Allow getting the config from remote server

config/go.mod

@@ -2,7 +2,10 @@ module git.faercol.me/faercol/http-boot-config/config
 
 go 1.20
 
-require github.com/stretchr/testify v1.8.4
+require (
+	github.com/google/uuid v1.3.0
+	github.com/stretchr/testify v1.8.4
+)
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect

config/go.sum

@@ -1,5 +1,7 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=

config/main.go

@@ -1,13 +1,17 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"flag"
+	"fmt"
 	"io/fs"
 	"os"
 
 	"git.faercol.me/faercol/http-boot-config/config/logger"
 	"git.faercol.me/faercol/http-boot-config/config/prober"
+	"git.faercol.me/faercol/http-boot-config/config/remote"
+	"github.com/google/uuid"
 )
 
 type action int
@@ -19,9 +23,12 @@ const (
 )
 
 type cliArgs struct {
-	debug  bool
-	colour bool
-	action action
+	debug       bool
+	colour      bool
+	action      action
+	id          uuid.UUID
+	remoteAddr  string
+	prettyPrint bool
 }
 
 var defaultArgs cliArgs = cliArgs{
@@ -34,9 +41,13 @@ func parseArgs() (cliArgs, error) {
 	args := defaultArgs
 	var firstArg int
 
-	getRemoteFlagSet := flag.NewFlagSet("get-remote", flag.ExitOnError)
 	listFlagSet := flag.NewFlagSet("list", flag.ExitOnError)
 
+	getRemoteFlagSet := flag.NewFlagSet("get-remote", flag.ExitOnError)
+	uuidFlag := getRemoteFlagSet.String("uuid", "", "Client UUID")
+	remoteFlag := getRemoteFlagSet.String("remote-host", "http://localhost:5000", "Address for the remote boot server")
+	jsonFlag := getRemoteFlagSet.Bool("json", false, "Display the result in JSON format")
+
 	debugFlag := flag.Bool("debug", false, "Display debug logs")
 	noColourFlag := flag.Bool("no-colour", false, "Disable colour logs")
 
@@ -57,6 +68,13 @@ func parseArgs() (cliArgs, error) {
 		listFlagSet.Parse(os.Args[firstArg:])
 	case actionGetRemote:
 		getRemoteFlagSet.Parse(os.Args[firstArg:])
+		parsedID, err := uuid.Parse(*uuidFlag)
+		if err != nil {
+			return args, fmt.Errorf("invalid format for uuid %q", *uuidFlag)
+		}
+		args.id = parsedID
+		args.remoteAddr = *remoteFlag
+		args.prettyPrint = !*jsonFlag
 	default:
 		flag.Parse()
 		return cliArgs{}, errors.New("missing an action")
@@ -88,8 +106,17 @@ func displayAppList(l *logger.SimpleLogger) {
 	}
 }
 
-func getRemoteConfig(l *logger.SimpleLogger) {
+func getRemoteConfig(l *logger.SimpleLogger, host string, id uuid.UUID, pretty bool) {
 	l.Info("Getting config from remote server...")
+	if pretty {
+		if err := remote.DisplayRemoteConfigPretty(context.Background(), host, id, l); err != nil {
+			l.Fatal(err.Error())
+		}
+	} else {
+		if err := remote.DisplayRemoteConfigJSON(context.Background(), host, id, l); err != nil {
+			l.Fatal(err.Error())
+		}
+	}
 }
 
 func main() {
@@ -99,12 +126,13 @@ func main() {
 		l.Fatalf("Invalid command: %s", err.Error())
 	}
 	l := logger.New(args.colour, args.debug)
+	fmt.Print("")
 
 	switch args.action {
 	case actionList:
 		displayAppList(l)
 	case actionGetRemote:
-		getRemoteConfig(l)
+		getRemoteConfig(l, args.remoteAddr, args.id, args.prettyPrint)
 	default:
 		l.Fatal("Unknown action")
 	}

config/remote/remote.go

@@ -0,0 +1,111 @@
+package remote
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"git.faercol.me/faercol/http-boot-config/config/logger"
+	"github.com/google/uuid"
+)
+
+var ErrNotEnrolled = errors.New("client not enrolled")
+
+const getBootRoute = "/config"
+const reqTimeout = 5 * time.Second
+
+type clientConfig struct {
+	EFIConfig struct {
+		ID      string `json:"ID"`
+		Name    string `json:"name"`
+		Options map[string]struct {
+			Name string `json:"name"`
+			Path string `json:"path"`
+		} `json:"options"`
+		SelectedOption string `json:"selected_option"`
+	} `json:"efi_config"`
+	NetConfig struct {
+		MulticastGroup string `json:"multicast_group"`
+		Port           int    `json:"port"`
+	} `json:"net_config"`
+}
+
+func getRemoteConfig(ctx context.Context, host string, id uuid.UUID, l *logger.SimpleLogger) ([]byte, error) {
+	subCtx, cancel := context.WithTimeout(ctx, reqTimeout)
+	defer cancel()
+	req, err := http.NewRequestWithContext(subCtx, http.MethodGet, host+getBootRoute, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+	q := req.URL.Query()
+	q.Add("id", id.String())
+	req.URL.RawQuery = q.Encode()
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to query server: %w", err)
+	}
+
+	switch resp.StatusCode {
+	case http.StatusBadRequest:
+		return nil, fmt.Errorf("invalid UUID")
+	case http.StatusNotFound:
+		return nil, ErrNotEnrolled
+	case http.StatusOK:
+		dat, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read response: %w", err)
+		}
+		return dat, nil
+	default:
+		return nil, fmt.Errorf("unexpected server error (%d)", resp.StatusCode)
+	}
+}
+
+func DisplayRemoteConfigJSON(ctx context.Context, host string, id uuid.UUID, l *logger.SimpleLogger) error {
+	dat, err := getRemoteConfig(ctx, host, id, l)
+	if err != nil {
+		return err
+	}
+
+	// We want to prettify the output for the user
+	buf := bytes.NewBuffer(nil)
+	if err := json.Indent(buf, dat, "", "  "); err != nil {
+		return fmt.Errorf("failed to format result: %w", err)
+	}
+
+	l.Info(buf.String())
+	return nil
+}
+
+func DisplayRemoteConfigPretty(ctx context.Context, host string, id uuid.UUID, l *logger.SimpleLogger) error {
+	dat, err := getRemoteConfig(ctx, host, id, l)
+	if err != nil {
+		return err
+	}
+
+	var parsedConf clientConfig
+	if err := json.Unmarshal(dat, &parsedConf); err != nil {
+		return fmt.Errorf("invalid JSON format for result: %w", err)
+	}
+
+	l.Infof("Got the following config for client %s:", parsedConf.EFIConfig.Name)
+	selectedOption, ok := parsedConf.EFIConfig.Options[parsedConf.EFIConfig.SelectedOption]
+	if !ok {
+		l.Info(" * No selected boot option for client")
+	} else {
+		l.Infof(" * Client is set to boot to %s", selectedOption.Name)
+	}
+	l.Info(" * Available options are:")
+	for _, option := range parsedConf.EFIConfig.Options {
+		l.Infof("\t - %s: %s", option.Name, option.Path)
+	}
+	l.Infof(" * Remote boot server is listening on %s:%d", parsedConf.NetConfig.MulticastGroup, parsedConf.NetConfig.Port)
+
+	return nil
+}