Implement new configuration strategy for pxeboot plugin (#241)

* Implement new configuration strategy for PXEBOOT plugin

* Fix tests

* Fix reuse complaince check

* Update readme

* Dynamically create test configuration data

Do not check in test configuration that small, go for dynamic generation
instead

---------

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

README.md

@@ -96,9 +96,7 @@ subnetLabel: subnet=dhcp
 The Metal plugin acts as a connection link between DHCP and the IronCore metal stack. It creates an `EndPoint` object for each machine with leased IP address. Those endpoints are then consumed by the metal operator, who then creates the corresponding `Machine` objects.
 
 ### Configuration
-The metal configuration consists of an inventory list. Currently, there are two different ways to provide an inventory list: either by specifying a MAC address filter or by providing the inventory list explicitly. If both a static list and a filter are specified in the `metal_config.yaml`, the static list gets a precedence, so the filter will be ignored.
-
-Providing an explicit static inventory list in `metal_config.yaml` goes as follows:
+The metal configuration consists of an inventory list. Currently, there are two different ways to provide an inventory list: either by specifying a MAC address filter or by providing the inventory list explicitly. If both a static list and a filter are specified in the `metal_config.yaml`, the static list gets a precedence, so the filter will be ignored. Providing an explicit static inventory list in `metal_config.yaml` goes as follows:
 ```yaml
 hosts:
   - name: server-01
@@ -129,7 +127,13 @@ The PXEBoot plugin implements an (i)PXE network boot.
 
 When configured properly, the PXEBoot plugin will [break the PXE chainloading loop](https://ipxe.org/howto/dhcpd#pxe_chainloading). In such a way legacy PXE clients will be handed out an iPXE environment, whereas iPXE clients (classified based on the user class for [IPv6](https://datatracker.ietf.org/doc/html/rfc8415#section-21.15) and [IPv4](https://www.rfc-editor.org/rfc/rfc3004.html#section-4)) will get the HTTP PXE boot script.
 ### Configuration
-Two parameters shall be passed as strings: an TFTP address to an iPXE environment and an HTTP(s) boot script address. The order matters!
+A TFTP address to an iPXE environment and an HTTP(s) boot script address shall be specified. Providing those in the `pxeboot_config.yaml` goes as follows:
+
+````yaml
+tftpServer: tftp://[2001:db8::1]/ipxe/x86_64/ipxe
+ipxeServer: http://[2001:db8::1]/ipxe/boot6
+````
+
 ### Notes
 - relays are supported for both IPv4 and IPv6
 - TFTP server as well as HTTP boot script server must be provided externally

config/default/config.yaml

@@ -13,5 +13,5 @@ data:
           - ipam: metal-api-system dhcp
           - onmetal:
           - dns: 2001:4860:4860::6464 2001:4860:4860::64
-          - pxeboot: tftp://[2001:db8::1]/ipxe/x86_64/ipxe http://[2001:db8::1]/ipxe/boot6
+          - pxeboot: pxeboot_config.yaml
           - httpboot: bootservice:http://example.com/boot-operator-endpoint:8083

example/config.yaml

@@ -16,6 +16,6 @@ server6:
         # announce DNS servers per DHCP
         - dns: 2001:4860:4860::6464 2001:4860:4860::64
         # implement (i)PXE boot
-        - pxeboot: tftp://[2001:db8::1]/ipxe/x86_64/ipxe http://[2001:db8::1]/ipxe/boot6
+        - pxeboot: pxeboot_config.yaml
         # create Endpoint objects in kubernetes
         - metal: metal_config.yaml

example/pxeboot_config.yaml

@@ -0,0 +1,2 @@
+tftpServer: tftp://[2001:db8::1]/ipxe/x86_64/ipxe
+ipxeServer: http://[2001:db8::1]/ipxe/boot6

internal/api/pxeboot_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 PxebootConfig struct {
+	TFTPServer string `yaml:"tftpServer"`
+	IPXEServer string `yaml:"ipxeServer"`
+}

plugins/pxeboot/plugin.go

@@ -14,16 +14,19 @@
 //
 // server6:
 //   - plugins:
-//   - pxeboot: tftp://[2001:db8::dead]/pxe-file http://[2001:db8:a::1]/ipxe-file
+//   - pxeboot: pxeboot_config.yaml
 
 package pxeboot
 
 import (
 	"fmt"
 	"net/url"
+	"os"
 
 	"github.com/insomniacslk/dhcp/dhcpv4"
 	"github.com/insomniacslk/dhcp/iana"
+	"github.com/ironcore-dev/fedhcp/internal/api"
+	"gopkg.in/yaml.v2"
 
 	"github.com/coredhcp/coredhcp/handler"
 	"github.com/coredhcp/coredhcp/logger"
@@ -45,19 +48,48 @@ var (
 	tftpBootFileOption, tftpServerNameOption, ipxeBootFileOption *dhcpv4.Option
 )
 
-func parseArgs(args ...string) (*url.URL, *url.URL, error) {
-	if len(args) != 2 {
-		return nil, nil, fmt.Errorf("exactly two arguments must be passed to PXEBOOT plugin, got %d", len(args))
+// args[0] = path to config file
+func parseArgs(args ...string) (string, error) {
+	if len(args) != 1 {
+		return "", fmt.Errorf("exactly one argument must be passed to the pxeboot plugin, got %d", len(args))
+	}
+	return args[0], nil
+}
+
+func loadConfig(args ...string) (*api.PxebootConfig, error) {
+	path, err := parseArgs(args...)
+	if err != nil {
+		return nil, fmt.Errorf("invalid configuration: %v", err)
 	}
 
-	tftp, err := url.Parse(args[0])
+	log.Debugf("Reading pxeboot config file %s", path)
+	configData, err := os.ReadFile(path)
 	if err != nil {
-		return nil, nil, err
+		return nil, fmt.Errorf("failed to read config file: %v", err)
 	}
 
-	ipxe, err := url.Parse(args[1])
+	config := &api.PxebootConfig{}
+	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, *url.URL, error) {
+	pxebootConfig, err := loadConfig(args...)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("invalid configuration: %v", err)
+	}
+
+	tftp, err := url.Parse(pxebootConfig.TFTPServer)
+	if err != nil {
+		return nil, nil, fmt.Errorf("invalid tftp url: %v", err)
+	}
+
+	ipxe, err := url.Parse(pxebootConfig.IPXEServer)
+	if err != nil {
+		return nil, nil, fmt.Errorf("invalid ipxe url: %v", err)
 	}
 
 	if tftp.Scheme != "tftp" || tftp.Host == "" || tftp.Path == "" || tftp.Path[0] != '/' || tftp.Path[1:] == "" {
@@ -67,13 +99,14 @@ func parseArgs(args ...string) (*url.URL, *url.URL, error) {
 	if (ipxe.Scheme != "http" && ipxe.Scheme != "https") || ipxe.Host == "" || ipxe.Path == "" {
 		return nil, nil, fmt.Errorf("malformed iPXE parameter, should be a valid URL")
 	}
+
 	return tftp, ipxe, nil
 }
 
 func setup4(args ...string) (handler.Handler4, error) {
-	tftp, ipxe, err := parseArgs(args...)
+	tftp, ipxe, err := parseConfig(args...)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("invalid configuration: %v", err)
 	}
 
 	opt1 := dhcpv4.OptBootFileName(tftp.Path[1:])
@@ -133,9 +166,9 @@ func pxeBootHandler4(req, resp *dhcpv4.DHCPv4) (*dhcpv4.DHCPv4, bool) {
 }
 
 func setup6(args ...string) (handler.Handler6, error) {
-	tftp, ipxe, err := parseArgs(args...)
+	tftp, ipxe, err := parseConfig(args...)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("invalid configuration: %v", err)
 	}
 
 	tftpOption = dhcpv6.OptBootFileURL(tftp.String())