[DynamoDB] refactor!: Use dynamodbattribute for Unmarshal; Add DescribeTable; (#48)

Author: evalphobia

dynamodb/client.go

@@ -72,7 +72,8 @@ func (svc *DynamoDB) CreateTable(design *TableDesign) error {
 		design.name = originalName
 		return err
 	}
-	design = newTableDesignFromDescription(out.TableDescription)
+
+	design = newTableDesignFromDescription(NewTableDescription(out.TableDescription))
 	svc.Infof("success on `CreateTable` operation; table=%s; status=%s;", design.GetName(), design.status)
 	return nil
 }
@@ -95,8 +96,8 @@ func (svc *DynamoDB) ForceDeleteTable(name string) error {
 	}
 	svc.tablesMu.Unlock()
 
-	design := newTableDesignFromDescription(out.TableDescription)
-	svc.Infof("success on `DeleteTable` operation; table=%s; status=%s;", tableName, design.status)
+	desc := NewTableDescription(out.TableDescription)
+	svc.Infof("success on `DeleteTable` operation; table=%s; status=%s;", tableName, desc.TableStatus)
 	return nil
 }
 
@@ -138,6 +139,24 @@ func (svc *DynamoDB) ListTables() ([]string, error) {
 	return list, nil
 }
 
+// DescribeTable executes `DescribeTable` operation and get table info.
+func (svc *DynamoDB) DescribeTable(name string) (TableDescription, error) {
+	res, err := svc.client.DescribeTable(&SDK.DescribeTableInput{
+		TableName: pointers.String(name),
+	})
+	switch {
+	case err != nil:
+		svc.Errorf("error on `DescribeTable` operation; table=%s; error=%s;", name, err.Error())
+		return TableDescription{}, err
+	case res == nil:
+		err := fmt.Errorf("response is nil")
+		svc.Errorf("error on `DescribeTable` operation; table=%s; error=%s;", name, err.Error())
+		return TableDescription{}, err
+	}
+
+	return NewTableDescription(res.Table), nil
+}
+
 // ========================
 // Query&Command Operation
 // ========================

dynamodb/condition.go

@@ -9,18 +9,6 @@ import (
 	"github.com/evalphobia/aws-sdk-go-wrapper/private/pointers"
 )
 
-const (
-	conditionEQ      = "="
-	conditionLE      = "<="
-	conditionLT      = "<"
-	conditionGE      = ">="
-	conditionGT      = ">"
-	conditionBETWEEN = "BETWEEN"
-
-	conditionOR  = "OR"
-	conditionAND = "AND"
-)
-
 // ConditionList contains multiple condition.
 type ConditionList struct {
 	keyAttributes map[string]string

dynamodb/const.go

@@ -0,0 +1,44 @@
+// DynamoDB utility
+
+package dynamodb
+
+import (
+	SDK "github.com/aws/aws-sdk-go/service/dynamodb"
+)
+
+const (
+	// attribvute types
+	AttributeTypeString    = "S"
+	AttributeTypeNumber    = "N"
+	AttributeTypeBinary    = "B"
+	AttributeTypeBool      = "BOOL"
+	AttributeTypeNull      = "NULL"
+	AttributeTypeMap       = "M"
+	AttributeTypeList      = "L"
+	AttributeTypeStringSet = "SS"
+	AttributeTypeNumberSet = "NS"
+	AttributeTypeBinarySet = "BS"
+
+	conditionEQ      = "="
+	conditionLE      = "<="
+	conditionLT      = "<"
+	conditionGE      = ">="
+	conditionGT      = ">"
+	conditionBETWEEN = SDK.ComparisonOperatorBetween
+	conditionOR      = SDK.ConditionalOperatorOr
+	conditionAND     = SDK.ConditionalOperatorAnd
+
+	// comparison operators
+	ComparisonOperatorEQ = SDK.ComparisonOperatorEq
+	ComparisonOperatorNE = "NE"
+	ComparisonOperatorGT = "GT"
+	ComparisonOperatorLT = "LT"
+	ComparisonOperatorGE = "GE"
+	ComparisonOperatorLE = "LE"
+
+	// key type name for DynamoDB Index.
+	KeyTypeHash  = SDK.KeyTypeHash
+	KeyTypeRange = SDK.KeyTypeRange
+
+	SelectCount = SDK.SelectCount
+)

dynamodb/item.go

@@ -6,16 +6,6 @@ import (
 	"github.com/evalphobia/aws-sdk-go-wrapper/private/pointers"
 )
 
-// comparison operators
-const (
-	ComparisonOperatorEQ = "EQ"
-	ComparisonOperatorNE = "NE"
-	ComparisonOperatorGT = "GT"
-	ComparisonOperatorLT = "LT"
-	ComparisonOperatorGE = "GE"
-	ComparisonOperatorLE = "LE"
-)
-
 // PutItem is wrapped struct for DynamoDB Item to put.
 type PutItem struct {
 	data       map[string]*SDK.AttributeValue

dynamodb/query_result.go

@@ -2,7 +2,7 @@ package dynamodb
 
 import (
 	SDK "github.com/aws/aws-sdk-go/service/dynamodb"
-	"github.com/mitchellh/mapstructure"
+	"github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute"
 )
 
 const defaultResultTag = "dynamodb"
@@ -20,29 +20,28 @@ type QueryResult struct {
 func (r QueryResult) ToSliceMap() []map[string]interface{} {
 	m := make([]map[string]interface{}, len(r.Items))
 	for i, item := range r.Items {
+		// benachmark: https://gist.github.com/evalphobia/c1b436ef15038bc9fc9c588ca0163c93#gistcomment-3120916
 		m[i] = UnmarshalAttributeValue(item)
 	}
 	return m
 }
 
-// Unmarshal parse DynamoDB item data and mapping value to given slice pointer sturct.
+// Unmarshal unmarshals given slice pointer sturct from DynamoDB item result to mapping.
 //     e.g. err = Unmarshal(&[]*yourStruct)
+// The struct tag `dynamodb:""` is used to unmarshal.
 func (r QueryResult) Unmarshal(v interface{}) error {
-	m := r.ToSliceMap()
+	return r.UnmarshalWithTagName(v, defaultResultTag)
+}
 
-	tagName := r.tagName
-	if tagName == "" {
-		tagName = defaultResultTag
-	}
+// UnmarshalWithTagName unmarshals given slice pointer sturct and tag name from DynamoDB item result to mapping.
+func (r QueryResult) UnmarshalWithTagName(v interface{}, structTag string) error {
+	decoder := dynamodbattribute.NewDecoder()
+	decoder.TagKey = structTag
 
-	decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
-		Metadata:         nil,
-		Result:           v,
-		TagName:          tagName,
-		WeaklyTypedInput: true,
-	})
-	if err != nil {
-		return err
+	items := make([]*SDK.AttributeValue, len(r.Items))
+	for i, m := range r.Items {
+		items[i] = &SDK.AttributeValue{M: m}
 	}
-	return decoder.Decode(m)
+	err := decoder.Decode(&SDK.AttributeValue{L: items}, v)
+	return err
 }

dynamodb/query_result_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func getTestQueryRsult(t *testing.T) *QueryResult {
+func getTestQueryResult(t *testing.T) *QueryResult {
 	setupQueryTable(t)
 	tbl := getTestTable(t)
 
@@ -20,7 +20,7 @@ func getTestQueryRsult(t *testing.T) *QueryResult {
 func TestToSliceMap(t *testing.T) {
 	assert := assert.New(t)
 
-	r := getTestQueryRsult(t)
+	r := getTestQueryResult(t)
 
 	list := r.ToSliceMap()
 	assert.Len(list, 2)
@@ -43,7 +43,7 @@ func TestUnmarshal(t *testing.T) {
 		LSIKey   string `dynamodb:"lsi_key"`
 	}
 
-	r := getTestQueryRsult(t)
+	r := getTestQueryResult(t)
 
 	var list []*myStruct
 	err := r.Unmarshal(&list)

dynamodb/sdk_attribute_definition.go

@@ -14,22 +14,26 @@ import (
 
 func newAttributeValue(typ string, val interface{}) *SDK.AttributeValue {
 	switch typ {
-	case "S":
+	case AttributeTypeString:
 		return newAttributeValueS(val)
-	case "N":
+	case AttributeTypeNumber:
 		return newAttributeValueN(val)
-	case "B":
+	case AttributeTypeBinary:
 		return newAttributeValueB(val)
-	case "BOOL":
+	case AttributeTypeBool:
 		return newAttributeValueBOOL(val)
-	case "SS":
+	case AttributeTypeStringSet:
 		return newAttributeValueSS(val)
-	case "NS":
+	case AttributeTypeNumberSet:
 		return newAttributeValueNS(val)
-	case "L":
+	case AttributeTypeBinarySet:
+		return newAttributeValueBS(val)
+	case AttributeTypeList:
 		return newAttributeValueL(val)
-	case "M":
+	case AttributeTypeMap:
 		return newAttributeValueM(val)
+	case AttributeTypeNull:
+		return newAttributeValueNull(val)
 	}
 	return nil
 }
@@ -100,6 +104,14 @@ func newAttributeValueL(val interface{}) *SDK.AttributeValue {
 	return &SDK.AttributeValue{L: list}
 }
 
+func newAttributeValueNull(val interface{}) *SDK.AttributeValue {
+	switch t := val.(type) {
+	case bool:
+		return &SDK.AttributeValue{NULL: pointers.Bool(t)}
+	}
+	return nil
+}
+
 // Create new AttributeValue from the type of value
 func createAttributeValue(v interface{}) *SDK.AttributeValue {
 	switch t := v.(type) {

dynamodb/sdk_attribute_value.go

@@ -8,12 +8,6 @@ import (
 	"github.com/evalphobia/aws-sdk-go-wrapper/private/pointers"
 )
 
-// key type name for DynamoDB Index.
-const (
-	KeyTypeHash  = "HASH"
-	KeyTypeRange = "RANGE"
-)
-
 // NewKeySchema creates new []*SDK.KeySchemaElement.
 func NewKeySchema(elements ...*SDK.KeySchemaElement) []*SDK.KeySchemaElement {
 	if len(elements) > 1 {

dynamodb/sdk_keyschema_element.go

@@ -29,15 +29,12 @@ type Table struct {
 // NewTable returns initialized *Table.
 func NewTable(svc *DynamoDB, name string) (*Table, error) {
 	tableName := svc.prefix + name
-	req, err := svc.client.DescribeTable(&SDK.DescribeTableInput{
-		TableName: pointers.String(tableName),
-	})
+	desc, err := svc.DescribeTable(tableName)
 	if err != nil {
-		svc.Errorf("error on `DescribeTable` operation; table=%s; error=%s;", name, err.Error())
 		return nil, err
 	}
 
-	design := newTableDesignFromDescription(req.Table)
+	design := newTableDesignFromDescription(desc)
 	return &Table{
 		service:        svc,
 		name:           name,
@@ -80,15 +77,12 @@ func (t *Table) SetDesign(design *TableDesign) {
 
 // RefreshDesign returns refreshed table design.
 func (t *Table) RefreshDesign() (*TableDesign, error) {
-	req, err := t.service.client.DescribeTable(&SDK.DescribeTableInput{
-		TableName: pointers.String(t.nameWithPrefix),
-	})
+	desc, err := t.service.DescribeTable(t.nameWithPrefix)
 	if err != nil {
-		t.service.Errorf("error on `DescribeTable` operation; table=%s; error=%s", t.nameWithPrefix, err.Error())
 		return nil, err
 	}
 
-	t.design = newTableDesignFromDescription(req.Table)
+	t.design = newTableDesignFromDescription(desc)
 	return t.design, nil
 }
 
@@ -152,7 +146,7 @@ func (t *Table) AddItem(item *PutItem) {
 // Put executes put operation from the write-waiting list (writeItem)
 func (t *Table) Put() error {
 	errList := newErrors()
-	// アイテムの保存処理
+	// save items in spool
 	for _, item := range t.putSpool {
 		err := t.validatePutItem(item)
 		if err != nil {
@@ -183,7 +177,7 @@ func (t *Table) BatchPut() error {
 		err := t.validatePutItem(item)
 		if err != nil {
 			errList.Add(err)
-			// バリデーションエラーのアイテムは送信スプールから除外するリストに加える
+			// add to ignore list
 			errorSpoolIndices = append(errorSpoolIndices, index)
 			continue
 		}
@@ -321,7 +315,7 @@ func (t *Table) Query(cond *ConditionList) (*QueryResult, error) {
 // Count executes Query operation and get Count.
 func (t *Table) Count(cond *ConditionList) (*QueryResult, error) {
 	return t.query(cond, &SDK.QueryInput{
-		Select: pointers.String("COUNT"),
+		Select: pointers.String(SelectCount),
 	})
 }