Merge pull request #22 from juanfont/json-output

Added JSON-formatted output to CLI

README.md

@@ -23,6 +23,7 @@ Headscale implements this coordination server.
 - [x] Basic routing (advertise & accept)
 - [ ] Share nodes between ~~users~~ namespaces
 - [x] Node registration via pre-auth keys
+- [X] JSON-formatted output
 - [ ] ACLs
 - [ ] DNS
 
@@ -79,6 +80,22 @@ Suggestions/PRs welcomed!
   ./headscale -n myfirstnamespace node register YOURMACHINEKEY
   ```
 
+Alternatively, you can use Auth Keys to register your machines:
+
+1. Create an authkey
+    ```shell
+    ./headscale -n myfirstnamespace preauthkey create --reusable --expiration 24h
+    ```
+
+2. Use the authkey from your machine to register it
+   ```shell
+   tailscale up -login-server YOUR_HEADSCALE_URL --authkey YOURAUTHKEY
+   ```
+
+
+Please bear in mind that all the commands from headscale support adding `-o json` or `-o json-line`  to get a nicely JSON-formatted output.
+
+
 ## Configuration reference
 
 Headscale's configuration file is named `config.json` or `config.yaml`. Headscale will look for it in `/etc/headscale`, `~/.headscale` and finally the directory from where the Headscale binary is executed.
@@ -131,7 +148,15 @@ To get a certificate automatically via [Let's Encrypt](https://letsencrypt.org/)
 
 ## Disclaimer
 
-1. I have nothing to do with Tailscale, or Tailscale Inc. 
+1. We have nothing to do with Tailscale, or Tailscale Inc.
 2. The purpose of writing this was to learn how Tailscale works.
-3. I don't use Headscale myself.
+3. ~~I don't use Headscale myself.~~
+
+
+
+## More on Tailscale
+
+- https://tailscale.com/blog/how-tailscale-works/
+- https://tailscale.com/blog/tailscale-key-management/
+- https://tailscale.com/blog/an-unlikely-database-migration/
 

cli.go

@@ -1,50 +1,45 @@
 package headscale
 
 import (
-	"fmt"
+	"errors"
 	"log"
 
 	"tailscale.com/wgengine/wgcfg"
 )
 
 // RegisterMachine is executed from the CLI to register a new Machine using its MachineKey
-func (h *Headscale) RegisterMachine(key string, namespace string) error {
+func (h *Headscale) RegisterMachine(key string, namespace string) (*Machine, error) {
 	ns, err := h.GetNamespace(namespace)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	mKey, err := wgcfg.ParseHexKey(key)
 	if err != nil {
-		log.Printf("Cannot parse client key: %s", err)
-		return err
+		return nil, err
 	}
 	db, err := h.db()
 	if err != nil {
 		log.Printf("Cannot open DB: %s", err)
-		return err
+		return nil, err
 	}
 	defer db.Close()
 	m := Machine{}
 	if db.First(&m, "machine_key = ?", mKey.HexString()).RecordNotFound() {
-		log.Printf("Cannot find machine with machine key: %s", mKey.Base64())
-		return err
+		return nil, errors.New("Machine not found")
 	}
 
 	if m.isAlreadyRegistered() {
-		fmt.Println("This machine already registered")
-		return nil
+		return nil, errors.New("Machine already registered")
 	}
 
 	ip, err := h.getAvailableIP()
 	if err != nil {
-		log.Println(err)
-		return err
+		return nil, err
 	}
 	m.IPAddress = ip.String()
 	m.NamespaceID = ns.ID
 	m.Registered = true
 	m.RegisterMethod = "cli"
 	db.Save(&m)
-	fmt.Println("Machine registered 🎉")
-	return nil
+	return &m, nil
 }

cmd/headscale/cli/namespaces.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"fmt"
 	"log"
+	"strings"
 
 	"github.com/spf13/cobra"
 )
@@ -22,16 +23,21 @@ var CreateNamespaceCmd = &cobra.Command{
 		return nil
 	},
 	Run: func(cmd *cobra.Command, args []string) {
+		o, _ := cmd.Flags().GetString("output")
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
-		_, err = h.CreateNamespace(args[0])
-		if err != nil {
-			fmt.Println(err)
+		namespace, err := h.CreateNamespace(args[0])
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(namespace, err, o)
 			return
 		}
-		fmt.Printf("Ook.\n")
+		if err != nil {
+			fmt.Printf("Error creating namespace: %s\n", err)
+			return
+		}
+		fmt.Printf("Namespace created\n")
 	},
 }
 
@@ -39,17 +45,22 @@ var ListNamespacesCmd = &cobra.Command{
 	Use:   "list",
 	Short: "List all the namespaces",
 	Run: func(cmd *cobra.Command, args []string) {
+		o, _ := cmd.Flags().GetString("output")
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
-		ns, err := h.ListNamespaces()
+		namespaces, err := h.ListNamespaces()
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(namespaces, err, o)
+			return
+		}
 		if err != nil {
 			fmt.Println(err)
 			return
 		}
 		fmt.Printf("ID\tName\n")
-		for _, n := range *ns {
+		for _, n := range *namespaces {
 			fmt.Printf("%d\t%s\n", n.ID, n.Name)
 		}
 	},

cmd/headscale/cli/nodes.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"fmt"
 	"log"
+	"strings"
 
 	"github.com/spf13/cobra"
 )
@@ -21,17 +22,22 @@ var RegisterCmd = &cobra.Command{
 		if err != nil {
 			log.Fatalf("Error getting namespace: %s", err)
 		}
+		o, _ := cmd.Flags().GetString("output")
 
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
-		err = h.RegisterMachine(args[0], n)
-		if err != nil {
-			fmt.Printf("Error: %s", err)
+		m, err := h.RegisterMachine(args[0], n)
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(m, err, o)
 			return
 		}
-		fmt.Println("Ook.")
+		if err != nil {
+			fmt.Printf("Cannot register machine: %s\n", err)
+			return
+		}
+		fmt.Printf("Machine registered\n")
 	},
 }
 
@@ -43,12 +49,18 @@ var ListNodesCmd = &cobra.Command{
 		if err != nil {
 			log.Fatalf("Error getting namespace: %s", err)
 		}
+		o, _ := cmd.Flags().GetString("output")
 
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
 		machines, err := h.ListMachinesInNamespace(n)
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(machines, err, o)
+			return
+		}
+
 		if err != nil {
 			log.Fatalf("Error getting nodes: %s", err)
 		}

cmd/headscale/cli/preauthkeys.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"fmt"
 	"log"
+	"strings"
 	"time"
 
 	"github.com/hako/durafmt"
@@ -22,14 +23,20 @@ var ListPreAuthKeys = &cobra.Command{
 		if err != nil {
 			log.Fatalf("Error getting namespace: %s", err)
 		}
+		o, _ := cmd.Flags().GetString("output")
 
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
 		keys, err := h.GetPreAuthKeys(n)
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(keys, err, o)
+			return
+		}
+
 		if err != nil {
-			fmt.Println(err)
+			fmt.Printf("Error getting the list of keys: %s\n", err)
 			return
 		}
 		for _, k := range *keys {
@@ -57,6 +64,7 @@ var CreatePreAuthKeyCmd = &cobra.Command{
 		if err != nil {
 			log.Fatalf("Error getting namespace: %s", err)
 		}
+		o, _ := cmd.Flags().GetString("output")
 
 		h, err := getHeadscaleApp()
 		if err != nil {
@@ -75,11 +83,15 @@ var CreatePreAuthKeyCmd = &cobra.Command{
 			expiration = &exp
 		}
 
-		_, err = h.CreatePreAuthKey(n, reusable, expiration)
+		k, err := h.CreatePreAuthKey(n, reusable, expiration)
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(k, err, o)
+			return
+		}
 		if err != nil {
 			fmt.Println(err)
 			return
 		}
-		fmt.Printf("Ook.\n")
+		fmt.Printf("Key: %s\n", k.Key)
 	},
 }

cmd/headscale/cli/routes.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"fmt"
 	"log"
+	"strings"
 
 	"github.com/spf13/cobra"
 )
@@ -26,16 +27,24 @@ var ListRoutesCmd = &cobra.Command{
 		if err != nil {
 			log.Fatalf("Error getting namespace: %s", err)
 		}
+		o, _ := cmd.Flags().GetString("output")
 
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
 		routes, err := h.GetNodeRoutes(n, args[0])
+
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(routes, err, o)
+			return
+		}
+
 		if err != nil {
 			fmt.Println(err)
 			return
 		}
+
 		fmt.Println(routes)
 	},
 }
@@ -54,15 +63,22 @@ var EnableRouteCmd = &cobra.Command{
 		if err != nil {
 			log.Fatalf("Error getting namespace: %s", err)
 		}
+		o, _ := cmd.Flags().GetString("output")
 
 		h, err := getHeadscaleApp()
 		if err != nil {
 			log.Fatalf("Error initializing: %s", err)
 		}
-		err = h.EnableNodeRoute(n, args[0], args[1])
+		route, err := h.EnableNodeRoute(n, args[0], args[1])
+		if strings.HasPrefix(o, "json") {
+			JsonOutput(route, err, o)
+			return
+		}
+
 		if err != nil {
 			fmt.Println(err)
 			return
 		}
+		fmt.Printf("Enabled route %s\n", route)
 	},
 }

cmd/headscale/cli/utils.go

@@ -1,6 +1,8 @@
 package cli
 
 import (
+	"encoding/json"
+	"fmt"
 	"io"
 	"log"
 	"os"
@@ -13,6 +15,10 @@ import (
 	"tailscale.com/tailcfg"
 )
 
+type ErrorOutput struct {
+	Error string
+}
+
 func absPath(path string) string {
 	// If a relative path is provided, prefix it with the the directory where
 	// the config file was found.
@@ -72,3 +78,35 @@ func loadDerpMap(path string) (*tailcfg.DERPMap, error) {
 	err = yaml.Unmarshal(b, &derpMap)
 	return &derpMap, err
 }
+
+func JsonOutput(result interface{}, errResult error, outputFormat string) {
+	var j []byte
+	var err error
+	switch outputFormat {
+	case "json":
+		if errResult != nil {
+			j, err = json.MarshalIndent(ErrorOutput{errResult.Error()}, "", "\t")
+			if err != nil {
+				log.Fatalln(err)
+			}
+		} else {
+			j, err = json.MarshalIndent(result, "", "\t")
+			if err != nil {
+				log.Fatalln(err)
+			}
+		}
+	case "json-line":
+		if errResult != nil {
+			j, err = json.Marshal(ErrorOutput{errResult.Error()})
+			if err != nil {
+				log.Fatalln(err)
+			}
+		} else {
+			j, err = json.Marshal(result)
+			if err != nil {
+				log.Fatalln(err)
+			}
+		}
+	}
+	fmt.Println(string(j))
+}

cmd/headscale/headscale.go

@@ -19,6 +19,11 @@ var versionCmd = &cobra.Command{
 	Short: "Print the version.",
 	Long:  "The version of headscale.",
 	Run: func(cmd *cobra.Command, args []string) {
+		o, _ := cmd.Flags().GetString("output")
+		if strings.HasPrefix(o, "json") {
+			cli.JsonOutput(map[string]string{"version": version}, nil, o)
+			return
+		}
 		fmt.Println(version)
 	},
 }
@@ -123,6 +128,8 @@ func main() {
 	cli.CreatePreAuthKeyCmd.PersistentFlags().Bool("reusable", false, "Make the preauthkey reusable")
 	cli.CreatePreAuthKeyCmd.Flags().StringP("expiration", "e", "", "Human-readable expiration of the key (30m, 24h, 365d...)")
 
+	headscaleCmd.PersistentFlags().StringP("output", "o", "", "Output format. Empty for human-readable, 'json' or 'json-line'")
+
 	if err := headscaleCmd.Execute(); err != nil {
 		fmt.Println(err)
 		os.Exit(-1)

routes.go

@@ -26,18 +26,18 @@ func (h *Headscale) GetNodeRoutes(namespace string, nodeName string) (*[]netaddr
 
 // EnableNodeRoute enables a subnet route advertised by a node (identified by
 // namespace and node name)
-func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr string) error {
+func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr string) (*netaddr.IPPrefix, error) {
 	m, err := h.GetMachine(namespace, nodeName)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	hi, err := m.GetHostInfo()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	route, err := netaddr.ParseIPPrefix(routeStr)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	for _, rIP := range hi.RoutableIPs {
@@ -45,7 +45,7 @@ func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr
 			db, err := h.db()
 			if err != nil {
 				log.Printf("Cannot open DB: %s", err)
-				return err
+				return nil, err
 			}
 
 			routes, _ := json.Marshal([]string{routeStr}) // TODO: only one for the time being, so overwriting the rest
@@ -53,6 +53,10 @@ func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr
 			db.Save(&m)
 			db.Close()
 
+			// THIS IS COMPLETELY USELESS.
+			// The peers map is stored in memory in the server process.
+			// Definetely not accessible from the CLI tool.
+			// We need RPC to the server - or some kind of 'needsUpdate' field in the DB
 			peers, _ := h.getPeers(*m)
 			h.pollMu.Lock()
 			for _, p := range *peers {
@@ -61,9 +65,9 @@ func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr
 				}
 			}
 			h.pollMu.Unlock()
-			return nil
+			return &rIP, nil
 		}
 	}
 
-	return errors.New("could not find routable range")
+	return nil, errors.New("could not find routable range")
 }

utils.go

@@ -105,8 +105,8 @@ func getRandomIP() (*net.IP, error) {
 	ipo, ipnet, err := net.ParseCIDR("100.64.0.0/10")
 	if err == nil {
 		ip := ipo.To4()
-		fmt.Println("In Randomize IPAddr: IP ", ip, " IPNET: ", ipnet)
-		fmt.Println("Final address is ", ip)
+		// fmt.Println("In Randomize IPAddr: IP ", ip, " IPNET: ", ipnet)
+		// fmt.Println("Final address is ", ip)
 		// fmt.Println("Broadcast address is ", ipb)
 		// fmt.Println("Network address is ", ipn)
 		r := mathrand.Uint32()
@@ -119,7 +119,7 @@ func getRandomIP() (*net.IP, error) {
 			ip[i] = ip[i] + (v &^ ipnet.Mask[i])
 			// fmt.Println("IP After: ", ip[i])
 		}
-		fmt.Println("FINAL IP: ", ip.String())
+		// fmt.Println("FINAL IP: ", ip.String())
 		return &ip, nil
 	}