mesh-controller/internal/catalogue/facts_test.go

package catalogue

import (
	"strings"
	"testing"
)

var threeMachines = map[string]string{"homer": "10.42.0.1", "marge": "10.42.0.2", "bart": ""}

// **`*.homer.internal` is homer. That is the whole rule.**
func TestEveryMachineIsAWildcardUnderItsOwnName(t *testing.T) {
	out := nodeZones(Resolution{Node: "homer"}, threeMachines)
	for _, want := range []string{
		"address=/homer.internal/10.42.0.1",
		"address=/marge.internal/10.42.0.2",
	} {
		if !strings.Contains(out, want) {
			t.Fatalf("missing %q:\n%s", want, out)
		}
	}
}

// A machine the mesh has a record for and cannot place is left out of both.
//
// **Not an oversight — the alternative is worse.** A name written with no address resolves to
// nothing, and a connection to that hangs. Leaving it out fails at once and says the name is
// unknown, which is a thing somebody can act on.
func TestAMachineWithNoAddressIsNotNamed(t *testing.T) {
	for _, out := range []string{
		nodeNames(Resolution{Node: "homer"}, threeMachines),
		nodeZones(Resolution{Node: "homer"}, threeMachines),
	} {
		if strings.Contains(out, "bart") {
			t.Fatalf("a machine with no address was named, so its name resolves to nothing:\n%s", out)
		}
	}
}

// A machine's own mesh name points at its address on the private network, not at loopback — or a
// service binding the name it was given is unreachable from everywhere else.
func TestAMachinesOwnNameIsItsMeshAddress(t *testing.T) {
	out := nodeNames(Resolution{Node: "homer"}, threeMachines)
	var line string
	for _, l := range strings.Split(out, "\n") {
		if strings.Contains(l, "homer.internal") {
			line = l
		}
	}
	if !strings.HasPrefix(line, "10.42.0.1") {
		t.Fatalf("a machine's own mesh name is not its mesh address: %q", line)
	}
	// And the loopback floor is still there, or things with nothing to do with the mesh break.
	if !strings.Contains(out, "127.0.0.1\tlocalhost") {
		t.Fatalf("the loopback floor was removed:\n%s", out)
	}
}

// A module says where it wants a fact, and is given a file.
func TestAModuleIsGivenTheFactsItAskedFor(t *testing.T) {
	m := Manifest{Module: "dnsmasq", Facts: map[string]string{FactNodeZones: "/etc/mesh/zones.conf"}}
	given, err := FactsInto(m, Resolution{Node: "homer"}, threeMachines)
	if err != nil {
		t.Fatal(err)
	}
	if len(given) != 1 {
		t.Fatalf("expected one file, got %d", len(given))
	}
	if given[0]["path"] != "/etc/mesh/zones.conf" || given[0]["type"] != "file" {
		t.Fatalf("not written where it was asked for: %v", given[0])
	}
	if !strings.Contains(given[0]["content"].(string), "homer.internal") {
		t.Fatalf("the file does not hold the fact: %v", given[0]["content"])
	}
}

// **Asking for a fact the mesh does not have is refused here, not on a machine.** A daemon that
// starts, reads a file nobody wrote, and answers no queries is a much worse way to find out.
func TestAskingForAFactTheMeshDoesNotHaveIsRefused(t *testing.T) {
	m := Manifest{Module: "dnsmasq", Facts: map[string]string{"the-weather": "/etc/weather"}}
	_, err := FactsInto(m, Resolution{}, nil)
	if err == nil {
		t.Fatal("a module asked for something nobody computes and was given nothing, silently")
	}
	for _, known := range []string{FactNodeNames, FactNodeZones} {
		if !strings.Contains(err.Error(), known) {
			t.Fatalf("the refusal does not say what would have worked: %v", err)
		}
	}
}

// And a relative path is refused, or a module decides where the mesh writes on a machine.
func TestAFactMustBeAskedForAtAnAbsolutePath(t *testing.T) {
	m := Manifest{Module: "dnsmasq", Facts: map[string]string{FactNodeNames: "etc/hosts"}}
	if _, err := FactsInto(m, Resolution{}, nil); err == nil {
		t.Fatal("a relative path was accepted")
	}
}

// **The names the control plane hands a resolution are already internal names** — `homer.internal`,
// the same map every container gets as its hosts. Appending the suffix again wrote
// `homer.internal.internal` into every hosts file and every resolver's zones, and the large mesh
// bed's name test was the first to read it back. Either key gives the same files.
func TestNamesKeyedByInternalNameAreNotSuffixedTwice(t *testing.T) {
	internal := map[string]string{"homer.internal": "10.42.0.1", "marge.internal": "10.42.0.2"}
	bare := map[string]string{"homer": "10.42.0.1", "marge": "10.42.0.2"}
	if a, b := nodeZones(Resolution{Node: "homer"}, internal), nodeZones(Resolution{Node: "homer"}, bare); a != b {
		t.Fatalf("the zones differ by how the names were keyed:\n%s\n---\n%s", a, b)
	}
	if a, b := nodeNames(Resolution{Node: "homer"}, internal), nodeNames(Resolution{Node: "homer"}, bare); a != b {
		t.Fatalf("the hosts differ by how the names were keyed:\n%s\n---\n%s", a, b)
	}
	zones := nodeZones(Resolution{Node: "homer"}, internal)
	if strings.Contains(zones, "internal.internal") || !strings.Contains(zones, "address=/homer.internal/10.42.0.1") {
		t.Fatalf("the zones carry a doubled suffix or miss the name:\n%s", zones)
	}
	hosts := nodeNames(Resolution{Node: "homer"}, internal)
	if !strings.Contains(hosts, "10.42.0.1\thomer.internal\thomer\t# this machine") {
		t.Fatalf("the hosts line for the machine itself is not name, bare name and the mark:\n%s", hosts)
	}
}