Method visitInDependencyOrder

pkg/compose/reconcile.go:381–419

visitInDependencyOrder processes services from leaves to roots so that dependencies are reconciled before the services that depend on them.

(g *Graph)

// visitInDependencyOrder processes services from leaves to roots so that
// dependencies are reconciled before the services that depend on them.
func (r *reconciler) visitInDependencyOrder(g *Graph) error {
	visited := map[string]bool{}
	// Sort vertex keys for deterministic plan output in tests
	keys := sortedKeys(g.Vertices)
	for {
		// Find a vertex whose all children are visited
		var next *Vertex
		for _, k := range keys {
			v := g.Vertices[k]
			if visited[v.Key] {
				continue
			}
			allChildrenVisited := true
			for _, child := range v.Children {
				if !visited[child.Key] {
					allChildrenVisited = false
					break
				}
			}
			if allChildrenVisited {
				next = v
				break
			}
		}
		if next == nil {
			break // all visited
		}
		visited[next.Key] = true

		service, err := r.project.GetService(next.Service)
		if err != nil {
			return err
		}
		if err := r.reconcileService(service); err != nil {
			return err
		}
	}
	return nil
}

// reconcileService handles a single service: scale down, recreate diverged,
// start stopped, scale up.