Option for delayed pre-pull

internal/commands/worker/config.go

@@ -41,7 +41,7 @@ type Config struct {
 
 	ResourceModifiers []*resourcemodifier.Modifier `yaml:"resource-modifiers"`
 
-	TartPrePull []string `yaml:"tart-pre-pull"`
+	TartPrePull *worker.TartPrePull `yaml:"tart-pre-pull"`
 }
 
 type ConfigLog struct {
@@ -227,7 +227,7 @@ func buildWorker(output io.Writer) (*worker.Worker, error) {
 		))
 	}
 
-	if len(config.TartPrePull) != 0 {
+	if config.TartPrePull != nil {
 		opts = append(opts, worker.WithTartPrePull(config.TartPrePull))
 	}
 

internal/executor/instance/abstract/abstract.go

@@ -27,6 +27,7 @@ type WarmableInstance interface {
 		ctx context.Context,
 		ident string,
 		env map[string]string,
+		lazyPull bool,
 		warmupScript string,
 		warmupTimeout time.Duration,
 		logger *echelon.Logger,

internal/executor/instance/persistentworker/isolation/tart/tart.go

@@ -104,11 +104,12 @@ func (tart *Tart) Warmup(
 	ctx context.Context,
 	ident string,
 	additionalEnvironment map[string]string,
+	lazyPull bool,
 	warmupScript string,
 	warmupTimeout time.Duration,
 	logger *echelon.Logger,
 ) error {
-	err := tart.bootVM(ctx, ident, additionalEnvironment, "", false, logger)
+	err := tart.bootVM(ctx, ident, additionalEnvironment, "", lazyPull, logger)
 	if err != nil {
 		return err
 	}

internal/executor/instance/persistentworker/isolation/vetu/vetu.go

@@ -95,11 +95,12 @@ func (vetu *Vetu) Warmup(
 	ctx context.Context,
 	ident string,
 	env map[string]string,
+	lazyPull bool,
 	_ string,
 	_ time.Duration,
 	logger *echelon.Logger,
 ) error {
-	return vetu.bootVM(ctx, ident, env, false, logger)
+	return vetu.bootVM(ctx, ident, env, lazyPull, logger)
 }
 
 func (vetu *Vetu) bootVM(

internal/worker/options.go

@@ -51,7 +51,7 @@ func WithResourceModifiersManager(resourceModifiersManager *resourcemodifier.Man
 	}
 }
 
-func WithTartPrePull(tartPrePull []string) Option {
+func WithTartPrePull(tartPrePull *TartPrePull) Option {
 	return func(e *Worker) {
 		e.tartPrePull = tartPrePull
 	}

internal/worker/prepull.go

@@ -0,0 +1,17 @@
+package worker
+
+import "time"
+
+type TartPrePull struct {
+	Images        []string      `yaml:"images"`
+	CheckInterval time.Duration `yaml:"check-interval"`
+	LastCheck     time.Time
+}
+
+func (pull TartPrePull) NeedsPrePull() bool {
+	if pull.CheckInterval == 0 {
+		return true
+	}
+
+	return time.Now().After(pull.LastCheck.Add(pull.CheckInterval))
+}

internal/worker/worker.go

@@ -60,7 +60,7 @@ type Worker struct {
 	standbyInstance          abstract.Instance
 	standbyInstanceStartedAt time.Time
 
-	tartPrePull []string
+	tartPrePull *TartPrePull
 }
 
 func New(opts ...Option) (*Worker, error) {
@@ -266,15 +266,6 @@ func (worker *Worker) tryCreateStandby(ctx context.Context) {
 		return
 	}
 
-	// Pre-pull the configured Tart VM images first
-	for _, image := range worker.tartPrePull {
-		worker.logger.Infof("pre-pulling Tart VM image %q...", image)
-
-		if err := tart.PrePull(ctx, image, worker.echelonLogger); err != nil {
-			worker.logger.Errorf("failed to pre-pull Tart VM image %q: %v", image, err)
-		}
-	}
-
 	worker.logger.Debugf("creating a new standby instance with isolation %s", worker.standbyConfig.Isolation)
 
 	standbyInstance, err := persistentworker.New(worker.standbyConfig.Isolation, worker.security,
@@ -285,9 +276,34 @@ func (worker *Worker) tryCreateStandby(ctx context.Context) {
 		return
 	}
 
+	lazyPull := false
+
+	if worker.tartPrePull != nil {
+		// Pre-pull the configured Tart VM images first
+		for _, image := range worker.tartPrePull.Images {
+			for _, attr := range standbyInstance.Attributes() {
+				if attr.Key == "image" && attr.Value.AsString() == image {
+					lazyPull = true
+				}
+			}
+
+			if !worker.tartPrePull.NeedsPrePull() {
+				continue
+			}
+
+			worker.logger.Infof("pre-pulling Tart VM image %q...", image)
+
+			if err := tart.PrePull(ctx, image, worker.echelonLogger); err != nil {
+				worker.logger.Errorf("failed to pre-pull Tart VM image %q: %v", image, err)
+				continue
+			}
+		}
+		worker.tartPrePull.LastCheck = time.Now()
+	}
+
 	worker.logger.Debugf("warming-up the standby instance")
 
-	if err := standbyInstance.(abstract.WarmableInstance).Warmup(ctx, "standby", nil,
+	if err := standbyInstance.(abstract.WarmableInstance).Warmup(ctx, "standby", nil, lazyPull,
 		worker.standbyConfig.Warmup.Script, worker.standbyConfig.Warmup.Timeout, worker.echelonLogger); err != nil {
 		worker.logger.Errorf("failed to warm-up a standby instance: %v", err)