fix: service restart (including extension services)

Fixes #6707

There was a race condition between different parts of the service code:
`Stop` waits for the event which is published before the service is
removed from the `running[id]` map, so if one does `Stop` followed by
`Start` (this is what `services restart` API does), by the time it goes
to `Start` it might be still in the `running[id]` map, so `Start` does
nothing.

Overall this code should be rewritten and simplified, but for now move
out sending these "terminal" events out so that by the time the event is
published, the service is stopped and removed from the `running[id]`
map.

Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

internal/app/machined/pkg/system/service_runner.go

@@ -6,6 +6,7 @@ package system
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
 	"sync"
@@ -182,12 +183,17 @@ func (svcrunner *ServiceRunner) waitFor(ctx context.Context, condition condition
 	}
 }
 
-// Start initializes the service and runs it
+// ErrSkip is returned by Run when service is skipped.
+var ErrSkip = errors.New("service skipped")
+
+// Run initializes the service and runs it.
+//
+// Run returns an error when a service stops.
 //
-// Start should be run in a goroutine.
+// Run should be run in a goroutine.
 //
 //nolint:gocyclo
-func (svcrunner *ServiceRunner) Start() {
+func (svcrunner *ServiceRunner) Run() error {
 	defer func() {
 		// reset context for the next run
 		svcrunner.ctxMu.Lock()
@@ -215,27 +221,21 @@ func (svcrunner *ServiceRunner) Start() {
 
 	if condition != nil {
 		if err := svcrunner.waitFor(ctx, condition); err != nil {
-			svcrunner.UpdateState(ctx, events.StateFailed, "Condition failed: %v", err)
-
-			return
+			return fmt.Errorf("condition failed: %w", err)
 		}
 	}
 
 	svcrunner.UpdateState(ctx, events.StatePreparing, "Running pre state")
 
 	if err := svcrunner.service.PreFunc(ctx, svcrunner.runtime); err != nil {
-		svcrunner.UpdateState(ctx, events.StateFailed, "Failed to run pre stage: %v", err)
-
-		return
+		return fmt.Errorf("failed to run pre stage: %w", err)
 	}
 
 	svcrunner.UpdateState(ctx, events.StatePreparing, "Creating service runner")
 
 	runnr, err := svcrunner.service.Runner(svcrunner.runtime)
 	if err != nil {
-		svcrunner.UpdateState(ctx, events.StateFailed, "Failed to create runner: %v", err)
-
-		return
+		return fmt.Errorf("failed to create runner: %w", err)
 	}
 
 	defer func() {
@@ -248,16 +248,14 @@ func (svcrunner *ServiceRunner) Start() {
 	}()
 
 	if runnr == nil {
-		svcrunner.UpdateState(ctx, events.StateSkipped, "Service skipped")
-
-		return
+		return ErrSkip
 	}
 
 	if err := svcrunner.run(ctx, runnr); err != nil {
-		svcrunner.UpdateState(ctx, events.StateFailed, "Failed running service: %v", err)
-	} else {
-		svcrunner.UpdateState(ctx, events.StateFinished, "Service finished successfully")
+		return fmt.Errorf("failed running service: %w", err)
 	}
+
+	return nil
 }
 
 //nolint:gocyclo