Add updateConfig code to load config changes if possible for every function

pkg/donut/donut-v2.go

@@ -25,6 +25,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"reflect"
 	"runtime/debug"
 	"sort"
 	"strconv"
@@ -71,11 +72,22 @@ type storedBucket struct {
 }
 
 // New instantiate a new donut
-func New(c *Config) (Interface, error) {
-	if err := quick.CheckData(c); err != nil {
-		return nil, iodine.New(err, nil)
+func New() (Interface, error) {
+	var conf *Config
+	var err error
+	conf, err = LoadConfig()
+	if err != nil {
+		conf = &Config{
+			Version:     "0.0.1",
+			MaxSize:     512000000,
+			NodeDiskMap: nil,
+			DonutName:   "",
+		}
+		if err := quick.CheckData(conf); err != nil {
+			return nil, iodine.New(err, nil)
+		}
 	}
-	a := API{config: c}
+	a := API{config: conf}
 	a.storedBuckets = metadata.NewCache()
 	a.nodes = make(map[string]node)
 	a.buckets = make(map[string]bucket)
@@ -107,10 +119,30 @@ func New(c *Config) (Interface, error) {
 	return a, nil
 }
 
+// updateConfig loads new config everytime
+func (donut API) updateConfig() {
+	// on error loading config's just return do not modify
+	conf, err := LoadConfig()
+	if err != nil {
+		return
+	}
+	if reflect.DeepEqual(donut.config, conf) {
+		return
+	}
+	if conf.MaxSize == donut.config.MaxSize {
+		return
+	}
+	donut.config = conf
+	donut.objects.SetMaxSize(conf.MaxSize)
+}
+
 // GetObject - GET object from cache buffer
 func (donut API) GetObject(w io.Writer, bucket string, object string) (int64, error) {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	if !IsValidBucket(bucket) {
 		return 0, iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
 	}
@@ -156,6 +188,9 @@ func (donut API) GetObject(w io.Writer, bucket string, object string) (int64, er
 func (donut API) GetPartialObject(w io.Writer, bucket, object string, start, length int64) (int64, error) {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	errParams := map[string]string{
 		"bucket": bucket,
 		"object": object,
@@ -211,6 +246,9 @@ func (donut API) GetPartialObject(w io.Writer, bucket, object string, start, len
 func (donut API) GetBucketMetadata(bucket string) (BucketMetadata, error) {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	if !IsValidBucket(bucket) {
 		return BucketMetadata{}, iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
 	}
@@ -233,6 +271,9 @@ func (donut API) GetBucketMetadata(bucket string) (BucketMetadata, error) {
 func (donut API) SetBucketMetadata(bucket string, metadata map[string]string) error {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	if !IsValidBucket(bucket) {
 		return iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
 	}
@@ -271,6 +312,21 @@ func isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) error {
 
 // CreateObject - create an object
 func (donut API) CreateObject(bucket, key, expectedMD5Sum string, size int64, data io.Reader, metadata map[string]string) (ObjectMetadata, error) {
+	donut.lock.Lock()
+	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
+	contentType := metadata["contentType"]
+	objectMetadata, err := donut.createObject(bucket, key, contentType, expectedMD5Sum, size, data)
+	// free
+	debug.FreeOSMemory()
+
+	return objectMetadata, iodine.New(err, nil)
+}
+
+// createObject - PUT object to cache buffer
+func (donut API) createObject(bucket, key, contentType, expectedMD5Sum string, size int64, data io.Reader) (ObjectMetadata, error) {
 	if size > int64(donut.config.MaxSize) {
 		generic := GenericObjectError{Bucket: bucket, Object: key}
 		return ObjectMetadata{}, iodine.New(EntityTooLarge{
@@ -279,17 +335,6 @@ func (donut API) CreateObject(bucket, key, expectedMD5Sum string, size int64, da
 			MaxSize:            strconv.FormatUint(donut.config.MaxSize, 10),
 		}, nil)
 	}
-	contentType := metadata["contentType"]
-	donut.lock.Lock()
-	objectMetadata, err := donut.createObject(bucket, key, contentType, expectedMD5Sum, size, data)
-	donut.lock.Unlock()
-	// free
-	debug.FreeOSMemory()
-	return objectMetadata, iodine.New(err, nil)
-}
-
-// createObject - PUT object to cache buffer
-func (donut API) createObject(bucket, key, contentType, expectedMD5Sum string, size int64, data io.Reader) (ObjectMetadata, error) {
 	if !IsValidBucket(bucket) {
 		return ObjectMetadata{}, iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
 	}
@@ -384,6 +429,9 @@ func (donut API) createObject(bucket, key, contentType, expectedMD5Sum string, s
 func (donut API) MakeBucket(bucketName, acl string) error {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	if donut.storedBuckets.Stats().Items == totalBuckets {
 		return iodine.New(TooManyBuckets{Bucket: bucketName}, nil)
 	}
@@ -422,6 +470,9 @@ func (donut API) MakeBucket(bucketName, acl string) error {
 func (donut API) ListObjects(bucket string, resources BucketResourcesMetadata) ([]ObjectMetadata, BucketResourcesMetadata, error) {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	if !IsValidBucket(bucket) {
 		return nil, BucketResourcesMetadata{IsTruncated: false}, iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
 	}
@@ -515,6 +566,9 @@ func (b byBucketName) Less(i, j int) bool { return b[i].Name < b[j].Name }
 func (donut API) ListBuckets() ([]BucketMetadata, error) {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	var results []BucketMetadata
 	if len(donut.config.NodeDiskMap) > 0 {
 		buckets, err := donut.listBuckets()
@@ -538,6 +592,9 @@ func (donut API) ListBuckets() ([]BucketMetadata, error) {
 func (donut API) GetObjectMetadata(bucket, key string) (ObjectMetadata, error) {
 	donut.lock.Lock()
 	defer donut.lock.Unlock()
+	// update Config if possible
+	donut.updateConfig()
+
 	// check if bucket exists
 	if !IsValidBucket(bucket) {
 		return ObjectMetadata{}, iodine.New(BucketNameInvalid{Bucket: bucket}, nil)