dynamo

package module
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 Go to latest Published: Jul 18, 2019 License: BSD-2-Clause Imports: 19 Imported by: 269

README

dynamo GoDoc

import "github.com/guregu/dynamo"

dynamo is an expressive DynamoDB client for Go, with an API heavily inspired by mgo. dynamo integrates with the official AWS SDK.

dynamo is still under development, so the API may change rarely. However, breaking changes will be avoided and the API can be considered relatively stable.

Example

package dynamo

import (
	"time"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/guregu/dynamo"
)

// Use struct tags much like the standard JSON library,
// you can embed anonymous structs too!
type widget struct {
	UserID int       // Hash key, a.k.a. partition key
	Time   time.Time // Range key, a.k.a. sort key

	Msg       string              `dynamo:"Message"`
	Count     int                 `dynamo:",omitempty"`
	Friends   []string            `dynamo:",set"` // Sets
	Set       map[string]struct{} `dynamo:",set"` // Map sets, too!
	SecretKey string              `dynamo:"-"`    // Ignored
	Category  string              `dynamo:"Category"` // Global Secondary Index
	Children  []any               // Lists
}


func main() {
	db := dynamo.New(session.New(), &aws.Config{Region: aws.String("us-west-2")})
	table := db.Table("Widgets")
	
	// put item
	w := widget{UserID: 613, Time: time.Now(), Msg: "hello"}
	err := table.Put(w).Run() 
	
	// get the same item 
	var result widget
	err = table.Get("UserID", w.UserID).
		Range("Time", dynamo.Equal, w.Time).
		Filter("'Count' = ? AND $ = ?", w.Count, "Message", w.Msg). // placeholders in expressions
		One(&result)
	
	// get by index 
	err = table.Get("Cateogry", "hoge").
		Index("category-index").
		One(&result)

	// get all items
	var results []widget
	err = table.Scan().All(&results)
}

Expressions

dynamo will help you write expressions used to filter results in queries and scans, and add conditions to puts and deletes.

Attribute names may be written as is if it is not a reserved word, or be escaped with single quotes (''). You may also use dollar signs ($) as placeholders for attribute names. DynamoDB has very large amount of reserved words so it may be a good idea to just escape everything.

Question marks (?) are used as placeholders for attribute values. DynamoDB doesn't have value literals, so you need to substitute everything.

Please see the DynamoDB reference on expressions for more information.

// Using single quotes to escape a reserved word, and a question mark as a value placeholder.
// Finds all items whose date is greater than or equal to lastUpdate.
table.Scan().Filter("'Date' >= ?", lastUpdate).All(&results)

// Using dollar signs as a placeholder for attribute names. 
// Deletes the item with an ID of 42 if its score is at or below the cutoff, and its name starts with G.
table.Delete("ID", 42).If("Score <= ? AND begins_with($, ?)", cutoff, "Name", "G").Run()

// Put a new item, only if it doesn't already exist.
table.Put(item{ID: 42}).If("attribute_not_exists(ID)").Run()

Encoding support

dynamo automatically handles the following interfaces:

This allows you to define custom encodings and provides built-in support for types such as time.Time.

Compatibility with the official AWS library

dynamo has been in development before the official AWS libraries were stable. We use a different encoder and decoder than the dynamodbattribute package. dynamo uses the dynamo struct tag instead of the dynamodbav struct tag, and we also prefer to automatically omit invalid values such as empty strings, whereas the dynamodbattribute package substitutes null values for them. Items that satisfy the dynamodbattribute.(Un)marshaler interfaces are compatibile with both libraries.

In order to use dynamodbattribute's encoding facilities, you must wrap objects passed to dynamo with dynamo.AWSEncoding. Here is a quick example:

// Notice the use of the dynamodbav struct tag
type book struct {
	ID    int    `dynamodbav:"id"`
	Title string `dynamodbav:"title"`
}
// Putting an item
err := db.Table("Books").Put(dynamo.AWSEncoding(book{
	ID:    42,
	Title: "Principia Discordia",
})).Run()
// When getting an item you MUST pass a pointer to AWSEncoding!
var someBook book
err := db.Table("Books").Get("ID", 555).One(dynamo.AWSEncoding(&someBook))

Integration tests

By default, tests are run in offline mode. Create a table called TestDB, with a Number Parition Key called UserID and a String Sort Key called Time. Change the table name with the environment variable DYNAMO_TEST_TABLE. You must specify DYNAMO_TEST_REGION, setting it to the AWS region where your test table is.

DYNAMO_TEST_REGION=us-west-2 go test github.com/guregu/dynamo/... -cover

License

BSD

Documentation

Overview

Package dynamo offers a rich DynamoDB client.

Index

Constants

View Source 
const (
	BinaryType KeyType = "B"
	StringType         = "S"
	NumberType         = "N"
	NoneType           = ""
)

Key types for table and index hash/range keys.

View Source 
const (
	Equal          Operator = "EQ"
	NotEqual                = "NE"
	Less                    = "LT"
	LessOrEqual             = "LE"
	Greater                 = "GT"
	GreaterOrEqual          = "GE"
	BeginsWith              = "BEGINS_WITH"
	Between                 = "BETWEEN"
)

Operators used for comparing against the range key in queries.

View Source 
const (
	// The table or index is ready for use.
	ActiveStatus Status = "ACTIVE"
	// The table or index is being created.
	CreatingStatus = "CREATING"
	// The table or index is being updated.
	UpdatingStatus = "UPDATING"
	// The table or index is being deleted.
	DeletingStatus = "DELETING"
)

Variables

View Source 
var (
	// 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")
)
View Source 
var RetryTimeout = 1 * time.Minute

RetryTimeout defines the maximum amount of time that requests will attempt to automatically retry for. In other words, this is the maximum amount of time that dynamo operations will block. RetryTimeout is only considered by methods that do not take a context. Higher values are better when using tables with lower throughput.

Functions

func Marshal 

func Marshal(v interface{}) (*dynamodb.AttributeValue, error)

Marshal converts the given value into a DynamoDB attribute value.

func MarshalItem 

func MarshalItem(v interface{}) (map[string]*dynamodb.AttributeValue, error)

MarshalItem converts the given struct into a DynamoDB item.

func Unmarshal 

func Unmarshal(av *dynamodb.AttributeValue, out interface{}) error

Unmarshal decodes a DynamoDB value into out, which must be a pointer.

func UnmarshalItem 

func UnmarshalItem(item map[string]*dynamodb.AttributeValue, out interface{}) error

Unmarshal decodes a DynamoDB item into out, which must be a pointer.

Types

type Batch 

type Batch struct {
	// contains filtered or unexported fields
}

Batch stores the names of the hash key and range key for creating new batches.

func (Batch) Get 

func (b Batch) Get(keys ...Keyed) *BatchGet

Get creates a new batch get item request with the given keys. 

table.Batch("ID", "Month").
	Get([]dynamo.Keys{{1, "2015-10"}, {42, "2015-12"}, {42, "1992-02"}}...).
	All(&results)

func (Batch) Write 

func (b Batch) Write() *BatchWrite

Write creates a new batch write request, to which puts and deletes can be added.

type BatchGet 

type BatchGet struct {
	// contains filtered or unexported fields
}

BatchGet is a BatchGetItem operation.

func (*BatchGet) All 

func (bg *BatchGet) All(out interface{}) error

All executes this request and unmarshals all results to out, which must be a pointer to a slice.

func (*BatchGet) AllWithContext added in v1.1.0 

func (bg *BatchGet) AllWithContext(ctx aws.Context, out interface{}) error

AllWithContext executes this request and unmarshals all results to out, which must be a pointer to a slice.

func (*BatchGet) And 

func (bg *BatchGet) And(keys ...Keyed) *BatchGet

And adds more keys to be gotten.

func (*BatchGet) Consistent 

func (bg *BatchGet) Consistent(on bool) *BatchGet

Consistent will, if on is true, make this batch use a strongly consistent read. Reads are eventually consistent by default. Strongly consistent reads are more resource-heavy than eventually consistent reads.

func (*BatchGet) ConsumedCapacity 

func (bg *BatchGet) ConsumedCapacity(cc *ConsumedCapacity) *BatchGet

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*BatchGet) Iter 

func (bg *BatchGet) Iter() Iter

Iter returns a results iterator for this batch.

type BatchWrite 

type BatchWrite struct {
	// contains filtered or unexported fields
}

BatchWrite is a BatchWriteItem operation.

func (*BatchWrite) ConsumedCapacity 

func (bw *BatchWrite) ConsumedCapacity(cc *ConsumedCapacity) *BatchWrite

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*BatchWrite) Delete 

func (bw *BatchWrite) Delete(keys ...Keyed) *BatchWrite

Delete adds delete operations for the given keys to this batch.

func (*BatchWrite) Put 

func (bw *BatchWrite) Put(items ...interface{}) *BatchWrite

Put adds put operations for items to this batch.

func (*BatchWrite) Run 

func (bw *BatchWrite) Run() (wrote int, err error)

Run executes this batch. For batches with more than 25 operations, an error could indicate that some records have been written and some have not. Consult the wrote return amount to figure out which operations have succeeded.

func (*BatchWrite) RunWithContext 

func (bw *BatchWrite) RunWithContext(ctx aws.Context) (wrote int, err error)

type Coder 

type Coder interface {
	Marshaler
	Unmarshaler
}

func AWSEncoding 

func AWSEncoding(v interface{}) Coder

AWSEncoding wraps an object, forcing it to use AWS's official dynamodbattribute package for encoding and decoding. This allows you to use the "dynamodbav" struct tags. When decoding, v must be a pointer.

type ConditionCheck added in v1.1.0 

type ConditionCheck struct {
	// contains filtered or unexported fields
}

ConditionCheck represents a condition for a write transaction to succeed. It is used along with WriteTx.Check.

func (*ConditionCheck) If added in v1.1.0 

func (check *ConditionCheck) If(expr string, args ...interface{}) *ConditionCheck

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. Multiple calls to If will be combined with AND.

func (*ConditionCheck) IfExists added in v1.1.0 

func (check *ConditionCheck) IfExists() *ConditionCheck

IfExists sets this check to succeed if the item exists.

func (*ConditionCheck) IfNotExists added in v1.1.0 

func (check *ConditionCheck) IfNotExists() *ConditionCheck

IfNotExists sets this check to succeed if the item does not exist.

func (*ConditionCheck) Range added in v1.1.0 

func (check *ConditionCheck) Range(rangeKey string, value interface{}) *ConditionCheck

Range specifies the name and value of the range key for this item.

type ConsumedCapacity 

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.
	LSI map[string]float64
	// Table is the amount of throughput consumed by the table.
	Table float64
	// TableName is the name of the table affected by this operation.
	TableName string
}

ConsumedCapacity represents the amount of throughput capacity consumed during an operation.

type CreateTable 

type CreateTable struct {
	// contains filtered or unexported fields
}

CreateTable is a request to create a new table. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_CreateTable.html

func (*CreateTable) Index 

func (ct *CreateTable) Index(index Index) *CreateTable

Index specifies an index to add to this table.

func (*CreateTable) OnDemand added in v1.2.0 

func (ct *CreateTable) OnDemand(enabled bool) *CreateTable

OnDemand specifies to create the table with on-demand (pay per request) billing mode, if enabled. On-demand mode is disabled by default.

func (*CreateTable) Project 

func (ct *CreateTable) Project(index string, projection IndexProjection, includeAttribs ...string) *CreateTable

Project specifies the projection type for the given table. When using IncludeProjection, you must specify the additional attributes to include via includeAttribs.

func (*CreateTable) Provision 

func (ct *CreateTable) Provision(readUnits, writeUnits int64) *CreateTable

Provision specifies the provisioned read and write capacity for this table. If Provision isn't called and on-demand mode is disabled, the table will be created with 1 unit each.

func (*CreateTable) ProvisionIndex 

func (ct *CreateTable) ProvisionIndex(index string, readUnits, writeUnits int64) *CreateTable

ProvisionIndex specifies the provisioned read and write capacity for the given global secondary index. Local secondary indices share their capacity with the table.

func (*CreateTable) Run 

func (ct *CreateTable) Run() error

Run creates this table or returns and error.

func (*CreateTable) RunWithContext 

func (ct *CreateTable) RunWithContext(ctx aws.Context) error

func (*CreateTable) Stream 

func (ct *CreateTable) Stream(view StreamView) *CreateTable

Stream enables DynamoDB Streams for this table which the specified type of view. Streams are disabled by default.

type DB 

type DB struct {
	// contains filtered or unexported fields
}

DB is a DynamoDB client.

func New 

func New(p client.ConfigProvider, cfgs ...*aws.Config) *DB

New creates a new client with the given configuration.

func NewFromIface 

func NewFromIface(client dynamodbiface.DynamoDBAPI) *DB

NewFromIface creates a new client with the given interface.

func (*DB) Client 

func (db *DB) Client() dynamodbiface.DynamoDBAPI

Client returns this DB's internal client used to make API requests.

func (*DB) CreateTable 

func (db *DB) CreateTable(name string, from interface{}) *CreateTable

CreateTable begins a new operation to create a table with the given name. The second parameter must be a struct with appropriate hash and range key struct tags for the primary key and all indices.

An example of a from struct follows: 

type UserAction struct {
	UserID string    `dynamo:"ID,hash" index:"Seq-ID-index,range"`
	Time   time.Time `dynamo:",range"`
	Seq    int64     `localIndex:"ID-Seq-index,range" index:"Seq-ID-index,hash"`
	UUID   string    `index:"UUID-index,hash"`
}

This creates a table with the primary hash key ID and range key Time. It creates two global secondary indices called UUID-index and Seq-ID-index, and a local secondary index called ID-Seq-index.

func (*DB) GetTx added in v1.1.0 

func (db *DB) GetTx() *GetTx

GetTx begins a new get transaction.

func (*DB) ListTables 

func (db *DB) ListTables() *ListTables

ListTables begins a new request to list all tables.

func (*DB) Table 

func (db *DB) Table(name string) Table

Table returns a Table handle specified by name.

func (*DB) WriteTx added in v1.1.0 

func (db *DB) WriteTx() *WriteTx

WriteTx begins a new write transaction.

type Delete 

type Delete struct {
	// contains filtered or unexported fields
}

Delete is a request to delete an item. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_DeleteItem.html

func (*Delete) ConsumedCapacity 

func (d *Delete) ConsumedCapacity(cc *ConsumedCapacity) *Delete

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*Delete) If 

func (d *Delete) If(expr string, args ...interface{}) *Delete

If specifies a conditional expression for this delete 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. Multiple calls to If will be combined with AND.

func (*Delete) OldValue 

func (d *Delete) OldValue(out interface{}) error

OldValue executes this delete request, unmarshaling the previous value to out. Returns ErrNotFound is there was no previous value.

func (*Delete) OldValueWithContext 

func (d *Delete) OldValueWithContext(ctx aws.Context, out interface{}) error

func (*Delete) Range 

func (d *Delete) Range(name string, value interface{}) *Delete

Range specifies the range key (a.k.a. sort key) to delete. Name is the name of the range key. Value is the value of the range key.

func (*Delete) Run 

func (d *Delete) Run() error

Run executes this delete request.

func (*Delete) RunWithContext 

func (d *Delete) RunWithContext(ctx aws.Context) error

type DeleteTable 

type DeleteTable struct {
	// contains filtered or unexported fields
}

DeleteTable is a request to delete a table. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_DeleteTable.html

func (*DeleteTable) Run 

func (dt *DeleteTable) Run() error

Run executes this request and deletes the table.

func (*DeleteTable) RunWithContext 

func (dt *DeleteTable) RunWithContext(ctx aws.Context) error

RunWithContext executes this request and deletes the table.

type DescribeTable 

type DescribeTable struct {
	// contains filtered or unexported fields
}

DescribeTable is a request for information about a table and its indexes. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_DescribeTable.html

func (*DescribeTable) Run 

func (dt *DescribeTable) Run() (Description, error)

Run executes this request and describe the table.

func (*DescribeTable) RunWithContext 

func (dt *DescribeTable) RunWithContext(ctx aws.Context) (Description, error)

type Description 

type Description struct {
	Name    string
	ARN     string
	Status  Status
	Created time.Time

	// Attribute name of the hash key (a.k.a. partition key).
	HashKey     string
	HashKeyType KeyType
	// Attribute name of the range key (a.k.a. sort key) or blank if nonexistant.
	RangeKey     string
	RangeKeyType KeyType

	// Provisioned throughput for this table.
	Throughput Throughput
	// OnDemand is true if on-demand (pay per request) billing mode is enabled.
	OnDemand bool

	// The number of items of the table, updated every 6 hours.
	Items int64
	// The size of this table in bytes, updated every 6 hours.
	Size int64

	// Global secondary indexes.
	GSI []Index
	// Local secondary indexes.
	LSI []Index

	StreamEnabled     bool
	StreamView        StreamView
	LatestStreamARN   string
	LatestStreamLabel string
}

Description contains information about a table.

func (Description) Active 

func (d Description) Active() bool

type GetTx added in v1.1.0 

type GetTx struct {
	// contains filtered or unexported fields
}

GetTx is a transaction to retrieve items. It can contain up to 10 operations and works across multiple tables. GetTx is analogous to TransactGetItems in DynamoDB's API. See: https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_TransactGetItems.html

func (*GetTx) All added in v1.1.0 

func (tx *GetTx) All(out interface{}) error

All executes this transaction and unmarshals every value to out, which must be a pointer to a slice.

func (*GetTx) AllWithContext added in v1.1.0 

func (tx *GetTx) AllWithContext(ctx aws.Context, out interface{}) error

AllWithContext executes this transaction and unmarshals every value to out, which must be a pointer to a slice.

func (*GetTx) ConsumedCapacity added in v1.1.0 

func (tx *GetTx) ConsumedCapacity(cc *ConsumedCapacity) *GetTx

ConsumedCapacity will measure the throughput capacity consumed by this transaction and add it to cc.

func (*GetTx) Get added in v1.1.0 

func (tx *GetTx) Get(q *Query) *GetTx

Get adds a get request to this transaction.

func (*GetTx) GetOne added in v1.1.0 

func (tx *GetTx) GetOne(q *Query, out interface{}) *GetTx

GetOne adds a get request to this transaction, and specifies out to which the results are marshaled. Out must be a pointer. You can use this multiple times in one transaction.

func (*GetTx) Run added in v1.1.0 

func (tx *GetTx) Run() error

Run executes this transaction and unmarshals everything specified by GetOne.

func (*GetTx) RunWithContext added in v1.1.0 

func (tx *GetTx) RunWithContext(ctx aws.Context) error

RunWithContext executes this transaction and unmarshals everything specified by GetOne.

type Index 

type Index struct {
	Name        string
	ARN         string
	Status      Status
	Backfilling bool // only for GSI

	// Local is true when this index is a local secondary index, otherwise it is a global secondary index.
	Local bool

	// Attribute name of the hash key (a.k.a. partition key).
	HashKey     string
	HashKeyType KeyType
	// Attribute name of the range key (a.k.a. sort key) or blank if nonexistant.
	RangeKey     string
	RangeKeyType KeyType

	// The provisioned throughput for this index.
	Throughput Throughput

	Items int64
	Size  int64

	ProjectionType IndexProjection
	// Non-key attributes for this index's projection (if ProjectionType is IncludeProjection).
	ProjectionAttribs []string
}

type IndexProjection 

type IndexProjection string

IndexProjection determines which attributes are mirrored into indices. 

var (
	// Only the key attributes of the modified item are written to the stream.
	KeysOnlyProjection IndexProjection = dynamodb.ProjectionTypeKeysOnly
	// All of the table attributes are projected into the index.
	AllProjection IndexProjection = dynamodb.ProjectionTypeAll
	// Only the specified table attributes are projected into the index.
	IncludeProjection IndexProjection = dynamodb.ProjectionTypeInclude
)

type Iter 

type Iter interface {
	// Next tries to unmarshal the next result into out.
	// Returns false when it is complete or if it runs into an error.
	Next(out interface{}) bool
	// NextWithContext tries to unmarshal the next result into out.
	// Returns false when it is complete or if it runs into an error.
	NextWithContext(ctx aws.Context, out interface{}) bool
	// Err returns the error encountered, if any.
	// You should check this after Next is finished.
	Err() error
}

Iter is an iterator for request results.

type KeyType 

type KeyType string

KeyType is used to specify the type of hash and range keys for tables and indexes.

type Keyed 

type Keyed interface {
	HashKey() interface{}
	RangeKey() interface{}
}

Keyed provides hash key and range key values.

type Keys 

type Keys [2]interface{}

Keys provides an easy way to specify the hash and range keys. 

table.Batch("ID", "Month").
	Get([]dynamo.Keys{{1, "2015-10"}, {42, "2015-12"}, {42, "1992-02"}}...).
	All(&results)

func (Keys) HashKey 

func (k Keys) HashKey() interface{}

HashKey returns the hash key's value.

func (Keys) RangeKey 

func (k Keys) RangeKey() interface{}

RangeKey returns the range key's value.

type ListTables 

type ListTables struct {
	// contains filtered or unexported fields
}

ListTables is a request to list tables. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_ListTables.html

func (*ListTables) All 

func (lt *ListTables) All() ([]string, error)

All returns every table or an error.

func (*ListTables) AllWithContext 

func (lt *ListTables) AllWithContext(ctx aws.Context) ([]string, error)

AllWithContext returns every table or an error.

func (*ListTables) Iter 

func (lt *ListTables) Iter() Iter

Iter returns an iterator of table names. This iterator's Next functions will only accept type *string as their out parameter.

type Marshaler 

type Marshaler interface {
	MarshalDynamo() (*dynamodb.AttributeValue, error)
}

Marshaler is the interface implemented by objects that can marshal themselves into an AttributeValue.

type Operator 

type Operator string

Operator is an operation to apply in key comparisons.

type Order 

type Order bool

Order is used for specifying the order of results. 

const (
	Ascending  Order = true  // ScanIndexForward = true
	Descending       = false // ScanIndexForward = false
)

Orders for sorting results.

type PagingIter 

type PagingIter interface {
	Iter
	// LastEvaluatedKey returns a key that can be passed to StartFrom in Query or Scan.
	// Combined with SearchLimit, it is useful for paginating partial results.
	LastEvaluatedKey() PagingKey
}

PagingIter is an iterator of request results that can also return a key used for splitting results.

type PagingKey 

type PagingKey map[string]*dynamodb.AttributeValue

PagingKey is a key used for splitting up partial results. Get a PagingKey from a PagingIter and pass it to StartFrom in Query or Scan.

type Put 

type Put struct {
	// contains filtered or unexported fields
}

Put is a request to create or replace an item. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_PutItem.html

func (*Put) ConsumedCapacity 

func (p *Put) ConsumedCapacity(cc *ConsumedCapacity) *Put

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*Put) If 

func (p *Put) If(expr string, args ...interface{}) *Put

If specifies a conditional expression for this put 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. Multiple calls to If will be combined with AND.

func (*Put) OldValue 

func (p *Put) OldValue(out interface{}) error

OldValue executes this put, unmarshaling the previous value into out. Returns ErrNotFound is there was no previous value.

func (*Put) OldValueWithContext 

func (p *Put) OldValueWithContext(ctx aws.Context, out interface{}) error

OldValueWithContext executes this put, unmarshaling the previous value into out. Returns ErrNotFound is there was no previous value.

func (*Put) Run 

func (p *Put) Run() error

Run executes this put.

func (*Put) RunWithContext 

func (p *Put) RunWithContext(ctx aws.Context) error

Run executes this put.

type Query 

type Query struct {
	// contains filtered or unexported fields
}

Query is a request to get one or more items in a table. Query uses the DynamoDB query for requests for multiple items, and GetItem for one. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Query.html and http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_GetItem.html

func (*Query) All 

func (q *Query) All(out interface{}) error

All executes this request and unmarshals all results to out, which must be a pointer to a slice.

func (*Query) AllWithContext 

func (q *Query) AllWithContext(ctx aws.Context, out interface{}) error

func (*Query) AllWithLastEvaluatedKey 

func (q *Query) AllWithLastEvaluatedKey(out interface{}) (PagingKey, error)

AllWithLastEvaluatedKey executes this request and unmarshals all results to out, which must be a pointer to a slice. This returns a PagingKey you can use with StartFrom to split up results.

func (*Query) AllWithLastEvaluatedKeyContext 

func (q *Query) AllWithLastEvaluatedKeyContext(ctx aws.Context, out interface{}) (PagingKey, error)

func (*Query) Consistent 

func (q *Query) Consistent(on bool) *Query

Consistent will, if on is true, make this query a strongly consistent read. Queries are eventually consistent by default. Strongly consistent reads are more resource-heavy than eventually consistent reads.

func (*Query) ConsumedCapacity 

func (q *Query) ConsumedCapacity(cc *ConsumedCapacity) *Query

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*Query) Count 

func (q *Query) Count() (int64, error)

Count executes this request, returning the number of results.

func (*Query) CountWithContext 

func (q *Query) CountWithContext(ctx aws.Context) (int64, error)

func (*Query) Filter 

func (q *Query) Filter(expr string, args ...interface{}) *Query

Filter takes an expression that all results will be evaluated against. 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. Multiple calls to Filter will be combined with AND.

func (*Query) Index 

func (q *Query) Index(name string) *Query

Index specifies the name of the index that this query will operate on.

func (*Query) Iter 

func (q *Query) Iter() PagingIter

Iter returns a results iterator for this request.

func (*Query) Limit 

func (q *Query) Limit(limit int64) *Query

Limit specifies the maximum amount of results to return.

func (*Query) One 

func (q *Query) One(out interface{}) error

One executes this query and retrieves a single result, unmarshaling the result to out.

func (*Query) OneWithContext 

func (q *Query) OneWithContext(ctx aws.Context, out interface{}) error

func (*Query) Order 

func (q *Query) Order(order Order) *Query

Order specifies the desired result order. Requires a range key (a.k.a. partition key) to be specified.

func (*Query) Project 

func (q *Query) Project(paths ...string) *Query

Project limits the result attributes to the given paths.

func (*Query) ProjectExpr 

func (q *Query) ProjectExpr(expr string, args ...interface{}) *Query

ProjectExpr limits the result attributes to the given expression. 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 (*Query) Range 

func (q *Query) Range(name string, op Operator, values ...interface{}) *Query

Range specifies the range key (a.k.a. sort key) or keys to get. For single item requests using One, op must be Equal. Name is the name of the range key. Op specifies the operator to use when comparing values.

func (*Query) SearchLimit 

func (q *Query) SearchLimit(limit int64) *Query

SearchLimit specifies the maximum amount of results to examine. If a filter is not specified, the number of results will be limited. If a filter is specified, the number of results to consider for filtering will be limited.

func (*Query) StartFrom 

func (q *Query) StartFrom(key PagingKey) *Query

StartFrom makes this query continue from a previous one. Use Query.Iter's LastEvaluatedKey.

type Scan 

type Scan struct {
	// contains filtered or unexported fields
}

Scan is a request to scan all the data in a table. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Scan.html

func (*Scan) All 

func (s *Scan) All(out interface{}) error

All executes this request and unmarshals all results to out, which must be a pointer to a slice.

func (*Scan) AllWithContext 

func (s *Scan) AllWithContext(ctx aws.Context, out interface{}) error

AllWithContext executes this request and unmarshals all results to out, which must be a pointer to a slice.

func (*Scan) AllWithLastEvaluatedKey 

func (s *Scan) AllWithLastEvaluatedKey(out interface{}) (PagingKey, error)

AllWithLastEvaluatedKey executes this request and unmarshals all results to out, which must be a pointer to a slice. It returns a key you can use with StartWith to continue this query.

func (*Scan) AllWithLastEvaluatedKeyContext 

func (s *Scan) AllWithLastEvaluatedKeyContext(ctx aws.Context, out interface{}) (PagingKey, error)

AllWithLastEvaluatedKeyContext executes this request and unmarshals all results to out, which must be a pointer to a slice. It returns a key you can use with StartWith to continue this query.

func (*Scan) Consistent 

func (s *Scan) Consistent(on bool) *Scan

Consistent will, if on is true, make this scan use a strongly consistent read. Scans are eventually consistent by default. Strongly consistent reads are more resource-heavy than eventually consistent reads.

func (*Scan) ConsumedCapacity 

func (s *Scan) ConsumedCapacity(cc *ConsumedCapacity) *Scan

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*Scan) Filter 

func (s *Scan) Filter(expr string, args ...interface{}) *Scan

Filter takes an expression that all results will be evaluated against. 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. Multiple calls to Filter will be combined with AND.

func (*Scan) Index 

func (s *Scan) Index(name string) *Scan

Index specifies the name of the index that Scan will operate on.

func (*Scan) Iter 

func (s *Scan) Iter() PagingIter

Iter returns a results iterator for this request.

func (*Scan) Limit 

func (s *Scan) Limit(limit int64) *Scan

Limit specifies the maximum amount of results to return.

func (*Scan) Project 

func (s *Scan) Project(paths ...string) *Scan

Project limits the result attributes to the given paths.

func (*Scan) SearchLimit 

func (s *Scan) SearchLimit(limit int64) *Scan

SearchLimit specifies a maximum amount of results to evaluate. Use this along with StartFrom and Iter's LastEvaluatedKey to split up results. Note that DynamoDB limits result sets to 1MB.

func (*Scan) StartFrom 

func (s *Scan) StartFrom(key PagingKey) *Scan

StartFrom makes this scan continue from a previous one. Use Scan.Iter's LastEvaluatedKey.

type Status 

type Status string

Status is an enumeration of table and index statuses.

type StreamView 

type StreamView string

StreamView determines what information is written to a table's stream. 

var (
	// Only the key attributes of the modified item are written to the stream.
	KeysOnlyView StreamView = dynamodb.StreamViewTypeKeysOnly
	// The entire item, as it appears after it was modified, is written to the stream.
	NewImageView StreamView = dynamodb.StreamViewTypeNewImage
	// The entire item, as it appeared before it was modified, is written to the stream.
	OldImageView StreamView = dynamodb.StreamViewTypeOldImage
	// Both the new and the old item images of the item are written to the stream.
	NewAndOldImagesView StreamView = dynamodb.StreamViewTypeNewAndOldImages
)

type Table 

type Table struct {
	// contains filtered or unexported fields
}

Table is a DynamoDB table.

func (Table) Batch 

func (table Table) Batch(hashAndRangeKeyName ...string) Batch

Batch creates a new batch with the given hash key name, and range key name if provided. For purely Put batches, neither is necessary.

func (Table) Check added in v1.1.0 

func (table Table) Check(hashKey string, value interface{}) *ConditionCheck

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) Delete 

func (table Table) Delete(name string, value interface{}) *Delete

Delete creates a new request to delete an item. Key is the name of the hash key (a.k.a. partition key). Value is the value of the hash key.

func (Table) DeleteTable 

func (table Table) DeleteTable() *DeleteTable

DeleteTable begins a new request to delete this table.

func (Table) Describe 

func (table Table) Describe() *DescribeTable

Describe begins a new request to describe this table.

func (Table) Get 

func (table Table) Get(name string, value interface{}) *Query

Get creates a new request to get an item. Name is the name of the hash key (a.k.a. partition key). Value is the value of the hash key.

func (Table) Name 

func (table Table) Name() string

Name returns this table's name.

func (Table) Put 

func (table Table) Put(item interface{}) *Put

Put creates a new request to create or replace an item.

func (Table) Scan 

func (table Table) Scan() *Scan

Scan creates a new request to scan this table.

func (Table) Update 

func (table Table) Update(hashKey string, value interface{}) *Update

Update creates a new request to modify an existing item.

func (Table) UpdateTable 

func (table Table) UpdateTable() *UpdateTable

UpdateTable makes changes to this table's settings.

type Throughput 

type Throughput struct {
	// Read capacity units.
	Read int64
	// Write capacity units.
	Write int64

	// Time at which throughput was last increased for this table.
	LastInc time.Time
	// Time at which throughput was last decreased for this table.
	LastDec time.Time
	// The number of throughput decreases in this UTC calendar day.
	DecsToday int64
}

type Unmarshaler 

type Unmarshaler interface {
	UnmarshalDynamo(av *dynamodb.AttributeValue) error
}

Unmarshaler is the interface implemented by objects that can unmarshal an AttributeValue into themselves.

type Update 

type Update struct {
	// contains filtered or unexported fields
}

Update represents changes to an existing item. It uses the UpdateItem API. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_UpdateItem.html

func (*Update) Add 

func (u *Update) Add(path string, value interface{}) *Update

Add adds value to path. Path can be a number or a set. If path represents a number, value is atomically added to the number. If path represents a set, value must be a slice, a map[*]struct{}, or map[*]bool. Path must be a top-level attribute.

func (*Update) AddFloatsToSet 

func (u *Update) AddFloatsToSet(path string, values ...float64) *Update

AddFloatsToSet adds the given values to the number set specified by path.

func (*Update) AddIntsToSet 

func (u *Update) AddIntsToSet(path string, values ...int) *Update

AddIntsToSet adds the given values to the number set specified by path.

func (*Update) AddStringsToSet 

func (u *Update) AddStringsToSet(path string, values ...string) *Update

AddStringsToSet adds the given values to the string set specified by path.

func (*Update) Append 

func (u *Update) Append(path string, value interface{}) *Update

Append appends value to the end of the list specified by path.

func (*Update) ConsumedCapacity 

func (u *Update) ConsumedCapacity(cc *ConsumedCapacity) *Update

ConsumedCapacity will measure the throughput capacity consumed by this operation and add it to cc.

func (*Update) DeleteFloatsFromSet 

func (u *Update) DeleteFloatsFromSet(path string, values ...float64) *Update

DeleteFloatsFromSet deletes the given values from the number set specified by path.

func (*Update) DeleteIntsFromSet 

func (u *Update) DeleteIntsFromSet(path string, values ...int) *Update

DeleteIntsFromSet deletes the given values from the number set specified by path.

func (*Update) DeleteStringsFromSet 

func (u *Update) DeleteStringsFromSet(path string, values ...string) *Update

DeleteStringsFromSet deletes the given values from the string set specified by path.

func (*Update) If 

func (u *Update) If(expr string, args ...interface{}) *Update

If specifies a conditional expression for this update 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. Multiple calls to Update will be combined with AND.

func (*Update) OldValue 

func (u *Update) OldValue(out interface{}) error

OldValue executes this update, encoding out with the previous value.

func (*Update) OldValueWithContext 

func (u *Update) OldValueWithContext(ctx aws.Context, out interface{}) error

func (*Update) Prepend 

func (u *Update) Prepend(path string, value interface{}) *Update

Prepend inserts value to the beginning of the list specified by path.

func (*Update) Range 

func (u *Update) Range(name string, value interface{}) *Update

Range specifies the range key (sort key) for the item to update.

func (*Update) Remove 

func (u *Update) Remove(paths ...string) *Update

Remove removes the paths from this item, deleting the specified attributes.

func (*Update) RemoveExpr 

func (u *Update) RemoveExpr(expr string, args ...interface{}) *Update

RemoveExpr performs a custom remove expression, substituting the args into expr as in filter expressions. 

RemoveExpr("MyList[$]", 5)

func (*Update) Run 

func (u *Update) Run() error

Run executes this update.

func (*Update) RunWithContext 

func (u *Update) RunWithContext(ctx aws.Context) error

func (*Update) Set 

func (u *Update) Set(path string, value interface{}) *Update

Set changes path to the given value. If value is an empty string or nil, path will be removed instead. Paths that are reserved words are automatically escaped. Use single quotes to escape complex values like 'User'.'Count'.

func (*Update) SetExpr 

func (u *Update) SetExpr(expr string, args ...interface{}) *Update

SetExpr performs a custom set expression, substituting the args into expr as in filter expressions. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_UpdateItem.html#DDB-UpdateItem-request-UpdateExpression 

SetExpr("MyMap.$.$ = ?", key1, key2, val)
SetExpr("'Counter' = 'Counter' + ?", 1)

func (*Update) SetIfNotExists 

func (u *Update) SetIfNotExists(path string, value interface{}) *Update

SetIfNotExists changes path to the given value, if it does not already exist.

func (*Update) SetSet 

func (u *Update) SetSet(path string, value interface{}) *Update

SetSet changes a set at the given path to the given value. SetSet marshals value to a string set, number set, or binary set. If value is of zero length or nil, path will be removed instead. Paths that are reserved words are automatically escaped. Use single quotes to escape complex values like 'User'.'Count'.

func (*Update) Value 

func (u *Update) Value(out interface{}) error

Value executes this update, encoding out with the new value.

func (*Update) ValueWithContext 

func (u *Update) ValueWithContext(ctx aws.Context, out interface{}) error

type UpdateTable 

type UpdateTable struct {
	// contains filtered or unexported fields
}

UpdateTable is a request to change a table's settings. See: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_UpdateTable.html

func (*UpdateTable) CreateIndex 

func (ut *UpdateTable) CreateIndex(index Index) *UpdateTable

CreateIndex adds a new secondary global index. You must specify the index name, keys, key types, projection. If this table is not on-demand you must also specify throughput.

func (*UpdateTable) DeleteIndex 

func (ut *UpdateTable) DeleteIndex(name string) *UpdateTable

DeleteIndex deletes the specified index.

func (*UpdateTable) DisableStream 

func (ut *UpdateTable) DisableStream() *UpdateTable

DisableStream disables this table's stream.

func (*UpdateTable) OnDemand added in v1.2.0 

func (ut *UpdateTable) OnDemand(enabled bool) *UpdateTable

OnDemand sets this table to use on-demand (pay per request) billing mode if enabled is true. If enabled is false, this table will be changed to provisioned billing mode.

func (*UpdateTable) Provision 

func (ut *UpdateTable) Provision(read, write int64) *UpdateTable

Provision sets this table's read and write throughput capacity.

func (*UpdateTable) ProvisionIndex 

func (ut *UpdateTable) ProvisionIndex(name string, read, write int64) *UpdateTable

ProvisionIndex updates a global secondary index's read and write throughput capacity.

func (*UpdateTable) Run 

func (ut *UpdateTable) Run() (Description, error)

Run executes this request and describes the table.

func (*UpdateTable) RunWithContext 

func (ut *UpdateTable) RunWithContext(ctx aws.Context) (Description, error)

func (*UpdateTable) Stream 

func (ut *UpdateTable) Stream(view StreamView) *UpdateTable

Stream enables streaming and sets the stream view type.

type WriteTx added in v1.1.0 

type WriteTx struct {
	// contains filtered or unexported fields
}

WriteTx is a transaction to delete, put, update, and check items. It can contain up to 10 operations and works across multiple tables. Two operations cannot target the same item. WriteTx is analogous to TransactWriteItems in DynamoDB's API. See: https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_TransactWriteItems.html

func (*WriteTx) Check added in v1.1.0 

func (tx *WriteTx) Check(check *ConditionCheck) *WriteTx

Check adds a conditional check to this transaction.

func (*WriteTx) ConsumedCapacity added in v1.1.0 

func (tx *WriteTx) ConsumedCapacity(cc *ConsumedCapacity) *WriteTx

ConsumedCapacity will measure the throughput capacity consumed by this transaction and add it to cc.

func (*WriteTx) Delete added in v1.1.0 

func (tx *WriteTx) Delete(d *Delete) *WriteTx

Delete adds a new delete operation to this transaction.

func (*WriteTx) Idempotent added in v1.1.0 

func (tx *WriteTx) Idempotent(enabled bool) *WriteTx

Idempotent marks this transaction is idempotent when enabled is true. An idempotent transaction ran multiple times will have the same effect as being ran once. An idempotent request is only good for 10 minutes, after that it will be considered a new request.

func (*WriteTx) Put added in v1.1.0 

func (tx *WriteTx) Put(p *Put) *WriteTx

Put adds a put operation to this transaction.

func (*WriteTx) Run added in v1.1.0 

func (tx *WriteTx) Run() error

Run executes this transaction.

func (*WriteTx) RunWithContext added in v1.1.0 

func (tx *WriteTx) RunWithContext(ctx aws.Context) error

RunWithContext executes this transaction.

func (*WriteTx) Update added in v1.1.0 

func (tx *WriteTx) Update(u *Update) *WriteTx

Update adds an update operation to this transaction.

Source Files

View all Source files

Directories

Path Synopsis
internal
exprs
Package exprs is the internal package for parsing DynamoDB "expressions", including condition expressions and filter expressions.
 Package exprs is the internal package for parsing DynamoDB "expressions", including condition expressions and filter expressions.

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