goriak

Current version: v3.2.1.
Riak KV version: 2.0 or higher, the latest version of Riak KV is always recommended.

What is goriak?

goriak is a wrapper around riak-go-client (version 1.9.0 or newer is required) to make it easier and more friendly for developers to use Riak KV.

• Documentation

Installation

As a Go module (requires Go 1.11 or later):

go get github.com/zegl/goriak/[email protected]

As a Go package:

go get -u gopkg.in/zegl/goriak.v3

Maps (Riak Data Types)

The main feature of goriak is that goriak automatically can marshal/unmarshal your Go types into Riak data types.

Set (Riak Data Types)

In the example below Name will be saved as a register, and Aliases will be a set.

type User struct {
    Name    string
    Aliases []string
}

user := User {
    Name:   "Foo",
    Alises: []string{"Foo", "Bar"},
}

goriak.Bucket("bucket-name", "bucket-type").Set(user).Key("key").Run(c)

Tags

Struct tags can be used to change the name of the item, or to ignore it.

type User struct {
    Name    string   `goriak:"-"`       // Ignore field
    Aliases []string `goriak:"aliases"` // Save as "aliases" in Riak KV
}

Get (Riak Data Types)

The map can later be retreived as a whole:

var res User
goriak.Bucket("bucket-name", "bucket-type").Get("key", &res).Run(c)

Supported Go types

Go Type	Riak Type
struct	map
string	register
[n]byte	register
[]byte	register
[]slice	set
[]slice	set
[][]byte	set
map	map
time.Time	register
int [1]	register

1: All signed and unsigned integer types are supported.

Golang map types

Supported key types: all integer types, string.
Supported value types: string, []byte.

Helper types

Some actions are more complicated then necessary with the use of the default Go types and MapOperations.

This is why goriak contains the types Counter, Set, Flag and Register. All of these types will help you performing actions such as incrementing a value, or adding/removing items.

Counters

Riak Counters is supported with the special goriak.Counter type.

Example:

type Article struct {
    Title string
    Views *goriak.Counter
}

// Get our object
var article Article
goriak.Bucket("articles", "map").Get("1-hello-world", &article).Run(con)

// Increase views by 1
err := article.Views.Increase(1).Exec(con)

// check err

Counter.Exec(con) will make a lightweight request to Riak, and the counter is the only object that will be updated.

You can also save the changes to your counter with SetMap(), this is useful if you want to change multiple counters at the same time.

Check godoc for more information.

Sets

You can chose to use goriak.Set to help you with Set related actions, such as adding and removing items. goriak.Set also has support for sending incremental actions to Riak so that you don't have to build that functionality yourself.

Example:

type Article struct {
    Title string
    Tags *goriak.Set
}

// Get our object
var article Article
goriak.Bucket("articles", "map").Get("1-hello-world", &article).Run(con)

// Add the tag "animals"
err := article.Tags.AddString("animals").Exec(con)

// check err

Check godoc for more information.

Values

Values can be automatically JSON Marshalled/Unmarshalled by using SetJSON() and GetJSON(). There is also SetRaw() and GetRaw() that works directly on []bytes.

JSON

// Set object
goriak.Bucket("bucket-name", "bucket-type").SetJSON(obj).Key("key").Run(con)

// Get object
goriak.Bucket("bucket-name", "bucket-type").GetJSON("key", &obj).Run(con)

MapOperation

There is a time in everyones life where you need to perform raw MapOperations on your Riak Data Values.

Some operations, such as RemoveFromSet requires a Context to perform the operation. A Context can be retreived from Get by setting a special context type.

type ourType struct {
    Aliases []string

    // The context from Riak will be added if the tag goriakcontext is provided
    Context []byte `goriak:"goriakcontext"`
}

// ... GetMap()

// Works with MapOperation from github.com/basho/riak-go-client
operation := goriak.NewMapOperation()
operation.AddToSet("Aliases", []byte("Baz"))

goriak.MapOperation("bucket-name", "bucket-type", "key", operation, val.Context)

Secondary Indexes

You can set secondary indexes automatically with SetJSON() by using struct tags.

Strings and all signed integer types are supported. Both as-is and in slices.

type User struct {
    Name    string `goriakindex:"nameindex_bin"`
    Aliases []string
}

Indexes can also be used in slices. If you are using a slice every value in the slice will be added to the index.

type User struct {
    Aliases []string `goriakindex:"aliasesindex_bin"`
}

When saved the next time the index will be updated.

KeysInIndex

Keys in a particular index can be retreived with KeysInIndex.

callback := func(item goriak.SecondaryIndexQueryResult) {
    // use item
}

goriak.Bucket("bucket-name", "bucket-type").
    KeysInIndex("nameindex_bin", "Value", callback).
    Run(con)

AddToIndex

An alternative way of setting Secondary Indexes is by using AddToIndex().

goriak.Bucket("bucket-name", "bucket-type").
    SetRaw(data).
    AddToIndex("indexname_bin", "value").
    Run(con)