svg for cycles/graph

cmd/cycles.go

@@ -31,6 +31,7 @@ var maxCycleLength int
 var cyclesTopN int
 var cyclesVerbose bool
 var cyclesSplitTestOnly bool
+var cyclesSVGOutput bool
 
 // cyclesFinder implements Johnson's algorithm for finding all elementary cycles
 // in a directed graph. Time complexity: O((V+E)(C+1)) where C is the number of cycles.
@@ -129,6 +130,9 @@ var cyclesCmd = &cobra.Command{
 				}
 			}
 		}
+		if cyclesSVGOutput {
+			return fmt.Errorf("--svg is not supported for cycles")
+		}
 
 		if jsonOutputCycles {
 			outputObj := map[string]interface{}{}
@@ -481,6 +485,7 @@ func init() {
 	cyclesCmd.Flags().IntVar(&maxCycleLength, "max-length", 0, "Limit cycles to length <= N (0 = no limit)")
 	cyclesCmd.Flags().IntVarP(&cyclesTopN, "top", "n", 10, "Number of top participants to show in summary")
 	cyclesCmd.Flags().BoolVar(&cyclesSplitTestOnly, "split-test-only", false, "Split cycles into test-only and non-test sections (uses go mod why -m)")
+	cyclesCmd.Flags().BoolVarP(&cyclesSVGOutput, "svg", "s", false, "(unsupported) placeholder for svg output")
 	cyclesCmd.Flags().StringSliceVar(&excludeModules, "exclude-modules", []string{}, "Exclude module path patterns (repeatable, supports * wildcard)")
 	cyclesCmd.Flags().StringSliceVarP(&mainModules, "mainModules", "m", []string{}, "Enter modules whose dependencies should be considered direct dependencies; defaults to the first module encountered in `go mod graph` output")
 	cyclesCmd.Flags().BoolVarP(&cyclesVerbose, "verbose", "v", false, "Include raw cycles with summary output")

cmd/graph.go

@@ -17,9 +17,11 @@ limitations under the License.
 package cmd
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"os"
+	"os/exec"
 	"sort"
 	"strings"
 	"text/tabwriter"
@@ -36,6 +38,7 @@ var graphTopMode string
 var graphTopN int
 var graphVerbose bool
 var graphSplitTestOnly bool
+var graphSVGOutput bool
 
 type graphNode struct {
 	Module       string `json:"module"`
@@ -68,8 +71,8 @@ var graphCmd = &cobra.Command{
 	- Direct edges (solid blue): from main module(s) to their direct dependencies
 	- Transitive edges (dashed gray): dependencies of dependencies`,
 	RunE: func(cmd *cobra.Command, args []string) error {
-		if graphDotOutput && graphJSONOutput {
-			return fmt.Errorf("--dot and --json are mutually exclusive")
+		if (graphDotOutput && graphJSONOutput) || (graphSVGOutput && graphJSONOutput) || (graphDotOutput && graphSVGOutput) {
+			return fmt.Errorf("--dot, --svg, and --json are mutually exclusive")
 		}
 		if graphTopMode != "" && graphDotOutput {
 			return fmt.Errorf("cannot use --top with --dot")
@@ -178,6 +181,9 @@ var graphCmd = &cobra.Command{
 			fmt.Print(fileContents)
 			return nil
 		}
+		if graphSVGOutput {
+			return outputGraphSVG(fileContents)
+		}
 		if graphVerbose {
 			fmt.Println("Main modules:")
 			printDeps(overview.MainModules)
@@ -307,6 +313,18 @@ func chainContains(chain Chain, dep string) bool {
 	return false
 }
 
+func outputGraphSVG(dot string) error {
+	cmd := exec.Command("dot", "-Tsvg")
+	cmd.Stdin = strings.NewReader(dot)
+	cmd.Stdout = os.Stdout
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("failed to render DOT as SVG via graphviz 'dot': %w: %s", err, strings.TrimSpace(stderr.String()))
+	}
+	return nil
+}
+
 func colorMainNode(mainNode string) string {
 	return fmt.Sprintf("MainNode [label=\"%s\", style=\"filled\" color=\"yellow\"]\n", mainNode)
 }
@@ -468,6 +486,7 @@ func init() {
 	graphCmd.Flags().BoolVar(&showEdgeTypes, "show-edge-types", false, "Distinguish direct vs transitive edges with colors/styles")
 	graphCmd.Flags().BoolVar(&graphDotOutput, "dot", false, "Output DOT graph to stdout")
 	graphCmd.Flags().BoolVarP(&graphJSONOutput, "json", "j", false, "Output graph data in JSON format")
+	graphCmd.Flags().BoolVarP(&graphSVGOutput, "svg", "s", false, "Render DOT output as SVG (requires graphviz 'dot')")
 	graphCmd.Flags().StringVar(&graphTopMode, "top", "", "Show top modules by degree: in, out, or both")
 	graphCmd.Flags().IntVarP(&graphTopN, "n", "n", 10, "Number of modules to show with --top")
 	graphCmd.Flags().BoolVar(&graphSplitTestOnly, "split-test-only", false, "Split graph into test-only and non-test sections (uses go mod why -m)")