service: align host tmp test path

cmd/metis/remote_cmd.go

@@ -380,7 +380,11 @@ func hasMountedChildren(children []struct {
 func humanHostPath(path string) string {
 	path = strings.TrimSpace(path)
 	if strings.HasPrefix(path, "/host-tmp/") {
-		return "/" + strings.TrimPrefix(path, "/host-tmp/")
+		trimmed := strings.TrimPrefix(path, "/host-tmp/")
+		if trimmed == "" {
+			return "/tmp"
+		}
+		return "/tmp/" + trimmed
 	}
 	if path == "/host-tmp" {
 		return "/tmp"

cmd/metis/remote_cmd_test.go

@@ -26,3 +26,9 @@ func TestOrasPushInvocationUsesRelativeWorkspacePaths(t *testing.T) {
 		t.Fatalf("unexpected metadata arg: %q", args[3])
 	}
 }
+
+func TestHumanHostPathMapsMountedTmpBackToHostTmp(t *testing.T) {
+	if got := humanHostPath("/host-tmp/metis-flash-test"); got != "/tmp/metis-flash-test" {
+		t.Fatalf("expected /tmp/metis-flash-test, got %q", got)
+	}
+}

pkg/service/remote.go

@@ -313,7 +313,7 @@ func (a *App) remoteDevicePodSpec(name, host, image string) map[string]any {
 					"command": []string{
 						"metis", "remote-devices",
 						"--max-device-bytes", fmt.Sprintf("%d", a.settings.MaxDeviceBytes),
-						"--host-tmp-dir", filepath.Join("/host-tmp", strings.TrimPrefix(a.settings.HostTmpDir, "/")),
+						"--host-tmp-dir", mountedHostTmpDir(a.settings.HostTmpDir),
 					},
 					"securityContext": map[string]any{"privileged": true, "runAsUser": 0},
 					"volumeMounts": []map[string]any{
@@ -412,7 +412,7 @@ func (a *App) remoteFlashPodSpec(name, host, image, node, device, artifactRef st
 						"--artifact-ref", artifactRef,
 						"--work-dir", "/workspace/flash",
 						"--harbor-registry", a.settings.HarborRegistry,
-						"--host-tmp-dir", filepath.Join("/host-tmp", strings.TrimPrefix(a.settings.HostTmpDir, "/")),
+						"--host-tmp-dir", mountedHostTmpDir(a.settings.HostTmpDir),
 					},
 					"securityContext": map[string]any{"privileged": true, "runAsUser": 0},
 					"envFrom": []map[string]any{
@@ -453,3 +453,15 @@ func inventoryNodeArch(spec *inventory.NodeSpec, class *inventory.NodeClass) str
 	}
 	return "arm64"
 }
+
+func mountedHostTmpDir(path string) string {
+	path = strings.TrimSpace(path)
+	switch {
+	case path == "", path == "/tmp":
+		return "/host-tmp"
+	case strings.HasPrefix(path, "/tmp/"):
+		return filepath.Join("/host-tmp", strings.TrimPrefix(path, "/tmp/"))
+	default:
+		return filepath.Join("/host-tmp", strings.TrimPrefix(path, "/"))
+	}
+}

pkg/service/remote_test.go

@@ -0,0 +1,12 @@
+package service
+
+import "testing"
+
+func TestMountedHostTmpDirMapsConfiguredTmpPathIntoMount(t *testing.T) {
+	if got := mountedHostTmpDir("/tmp/metis-flash-test"); got != "/host-tmp/metis-flash-test" {
+		t.Fatalf("expected /host-tmp/metis-flash-test, got %q", got)
+	}
+	if got := mountedHostTmpDir("/tmp"); got != "/host-tmp" {
+		t.Fatalf("expected /host-tmp, got %q", got)
+	}
+}