Run builds and checks in a per-node build slice with CPU, IO and memory limits (issue 1798)

internal/builder/kill_test.go

@@ -143,3 +143,24 @@ func TestAVolumeAlreadyGoneIsNoFailure(t *testing.T) {
 		t.Fatalf("%d %v", n, err)
 	}
 }
+
+// A node's build slice limits everything a build or check starts (novox/hq issue 1798): with a parent
+// set, every `docker run` joins it, so the node's CPU and IO weights and memory cap bind the container;
+// with none set the arguments are as they always were.
+func TestEveryContainerJoinsTheNodesBuildSlice(t *testing.T) {
+	was := CgroupParent
+	defer func() { CgroupParent = was }()
+	CgroupParent = "mesh-build.slice"
+	got := LabelledArgs("docker", []string{"run", "--rm", "img", "sh"}, "build-1")
+	want := []string{"run", "--label", "mesh.build=build-1", "--cgroup-parent", "mesh-build.slice", "--rm", "img", "sh"}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("1798/AC1: docker run became %v", got)
+	}
+	if got := LabelledArgs("docker", []string{"build", "."}, "build-1"); !reflect.DeepEqual(got, []string{"build", "."}) {
+		t.Errorf("a docker build became %v", got)
+	}
+	CgroupParent = ""
+	if got := LabelledArgs("docker", []string{"run", "img"}, "build-1"); !reflect.DeepEqual(got, []string{"run", "--label", "mesh.build=build-1", "img"}) {
+		t.Errorf("1798/AC1: with no slice, docker run became %v", got)
+	}
+}