Make it possible to actually use redis for caching through the config flags

cli/flags.go

@@ -126,6 +126,13 @@ var (
 			EnvVars: []string{"BLACKLISTED_PATHS"},
 		},
 
+		&cli.StringFlag{
+			Name:    "redis-url",
+			Value:   "",
+			Usage:   "use redis instead of the built-in memory cache (recommended)",
+			EnvVars: []string{"REDIS_URL"},
+		},
+
 		&cli.StringFlag{
 			Name:    "log-level",
 			Value:   "warn",

config/config.go

@@ -6,6 +6,7 @@ type Config struct {
 	Gitea    GiteaConfig
 	Database DatabaseConfig
 	ACME     ACMEConfig
+	RedisURL string `default:""`
 }
 
 type ServerConfig struct {

config/setup.go

@@ -54,6 +54,9 @@ func MergeConfig(ctx *cli.Context, config *Config) {
 	mergeGiteaConfig(ctx, &config.Gitea)
 	mergeDatabaseConfig(ctx, &config.Database)
 	mergeACMEConfig(ctx, &config.ACME)
+	if ctx.IsSet("redis-url") {
+		config.RedisURL = ctx.String("redis-url")
+	}
 }
 
 func mergeServerConfig(ctx *cli.Context, config *ServerConfig) {

server/cache/redis.go

@@ -36,13 +36,9 @@ func (r *RedisCache) Remove(key string) {
 	}
 }
 
-func NewRedisCache() ICache {
+func NewRedisCache(opts *redis.Options) ICache {
 	return &RedisCache{
 		context.Background(),
-		redis.NewClient(&redis.Options{
+		redis.NewClient(opts),
-			Addr:     "localhost:6379",
-			Password: "", // no password set
-			DB:       0,  // use default DB
-		}),
 	}
 }

server/startup.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/OrlovEvgeny/go-mcache"
+	"github.com/redis/go-redis/v9"
 	"net"
 	"net/http"
 	"os"
@@ -71,16 +72,33 @@ func Serve(ctx *cli.Context) error {
 	}
 	defer closeFn()
 
+	// keyCache stores the parsed certificate objects (Redis is no advantage here)
 	keyCache := mcache.New()
-	challengeCache := cache.NewInMemoryCache()
+	// dnsLookupCache stores DNS lookups for custom domains (Redis is no advantage here)
-	// canonicalDomainCache stores canonical domains
-	canonicalDomainCache := cache.NewInMemoryCache()
-	// dnsLookupCache stores DNS lookups for custom domains
 	dnsLookupCache := mcache.New()
+
+	var redisErr error = nil
+	createCache := func() cache.ICache {
+		if cfg.RedisURL != "" {
+			opts, err := redis.ParseURL(cfg.RedisURL)
+			if err != nil {
+				redisErr = err
+			}
+			return cache.NewRedisCache(opts)
+		}
+		return cache.NewInMemoryCache()
+	}
+	// challengeCache stores the certificate challenges
+	challengeCache := createCache()
+	// canonicalDomainCache stores canonical domains
+	canonicalDomainCache := createCache()
 	// redirectsCache stores redirects in _redirects files
-	redirectsCache := cache.NewInMemoryCache()
+	redirectsCache := createCache()
 	// clientResponseCache stores responses from the Gitea server
-	clientResponseCache := cache.NewInMemoryCache()
+	clientResponseCache := createCache()
+	if redisErr != nil {
+		return redisErr
+	}
 
 	giteaClient, err := gitea.NewClient(cfg.Gitea, clientResponseCache)
 	if err != nil {