cleanup: move KMS functionality into its own package

A new "internal/kms" package is introduced, it holds the API that can be
consumed by the RBD components.

The KMS providers are currently in the same package as the API. With
later follow-up changes the providers will be placed in their own
sub-package.

Because of the name of the package "kms", the types, functions and
structs inside the package should not be prefixed with KMS anymore:

    internal/kms/kms.go:213:6: type name will be used as kms.KMSInitializerArgs by other packages, and that stutters; consider calling this InitializerArgs (golint)

Updates: #852
Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/kms/vault_test.go

@@ -0,0 +1,132 @@
+/*
+Copyright 2020 The Ceph-CSI Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kms
+
+import (
+	"errors"
+	"os"
+	"testing"
+
+	loss "github.com/libopenstorage/secrets"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDetectAuthMountPath(t *testing.T) {
+	t.Parallel()
+	authMountPath, err := detectAuthMountPath(vaultDefaultAuthPath)
+	if err != nil {
+		t.Errorf("detectAuthMountPath() failed: %s", err)
+	}
+	if authMountPath != "kubernetes" {
+		t.Errorf("authMountPath should be set to 'kubernetes', but is: %s", authMountPath)
+	}
+
+	authMountPath, err = detectAuthMountPath("kubernetes")
+	if err != nil {
+		t.Errorf("detectAuthMountPath() failed: %s", err)
+	}
+	if authMountPath != "kubernetes" {
+		t.Errorf("authMountPath should be set to 'kubernetes', but is: %s", authMountPath)
+	}
+}
+
+func TestCreateTempFile(t *testing.T) {
+	t.Parallel()
+	data := []byte("Hello World!")
+	tmpfile, err := createTempFile("my-file", data)
+	if err != nil {
+		t.Errorf("createTempFile() failed: %s", err)
+	}
+	if tmpfile == "" {
+		t.Errorf("createTempFile() returned an empty filename")
+	}
+
+	err = os.Remove(tmpfile)
+	if err != nil {
+		t.Errorf("failed to remove tmpfile (%s): %s", tmpfile, err)
+	}
+}
+
+func TestSetConfigString(t *testing.T) {
+	t.Parallel()
+	const defaultValue = "default-value"
+	options := make(map[string]interface{})
+
+	// noSuchOption: no default value, option unavailable
+	noSuchOption := ""
+	err := setConfigString(&noSuchOption, options, "nonexistent")
+	switch {
+	case err == nil:
+		t.Error("did not get an error when one was expected")
+	case !errors.Is(err, errConfigOptionMissing):
+		t.Errorf("expected errConfigOptionMissing, but got %T: %s", err, err)
+	case noSuchOption != "":
+		t.Error("value should not have been modified")
+	}
+
+	// noOptionDefault: default value, option unavailable
+	noOptionDefault := defaultValue
+	err = setConfigString(&noOptionDefault, options, "nonexistent")
+	switch {
+	case err == nil:
+		t.Error("did not get an error when one was expected")
+	case !errors.Is(err, errConfigOptionMissing):
+		t.Errorf("expected errConfigOptionMissing, but got %T: %s", err, err)
+	case noOptionDefault != defaultValue:
+		t.Error("value should not have been modified")
+	}
+
+	// optionDefaultOverload: default value, option available
+	optionDefaultOverload := defaultValue
+	options["set-me"] = "non-default"
+	err = setConfigString(&optionDefaultOverload, options, "set-me")
+	switch {
+	case err != nil:
+		t.Errorf("unexpected error returned: %s", err)
+	case optionDefaultOverload != "non-default":
+		t.Error("optionDefaultOverload should have been updated")
+	}
+}
+
+func TestDefaultVaultDestroyKeys(t *testing.T) {
+	t.Parallel()
+
+	vc := &vaultConnection{}
+	config := make(map[string]interface{})
+	config["vaultAddress"] = "https://vault.test.example.com"
+	err := vc.initConnection(config)
+	require.NoError(t, err)
+	keyContext := vc.getDeleteKeyContext()
+	destroySecret, ok := keyContext[loss.DestroySecret]
+	assert.NotEqual(t, destroySecret, "")
+	assert.True(t, ok)
+
+	// setting vaultDestroyKeys to !true should remove the loss.DestroySecret entry
+	config["vaultDestroyKeys"] = "false"
+	err = vc.initConnection(config)
+	require.NoError(t, err)
+	keyContext = vc.getDeleteKeyContext()
+	_, ok = keyContext[loss.DestroySecret]
+	assert.False(t, ok)
+}
+
+func TestVaultKMSRegistered(t *testing.T) {
+	t.Parallel()
+	_, ok := kmsManager.providers[kmsTypeVault]
+	assert.True(t, ok)
+}