Add cf mta-graph command for local mtad.yaml dependency graph

commands/mta_graph_command.go

@@ -0,0 +1,140 @@
+package commands
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"code.cloudfoundry.org/cli/v8/plugin"
+	"github.com/cloudfoundry-incubator/multiapps-cli-plugin/ui"
+	"github.com/cloudfoundry-incubator/multiapps-cli-plugin/util"
+	"gopkg.in/yaml.v3"
+)
+
+type MtaGraphCommand struct {
+	name          string
+	cliConnection plugin.CliConnection
+}
+
+func NewMtaGraphCommand() *MtaGraphCommand {
+	return &MtaGraphCommand{}
+}
+
+func (c *MtaGraphCommand) GetPluginCommand() plugin.Command {
+	return plugin.Command{
+		Name:     "mta-graph",
+		HelpText: "Render the dependency graph of an MTA descriptor as DOT",
+		UsageDetails: plugin.Usage{
+			Usage: "cf mta-graph <path-to-mtad.yaml>",
+		},
+	}
+}
+
+func (c *MtaGraphCommand) Initialize(name string, cliConnection plugin.CliConnection) {
+	c.name = name
+	c.cliConnection = cliConnection
+}
+
+func (c *MtaGraphCommand) Execute(args []string) ExecutionStatus {
+	if len(args) == 0 {
+		ui.Failed("Usage: cf mta-graph <path-to-mtad.yaml>")
+		return Failure
+	}
+	data, err := os.ReadFile(args[0])
+	if err != nil {
+		ui.Failed("Could not read file %s: %s", args[0], err)
+		return Failure
+	}
+
+	descriptor, err := parseDescriptor(data)
+	if err != nil {
+		ui.Failed("Could not parse descriptor: %s", err)
+		return Failure
+	}
+
+	fmt.Print(buildDot(descriptor))
+	return Success
+}
+
+// executeInternal satisfies the Command interface (never called for this command).
+func (c *MtaGraphCommand) executeInternal(_ []string, _ string, _ *flag.FlagSet, _ util.CloudFoundryTarget) ExecutionStatus {
+	return Failure
+}
+
+func (c *MtaGraphCommand) defineCommandOptions(_ *flag.FlagSet) {}
+
+// ---- descriptor model ----
+
+type mtadDescriptor struct {
+	Modules   []mtadModule   `yaml:"modules"`
+	Resources []mtadResource `yaml:"resources"`
+}
+
+type mtadModule struct {
+	Name     string          `yaml:"name"`
+	Provides []mtadProvided  `yaml:"provides"`
+	Requires []mtadRequired  `yaml:"requires"`
+}
+
+type mtadProvided struct {
+	Name string `yaml:"name"`
+}
+
+type mtadRequired struct {
+	Name string `yaml:"name"`
+}
+
+type mtadResource struct {
+	Name string `yaml:"name"`
+}
+
+func parseDescriptor(data []byte) (*mtadDescriptor, error) {
+	var d mtadDescriptor
+	if err := yaml.Unmarshal(data, &d); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}
+
+// ---- DOT builder ----
+
+func buildDot(d *mtadDescriptor) string {
+	providedDepToModule := make(map[string]string)
+	for _, m := range d.Modules {
+		for _, p := range m.Provides {
+			providedDepToModule[p.Name] = m.Name
+		}
+	}
+
+	resourceNames := make(map[string]bool)
+	for _, r := range d.Resources {
+		resourceNames[r.Name] = true
+	}
+
+	dot := "digraph mta {\n"
+	dot += "  rankdir=LR;\n"
+	dot += "  node [fontname=\"Helvetica\" fontsize=11];\n"
+	dot += "  edge [fontname=\"Helvetica\" fontsize=10];\n"
+	for _, m := range d.Modules {
+		dot += fmt.Sprintf("  %q [shape=box style=\"rounded,filled\" fillcolor=\"#DCE9F7\" color=\"#4A7AB5\"];\n", m.Name)
+	}
+	dot += "  { rank=same;"
+	for _, r := range d.Resources {
+		dot += fmt.Sprintf(" %q", r.Name)
+	}
+	dot += " }\n"
+	for _, r := range d.Resources {
+		dot += fmt.Sprintf("  %q [shape=cylinder style=filled fillcolor=\"#EDEDED\" color=\"#8A8A8A\"];\n", r.Name)
+	}
+	for _, m := range d.Modules {
+		for _, req := range m.Requires {
+			if provider, ok := providedDepToModule[req.Name]; ok {
+				dot += fmt.Sprintf("  %q -> %q [label=\"provides %s\" color=\"#4A7AB5\" fontcolor=\"#4A7AB5\"];\n", provider, m.Name, req.Name)
+			} else if resourceNames[req.Name] {
+				dot += fmt.Sprintf("  %q -> %q [label=\"requires\" style=dashed color=\"#8A8A8A\" fontcolor=\"#8A8A8A\"];\n", m.Name, req.Name)
+			}
+		}
+	}
+	dot += "}\n"
+	return dot
+}

multiapps_plugin.go

@@ -31,6 +31,7 @@ var Commands = []commands.Command{
 	commands.NewMtaOperationsCommand(),
 	commands.NewPurgeConfigCommand(),
 	commands.NewRollbackMtaCommand(),
+	commands.NewMtaGraphCommand(),
 }
 
 // Run runs this plugin