,8 +102,13 @@ var Command = cli.Command{
 					return fmt.Errorf("failed to parse %s affinity: %w", rgAffinity, err)
 				}
 
-				spec.Profile.Spec.Total = reqs
-				spec.Profile.Spec.Rate = rate
+				specs := spec.Profile.GetSpecs()
+				specs[0].Total = reqs
+				specs[0].Rate = rate
+
+				// Update profile with modified specs
+				spec.Profile.SetFirstSpec(specs[0])
+
 				spec.NodeAffinity = affinityLabels
 
 				data, _ := yaml.Marshal(spec)