sqlcache
sqlcache is a caching middleware for database/sql
that enables existing Go programs to add caching in a declarative way.
It leverages APIs provided by the handy sqlmw
project and is inspired from slonik-interceptor-query-cache.
This liberates your Go program from maintaining imperative code that repeatedly implements the cache-aside pattern. Your program will perceive the database client/driver as a read-through cache.
Tested with PostgreSQL database with pgx as the underlying driver.
Cache backends supported:
It's easy to add other caching backends by implementing the cache.Cacher
interface.
Usage
Create a backend cache instance and install the interceptor:
import (
"database/sql"
redis "github.com/go-redis/redis/v7"
"github.com/jackc/pgx/v4/stdlib"
"github.com/prashanthpai/sqlcache"
)
func main() {
...
rc := redis.NewUniversalClient(&redis.UniversalOptions{
Addrs: []string{"127.0.0.1:6379"},
})
// create a sqlcache.Interceptor instance with the desired backend
interceptor, err := sqlcache.NewInterceptor(&sqlcache.Config{
Cache: sqlcache.NewRedis(rc, "sqc"),
})
...
// wrap pgx driver with cache interceptor and register it
sql.Register("pgx-with-cache", interceptor.Driver(stdlib.GetDefaultDriver()))
// open the database using the wrapped driver
db, err := sql.Open("pgx-with-cache", dsn)
...
Caching is controlled using cache attributes which are SQL comments starting
with @cache-
prefix. Only queries with cache attributes are cached.
Cache attributes:
Cache attribute | Description | Required? | Default |
---|---|---|---|
@cache-ttl |
Number (in seconds) to cache the query for. | Yes | N/A |
@cache-max-rows |
Don't cache if number of rows in query response exceeds this limit. | Yes | N/A |
Example query:
rows, err := db.QueryContext(context.TODO(), `
-- @cache-ttl 30
-- @cache-max-rows 10
SELECT name, pages FROM books WHERE pages > $1`, 100)
See example/main.go for a full working example.