feat(harness): implement subject image or version pinning for each case

Author: erenaslandev

cmd/harness/main.go

@@ -149,7 +149,7 @@ func testCmd() *cobra.Command {
 							continue
 						}
 						for _, s := range subs {
-							pairs = append(pairs, runPair{tc: tc, subject: s})
+							pairs = append(pairs, runPair{tc: tc, subject: applyCasePin(s, tc)})
 						}
 					}
 					if len(subjectsToLoop) > 1 {
@@ -194,7 +194,7 @@ func testCmd() *cobra.Command {
 						}
 					}
 					for _, s := range subjects {
-						pairs = append(pairs, runPair{tc: tc, subject: s})
+						pairs = append(pairs, runPair{tc: tc, subject: applyCasePin(s, tc)})
 					}
 				}
 				if len(pairs) == 0 {
@@ -685,6 +685,21 @@ func versionCmd() *cobra.Command {
 	}
 }
 
+// applyCasePin overlays a case's subject_image/subject_version pin onto a
+// registry-resolved Subject. The global --image/--version CLI flags are applied
+// later in runner.applySubjectOverrides, so an explicit CLI flag still wins:
+//
+//	CLI --image/--version  >  case subject_image/subject_version  >  registry default
+func applyCasePin(s config.Subject, tc *config.TestCase) config.Subject {
+	if tc.SubjectImage != "" {
+		s = s.WithImage(tc.SubjectImage)
+	}
+	if tc.SubjectVersion != "" {
+		s = s.WithVersion(tc.SubjectVersion)
+	}
+	return s
+}
+
 func resolveSubjects(tc *config.TestCase, subjectFlag string) ([]config.Subject, error) {
 	if subjectFlag != "" {
 		// Support comma-separated subjects: -s vector,fluent-bit,logstash

cmd/harness/main_test.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/VirtualMetric/PipeBench/internal/config"
+)
+
+// TestApplyCasePin verifies that a case-level subject pin is applied with the
+// correct precedence:
+//
+//	CLI --image/--version  >  case subject_image/subject_version  >  registry default
+func TestApplyCasePin(t *testing.T) {
+	t.Run("pin overrides registry default", func(t *testing.T) {
+		base := config.Subject{Image: "vmetric/director", Version: "2.0.3"}
+		tc := &config.TestCase{
+			SubjectImage:   "vmetric/director-enterprise",
+			SubjectVersion: "latest",
+		}
+		got := applyCasePin(base, tc)
+		if got.Image != "vmetric/director-enterprise" {
+			t.Errorf("image: got %q, want %q", got.Image, "vmetric/director-enterprise")
+		}
+		if got.Version != "latest" {
+			t.Errorf("version: got %q, want %q", got.Version, "latest")
+		}
+	})
+
+	t.Run("empty pin leaves subject unchanged", func(t *testing.T) {
+		base := config.Subject{Image: "vmetric/director", Version: "2.0.3"}
+		tc := &config.TestCase{}
+		got := applyCasePin(base, tc)
+		if got.Image != "vmetric/director" {
+			t.Errorf("image: got %q, want %q", got.Image, "vmetric/director")
+		}
+		if got.Version != "2.0.3" {
+			t.Errorf("version: got %q, want %q", got.Version, "2.0.3")
+		}
+	})
+
+	t.Run("CLI WithImage/WithVersion overrides pin (precedence)", func(t *testing.T) {
+		// Simulate: registry default → applyCasePin (enterprise pin) →
+		// Subject.WithImage/WithVersion (CLI flags, applied by applySubjectOverrides).
+		base := config.Subject{Image: "vmetric/director", Version: "2.0.3"}
+		tc := &config.TestCase{
+			SubjectImage:   "vmetric/director-enterprise",
+			SubjectVersion: "latest",
+		}
+		pinned := applyCasePin(base, tc)
+
+		// CLI --image=vmetric/director overrides the enterprise pin.
+		final := pinned.WithImage("vmetric/director").WithVersion("3.0.0")
+		if final.Image != "vmetric/director" {
+			t.Errorf("image: got %q, want %q (CLI must win)", final.Image, "vmetric/director")
+		}
+		if final.Version != "3.0.0" {
+			t.Errorf("version: got %q, want %q (CLI must win)", final.Version, "3.0.0")
+		}
+		// Pin must not mutate the original.
+		if pinned.Image != "vmetric/director-enterprise" {
+			t.Errorf("pin must not mutate: got %q after WithImage call", pinned.Image)
+		}
+	})
+}

internal/config/case.go

@@ -88,6 +88,15 @@ type TestCase struct {
 	// ingest. Generalizes the original hardcoded tls_tcp guard.
 	Requires []string `yaml:"requires"`
 
+	// SubjectImage and SubjectVersion pin the subject container image for this
+	// specific case. Applied after the registry default and before the global
+	// CLI --image/--version flags, so: CLI flag > case pin > registry default.
+	// Leave empty to use the registry default (or whatever --image/--version
+	// specifies). Non-strict YAML decode means older harness binaries silently
+	// ignore these fields — they fall back to the registry default.
+	SubjectImage   string `yaml:"subject_image"`
+	SubjectVersion string `yaml:"subject_version"`
+
 	Subjects       []string                 `yaml:"subjects"`
 	Configurations map[string]Configuration `yaml:"configurations"`
 	Correctness    CorrectnessConfig        `yaml:"correctness"`

internal/orchestrator/docker.go

@@ -509,6 +509,7 @@ services:
     user: "0:0"
 {{- end }}
 {{- if .AgentCommand }}
+    entrypoint: ""
     command: {{ .AgentCommand }}
 {{- end }}
 {{- if .AgentEnv }}