dbwriter.go

package main

import (
	"github.com/garyburd/redigo/redis"
)

// DBWriter is an interface for database writers.
type DBWriter interface {
	Writer()
	AddKey(blocking bool, key string, value interface{})
	DeleteKey(blocking bool, key ...string)
	SetAdd(blocking bool, key string, members ...interface{})
	SetRemove(blocking bool, key string, members ...interface{})
	CloseConn()
}

// command consists of a command and arguments to be sent to
// a database with a DBWriter.
type command struct {
	comm string
	args []interface{}
}

// redisWriter is a DBWriter for redis.
type redisWriter struct {
	conn        *redis.Conn
	commChannel chan command
}

// write from redisWriter sends specified commands and arguments
// to the object's communication channel.
func (rw *redisWriter) write(blocking bool, comm string, args ...interface{}) {
	if blocking {
		rw.commChannel <- command{comm: comm, args: args}
	} else {
		select {
		case rw.commChannel <- command{comm: comm, args: args}:
		default:
		}
	}
}

// writer from redisWriter sends commands and arguments from the
// object's communication channel to the redis database.
func (rw *redisWriter) Writer() {
	for c := range rw.commChannel {
		(*rw.conn).Do(c.comm, c.args...)
	}
}

// AddKey from redisWriter adds a specified key and value to redis.
func (rw *redisWriter) AddKey(blocking bool, key string, value interface{}) {
	rw.write(blocking, "SET", key, value)
}

// DeleteKey from redisWriter deletes a specified key from redis.
func (rw *redisWriter) DeleteKey(blocking bool, key ...string) {
	rw.write(blocking, "DEL", key)
}

// SetAdd from redisWriter adds members to a set in redis.
func (rw *redisWriter) SetAdd(blocking bool, key string, members ...interface{}) {
	rw.write(blocking, "SADD", key, members)
}

// SetRemove from redisWriter removes members from a set in redis.
func (rw *redisWriter) SetRemove(blocking bool, key string, members ...interface{}) {
	rw.write(blocking, "SREM", members)
}

// CloseConn from redisWriter closes the connection to redis.
func (rw *redisWriter) CloseConn() {
	(*rw.conn).Close()
}