MM-14143 config cleanup final (#10374)

* TestGetLicenseFileFromDisk: avoid using fileutils.FindConfigFile

* config: abstract config-related file access, extend memory store

* simplify config validate to avoid file knowledge

* fix relative file tests

* cluster: fix ConfigChanged event

The old and new configurations were swapped when notifying the enterprise code of configuration changes, creating needless instability in propagating config updates across a cluster.

* config/database: ignore duplicates

* test cleanup

* remove unnecessary Save() in test

config/memory.go

@@ -5,7 +5,7 @@ package config
 
 import (
 	"bytes"
-	"encoding/json"
+	"fmt"
 	"io/ioutil"
 
 	"github.com/pkg/errors"
@@ -15,24 +15,50 @@ import (
 
 // memoryStore implements the Store interface. It is meant primarily for testing.
 type memoryStore struct {
-	emitter
-
-	Config               *model.Config
-	EnvironmentOverrides map[string]interface{}
+	commonStore
 
 	allowEnvironmentOverrides bool
+	validate                  bool
+	files                     map[string][]byte
+	savedConfig               *model.Config
 }
 
-// NewMemoryStore creates a new memoryStore instance.
-func NewMemoryStore(allowEnvironmentOverrides bool) (*memoryStore, error) {
-	defaultCfg := &model.Config{}
-	defaultCfg.SetDefaults()
+// MemoryStoreOptions makes configuration of the memory store explicit.
+type MemoryStoreOptions struct {
+	IgnoreEnvironmentOverrides bool
+	SkipValidation             bool
+	InitialConfig              *model.Config
+	InitialFiles               map[string][]byte
+}
+
+// NewMemoryStore creates a new memoryStore instance with default options.
+func NewMemoryStore() (*memoryStore, error) {
+	return NewMemoryStoreWithOptions(&MemoryStoreOptions{})
+}
+
+// NewMemoryStoreWithOptions creates a new memoryStore instance.
+func NewMemoryStoreWithOptions(options *MemoryStoreOptions) (*memoryStore, error) {
+	savedConfig := options.InitialConfig
+	if savedConfig == nil {
+		savedConfig = &model.Config{}
+		savedConfig.SetDefaults()
+	}
+
+	initialFiles := options.InitialFiles
+	if initialFiles == nil {
+		initialFiles = make(map[string][]byte)
+	}
 
 	ms := &memoryStore{
-		Config:                    defaultCfg,
-		allowEnvironmentOverrides: allowEnvironmentOverrides,
+		allowEnvironmentOverrides: !options.IgnoreEnvironmentOverrides,
+		validate:                  !options.SkipValidation,
+		files:                     initialFiles,
+		savedConfig:               savedConfig,
 	}
 
+	ms.commonStore.config = &model.Config{}
+	ms.commonStore.config.SetDefaults()
+
 	if err := ms.Load(); err != nil {
 		return nil, err
 	}
@@ -40,59 +66,89 @@ func NewMemoryStore(allowEnvironmentOverrides bool) (*memoryStore, error) {
 	return ms, nil
 }
 
-// Get fetches the current, cached configuration.
-func (ms *memoryStore) Get() *model.Config {
-	return ms.Config
-}
-
-// GetEnvironmentOverrides fetches the configuration fields overridden by environment variables.
-func (ms *memoryStore) GetEnvironmentOverrides() map[string]interface{} {
-	return ms.EnvironmentOverrides
-}
-
 // Set replaces the current configuration in its entirety.
 func (ms *memoryStore) Set(newCfg *model.Config) (*model.Config, error) {
-	oldCfg := ms.Config
+	validate := ms.commonStore.validate
+	if !ms.validate {
+		validate = nil
+	}
 
-	newCfg.SetDefaults()
-	ms.Config = newCfg
-
-	return oldCfg, nil
+	return ms.commonStore.set(newCfg, validate, ms.persist)
 }
 
-// serialize converts the given configuration into JSON bytes for persistence.
-func (ms *memoryStore) serialize(cfg *model.Config) ([]byte, error) {
-	return json.MarshalIndent(cfg, "", "    ")
+// persist copies the active config to the saved config.
+func (ms *memoryStore) persist(cfg *model.Config) error {
+	ms.savedConfig = cfg.Clone()
+
+	return nil
 }
 
-// Load applies environment overrides to the current config as if a re-load had occurred.
+// Load applies environment overrides to the default config as if a re-load had occurred.
 func (ms *memoryStore) Load() (err error) {
 	var cfgBytes []byte
-	cfgBytes, err = ms.serialize(ms.Config)
+	cfgBytes, err = marshalConfig(ms.savedConfig)
 	if err != nil {
 		return errors.Wrap(err, "failed to serialize config")
 	}
 
 	f := ioutil.NopCloser(bytes.NewReader(cfgBytes))
 
-	allowEnvironmentOverrides := true
-	loadedCfg, environmentOverrides, err := unmarshalConfig(f, allowEnvironmentOverrides)
-	if err != nil {
-		return errors.Wrap(err, "failed to load config")
+	validate := ms.commonStore.validate
+	if !ms.validate {
+		validate = nil
 	}
 
-	ms.Config = loadedCfg
-	ms.EnvironmentOverrides = environmentOverrides
+	return ms.commonStore.load(f, false, validate, ms.persist)
+}
+
+// GetFile fetches the contents of a previously persisted configuration file.
+func (ms *memoryStore) GetFile(name string) ([]byte, error) {
+	ms.configLock.RLock()
+	defer ms.configLock.RUnlock()
+
+	data, ok := ms.files[name]
+	if !ok {
+		return nil, fmt.Errorf("file %s not stored", name)
+	}
+
+	return data, nil
+}
+
+// SetFile sets or replaces the contents of a configuration file.
+func (ms *memoryStore) SetFile(name string, data []byte) error {
+	ms.configLock.Lock()
+	defer ms.configLock.Unlock()
+
+	ms.files[name] = data
+
+	return nil
+}
+
+// HasFile returns true if the given file was previously persisted.
+func (ms *memoryStore) HasFile(name string) (bool, error) {
+	ms.configLock.RLock()
+	defer ms.configLock.RUnlock()
+
+	_, ok := ms.files[name]
+	return ok, nil
+}
+
+// RemoveFile removes a previously persisted configuration file.
+func (ms *memoryStore) RemoveFile(name string) error {
+	ms.configLock.Lock()
+	defer ms.configLock.Unlock()
+
+	delete(ms.files, name)
 
 	return nil
 }
 
 // String returns a hard-coded description, as there is no backing store.
 func (ms *memoryStore) String() string {
-	return "mock://"
+	return "memory://"
 }
 
-// Close does nothing for a mock store.
+// Close does nothing for a memory store.
 func (ms *memoryStore) Close() error {
 	return nil
 }