Rework graph construction & processing

pkg/envoy/builder.go

@@ -0,0 +1,81 @@
+package graph
+
+import (
+	"context"
+)
+
+type (
+	graphBuilder struct {
+		s resourceSanitizer
+		v resourceValidator
+	}
+
+	// Some special bits
+	resourceSanitizer interface {
+		Sanitize(ctx context.Context, r Resource, missing NodeRefSet) error
+	}
+	resourceValidator interface {
+		Validate(ctx context.Context, r Resource) error
+	}
+)
+
+func NewGraphBuilder(s resourceSanitizer, v resourceValidator) *graphBuilder {
+	return &graphBuilder{
+		s: s,
+		v: v,
+	}
+}
+
+func (b *graphBuilder) Build(ctx context.Context, rr ...Resource) (*graph, error) {
+	g := newGraph()
+
+	// Prepare nodes for all resources
+	nn := make(nodeSet, 0, len(rr))
+	for _, r := range rr {
+		nn = nn.add(newNode(r))
+	}
+
+	// Index all resources for nicer lookups
+	nIndex := make(nodeIndex)
+	nIndex.Add(nn...)
+
+	// Build the graph
+	for _, cNode := range nn {
+		refs := cNode.res.Refs()
+		missingRefs := make(NodeRefSet, 0, len(refs))
+
+		// Attempt to connect all available nodes
+		for _, ref := range refs {
+			rNode := nIndex.GetRef(ref)
+
+			if rNode == nil {
+				missingRefs = append(missingRefs, ref)
+				continue
+			}
+
+			// The resource is available; we can connect the two
+			g.addChild(cNode, rNode)
+			g.addParent(rNode, cNode)
+		}
+
+		// Go for a quick sanitization
+		if b.s != nil {
+			err := b.s.Sanitize(ctx, cNode.res, missingRefs)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		// Go for a quick validation
+		if b.v != nil {
+			err := b.v.Validate(ctx, cNode.res)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		g.addNode(cNode)
+	}
+
+	return g, nil
+}