dimkr/dohli

// this file is part of dohli.
//
// Copyright (c) 2020 Dima Krasner
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

// Package queue implements a task queue.
package queue

import (
    "os"

    "gopkg.in/redis.v5"
)

// Queue is a task queue.
type Queue struct {
    redisClient *redis.Client
}

// OpenQueue creates a new task queue.
func OpenQueue() (*Queue, error) {
    opts, err := redis.ParseURL(os.Getenv("REDIS_URL"))
    if err != nil {
        return nil, err
    }
    redisClient := redis.NewClient(opts)

    return &Queue{redisClient: redisClient}, nil
}

// Push pushes a new task to the queue.
func (q *Queue) Push(msg string) error {
    _, err := q.redisClient.RPush("messages", msg).Result()
    return err
}

// Pop pops a task and blocks if the queue is empty.
func (q *Queue) Pop() (string, error) {
    popped, err := q.redisClient.BLPop(0, "messages").Result()
    if err != nil {
        return "", err
    }

    return popped[1], nil
}