TUN-4063: Cleanup dependencies between packages.

- Move packages the provide generic functionality (such as config) from `cmd` subtree to top level.
- Remove all dependencies on `cmd` subtree from top level packages.
- Consolidate all code dealing with token generation and transfer to a single cohesive package.

config/manager_test.go

@@ -0,0 +1,88 @@
+package config
+
+import (
+	"os"
+	"testing"
+
+	"github.com/cloudflare/cloudflared/watcher"
+
+	"github.com/rs/zerolog"
+	"github.com/stretchr/testify/assert"
+)
+
+type mockNotifier struct {
+	configs []Root
+}
+
+func (n *mockNotifier) ConfigDidUpdate(c Root) {
+	n.configs = append(n.configs, c)
+}
+
+type mockFileWatcher struct {
+	path     string
+	notifier watcher.Notification
+	ready    chan struct{}
+}
+
+func (w *mockFileWatcher) Start(n watcher.Notification) {
+	w.notifier = n
+	w.ready <- struct{}{}
+}
+
+func (w *mockFileWatcher) Add(string) error {
+	return nil
+}
+
+func (w *mockFileWatcher) Shutdown() {
+
+}
+
+func (w *mockFileWatcher) TriggerChange() {
+	w.notifier.WatcherItemDidChange(w.path)
+}
+
+func TestConfigChanged(t *testing.T) {
+	filePath := "config.yaml"
+	f, err := os.Create(filePath)
+	assert.NoError(t, err)
+	defer func() {
+		_ = f.Close()
+		_ = os.Remove(filePath)
+	}()
+	c := &Root{
+		Forwarders: []Forwarder{
+			{
+				URL:      "test.daltoniam.com",
+				Listener: "127.0.0.1:8080",
+			},
+		},
+	}
+	configRead := func(configPath string, log *zerolog.Logger) (Root, error) {
+		return *c, nil
+	}
+	wait := make(chan struct{})
+	w := &mockFileWatcher{path: filePath, ready: wait}
+
+	log := zerolog.Nop()
+
+	service, err := NewFileManager(w, filePath, &log)
+	service.ReadConfig = configRead
+	assert.NoError(t, err)
+
+	n := &mockNotifier{}
+	go service.Start(n)
+
+	<-wait
+	c.Forwarders = append(c.Forwarders, Forwarder{URL: "add.daltoniam.com", Listener: "127.0.0.1:8081"})
+	w.TriggerChange()
+
+	service.Shutdown()
+
+	assert.Len(t, n.configs, 2, "did not get 2 config updates as expected")
+	assert.Len(t, n.configs[0].Forwarders, 1, "not the amount of forwarders expected")
+	assert.Len(t, n.configs[1].Forwarders, 2, "not the amount of forwarders expected")
+
+	assert.Equal(t, n.configs[0].Forwarders[0].Hash(), c.Forwarders[0].Hash(), "forwarder hashes don't match")
+	assert.Equal(t, n.configs[1].Forwarders[0].Hash(), c.Forwarders[0].Hash(), "forwarder hashes don't match")
+	assert.Equal(t, n.configs[1].Forwarders[1].Hash(), c.Forwarders[1].Hash(), "forwarder hashes don't match")
+}