Implement new configuration strategy for httpboot plugin (#243)

* Implement new configuration strategy for HTTPBOOT plugin

* Fix complaince check

* Add test configs dynamically

* Update Readme.md

* Refactor tests

Fix some debugging output

---------

Co-authored-by: kkumar <[email protected]>
Co-authored-by: Damyan Yordanov <[email protected]>

README.md

@@ -30,9 +30,14 @@ Implements HTTP boot from [Unifed Kernel Image](https://uapi-group.org/specifica
 Delivers the HTTP boot image as a [BootFileURL](https://www.rfc-editor.org/rfc/rfc5970.html#section-3.2). Based on configuration it delivers either a client-specific UKIs dynamically or a default UKI for all clients. When client-specific UKIs are configured, IPv6 relays *must* be used, so the client can be identified based on its link-local address (which the relay always provides).
 
 ### Configuration
-A single HTTP(s) URL shall be passed as a string. It must be either
+A single HTTP(s) URL shall be passed as a string in `httpboot_config.yaml` as given below. It must be either
 - a direct URL to an UKI (default UKI for all clients)
-- magic identifier `bootservice:`+ a URL to a boot service delivering dynamically client-specific UKIs based on client identification
+- `clientSpecific: false` deliver default UKI for all clients via a static address
+- `clientSpecific: true` use a boot service delivering dynamically client-specific UKIs, based on client identification
+````yaml
+bootFile: http://[2001:db8::1]/default-image.uki
+clientSpecific: false
+````
 ### Notes
 - not tested on IPv4
 - IPv6 relays are supported

config/default/config.yaml

@@ -14,4 +14,4 @@ data:
           - onmetal:
           - dns: 2001:4860:4860::6464 2001:4860:4860::64
           - pxeboot: pxeboot_config.yaml
-          - httpboot: bootservice:http://example.com/boot-operator-endpoint:8083
+          - httpboot: httpboot_config.yaml

example/config.yaml

@@ -8,7 +8,7 @@ server6:
         # always provide the same IP address, no matter who's asking:
         # - bluefield: bluefield_config.yaml
         # implement HTTPBoot
-        - httpboot: http://[2001:db8::1]/image.uki
+        - httpboot: httpboot_config.yaml
         # add leased IPs to ironcore's IPAM
         - ipam: ipam_config.yaml
         # lease IPs based on /127 subnets coming from relays running on the switches

example/httpboot_config.yaml

@@ -0,0 +1,2 @@
+bootFile: http://[2001:db8::1]/default-image.uki
+clientSpecific: false

internal/api/httpboot_config.go

@@ -0,0 +1,9 @@
+// SPDX-FileCopyrightText: 2024 SAP SE or an SAP affiliate company and IronCore contributors
+// SPDX-License-Identifier: MIT
+
+package api
+
+type HttpBootConfig struct {
+	BootFile       string `yaml:"bootFile"`
+	ClientSpecific bool   `yaml:"clientSpecific"`
+}

plugins/httpboot/plugin.go

@@ -10,13 +10,16 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"os"
 	"strings"
 
 	"github.com/coredhcp/coredhcp/handler"
 	"github.com/coredhcp/coredhcp/logger"
 	"github.com/coredhcp/coredhcp/plugins"
 	"github.com/insomniacslk/dhcp/dhcpv4"
 	"github.com/insomniacslk/dhcp/dhcpv6"
+	"github.com/ironcore-dev/fedhcp/internal/api"
+	"gopkg.in/yaml.v2"
 )
 
 var bootFile4 string
@@ -33,27 +36,50 @@ var Plugin = plugins.Plugin{
 
 const httpClient = "HTTPClient"
 
-func parseArgs(args ...string) (*url.URL, bool, error) {
+func parseArgs(args ...string) (string, error) {
 	if len(args) != 1 {
-		return nil, false, fmt.Errorf("exactly one argument must be passed to the httpboot plugin, got %d", len(args))
+		return "", fmt.Errorf("exactly one argument must be passed to the plugin, got %d", len(args))
 	}
-	arg := args[0]
-	useBootService := strings.HasPrefix(arg, "bootservice:")
-	if useBootService {
-		arg = strings.TrimPrefix(arg, "bootservice:")
+	return args[0], nil
+}
+
+func loadConfig(args ...string) (*api.HttpBootConfig, error) {
+	path, err := parseArgs(args...)
+	if err != nil {
+		return nil, fmt.Errorf("invalid configuration: %v", err)
+	}
+
+	log.Debugf("Reading config file %s", path)
+	configData, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read config file: %v", err)
+	}
+
+	config := &api.HttpBootConfig{}
+	if err = yaml.Unmarshal(configData, config); err != nil {
+		return nil, fmt.Errorf("failed to parse config file: %v", err)
+	}
+	return config, nil
+}
+
+func parseConfig(args ...string) (*url.URL, bool, error) {
+	httpbootConfig, err := loadConfig(args...)
+	if err != nil {
+		return nil, false, fmt.Errorf("erorr loading plugin configuration: %v", err)
 	}
+	arg := httpbootConfig.BootFile
 	parsedURL, err := url.Parse(arg)
 	if err != nil {
 		return nil, false, fmt.Errorf("invalid URL: %v", err)
 	}
 	if (parsedURL.Scheme != "http" && parsedURL.Scheme != "https") || parsedURL.Host == "" || parsedURL.Path == "" {
 		return nil, false, fmt.Errorf("malformed httpboot parameter, should be a valid HTTP(s) URL")
 	}
-	return parsedURL, useBootService, nil
+	return parsedURL, httpbootConfig.ClientSpecific, nil
 }
 
 func setup6(args ...string) (handler.Handler6, error) {
-	u, ubs, err := parseArgs(args...)
+	u, ubs, err := parseConfig(args...)
 	if err != nil {
 		return nil, fmt.Errorf("invalid configuration: %v", err)
 	}
@@ -64,7 +90,7 @@ func setup6(args ...string) (handler.Handler6, error) {
 }
 
 func setup4(args ...string) (handler.Handler4, error) {
-	u, ubs, err := parseArgs(args...)
+	u, ubs, err := parseConfig(args...)
 	if err != nil {
 		return nil, fmt.Errorf("invalid configuration: %v", err)
 	}