snapshot: Lock instances before making snapshot

cmd/instance_lock.go

@@ -0,0 +1,67 @@
+package cmd
+
+import (
+	wisski_distillery "github.com/FAU-CDI/wisski-distillery"
+	"github.com/FAU-CDI/wisski-distillery/internal/core"
+	"github.com/tkw1536/goprogram/exit"
+)
+
+// InstanceLock is then 'instance_lock' command
+var InstanceLock wisski_distillery.Command = instanceLock{}
+
+type instanceLock struct {
+	Lock        bool `short:"l" long:"lock" description:"Lock the provided WissKI instance"`
+	Unlock      bool `short:"u" long:"unlock" description:"Unlock the provided WissKI instance"`
+	Positionals struct {
+		Slug string `positional-arg-name:"SLUG" required:"1-1" description:"slug of instance to lock or unlock"`
+	} `positional-args:"true"`
+}
+
+func (instanceLock) Description() wisski_distillery.Description {
+	return wisski_distillery.Description{
+		Requirements: core.Requirements{
+			NeedsDistillery: true,
+		},
+		Command:     "instance_lock",
+		Description: "Locks or unlocks a WissKI instance",
+	}
+}
+
+var errLockUnlockExcluded = exit.Error{
+	Message:  "Exactly one of `--lock` and `--unlock` must be provied",
+	ExitCode: exit.ExitCommandArguments,
+}
+
+func (l instanceLock) AfterParse() error {
+	if l.Lock == l.Unlock {
+		return errLockUnlockExcluded
+	}
+	return nil
+}
+
+var errNotUnlock = exit.Error{
+	Message:  "Unable to unlock instance: Not locked",
+	ExitCode: exit.ExitCommandArguments,
+}
+
+func (l instanceLock) Run(context wisski_distillery.Context) error {
+	instance, err := context.Environment.Instances().WissKI(l.Positionals.Slug)
+	if err != nil {
+		return err
+	}
+
+	if l.Unlock {
+		if !instance.Unlock() {
+			return errNotUnlock
+		}
+		context.Println("unlocked")
+		return nil
+	}
+
+	if err := instance.TryLock(); err != nil {
+		return err
+	}
+
+	context.Println("locked")
+	return nil
+}