Merge pull request #84 from guregu/tx

Transactions

bench_test.go

@@ -3,8 +3,6 @@ package dynamo
 import (
 	"testing"
 	"time"
-
-	"github.com/guregu/toki"
 )
 
 var (
@@ -16,7 +14,7 @@ var (
 		Page:        1,
 		SkipThis:    "i should disappear",
 		Bonus:       &arbitraryNumber,
-		TestText:    toki.MustParseTime("1:2:3"),
+		TestText:    time.Now(),
 		StringSlice: []string{"A", "B", "C", "QQQ"},
 		embedMe: embedMe{
 			Extra: true,
@@ -117,7 +115,7 @@ type fancyObject struct {
 	SkipThis  string `dynamo:"-"`
 	Bonus     *int   `dynamo:",omitempty"`
 
-	TestText  toki.Time
+	TestText  time.Time
 	SkipMePlz time.Time `dynamo:",omitempty"`
 
 	StringSlice []string

conditioncheck.go

@@ -0,0 +1,95 @@
+package dynamo
+
+import (
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/dynamodb"
+)
+
+// ConditionCheck represents a condition for a write transaction to succeed.
+// It is used along with WriteTx.Check.
+type ConditionCheck struct {
+	table      Table
+	hashKey    string
+	hashValue  *dynamodb.AttributeValue
+	rangeKey   string
+	rangeValue *dynamodb.AttributeValue
+
+	condition string
+	subber
+
+	err error
+}
+
+// Check creates a new ConditionCheck, which represents a condition for a write transaction to succeed.
+// hashKey specifies the name of the table's hash key and value specifies the value of the hash key.
+// You must use Range to specify a range key for tables with hash and range keys.
+func (table Table) Check(hashKey string, value interface{}) *ConditionCheck {
+	check := &ConditionCheck{
+		table:   table,
+		hashKey: hashKey,
+	}
+	check.hashValue, check.err = marshal(value, "")
+	return check
+}
+
+// Range specifies the name and value of the range key for this item.
+func (check *ConditionCheck) Range(rangeKey string, value interface{}) *ConditionCheck {
+	check.rangeKey = rangeKey
+	var err error
+	check.rangeValue, err = marshal(value, "")
+	check.setError(err)
+	return check
+}
+
+// If specifies a conditional expression for this coniditon check to succeed.
+// Use single quotes to specificy reserved names inline (like 'Count').
+// Use the placeholder ? within the expression to substitute values, and use $ for names.
+// You need to use quoted or placeholder names when the name is a reserved word in DynamoDB.
+func (check *ConditionCheck) If(expr string, args ...interface{}) *ConditionCheck {
+	cond, err := check.subExpr(expr, args...)
+	check.setError(err)
+	check.condition = cond
+	return check
+}
+
+// IfExists sets this check to succeed if the item exists.
+func (check *ConditionCheck) IfExists() *ConditionCheck {
+	return check.If("attribute_exists($)", check.hashKey)
+}
+
+// IfNotExists sets this check to succeed if the item does not exist.
+func (check *ConditionCheck) IfNotExists() *ConditionCheck {
+	return check.If("attribute_not_exists($)", check.hashKey)
+}
+
+func (check *ConditionCheck) writeTxItem() (*dynamodb.TransactWriteItem, error) {
+	if check.err != nil {
+		return nil, check.err
+	}
+	item := &dynamodb.ConditionCheck{
+		TableName: aws.String(check.table.name),
+		Key:       check.keys(),
+		ExpressionAttributeNames:  check.nameExpr,
+		ExpressionAttributeValues: check.valueExpr,
+	}
+	if check.condition != "" {
+		item.ConditionExpression = aws.String(check.condition)
+	}
+	return &dynamodb.TransactWriteItem{
+		ConditionCheck: item,
+	}, nil
+}
+
+func (check *ConditionCheck) keys() map[string]*dynamodb.AttributeValue {
+	keys := map[string]*dynamodb.AttributeValue{check.hashKey: check.hashValue}
+	if check.rangeKey != "" {
+		keys[check.rangeKey] = check.rangeValue
+	}
+	return keys
+}
+
+func (check *ConditionCheck) setError(err error) {
+	if check.err == nil {
+		check.err = err
+	}
+}

delete.go

@@ -132,6 +132,23 @@ func (d *Delete) deleteInput() *dynamodb.DeleteItemInput {
 	return input
 }
 
+func (d *Delete) writeTxItem() (*dynamodb.TransactWriteItem, error) {
+	if d.err != nil {
+		return nil, d.err
+	}
+	input := d.deleteInput()
+	item := &dynamodb.TransactWriteItem{
+		Delete: &dynamodb.Delete{
+			TableName: input.TableName,
+			Key:       input.Key,
+			ExpressionAttributeNames:  input.ExpressionAttributeNames,
+			ExpressionAttributeValues: input.ExpressionAttributeValues,
+			ConditionExpression:       input.ConditionExpression,
+		},
+	}
+	return item, nil
+}
+
 func (d *Delete) key() map[string]*dynamodb.AttributeValue {
 	key := map[string]*dynamodb.AttributeValue{
 		d.hashKey: d.hashValue,

encode.go

@@ -1,6 +1,7 @@
 package dynamo
 
 import (
+	"bytes"
 	"encoding"
 	"fmt"
 	"reflect"
@@ -443,3 +444,27 @@ func isZero(rv reflect.Value) bool {
 	z := reflect.Zero(rv.Type())
 	return rv.Interface() == z.Interface()
 }
+
+// only works for primary key types
+func isAVEqual(a, b *dynamodb.AttributeValue) bool {
+	if a.S != nil {
+		if b.S == nil {
+			return false
+		}
+		return *a.S == *b.S
+	}
+	if a.N != nil {
+		if b.N == nil {
+			return false
+		}
+		// TODO: parse numbers?
+		return *a.N == *b.N
+	}
+	if a.B != nil {
+		if b.B == nil {
+			return false
+		}
+		return bytes.Equal(a.B, b.B)
+	}
+	return false
+}

go.mod

@@ -0,0 +1,10 @@
+module github.com/guregu/dynamo
+
+require (
+	github.com/aws/aws-sdk-go v1.16.15
+	github.com/cenkalti/backoff v2.1.1+incompatible
+	github.com/gofrs/uuid v3.1.0+incompatible
+	github.com/stretchr/testify v1.3.0 // indirect
+	golang.org/x/net v0.0.0-20190108155000-395948e2f546
+	golang.org/x/text v0.3.0 // indirect
+)

go.sum

@@ -0,0 +1,19 @@
+github.com/aws/aws-sdk-go v1.16.15 h1:kQyxfRyjAwIYjf0225sn/pn+WAlncKyI8dmT3+ItMFE=
+github.com/aws/aws-sdk-go v1.16.15/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
+github.com/cenkalti/backoff v2.1.1+incompatible h1:tKJnvO2kl0zmb/jA5UKAt4VoEVw1qxKWjE/Bpp46npY=
+github.com/cenkalti/backoff v2.1.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gofrs/uuid v3.1.0+incompatible h1:q2rtkjaKT4YEr6E1kamy0Ha4RtepWlQBedyHx0uzKwA=
+github.com/gofrs/uuid v3.1.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af h1:pmfjZENx5imkbgOkpRUYLnmbU7UEFbjtDA2hxJ1ichM=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+golang.org/x/net v0.0.0-20190108155000-395948e2f546 h1:tkMg6+6TF2qZ/3I8fw+DiNgPSsABxdVIqWE90w8Vxzk=
+golang.org/x/net v0.0.0-20190108155000-395948e2f546/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

put.go

@@ -115,6 +115,25 @@ func (p *Put) input() *dynamodb.PutItemInput {
 	return input
 }
 
+func (p *Put) writeTxItem() (*dynamodb.TransactWriteItem, error) {
+	if p.err != nil {
+		return nil, p.err
+	}
+	input := p.input()
+	item := &dynamodb.TransactWriteItem{
+		Put: &dynamodb.Put{
+			TableName: input.TableName,
+			Item:      input.Item,
+			ExpressionAttributeNames:  input.ExpressionAttributeNames,
+			ExpressionAttributeValues: input.ExpressionAttributeValues,
+			ConditionExpression:       input.ConditionExpression,
+			// TODO: add support when aws-sdk-go updates
+			// ReturnValuesOnConditionCheckFailure: aws.String(dynamodb.ReturnValuesOnConditionCheckFailureAllOld),
+		},
+	}
+	return item, nil
+}
+
 func (p *Put) setError(err error) {
 	if p.err != nil {
 		p.err = err

query.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/dynamodb"
-	// "github.com/davecgh/go-spew/spew"
 )
 
 // Query is a request to get one or more items in a table.
@@ -39,7 +38,7 @@ type Query struct {
 }
 
 var (
-	// ErrNotFound is returned when no items could be found in Get or OldValue a and similar operations.
+	// ErrNotFound is returned when no items could be found in Get or OldValue and similar operations.
 	ErrNotFound = errors.New("dynamo: no item found")
 	// ErrTooMany is returned when one item was requested, but the query returned multiple items.
 	ErrTooMany = errors.New("dynamo: too many items")
@@ -525,6 +524,21 @@ func (q *Query) getItemInput() *dynamodb.GetItemInput {
 	return req
 }
 
+func (q *Query) getTxItem() (*dynamodb.TransactGetItem, error) {
+	if !q.canGetItem() {
+		return nil, errors.New("dynamo: transaction Query is too complex; no indexes or filters are allowed")
+	}
+	input := q.getItemInput()
+	return &dynamodb.TransactGetItem{
+		Get: &dynamodb.Get{
+			TableName: input.TableName,
+			Key:       input.Key,
+			ExpressionAttributeNames: input.ExpressionAttributeNames,
+			ProjectionExpression:     input.ProjectionExpression,
+		},
+	}, nil
+}
+
 func (q *Query) keys() map[string]*dynamodb.AttributeValue {
 	keys := map[string]*dynamodb.AttributeValue{
 		q.hashKey: q.hashValue,

table.go

@@ -76,6 +76,10 @@ func (dt *DeleteTable) input() *dynamodb.DeleteTableInput {
 type ConsumedCapacity struct {
 	// Total is the total number of capacity units consumed during this operation.
 	Total float64
+	// Read is the total number of read capacity units consumed during this operation.
+	Read float64
+	// Write is the total number of write capacity units consumed during this operation.
+	Write float64
 	// GSI is a map of Global Secondary Index names to consumed capacity units.
 	GSI map[string]float64
 	// GSI is a map of Local Secondary Index names to consumed capacity units.
@@ -93,6 +97,12 @@ func addConsumedCapacity(cc *ConsumedCapacity, raw *dynamodb.ConsumedCapacity) {
 	if raw.CapacityUnits != nil {
 		cc.Total += *raw.CapacityUnits
 	}
+	if raw.ReadCapacityUnits != nil {
+		cc.Read += *raw.ReadCapacityUnits
+	}
+	if raw.WriteCapacityUnits != nil {
+		cc.Write += *raw.WriteCapacityUnits
+	}
 	if len(raw.GlobalSecondaryIndexes) > 0 {
 		if cc.GSI == nil {
 			cc.GSI = make(map[string]float64, len(raw.GlobalSecondaryIndexes))