Awesome
Riaken Struct
High level struct wrapper for riaken-core.
It provides the ability to pass structs in and out of Riak as other formats such as JSON, XML, etc.
Install
go get gopkg.in/riaken/riaken-struct.v1
Documentation
http://godoc.org/gopkg.in/riaken/riaken-struct.v1
The following methods being wrapped for struct usage are:
- Object->Fetch
- Object->Store
- Query->SecondaryIndexes
- Query->Search
The rest of the underlying riaken-core API is exposed as normal.
Usage
Client
Not much different from riaken-core, with the exception of passing a marshaller.
package main
import "log"
import "github.com/riaken/riaken-struct"
func main() {
// Marshaller
marshaller := NewStructMarshal("json", JsonMarshaller, JsonUnmarshaller)
// Riak cluster addresses
addrs := []string{"127.0.0.1:8083", "127.0.0.1:8084", "127.0.0.1:8085", "127.0.0.1:8086", "127.0.0.1:8087"}
// Create a client, passing the addresses, and number of connections to maintain per cluster node
client := riaken_struct.NewClient(addrs, 1, marshaller)
// Dial the servers
if err := client.Dial(); err != nil {
log.Fatal(err.Error()) // all nodes are down
}
// Gracefully close all the connections when finished
defer client.Close()
// Grab a session to interact with the cluster
session := client.Session()
// Release the session
defer session.Release()
}
The marshaller allows structs with tag data to be parsed to and from their target format, in this case JSON. If a format other than JSON is desired consider using struct_marshall.go as a guideline.
Note that all methods can utilize the same Do() construct as riaken-core.
Object
Standard struct data.
type User struct {
Name string `json:"name"`
}
Store
user := &User{
Name: "User",
}
bucket := session.GetBucket("b1")
object := bucket.Object("o1")
if _, err := object.Store(user); err != nil {
log.Error(err.Error())
}
Fetch
check := User{}
if _, err := object.Fetch(&check); err != nil {
log.Error(err.Error())
}
log.Print(check.Name) // User
Query
Since we are querying out fields where we don't know the keys, there are a few things to note.
type Animal struct {
Id string
Name string `json:"name" riak:"index"`
}
Idis arbitrarily named, but necessary. It will contain the key from the server.riak:"index"allows us to specify this member as a queryable 2i index.
Note that each method below chains with Key() and Out(). The first specifies the struct member in which to place the key, the second the struct slice to output results to.
These can potentially run the application out of memory, so use with care. As opposed to their lower level riaken-core counterparts they actively fetch the object for every key found as well (without duplicates). If lower level behavior is desired through this driver consider calling session.Query().CoreQuery() and manually fetching objects as required.
Secondary Indexes
var check []Animal
query := session.Query()
if _, err := query.Key("Id").Out(&check).SecondaryIndexes([]byte("animals"), []byte("name_bin"), []byte("chicken"), nil, nil, 0, nil); err != nil {
log.Error(err.Error())
}
Search
var animals []Animal
query := session.Query()
if _, err := query.Key("Id").Out(&animals).Search([]byte("animals"), []byte("name:pig OR name:dog")); err != nil {
log.Error(err.Error())
}
Author
Brian Jones - mojobojo@gmail.com - https://twitter.com/mojobojo