README
¶
go-blobqueue
About
Blobqueue provides an interface used to manipulate a queue of objects marshalled into []byte (the blob part).
Two implementations are provided:
blobqueue/memory: a pure go native implementation based on a[][]byteblobqueue/redisqueue: an implementation using a Redis list. (using Redis client go-redis/redis)
Getting started
1. Memory
This example shows how to create a basic and safe memory queue. A safe queue wraps another one to properly handles locks.
import (
"fmt"
"github.com/blueboardio/go-blobqueue"
"github.com/blueboardio/go-blobqueue/memory"
)
func getStarted() {
// unsafeQueue implements Queue so you could use it as it is, but it's not safe against race conditions.
unsafeQueue := memory.Queue{}
// This queue handles locks properly.
queue := blobqueue.SafeQueue(&unsafeQueue)
}
2. Redis
This example show how to create a Redis based queue.
import (
"fmt"
"github.com/blueboardio/go-blobqueue/queueredis"
"github.com/go-redis/redis"
)
func getStarted() {
client := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
Password: "",
DB: 0,
})
// Instantiate a redis queue storing its data under the key "hello_world_queue"
queue := queueredis.New(client, "hello_world_queue")
}
3. Usage
You can now use theses queues like so:
queue.Push([]byte("world"))
queue.Unshift([]byte("hello"))
list, _ := queue.List()
fmt.Println(list)
// Bytes: [[104 101 108 108 111] [119 111 114 108 100]]
// Strings: ["hello" "world"]
first, _ := queue.Shift()
list, _ = queue.List()
fmt.Println(first, list)
// Bytes: [104 101 108 108 111] [[119 111 114 108 100]]
// Strings: "hello" ["world"]
See GoDoc for all available methods.
Testing
The package blobqueue/queuetesting provides a test suite to validate implementation of bloqueue.Queue.
Running Redis implementation test
Redis implementation depends on a Redis connection, so you'll need to have a working Redis server to pass tests. In order to connect when running tests you'll have to set these environment variables:
| Name | Usage | Example |
|---|---|---|
| TEST_QUEUEREDIS_ADDR | The redis host used to set connection | localhost:6379 |
| TEST_QUEUEREDIS_PWD | The password to use | |
| TEST_QUEUEREDIS_DB | The database index to use | 0 |
Documentation
¶
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrIndexOutOfRange = errors.New("index out of range") ErrQueueIsEmpty = errors.New("empty queue") )
These variables defines typed errors.
Functions ¶
This section is empty.
Types ¶
type Must ¶ added in v0.2.0
type Must struct {
Queue Queue
}
Must wraps a Queue with methods that panic instead of returning error.
Example ¶
q := blobqueue.Must{new(memory.Queue)}
fmt.Println(q.Len())
q.Unshift([]byte("AA"))
q.Push([]byte("BB"))
fmt.Printf("%s\n", q.List())
fmt.Println(q.Len())
fmt.Printf("%s %s\n", q.Pop(), q.Shift())
fmt.Println(q.Len())
Output: 0 [AA BB] 2 BB AA 0
func (Must) Empty ¶ added in v0.2.0
func (q Must) Empty()
Empty transforms errors from Queue.Empty into panic.
type Queue ¶
type Queue interface {
// List returns all the items of the queue as [][]byte.
List() ([][]byte, error)
// Push appends the queue with a new elem (val).
Push(val []byte) error
// Unshift add a new elem at the beggining of the queue.
Unshift(val []byte) error
// Pop deletes the last element of the queue, it returns this precise element.
// If the queue is empty it returns error ErrQueueIsEmpty.
Pop() ([]byte, error)
// Shift deletes the first element of the queue, it returns this precise element.
// If the queue is empty it returns error ErrQueueIsEmpty.
Shift() ([]byte, error)
// Len returns the length of the queue.
Len() (int, error)
// Empty clears the queue.
Empty() error
}
Queue is an interface providing operations to handle queues. All methods may return an error as its implementation may have runtime failures.
Source Files
Directories