rl404/go-malscraper

package cacher

import (
    "time"

    "github.com/rl404/go-malscraper/service"
)

// Cacher intercepts request to check the requested
// data to cache before actually access and parse
// MyAnimeList web.
type Cacher struct {
    api    service.API
    cacher service.Cacher
    logger service.Logger
}

// New to create new cacher.
func New(api service.API, c service.Cacher, l service.Logger) service.API {
    return &Cacher{
        api:    api,
        cacher: newCacherLog(c, l),
        logger: l,
    }
}

// Simple cacher wrapper with log to prevent writing
// repetitive log code.
type cacherLog struct {
    cacher service.Cacher
    logger service.Logger
}

// Testable time since func.
var timeSince = time.Since

func newCacherLog(c service.Cacher, l service.Logger) service.Cacher {
    return &cacherLog{
        cacher: c,
        logger: l,
    }
}

// Get to get data from cache with log.
func (c cacherLog) Get(key string, data interface{}) error {
    c.logger.Trace("[%s] retrieving cache...", key)
    t := time.Now()
    if err := c.cacher.Get(key, data); err != nil {
        c.logger.Warn("[%s] failed retrieving cache: %s", key, err.Error())
        return err
    }
    c.logger.Debug("[%s] cache found (%s)", key, timeSince(t).Truncate(time.Microsecond))
    return nil
}

// Set to save data to cache with log.
func (c cacherLog) Set(key string, data interface{}) error {
    c.logger.Trace("[%s] saving cache...", key)
    t := time.Now()
    if err := c.cacher.Set(key, data); err != nil {
        c.logger.Error("[%s] failed saving cache: %s", key, err.Error())
        return err
    }
    c.logger.Debug("[%s] cache saved (%s)", key, timeSince(t).Truncate(time.Microsecond))
    return nil
}

// Delete to delete data in cache with log.
func (c cacherLog) Delete(key string) error {
    c.logger.Trace("[%s] deleting cache...", key)
    t := time.Now()
    if err := c.cacher.Delete(key); err != nil {
        c.logger.Error("[%s] failed deleting cache: %s", key, err.Error())
        return err
    }
    c.logger.Debug("[%s] cache deleted (%s)", key, timeSince(t).Truncate(time.Microsecond))
    return nil
}

// Close to close cache connection.
func (c cacherLog) Close() error {
    return c.cacher.Close()
}