feat: add webconfig service

If no configuration source is provided (on baremetal only for now), Talos will set of a simple web service to receive its configuration via an HTTP POST request, on port 80 or 443.
It also serves a simple web form for interactive submission from the browser.

Fixes siderolabs#2593

Signed-off-by: Seán C McCord <[email protected]>

internal/app/machined/pkg/runtime/v1alpha1/platform/container/container.go

@@ -7,14 +7,14 @@ package container
 import (
 	"context"
 	"encoding/base64"
-	"errors"
 	"log"
 	"net"
 	"os"
 
 	"github.com/talos-systems/go-procfs/procfs"
 
 	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime"
+	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime/v1alpha1/platform/errors"
 )
 
 // Container is a platform for installing Talos via an Container image.
@@ -29,9 +29,9 @@ func (c *Container) Name() string {
 func (c *Container) Configuration(context.Context) ([]byte, error) {
 	log.Printf("fetching machine config from: USERDATA environment variable")
 
-	s, ok := os.LookupEnv("USERDATA")
-	if !ok {
-		return nil, errors.New("missing USERDATA environment variable")
+	s := os.Getenv("USERDATA")
+	if s == "" {
+		return nil, errors.ErrNoConfigSource
 	}
 
 	decoded, err := base64.StdEncoding.DecodeString(s)

internal/app/machined/pkg/runtime/v1alpha1/platform/errors/errors.go

@@ -0,0 +1,10 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package errors
+
+import "errors"
+
+// ErrNoConfigSource indicates that the platform does not have a configured source for the configuration.
+var ErrNoConfigSource = errors.New("no configuration source")

internal/app/machined/pkg/runtime/v1alpha1/platform/metal/metal.go

@@ -21,6 +21,7 @@ import (
 	"github.com/talos-systems/go-blockdevice/blockdevice/probe"
 
 	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime"
+	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime/v1alpha1/platform/errors"
 	"github.com/talos-systems/talos/pkg/download"
 	"github.com/talos-systems/talos/pkg/machinery/constants"
 )
@@ -43,7 +44,7 @@ func (m *Metal) Name() string {
 func (m *Metal) Configuration(ctx context.Context) ([]byte, error) {
 	var option *string
 	if option = procfs.ProcCmdline().Get(constants.KernelParamConfig).First(); option == nil {
-		return nil, fmt.Errorf("no config option was found")
+		return nil, errors.ErrNoConfigSource
 	}
 
 	log.Printf("fetching machine config from: %q", *option)

internal/app/machined/pkg/runtime/v1alpha1/v1alpha1_sequencer_tasks.go

@@ -40,6 +40,7 @@ import (
 	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime"
 	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime/v1alpha1/bootloader"
 	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub"
+	perrors "github.com/talos-systems/talos/internal/app/machined/pkg/runtime/v1alpha1/platform/errors"
 	"github.com/talos-systems/talos/internal/app/machined/pkg/system"
 	"github.com/talos-systems/talos/internal/app/machined/pkg/system/events"
 	"github.com/talos-systems/talos/internal/app/machined/pkg/system/services"
@@ -51,6 +52,7 @@ import (
 	"github.com/talos-systems/talos/internal/pkg/kmsg"
 	"github.com/talos-systems/talos/internal/pkg/kubeconfig"
 	"github.com/talos-systems/talos/internal/pkg/mount"
+	"github.com/talos-systems/talos/internal/pkg/webconfig"
 	"github.com/talos-systems/talos/pkg/cmd"
 	"github.com/talos-systems/talos/pkg/conditions"
 	"github.com/talos-systems/talos/pkg/images"
@@ -428,6 +430,13 @@ func LoadConfig(seq runtime.Sequence, data interface{}) (runtime.TaskExecutionFu
 			defer ctxCancel()
 
 			b, e := fetchConfig(fetchCtx, r)
+			if errors.Is(e, perrors.ErrNoConfigSource) {
+				b, e = receiveConfigViaWebconfig(ctx, logger, r)
+				if e != nil {
+					return fmt.Errorf("failed to receive config via webconfig: %w", err)
+				}
+			}
+
 			if e != nil {
 				return e
 			}
@@ -541,6 +550,29 @@ func fetchConfig(ctx context.Context, r runtime.Runtime) (out []byte, err error)
 	return b, nil
 }
 
+func receiveConfigViaWebconfig(ctx context.Context, logger *log.Logger, r runtime.Runtime) ([]byte, error) {
+	cfgBytes, err := webconfig.Run(ctx, logger, r.State().Platform().Mode())
+	if err != nil {
+		return nil, fmt.Errorf("failed to receive config via webconfig: %w", err)
+	}
+
+	provider, err := configloader.NewFromBytes(cfgBytes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create config provider from webconfig bytes: %w", err)
+	}
+
+	if err = provider.Validate(r.State().Platform().Mode()); err != nil {
+		return nil, fmt.Errorf("failed to validate config received from webconfig: %w", err)
+	}
+
+	processedBytes, err := provider.Bytes()
+	if err != nil {
+		return nil, fmt.Errorf("failed to export validated webconfig to bytes: %w", err)
+	}
+
+	return processedBytes, nil
+}
+
 // ValidateConfig validates the config.
 func ValidateConfig(seq runtime.Sequence, data interface{}) (runtime.TaskExecutionFunc, string) {
 	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) error {