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root.go
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root.go
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// Copyright © 2015 Bjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com>
//
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package cmd
import (
"fmt"
"os"
"log"
"net/http"
"sync/atomic"
"time"
"github.com/bep/alfn/lib"
"github.com/fsnotify/fsnotify"
"github.com/spf13/cobra"
"github.com/spf13/viper"
"gopkg.in/tylerb/graceful.v1"
)
var appValue atomic.Value // wee ned to hot swap it
var app = func() *lib.App {
return appValue.Load().(*lib.App)
}
// flags
var cfgFile string
var serverPort int
var serverInterface string
var rootCmd = &cobra.Command{
Use: "alfn",
Short: "Runs a web server and a feed aggregator with filters and a limiter.",
Long: `Runs a web server and a feed aggregator with filters and a limiter.`,
RunE: func(cmd *cobra.Command, args []string) error {
return startup()
},
}
// Execute adds all child commands to the root command and sets flags appropriately.
func Execute() {
if err := rootCmd.Execute(); err != nil {
fmt.Println(err)
os.Exit(-1)
}
}
func init() {
cobra.OnInitialize(initConfig)
rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.alfn/config.toml)")
rootCmd.Flags().IntVarP(&serverPort, "port", "p", 1926, "port on which the server will listen")
rootCmd.Flags().StringVarP(&serverInterface, "bind", "", "127.0.0.1", "interface to which the server will bind")
}
// Read in config file and ENV variables if set.
func initConfig() {
if cfgFile != "" {
viper.SetConfigFile(cfgFile)
}
viper.SetConfigName("config")
viper.AddConfigPath("$HOME/.alfn")
viper.AddConfigPath("/etc/alfn/")
viper.AutomaticEnv()
if err := viper.ReadInConfig(); err != nil {
log.Fatalln("error: Failed to read config:", err)
}
fmt.Println("Using config file:", viper.ConfigFileUsed())
}
func startup() error {
var config lib.Config
if err := viper.Unmarshal(&config); err != nil {
return err
}
serverAndPort := fmt.Sprintf("%s:%d", serverInterface, serverPort)
if config.Feed.Link == "" {
config.Feed.Link = "http://" + serverAndPort
}
if config.Feed.MaxItems <= 0 {
config.Feed.MaxItems = 10
}
// enable live reloading of config
viper.OnConfigChange(func(e fsnotify.Event) {
fmt.Println("Config", e.Name, "changed ...")
if err := viper.Unmarshal(&config); err != nil {
fmt.Println("error: Failed to reload config: ", err)
return
}
shutdownIfNeededAndStart(config)
})
viper.WatchConfig()
shutdownIfNeededAndStart(config)
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
w.Header().Set("Content-Type", "application/rss+xml; charset=utf-8")
fmt.Fprintf(w, app().GetFeed())
})
fmt.Printf("\nStarting server on http://%s ...\n\n", serverAndPort)
graceful.Run(serverAndPort, 10*time.Second, mux)
app().Shutdown()
fmt.Println("\nStopped ...")
return nil
}
func shutdownIfNeededAndStart(cfg lib.Config) {
if a, ok := appValue.Load().(*lib.App); ok {
// close it down and create a new one
a.Shutdown()
}
appValue.Store(lib.NewApp(cfg).Run())
}