1 files changed, 205 insertions, 0 deletions
diff --git a/cli/internal/graphvisualizer/graphvisualizer.go b/cli/internal/graphvisualizer/graphvisualizer.go
new file mode 100644
index 0000000..4e134b2
--- /dev/null
+++ b/cli/internal/graphvisualizer/graphvisualizer.go
@@ -0,0 +1,205 @@
+package graphvisualizer
+
+import (
+	"fmt"
+	"io"
+	"math/rand"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"github.com/fatih/color"
+	"github.com/mitchellh/cli"
+	"github.com/pyr-sh/dag"
+	"github.com/vercel/turbo/cli/internal/turbopath"
+	"github.com/vercel/turbo/cli/internal/ui"
+	"github.com/vercel/turbo/cli/internal/util"
+	"github.com/vercel/turbo/cli/internal/util/browser"
+)
+
+// GraphVisualizer requirements
+type GraphVisualizer struct {
+	repoRoot  turbopath.AbsoluteSystemPath
+	ui        cli.Ui
+	TaskGraph *dag.AcyclicGraph
+}
+
+// hasGraphViz checks for the presence of https://graphviz.org/
+func hasGraphViz() bool {
+	err := exec.Command("dot", "-V").Run()
+	return err == nil
+}
+
+func getRandChar() string {
+	i := rand.Intn(25) + 65
+	return string(rune(i))
+}
+
+func getRandID() string {
+	return getRandChar() + getRandChar() + getRandChar() + getRandChar()
+}
+
+// New creates an instance of ColorCache with helpers for adding colors to task outputs
+func New(repoRoot turbopath.AbsoluteSystemPath, ui cli.Ui, TaskGraph *dag.AcyclicGraph) *GraphVisualizer {
+	return &GraphVisualizer{
+		repoRoot:  repoRoot,
+		ui:        ui,
+		TaskGraph: TaskGraph,
+	}
+}
+
+// Converts the TaskGraph dag into a string
+func (g *GraphVisualizer) generateDotString() string {
+	return string(g.TaskGraph.Dot(&dag.DotOpts{
+		Verbose:    true,
+		DrawCycles: true,
+	}))
+}
+
+// Outputs a warning when a file was requested, but graphviz is not available
+func (g *GraphVisualizer) graphVizWarnUI() {
+	g.ui.Warn(color.New(color.FgYellow, color.Bold, color.ReverseVideo).Sprint(" WARNING ") + color.YellowString(" `turbo` uses Graphviz to generate an image of your\ngraph, but Graphviz isn't installed on this machine.\n\nYou can download Graphviz from https://graphviz.org/download.\n\nIn the meantime, you can use this string output with an\nonline Dot graph viewer."))
+}
+
+// RenderDotGraph renders a dot graph string for the current TaskGraph
+func (g *GraphVisualizer) RenderDotGraph() {
+	g.ui.Output("")
+	g.ui.Output(g.generateDotString())
+}
+
+type nameCache map[string]string
+
+func (nc nameCache) getName(in string) string {
+	if existing, ok := nc[in]; ok {
+		return existing
+	}
+	newName := getRandID()
+	nc[in] = newName
+	return newName
+}
+
+type sortableEdge dag.Edge
+type sortableEdges []sortableEdge
+
+// methods mostly copied from marshalEdges in the dag library
+func (e sortableEdges) Less(i, j int) bool {
+	iSrc := dag.VertexName(e[i].Source())
+	jSrc := dag.VertexName(e[j].Source())
+	if iSrc < jSrc {
+		return true
+	} else if iSrc > jSrc {
+		return false
+	}
+	return dag.VertexName(e[i].Target()) < dag.VertexName(e[j].Target())
+}
+func (e sortableEdges) Len() int      { return len(e) }
+func (e sortableEdges) Swap(i, j int) { e[i], e[j] = e[j], e[i] }
+
+func (g *GraphVisualizer) generateMermaid(out io.StringWriter) error {
+	if _, err := out.WriteString("graph TD\n"); err != nil {
+		return err
+	}
+	cache := make(nameCache)
+	// cast edges to our custom type so we can sort them
+	// this allows us to generate the same graph every time
+	var edges sortableEdges
+	for _, edge := range g.TaskGraph.Edges() {
+		edges = append(edges, sortableEdge(edge))
+	}
+	sort.Sort(edges)
+	for _, edge := range edges {
+		left := dag.VertexName(edge.Source())
+		right := dag.VertexName(edge.Target())
+		leftName := cache.getName(left)
+		rightName := cache.getName(right)
+		if _, err := out.WriteString(fmt.Sprintf("\t%v(\"%v\") --> %v(\"%v\")\n", leftName, left, rightName, right)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// GenerateGraphFile saves a visualization of the TaskGraph to a file (or renders a DotGraph as a fallback))
+func (g *GraphVisualizer) GenerateGraphFile(outputName string) error {
+	outputFilename := g.repoRoot.UntypedJoin(outputName)
+	ext := outputFilename.Ext()
+	// use .jpg as default extension if none is provided
+	if ext == "" {
+		ext = ".jpg"
+		outputFilename = g.repoRoot.UntypedJoin(outputName + ext)
+	}
+	if ext == ".mermaid" {
+		f, err := outputFilename.Create()
+		if err != nil {
+			return fmt.Errorf("error creating file: %w", err)
+		}
+		defer util.CloseAndIgnoreError(f)
+		if err := g.generateMermaid(f); err != nil {
+			return err
+		}
+		g.ui.Output(fmt.Sprintf("✔ Generated task graph in %s", ui.Bold(outputFilename.ToString())))
+		return nil
+	}
+	graphString := g.generateDotString()
+	if ext == ".html" {
+		f, err := outputFilename.Create()
+		if err != nil {
+			return fmt.Errorf("error creating file: %w", err)
+		}
+		defer f.Close() //nolint errcheck
+		_, writeErr1 := f.WriteString(`<!DOCTYPE html>
+    <html>
+    <head>
+      <meta charset="utf-8">
+      <title>Graph</title>
+    </head>
+    <body>
+      <script src="https://cdn.jsdelivr.net/npm/viz.js@2.1.2-pre.1/viz.js"></script>
+      <script src="https://cdn.jsdelivr.net/npm/viz.js@2.1.2-pre.1/full.render.js"></script>
+      <script>`)
+		if writeErr1 != nil {
+			return fmt.Errorf("error writing graph contents: %w", writeErr1)
+		}
+
+		_, writeErr2 := f.WriteString("const s = `" + graphString + "`.replace(/\\_\\_\\_ROOT\\_\\_\\_/g, \"Root\").replace(/\\[root\\]/g, \"\");new Viz().renderSVGElement(s).then(el => document.body.appendChild(el)).catch(e => console.error(e));")
+		if writeErr2 != nil {
+			return fmt.Errorf("error creating file: %w", writeErr2)
+		}
+
+		_, writeErr3 := f.WriteString(`
+    </script>
+  </body>
+  </html>`)
+		if writeErr3 != nil {
+			return fmt.Errorf("error creating file: %w", writeErr3)
+		}
+
+		g.ui.Output("")
+		g.ui.Output(fmt.Sprintf("✔ Generated task graph in %s", ui.Bold(outputFilename.ToString())))
+		if ui.IsTTY {
+			if err := browser.OpenBrowser(outputFilename.ToString()); err != nil {
+				g.ui.Warn(color.New(color.FgYellow, color.Bold, color.ReverseVideo).Sprintf("failed to open browser. Please navigate to file://%v", filepath.ToSlash(outputFilename.ToString())))
+			}
+		}
+		return nil
+	}
+	hasDot := hasGraphViz()
+	if hasDot {
+		dotArgs := []string{"-T" + ext[1:], "-o", outputFilename.ToString()}
+		cmd := exec.Command("dot", dotArgs...)
+		cmd.Stdin = strings.NewReader(graphString)
+		if err := cmd.Run(); err != nil {
+			return fmt.Errorf("could not generate task graphfile %v:  %w", outputFilename, err)
+		}
+		g.ui.Output("")
+		g.ui.Output(fmt.Sprintf("✔ Generated task graph in %s", ui.Bold(outputFilename.ToString())))
+
+	} else {
+		g.ui.Output("")
+		// User requested a file, but we're falling back to console here so warn about installing graphViz correctly
+		g.graphVizWarnUI()
+		g.RenderDotGraph()
+	}
+	return nil
+}