private/mud: helpers to print dependency graph with dot

Change-Id: Ieb49a5c71d680ab03b12c7e0cf38ebbe3badba5e

private/mud/dot.go

@@ -0,0 +1,125 @@
+// Copyright (C) 2024 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+package mud
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"reflect"
+	"strings"
+
+	"github.com/zeebo/errs"
+)
+
+// DotAll generates graph report of the modules in dot format.
+func DotAll(w io.Writer, ball *Ball) (err error) {
+	return Dot(w, ball.registry)
+}
+
+// Dot generates graph report of the modules in dot format, but only the selected components are included.
+func Dot(w io.Writer, components []*Component) (err error) {
+	p := func(args ...any) {
+		if err != nil {
+			return
+		}
+		_, err = fmt.Fprint(w, args...)
+	}
+	pf := func(format string, args ...any) {
+		if err != nil {
+			return
+		}
+		_, err = fmt.Fprintf(w, format, args...)
+	}
+
+	p("digraph G {\n")
+	p("\tnode [style=filled, shape=box, fillcolor=white];\n")
+	defer p("}\n")
+
+	annotationStr := func(c *Component) string {
+		annotations := []string{}
+		for _, tag := range c.tags {
+			annotations = append(annotations, fmt.Sprintf("%s", tag))
+		}
+
+		annotationStr := strings.Join(annotations, "\n")
+		if len(annotationStr) > 0 {
+			annotationStr = "\n" + annotationStr
+		}
+		return annotationStr
+	}
+
+	covered := map[reflect.Type]struct{}{}
+	for _, component := range components {
+		componentID := typeLabel(component.target)
+
+		entries := []string{"label=\"" + component.Name() + annotationStr(component) + "\""}
+		if component.instance == nil {
+			entries = append(entries, "color=darkgray", "fontcolor=darkgray")
+		}
+		if component.run != nil && !component.run.started.IsZero() && component.run.finished.IsZero() {
+			entries = append(entries, "fillcolor=green")
+		}
+
+		entries = append(entries, "URL=\"./"+strings.ReplaceAll(componentID, "/", "_")+"\"")
+
+		pf("%q [%v];\n", componentID, strings.Join(entries, " "))
+
+		covered[component.target] = struct{}{}
+	}
+
+	for _, component := range components {
+		for _, dep := range component.requirements {
+			if _, found := covered[dep]; !found {
+				continue
+			}
+			componentID := typeLabel(component.target)
+			pf("%q -> %q;\n", componentID, typeLabel(dep))
+		}
+
+	}
+	return err
+
+}
+
+// GenerateComponentsGraph generates dot and svg file including the selected components.
+func GenerateComponentsGraph(fileprefix string, components []*Component) error {
+	var b bytes.Buffer
+	if err := Dot(&b, components); err != nil {
+		_, err = fmt.Fprintf(os.Stderr, "fail: %v\n", err)
+		if err != nil {
+			return errs.Wrap(err)
+		}
+	} else {
+		err = os.WriteFile(fileprefix+".dot", b.Bytes(), 0644)
+		if err != nil {
+			return errs.Wrap(err)
+		}
+		output, err := exec.Command("dot", "-Tsvg", fileprefix+".dot", "-o", fileprefix+".svg").CombinedOutput()
+		if err != nil {
+			return errs.New("Execution of dot is failed with %s, %v", output, err)
+		}
+	}
+	return nil
+}
+
+// MustGenerateGraph generates dot and svg files from components selected by the selector.
+func MustGenerateGraph(ball *Ball, fileprefix string, selector ComponentSelector) {
+	var components []*Component
+	for _, c := range ball.registry {
+		if selector(c) {
+			components = append(components, c)
+		}
+	}
+	err := GenerateComponentsGraph(fileprefix, components)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func typeLabel(t reflect.Type) string {
+	return fullyQualifiedTypeName(t)
+}

private/mud/dot_test.go

@@ -0,0 +1,21 @@
+// Copyright (C) 2024 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+package mud
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestDot(t *testing.T) {
+	t.Skip("This test required dot executable")
+	dir := t.TempDir()
+	ball := NewBall()
+	Provide[DB](ball, NewDB)
+	Provide[Service1](ball, NewService1)
+	Provide[Service2](ball, NewService2)
+
+	// We don't really assert the results, as it may be changed, but it should be executed.
+	MustGenerateGraph(ball, filepath.Join(dir, "graph"), All)
+}