Method getOrCreateInstance

modules/generator/generator.go:209–243

(instanceID string)

}

func (g *Generator) getOrCreateInstance(instanceID string) (*instance, error) {
	// Fast path: check with read lock first
	inst, ok := g.getInstanceByID(instanceID)
	if ok {
		return inst, nil
	}

	g.instancesMtx.Lock()
	defer g.instancesMtx.Unlock()

	// Double-check after acquiring write lock
	if inst, ok := g.instances[instanceID]; ok {
		return inst, nil
	}

	// Check if this instance creation failed previously
	if failedAt, ok := g.failedInstances[instanceID]; ok {
		if time.Since(failedAt) < failureBackoff {
			return nil, errInstanceCreationBackoff
		}
		// Backoff expired, clear the failure and retry
		delete(g.failedInstances, instanceID)
	}

	inst, err := g.createInstance(instanceID)
	if err != nil {
		g.failedInstances[instanceID] = time.Now()
		level.Error(g.logger).Log("msg", "instance creation failed, will retry after backoff",
			"backoff", failureBackoff, "tenant", instanceID, "err", err)
		return nil, err
	}

	g.instances[instanceID] = inst
	return inst, nil
}

func (g *Generator) getInstanceByID(id string) (*instance, bool) {
	g.instancesMtx.RLock()