emissary/internal/agent/controller/openwrt/uci_controller.go

package openwrt

import (
	"bytes"
	"context"
	"os"
	"os/exec"

	"forge.cadoles.com/Cadoles/emissary/internal/agent"
	"forge.cadoles.com/Cadoles/emissary/internal/openwrt/uci"
	ucispec "forge.cadoles.com/Cadoles/emissary/internal/spec/uci"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/logger"
)

type UCIController struct {
	binPath             string
	currentSpecRevision int
}

// Name implements node.Controller.
func (*UCIController) Name() string {
	return "uci-controller"
}

// Reconcile implements node.Controller.
func (c *UCIController) Reconcile(ctx context.Context, state *agent.State) error {
	uciSpec := ucispec.NewSpec()

	if err := state.GetSpec(ucispec.Name, ucispec.Version, uciSpec); err != nil {
		if errors.Is(err, agent.ErrSpecNotFound) {
			logger.Info(ctx, "could not find uci spec, doing nothing")

			return nil
		}

		return errors.WithStack(err)
	}

	logger.Info(ctx, "retrieved spec",
		logger.F("name", uciSpec.SpecDefinitionName()),
		logger.F("version", uciSpec.SpecDefinitionVersion()),
		logger.F("revision", uciSpec.SpecRevision()),
	)

	if c.currentSpecRevision == uciSpec.SpecRevision() {
		logger.Info(ctx, "spec revision did not change, doing nothing")

		return nil
	}

	if err := c.updateConfiguration(ctx, uciSpec); err != nil {
		err = errors.WithStack(err)
		logger.Error(ctx, "could not update configuration", logger.CapturedE(err))

		return nil
	}

	c.currentSpecRevision = uciSpec.SpecRevision()
	logger.Info(ctx, "updating current spec revision", logger.F("revision", c.currentSpecRevision))

	return nil
}

func (c *UCIController) updateConfiguration(ctx context.Context, spec *ucispec.Spec) error {
	logger.Info(ctx, "importing uci config")

	if err := c.importConfig(ctx, spec.Config); err != nil {
		return errors.WithStack(err)
	}

	if err := c.execPostImportCommands(ctx, spec.PostImportCommands); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

func (c *UCIController) importConfig(ctx context.Context, uci *uci.UCI) error {
	cmd := exec.CommandContext(ctx, c.binPath, "import")

	var buf bytes.Buffer

	if _, err := buf.WriteString(uci.Export()); err != nil {
		return errors.WithStack(err)
	}

	cmd.Stdin = &buf
	cmd.Stderr = os.Stderr
	cmd.Stdout = os.Stdout

	if err := cmd.Run(); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

func (c *UCIController) execPostImportCommands(ctx context.Context, commands []*ucispec.UCIPostImportCommand) error {
	for _, postImportCmd := range commands {
		cmd := exec.CommandContext(ctx, postImportCmd.Command, postImportCmd.Args...)

		cmd.Stderr = os.Stderr
		cmd.Stdout = os.Stdout

		if err := cmd.Run(); err != nil {
			return errors.WithStack(err)
		}
	}

	return nil
}

func NewUCIController(binPath string) *UCIController {
	return &UCIController{
		binPath:             binPath,
		currentSpecRevision: -1,
	}
}

var _ agent.Controller = &UCIController{}