Refactored msgbus client CLI to use cobra
This commit is contained in:
James Mills
parent
1dded6cc6b
commit
2f7d09660f
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@ -1,88 +1,5 @@
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package main
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import (
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"flag"
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"io/ioutil"
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"log"
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"os"
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"os/signal"
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"syscall"
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"github.com/prologic/msgbus/client"
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)
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const defaultTopic = "hello"
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func main() {
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var url string
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flag.StringVar(
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&url, "url",
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"http://localhost:8000", "url to connect to",
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)
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flag.Parse()
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client := client.NewClient(url, nil)
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if flag.Arg(0) == "sub" {
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subscribe(client, flag.Arg(1))
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} else if flag.Arg(0) == "pub" {
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publish(client, flag.Arg(1), flag.Arg(2))
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} else if flag.Arg(0) == "pull" {
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pull(client, flag.Arg(1))
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} else {
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log.Fatalf("invalid command %s", flag.Arg(0))
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}
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}
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func publish(client *client.Client, topic, message string) {
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if topic == "" {
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topic = defaultTopic
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}
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if message == "" || message == "-" {
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log.Printf("Reading message from stdin...\n")
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buf, err := ioutil.ReadAll(os.Stdin)
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if err != nil {
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log.Fatalf("error reading message from stdin: %s", err)
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}
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message = string(buf[:])
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}
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err := client.Publish(topic, message)
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if err != nil {
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log.Fatalf("error publishing message: %s", err)
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}
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}
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func pull(client *client.Client, topic string) {
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if topic == "" {
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topic = defaultTopic
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}
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client.Pull(topic)
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}
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func subscribe(client *client.Client, topic string) {
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if topic == "" {
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topic = defaultTopic
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}
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s := client.Subscribe(topic)
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go s.Run()
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sigs := make(chan os.Signal, 1)
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done := make(chan bool, 1)
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signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
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go func() {
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sig := <-sigs
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log.Printf("caught signal %s: ", sig)
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s.Stop()
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done <- true
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}()
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<-done
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Execute()
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}
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@ -0,0 +1,67 @@
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package main
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import (
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"io/ioutil"
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"log"
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"os"
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"github.com/spf13/cobra"
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"github.com/prologic/msgbus/client"
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)
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// pubCmd represents the pub command
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var pubCmd = &cobra.Command{
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Use: "pub [flags] <topic> [<message>|-]",
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Short: "Publish a new message",
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Long: `This publishes a new message either from positional command-line
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arguments or from standard input if - is used as the first and only argument.
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This is an asynchronous operation and does not wait for a response unless the
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-w/--wait option is also present.`,
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Args: cobra.MinimumNArgs(1),
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Run: func(cmd *cobra.Command, args []string) {
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uri := cmd.Flag("uri").Value.String()
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client := client.NewClient(uri, nil)
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topic := args[0]
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message := ""
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if len(args) == 2 {
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message = args[1]
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}
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publish(client, topic, message)
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},
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}
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func init() {
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RootCmd.AddCommand(pubCmd)
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pubCmd.Flags().BoolP(
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"wait", "w", false,
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"Waits for a response and prints it before terminating",
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)
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}
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const defaultTopic = "hello"
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func publish(client *client.Client, topic, message string) {
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if topic == "" {
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topic = defaultTopic
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}
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if message == "" || message == "-" {
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log.Printf("Reading message from stdin...\n")
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buf, err := ioutil.ReadAll(os.Stdin)
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if err != nil {
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log.Fatalf("error reading message from stdin: %s", err)
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}
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message = string(buf[:])
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}
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err := client.Publish(topic, message)
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if err != nil {
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log.Fatalf("error publishing message: %s", err)
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}
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}
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@ -0,0 +1,40 @@
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package main
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import (
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"github.com/spf13/cobra"
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"github.com/prologic/msgbus/client"
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)
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// pullCmd represents the pub command
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var pullCmd = &cobra.Command{
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Use: "pull [flags] <topic>",
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Short: "Pulls a message from a given topic",
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Long: `This pulls a message from the given topic if there are any messages
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and prints the message to standard output. Otherwise if the queue for the
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given topic is empty, this does nothing.
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This is primarily useful in situations where a subscription was lost and you
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want to "catch up" and pull any messages left in the queue for that topic.`,
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Args: cobra.MinimumNArgs(1),
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Run: func(cmd *cobra.Command, args []string) {
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uri := cmd.Flag("uri").Value.String()
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client := client.NewClient(uri, nil)
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topic := args[0]
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pull(client, topic)
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},
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}
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func init() {
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RootCmd.AddCommand(pullCmd)
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}
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func pull(client *client.Client, topic string) {
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if topic == "" {
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topic = defaultTopic
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}
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client.Pull(topic)
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}
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@ -0,0 +1,73 @@
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package main
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import (
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"fmt"
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"os"
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"github.com/mitchellh/go-homedir"
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"github.com/spf13/cobra"
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"github.com/spf13/viper"
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)
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var configFile string
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// RootCmd represents the base command when called without any subcommands
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var RootCmd = &cobra.Command{
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Use: "msgbus",
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Short: "Command-line client for msgbus",
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Long: `This is the command-line client for the msgbus daemon msgbusd.
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This lets you publish, subscribe and pull messages from a running msgbusd
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instance. This is the reference implementation of using the msgbus client
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library for publishing and subscribing to topics.`,
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}
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// Execute adds all child commands to the root command
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// and sets flags appropriately.
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// This is called by main.main(). It only needs to happen once to the rootCmd.
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func Execute() {
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if err := RootCmd.Execute(); err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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}
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func init() {
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cobra.OnInitialize(initConfig)
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RootCmd.PersistentFlags().StringVar(
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&configFile, "config", "",
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"config file (default is $HOME/.msgbus.yaml)",
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)
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RootCmd.PersistentFlags().StringP(
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"uri", "u", "http://localhost:8000",
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"URI to connect to msgbusd",
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)
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}
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// initConfig reads in config file and ENV variables if set.
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func initConfig() {
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if configFile != "" {
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// Use config file from the flag.
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viper.SetConfigFile(configFile)
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} else {
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// Find home directory.
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home, err := homedir.Dir()
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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// Search config in home directory with name ".cobra-example" (without extension).
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viper.AddConfigPath(home)
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viper.SetConfigName(".cobra-example")
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}
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viper.AutomaticEnv() // read in environment variables that match
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// If a config file is found, read it in.
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if err := viper.ReadInConfig(); err == nil {
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fmt.Println("Using config file:", viper.ConfigFileUsed())
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}
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}
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@ -0,0 +1,56 @@
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package main
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import (
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"log"
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"os"
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"os/signal"
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"syscall"
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"github.com/spf13/cobra"
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"github.com/prologic/msgbus/client"
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)
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// subCmd represents the pub command
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var subCmd = &cobra.Command{
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Use: "sub [flags] <topic>",
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Short: "Subscribe to a topic",
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Long: `This subscribes to the given topic and for every message published
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to the topic, the message is printed to standard output.`,
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Args: cobra.MinimumNArgs(1),
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Run: func(cmd *cobra.Command, args []string) {
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uri := cmd.Flag("uri").Value.String()
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client := client.NewClient(uri, nil)
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topic := args[0]
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subscribe(client, topic)
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},
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}
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func init() {
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RootCmd.AddCommand(subCmd)
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}
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func subscribe(client *client.Client, topic string) {
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if topic == "" {
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topic = defaultTopic
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}
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s := client.Subscribe(topic)
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go s.Run()
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sigs := make(chan os.Signal, 1)
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done := make(chan bool, 1)
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signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
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go func() {
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sig := <-sigs
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log.Printf("caught signal %s: ", sig)
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s.Stop()
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done <- true
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}()
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<-done
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}
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