From 2f7463ebe318b13eabf5e31a5535e97f04014001 Mon Sep 17 00:00:00 2001
From: Pavel Sviderski <me@psviderski.name>
Date: Wed, 25 Sep 2024 23:59:56 +1000
Subject: [PATCH] refactor corrosion into interface service

---
 internal/machine/corrosion.go | 38 +++++++++++++++++++++++++++++++++++
 internal/machine/machine.go   |  4 +++-
 internal/machine/network.go   | 13 +++++++++++-
 3 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 internal/machine/corrosion.go

diff --git a/internal/machine/corrosion.go b/internal/machine/corrosion.go
new file mode 100644
index 00000000..d0d4b273
--- /dev/null
+++ b/internal/machine/corrosion.go
@@ -0,0 +1,38 @@
+package machine
+
+import (
+	"fmt"
+	"log/slog"
+	"os/exec"
+)
+
+const (
+	CorrosionSystemdUnit = "uncloud-corrosion.service"
+)
+
+type CorrosionService interface {
+	Configure() error
+	Start() error
+}
+
+type CorrosionSystemdService struct {
+	Unit    string
+	DataDir string
+}
+
+func (s *CorrosionSystemdService) Configure() error {
+	return nil
+}
+
+func (s *CorrosionSystemdService) Start() error {
+	unit := s.Unit
+	if unit == "" {
+		unit = CorrosionSystemdUnit
+	}
+
+	if _, err := exec.Command("systemctl", "start", unit).Output(); err != nil {
+		return fmt.Errorf("start %s: %w", unit, err)
+	}
+	slog.Info("Corrosion systemd service started.", "unit", unit)
+	return nil
+}
diff --git a/internal/machine/machine.go b/internal/machine/machine.go
index 2fbd941b..30933369 100644
--- a/internal/machine/machine.go
+++ b/internal/machine/machine.go
@@ -15,6 +15,7 @@ import (
 	"net/netip"
 	"os"
 	"os/user"
+	"path/filepath"
 	"strconv"
 	"uncloud/internal/machine/api/pb"
 	"uncloud/internal/machine/cluster"
@@ -173,7 +174,8 @@ func (m *Machine) Run(ctx context.Context) error {
 					var err error
 					slog.Info("Starting network controller.")
 					networkServer := newGRPCServer(m, m.cluster)
-					ctrl, err = newNetworkController(m.state, networkServer, m.newMachinesCh)
+					corrosion := &CorrosionSystemdService{DataDir: filepath.Join(m.config.DataDir, "corrosion")}
+					ctrl, err = newNetworkController(m.state, networkServer, corrosion, m.newMachinesCh)
 					if err != nil {
 						return fmt.Errorf("initialise network controller: %w", err)
 					}
diff --git a/internal/machine/network.go b/internal/machine/network.go
index 64e96ff5..5d9ff879 100644
--- a/internal/machine/network.go
+++ b/internal/machine/network.go
@@ -23,12 +23,15 @@ type networkController struct {
 	state         *State
 	wgnet         *network.WireGuardNetwork
 	server        *grpc.Server
+	corrosion     CorrosionService
 	newMachinesCh <-chan *pb.MachineInfo
 	// TODO: DNS server/resolver listening on the machine IP, e.g. 10.210.0.1:53. It can't listen on 127.0.X.X
 	//  like resolved does because it needs to be reachable from both the host and the containers.
 }
 
-func newNetworkController(state *State, server *grpc.Server, newMachCh <-chan *pb.MachineInfo) (
+func newNetworkController(
+	state *State, server *grpc.Server, corrosion CorrosionService, newMachCh <-chan *pb.MachineInfo,
+) (
 	*networkController, error,
 ) {
 	slog.Info("Starting WireGuard network.")
@@ -41,6 +44,7 @@ func newNetworkController(state *State, server *grpc.Server, newMachCh <-chan *p
 		state:         state,
 		wgnet:         wgnet,
 		server:        server,
+		corrosion:     corrosion,
 		newMachinesCh: newMachCh,
 	}, nil
 }
@@ -51,6 +55,13 @@ func (nc *networkController) Run(ctx context.Context) error {
 	}
 	slog.Info("WireGuard network configured.")
 
+	if err := nc.corrosion.Configure(); err != nil {
+		return err
+	}
+	if err := nc.corrosion.Start(); err != nil {
+		return err
+	}
+
 	errGroup, ctx := errgroup.WithContext(ctx)
 
 	// Start the network API server. Assume the management IP can't be changed when the network is running.