From 9b550f4be24e5acad336157479e20510f7ec8aaf Mon Sep 17 00:00:00 2001
From: sittichok Ouamsiri <sutichok46@gmail.com>
Date: Mon, 15 Jun 2026 21:45:29 +0700
Subject: [PATCH] feat: .env.example

---
 .env.example                                 | 34 ++++++++++++++++++++
 backend/internal/adapter/rediscache/cache.go |  4 +--
 backend/internal/config/config.go            |  8 +++--
 backend/internal/di/container.go             |  2 +-
 4 files changed, 42 insertions(+), 6 deletions(-)
 create mode 100644 .env.example

diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..49a9d30
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,34 @@
+# ── Storage ──────────────────────────────────────────────────────────────────
+STORE=postgres
+DATABASE_URL=postgres://snip:snip@localhost:5432/snip?sslmode=disable
+
+# ── Redis ─────────────────────────────────────────────────────────────────────
+REDIS_ADDR=localhost:6379
+REDIS_PASSWORD=
+REDIS_DB=0
+# Namespace prefix for all Redis keys — set this when sharing a Redis instance
+# with other apps, e.g. REDIS_KEY_PREFIX=snip: → keys look like snip:code:abc
+REDIS_KEY_PREFIX=
+
+# ── App ───────────────────────────────────────────────────────────────────────
+PUBLIC_URL=http://localhost:8080
+SHORT_DOMAIN=localhost:8080
+POST_LOGIN_REDIRECT=/dashboard
+FRONTEND_DIST=./web
+
+# ── Security ──────────────────────────────────────────────────────────────────
+SESSION_SECRET=change-me-in-production
+COOKIE_SECURE=false
+
+# ── Google OAuth (optional) ───────────────────────────────────────────────────
+GOOGLE_CLIENT_ID=
+GOOGLE_CLIENT_SECRET=
+
+# ── Generic OIDC (optional) ───────────────────────────────────────────────────
+OIDC_ISSUER=
+OIDC_CLIENT_ID=
+OIDC_CLIENT_SECRET=
+
+# ── Misc ──────────────────────────────────────────────────────────────────────
+# How often buffered click counts are flushed to Postgres (seconds)
+CLICK_FLUSH_SECONDS=10
diff --git a/backend/internal/adapter/rediscache/cache.go b/backend/internal/adapter/rediscache/cache.go
index a189055..e18af6e 100644
--- a/backend/internal/adapter/rediscache/cache.go
+++ b/backend/internal/adapter/rediscache/cache.go
@@ -17,13 +17,13 @@ type Cache struct {
 	prefix string
 }
 
-func New(ctx context.Context, addr, password string, db int) (*Cache, error) {
+func New(ctx context.Context, addr, password string, db int, keyPrefix string) (*Cache, error) {
 	rdb := redis.NewClient(&redis.Options{Addr: addr, Password: password, DB: db})
 	if err := rdb.Ping(ctx).Err(); err != nil {
 		_ = rdb.Close()
 		return nil, err
 	}
-	return &Cache{rdb: rdb, prefix: "code:"}, nil
+	return &Cache{rdb: rdb, prefix: keyPrefix + "code:"}, nil
 }
 
 func (c *Cache) key(code string) string { return c.prefix + code }
diff --git a/backend/internal/config/config.go b/backend/internal/config/config.go
index 1fb18be..f7545be 100644
--- a/backend/internal/config/config.go
+++ b/backend/internal/config/config.go
@@ -12,9 +12,10 @@ type Config struct {
 	Store       string
 	DatabaseURL string
 
-	RedisAddr     string
-	RedisPassword string
-	RedisDB       int
+	RedisAddr      string
+	RedisPassword  string
+	RedisDB        int
+	RedisKeyPrefix string
 
 	// PublicURL is the externally reachable base (used to build OAuth callback
 	// URLs). PostLoginRedirect is where users land after a successful login.
@@ -76,6 +77,7 @@ func Load() Config {
 		RedisAddr:          env("REDIS_ADDR", "localhost:6379"),
 		RedisPassword:      env("REDIS_PASSWORD", ""),
 		RedisDB:            envInt("REDIS_DB", 0),
+		RedisKeyPrefix:     env("REDIS_KEY_PREFIX", ""),
 		PublicURL:          env("PUBLIC_URL", "http://localhost:8080"),
 		PostLoginRedirect:  env("POST_LOGIN_REDIRECT", "/dashboard"),
 		FrontendDist:       env("FRONTEND_DIST", "./web"),
diff --git a/backend/internal/di/container.go b/backend/internal/di/container.go
index 04e20cd..4401ee0 100644
--- a/backend/internal/di/container.go
+++ b/backend/internal/di/container.go
@@ -56,7 +56,7 @@ func (c *Container) buildInfra(ctx context.Context) (*infra, error) {
 	if err != nil {
 		return nil, err
 	}
-	cache, err := rediscache.New(ctx, c.cfg.RedisAddr, c.cfg.RedisPassword, c.cfg.RedisDB)
+	cache, err := rediscache.New(ctx, c.cfg.RedisAddr, c.cfg.RedisPassword, c.cfg.RedisDB, c.cfg.RedisKeyPrefix)
 	if err != nil {
 		pool.Close()
 		return nil, err