Why is there no cache operation with custom expiration time in the monc package?

[NicetomeetUUU]

I'm learning the go-zero framework and cannot find the cache operation with custom expiration time in monc package.

[kevwan]

monc package supports custom expiration time through the cache.WithExpiry() option! Here's how you can use it:

Using Custom Expiration Time

When creating a monc.Model, you can pass cache.WithExpiry(duration) as an option to monc.MustNewModel:

import (
    "time"
    "github.com/zeromicro/go-zero/core/stores/cache"
    "github.com/zeromicro/go-zero/core/stores/monc"
)

// Example: Set cache expiration to 1 hour
model := monc.MustNewModel(uri, db, collection, cacheConf, cache.WithExpiry(time.Hour))

// Example: Set cache expiration to 30 minutes
model := monc.MustNewModel(uri, db, collection, cacheConf, cache.WithExpiry(30*time.Minute))

Default Expiration Time

As you mentioned, the default expiration time is indeed 7 days. This is defined in the core/stores/cache/cacheopt.go file:

const (
    defaultExpiry = time.Hour * 24 * 7  // 7 days
    defaultNotFoundExpiry = time.Minute
)

How It Works

1. The cache.WithExpiry() function returns a cache.Option that customizes the cache expiration time
2. This option is passed to the cache layer when creating the monc.Model
3. All cache operations will use this custom expiration time instead of the default 7 days

Additional Options

You can also use cache.WithNotFoundExpiry() to customize the expiration time for "not found" cache entries:

model := monc.MustNewModel(uri, db, collection, cacheConf, 
    cache.WithExpiry(time.Hour),           // Cache hits expire in 1 hour
    cache.WithNotFoundExpiry(5*time.Minute), // Cache misses expire in 5 minutes
)

This feature allows you to have fine-grained control over your cache expiration strategy based on your application's needs.