Merge pull request #12 from logan-bobo/feat/url-cache

feat: redis cache for GET requests to short URLs

docker-compose.yaml

@@ -33,5 +33,11 @@ services:
       interval: 2s
       timeout: 5s
       retries: 10
+  redis:
+    image: 'bitnami/redis:latest'
+    environment:
+      - ALLOW_EMPTY_PASSWORD=yes
+    ports:
+      - 5003:6379
 volumes:
   pgdata:

go.mod

@@ -3,8 +3,11 @@ module url-short
 go 1.22.3
 
 require (
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
 	github.com/golang-jwt/jwt/v5 v5.2.1 // indirect
 	github.com/lib/pq v1.10.9 // indirect
+	github.com/redis/go-redis/v9 v9.5.3 // indirect
 	golang.org/x/crypto v0.24.0 // indirect
 )

go.sum

@@ -1,8 +1,14 @@
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
 github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
 github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
 github.com/golang-jwt/jwt/v5 v5.2.1 h1:OuVbFODueb089Lh128TAcimifWaLhJwVflnrgM17wHk=
 github.com/golang-jwt/jwt/v5 v5.2.1/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
+github.com/redis/go-redis/v9 v9.5.3 h1:fOAp1/uJG+ZtcITgZOfYFmTKPE7n4Vclj1wZFgRciUU=
+github.com/redis/go-redis/v9 v9.5.3/go.mod h1:hdY0cQFCN4fnSYT6TkisLufl/4W5UIXyv0b/CLO2V2M=
 golang.org/x/crypto v0.24.0 h1:mnl8DM0o513X8fdIkmyFE/5hTYxbwYOjDS/+rK6qpRI=
 golang.org/x/crypto v0.24.0/go.mod h1:Z1PMYSOR5nyMcyAVAIQSKCDwalqy85Aqn1x3Ws4L5DM=

handlers.go

@@ -15,13 +15,15 @@ import (
 	"time"
 
 	"github.com/golang-jwt/jwt/v5"
+	"github.com/redis/go-redis/v9"
 	"golang.org/x/crypto/bcrypt"
 
 	"url-short/internal/database"
 )
 
 type apiConfig struct {
 	DB        *database.Queries
+	RDB       *redis.Client
 	JWTSecret string
 }
 
@@ -64,11 +66,9 @@ type APIUserResponseNoToken struct {
 }
 
 func (apiCfg *apiConfig) healthz(w http.ResponseWriter, r *http.Request) {
-	payload := HealthResponse{
+	respondWithJSON(w, http.StatusOK, HealthResponse{
 		Status: "ok",
-	}
-
-	respondWithJSON(w, http.StatusOK, payload)
+	})
 }
 
 func (apiCfg *apiConfig) postLongURL(w http.ResponseWriter, r *http.Request, user database.User) {
@@ -125,15 +125,60 @@ func (apiCfg *apiConfig) getShortURL(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	row, err := apiCfg.DB.SelectURL(r.Context(), query)
+	cacheVal, err := apiCfg.RDB.Get(r.Context(), query).Result()
 
-	if err != nil {
+	switch {
+	case err == redis.Nil:
+		log.Printf("cache miss, key %s does not exists, writing to redis", query)
+
+		row, err := apiCfg.DB.SelectURL(r.Context(), query)
+
+		if err != nil {
+			log.Println(err)
+			respondWithError(w, http.StatusInternalServerError, "database error")
+			return
+		}
+
+		err = apiCfg.RDB.Set(r.Context(), query, row.LongUrl, (time.Hour * 1)).Err()
+
+		if err != nil {
+			log.Printf("could not write to redis cache %s", err)
+		}
+
+		http.Redirect(w, r, row.LongUrl, http.StatusMovedPermanently)
+		return
+
+	case err != nil:
 		log.Println(err)
-		respondWithError(w, http.StatusInternalServerError, "database error")
+
+		row, err := apiCfg.DB.SelectURL(r.Context(), query)
+
+		if err != nil {
+			log.Println(err)
+			respondWithError(w, http.StatusInternalServerError, "database error")
+			return
+		}
+
+		http.Redirect(w, r, row.LongUrl, http.StatusMovedPermanently)
+		return
+
+	case cacheVal == "":
+		log.Printf("key %s does not have a value", query)
+
+		row, err := apiCfg.DB.SelectURL(r.Context(), query)
+
+		if err != nil {
+			log.Println(err)
+			respondWithError(w, http.StatusInternalServerError, "database error")
+			return
+		}
+
+		http.Redirect(w, r, row.LongUrl, http.StatusMovedPermanently)
 		return
 	}
 
-	http.Redirect(w, r, row.LongUrl, http.StatusMovedPermanently)
+	log.Printf("cache hit for key %s", cacheVal)
+	http.Redirect(w, r, cacheVal, http.StatusMovedPermanently)
 }
 
 func (apiCfg *apiConfig) deleteShortURL(w http.ResponseWriter, r *http.Request, user database.User) {
@@ -185,6 +230,12 @@ func (apiCfg *apiConfig) putShortURL(w http.ResponseWriter, r *http.Request, use
 		return
 	}
 
+	err = apiCfg.RDB.Set(r.Context(), query, payload.LongURL, (time.Hour * 1)).Err()
+
+	if err != nil {
+		log.Println(err)
+	}
+
 	respondWithJSON(w, http.StatusOK, ShortURLUpdateResponse{
 		LongURL:  payload.LongURL,
 		ShortURL: query,

main.go

@@ -5,14 +5,17 @@ import (
 	"log"
 	"net/http"
 	"os"
+
 	"url-short/internal/database"
 
 	_ "github.com/lib/pq"
+	"github.com/redis/go-redis/v9"
 )
 
 func main() {
 	serverPort := os.Getenv("SERVER_PORT")
 	dbURL := os.Getenv("PG_CONN")
+	rdbURL := os.Getenv("RDB_CONN")
 	jwtSecret := os.Getenv("JWT_SECRET")
 
 	db, err := sql.Open("postgres", dbURL)
@@ -30,8 +33,17 @@ func main() {
 		Handler: mux,
 	}
 
+	opt, err := redis.ParseURL(rdbURL)
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	redisClient := redis.NewClient(opt)
+
 	apiCfg := apiConfig{
 		DB:        dbQueries,
+		RDB:       redisClient,
 		JWTSecret: jwtSecret,
 	}