[refactor] Simplified selecting cache datasource and fail-safe mechanism

pkg/cache/cache.go

@@ -0,0 +1,39 @@
+//           ___   ____               ___       ___
+// \ \  / / | _   |  __| \ \  / / || | __  || || _ |
+//  \ \/ /  |___  | |__   \ \/ /  || |___  || ||___|
+//   \  /   | _   | _  |   \  /   ||  __ | || ||\\
+//    \/    |___  |___ |    \/    || ____| || || \\
+//
+// Copyright (c) 2021 Piotr Biernat. https://pbiernat.dev. MIT License
+// Repo: https://git.pbiernat.dev/golang/vegvisir
+
+package cache
+
+import (
+	"log"
+	"vegvisir/pkg/config"
+)
+
+const (
+	TYPE_REDIS  = "redis"
+	TYPE_MEMORY = "memory"
+)
+
+func GetCacheDatastore(config config.Cache) *CacheDatastore {
+	var datastore CacheDatastore
+
+	if config.Type == TYPE_REDIS {
+		datastore = NewRedisDatastore(config.Host, config.Port)
+	} else {
+		datastore = NewMemoryDatastore()
+	}
+
+	//fail-safe switch to memory datasource
+	if !datastore.IsConnected() {
+		log.Println("Cache server is not responding, switching to memory cache.")
+
+		datastore = NewMemoryDatastore()
+	}
+
+	return &datastore
+}

pkg/config/config.go

@@ -17,6 +17,7 @@ import (
 
 type Config struct {
 	Server   Server
+	Cache    Cache
 	Backends map[string]Backend
 
 	confPath string
@@ -27,6 +28,17 @@ type Server struct {
 	Port    int
 }
 
+type Cache struct {
+	Type        string
+	Host        string
+	Port        int
+	Username    string
+	Password    string
+	Database    string
+	RouteTtl    int
+	ResponseTtl int
+}
+
 type Backend struct {
 	PrefixUrl      string
 	BackendAddress string

pkg/main.go

@@ -19,15 +19,13 @@ import (
 )
 
 var (
-	cFile = flag.String("c", "vegvisir.json", "Path to config file")
+	cPath = flag.String("c", "vegvisir.json", "Path to config file")
-
 	// for profiling...
 	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to `file`")
 	memprofile = flag.String("memprofile", "", "write memory profile to `file`")
 )
 
 func main() {
-
 	flag.Parse()
 	// cpu profiling
 	if *cpuprofile != "" {
@@ -42,7 +40,7 @@ func main() {
 		defer pprof.StopCPUProfile()
 	}
 
-	server.NewServer(*cFile).Run()
+	server.NewServer(*cPath).Run()
 
 	// memory profiling
 	if *memprofile != "" {

pkg/server/server.go

@@ -40,23 +40,13 @@ func NewServer(cPath string) *Server {
 		log.Fatalln("Unable to find config file: ", cPath, err)
 	}
 
-	server := &Server{
+	datastore := cache.GetCacheDatastore(config.Cache)
+
+	return &Server{
 		config: config,
+		router: NewRouter(config, *datastore, config.Cache.RouteTtl),
+		respCM: cache.NewResponseCacheManager(*datastore, config.Cache.ResponseTtl),
 	}
-
-	redisDS := cache.NewRedisDatastore("127.0.0.1", 6379) // FIXME use config or env...
-	if !redisDS.IsConnected() {
-		log.Println("Redis server not responding, switching to memory cache...")
-
-		memDS := cache.NewMemoryDatastore()
-		server.router = NewRouter(config, memDS, 30)             //FIXME for memory datasource ttl is useles right now...
-		server.respCM = cache.NewResponseCacheManager(memDS, 30) //FIXME for memory datasource ttl is useles right now...
-	} else {
-		server.router = NewRouter(config, redisDS, 30)             //FIXME use ttl(seconds) from config or env...
-		server.respCM = cache.NewResponseCacheManager(redisDS, 30) //FIXME use ttl(seconds) from config or env...
-	}
-
-	return server
 }
 
 func (s *Server) Run() {

vegvisir.json.dist

@@ -29,5 +29,15 @@
                 "target": "article-global/$1"
             }]
         }
+    },
+    "cache": {
+        "type": "redis",
+        "host": "localhost",
+        "port": 6379,
+        "username": "",
+        "password": "",
+        "database": "0",
+        "routeTtl": 300,
+        "responseTtl": 300
     }
 }