Golang Graph.Validate方法代碼示例

// Graph builds a dependency graph of all the resources for infrastructure
// change.
//
// This dependency graph shows the correct order that any resources need
// to be operated on.
//
// The Meta field of a graph Noun can contain one of the follow types. A
// description is next to each type to explain what it is.
//
//   *GraphNodeResource - A resource. See the documentation of this
//     struct for more details.
//   *GraphNodeResourceProvider - A resource provider that needs to be
//     configured at this point.
//
func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
	if opts.Config == nil {
		return nil, errors.New("Config is required for Graph")
	}

	log.Printf("[DEBUG] Creating graph...")

	g := new(depgraph.Graph)

	// First, build the initial resource graph. This only has the resources
	// and no dependencies.
	graphAddConfigResources(g, opts.Config, opts.State)

	// Add explicit dependsOn dependencies to the graph
	graphAddExplicitDeps(g)

	// Next, add the state orphans if we have any
	if opts.State != nil {
		graphAddOrphans(g, opts.Config, opts.State)
	}

	// Map the provider configurations to all of the resources
	graphAddProviderConfigs(g, opts.Config)

	// Setup the provisioners. These may have variable dependencies,
	// and must be done before dependency setup
	if err := graphMapResourceProvisioners(g, opts.Provisioners); err != nil {
		return nil, err
	}

	// Add all the variable dependencies
	graphAddVariableDeps(g)

	// Build the root so that we have a single valid root
	graphAddRoot(g)

	// If providers were given, lets associate the proper providers and
	// instantiate them.
	if len(opts.Providers) > 0 {
		// Add missing providers from the mapping
		if err := graphAddMissingResourceProviders(g, opts.Providers); err != nil {
			return nil, err
		}

		// Initialize all the providers
		if err := graphInitResourceProviders(g, opts.Providers); err != nil {
			return nil, err
		}

		// Map the providers to resources
		if err := graphMapResourceProviders(g); err != nil {
			return nil, err
		}
	}

	// If we have a diff, then make sure to add that in
	if opts.Diff != nil {
		if err := graphAddDiff(g, opts.Diff); err != nil {
			return nil, err
		}
	}

	// Validate
	if err := g.Validate(); err != nil {
		return nil, err
	}

	log.Printf(
		"[DEBUG] Graph created and valid. %d nouns.",
		len(g.Nouns))

	return g, nil
}