From 933127cc0e175a86bc50d871647f20aa1e129222 Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Fri, 8 Jan 2021 07:16:48 -0800
Subject: [PATCH] Support command-line flags to configure redis connection and
 port to use

---
 Makefile               |  4 ++--
 main.go                | 45 +++++++++++++++++++++++++++++++++---------
 redis_info_handlers.go |  2 +-
 ui/src/api.ts          |  6 +++++-
 4 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/Makefile b/Makefile
index 53ddbeb..9998416 100644
--- a/Makefile
+++ b/Makefile
@@ -2,10 +2,10 @@ assets:
 	cd ./ui && yarn build
 
 # TODO: Update this once go1.16 is released.
-go_bin:
+go_binary:
 	go1.16beta1 build -o asynqmon .
 
 # Target to build a release binary.
-build: assets go_bin
+build: assets go_binary
 
 
diff --git a/main.go b/main.go
index f17a9d1..186dfb3 100644
--- a/main.go
+++ b/main.go
@@ -1,8 +1,10 @@
 package main
 
 import (
+	"crypto/tls"
 	"embed"
 	"errors"
+	"flag"
 	"fmt"
 	"io/fs"
 	"log"
@@ -16,6 +18,23 @@ import (
 	"github.com/rs/cors"
 )
 
+// Command-line flags
+var (
+	flagPort          int
+	flagRedisAddr     string
+	flagRedisDB       int
+	flagRedisPassword string
+	flagRedisTLS      string
+)
+
+func init() {
+	flag.IntVar(&flagPort, "port", 8080, "port number to use for web ui server")
+	flag.StringVar(&flagRedisAddr, "redis_addr", "localhost:6379", "address of redis server to connect to")
+	flag.IntVar(&flagRedisDB, "redis_db", 0, "redis database number")
+	flag.StringVar(&flagRedisPassword, "redis_password", "", "password to use when connecting to redis server")
+	flag.StringVar(&flagRedisTLS, "redis_tls", "", "server name for TLS validation used when connecting to redis server")
+}
+
 // staticFileServer implements the http.Handler interface, so we can use it
 // to respond to HTTP requests. The path to the static directory and
 // path to the index file within that static directory are used to
@@ -65,22 +84,30 @@ func (srv *staticFileServer) indexFilePath() string {
 	return filepath.Join(srv.staticDirPath, srv.indexFileName)
 }
 
-const (
-	addr      = "127.0.0.1:8080"
-	redisAddr = "localhost:6379" // TODO: make this configurable
-)
-
 //go:embed ui/build/*
 var staticContents embed.FS
 
 func main() {
+	flag.Parse()
+
+	var tlsConfig *tls.Config
+	if flagRedisTLS != "" {
+		tlsConfig = &tls.Config{ServerName: flagRedisTLS}
+	}
+
 	inspector := asynq.NewInspector(asynq.RedisClientOpt{
-		Addr: redisAddr,
+		Addr:      flagRedisAddr,
+		DB:        flagRedisDB,
+		Password:  flagRedisPassword,
+		TLSConfig: tlsConfig,
 	})
 	defer inspector.Close()
 
 	rdb := redis.NewClient(&redis.Options{
-		Addr: redisAddr,
+		Addr:      flagRedisAddr,
+		DB:        flagRedisDB,
+		Password:  flagRedisPassword,
+		TLSConfig: tlsConfig,
 	})
 	defer rdb.Close()
 
@@ -156,11 +183,11 @@ func main() {
 
 	srv := &http.Server{
 		Handler:      handler,
-		Addr:         addr,
+		Addr:         fmt.Sprintf(":%d", flagPort),
 		WriteTimeout: 10 * time.Second,
 		ReadTimeout:  10 * time.Second,
 	}
 
-	fmt.Printf("Asynq Monitoring WebUI server is running on %s\n", addr)
+	fmt.Printf("Asynq Monitoring WebUI server is listening on port %d\n", flagPort)
 	log.Fatal(srv.ListenAndServe())
 }
diff --git a/redis_info_handlers.go b/redis_info_handlers.go
index 560e9ac..2dc0cbe 100644
--- a/redis_info_handlers.go
+++ b/redis_info_handlers.go
@@ -30,7 +30,7 @@ func newRedisInfoHandlerFunc(rdb *redis.Client) http.HandlerFunc {
 		}
 		info := parseRedisInfo(res)
 		resp := RedisInfoResponse{
-			Addr:    redisAddr,
+			Addr:    flagRedisAddr,
 			Info:    info,
 			RawInfo: res,
 		}
diff --git a/ui/src/api.ts b/ui/src/api.ts
index 4d08822..4d2f3f4 100644
--- a/ui/src/api.ts
+++ b/ui/src/api.ts
@@ -1,7 +1,11 @@
 import axios from "axios";
 import queryString from "query-string";
 
-const BASE_URL = "http://localhost:8080/api";
+// In production build, API server is on listening on the same port as
+// the static file server.
+// In developement, we assume that the API server is listening on port 8080.
+const BASE_URL =
+  process.env.NODE_ENV === "production" ? "/api" : "http://localhost:8080/api";
 
 export interface ListQueuesResponse {
   queues: Queue[];