feat: automatically generate context ignore paths

gen/context_paths/context_paths.go

@@ -0,0 +1,131 @@
+// gen/context_paths generates the ignore paths for the user context since
+// gin will not less apply the middleware to only specific paths.
+//
+// The generator reads every controller and looks for the //context:ignore comment.
+// The format for the context ignore comment is:
+//
+// //contxt:ignore /api/mypath GET,POST
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/format"
+	"os"
+	"strings"
+	"text/template"
+
+	_ "embed"
+
+	"golang.org/x/tools/go/packages"
+)
+
+//go:embed paths.tmpl
+var pathsTmplSrc string
+
+var pathsTmpl = template.Must(template.New("paths").Parse(pathsTmplSrc))
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Printf("Failed to generate: %s", err.Error())
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	// load pkg
+	pkgConfig := &packages.Config{
+		Mode: packages.NeedFiles,
+	}
+
+	pkgs, err := packages.Load(pkgConfig, "github.com/tinyauthapp/tinyauth/internal/controller")
+
+	if err != nil {
+		return fmt.Errorf("failed to load pkg: %w", err)
+	}
+
+	if len(pkgs) == 0 {
+		return fmt.Errorf("failed to get controllers package")
+	}
+
+	pkg := pkgs[0]
+
+	// for each file we check the comments and either add or remove the context
+	var contextIgnorePaths []string
+
+	for _, gofile := range pkg.GoFiles {
+		// read the file
+		file, err := os.ReadFile(gofile)
+
+		if err != nil {
+			fmt.Printf("Failed to read %s, ignoring", gofile)
+			continue
+		}
+
+		// get the comment lines
+		lines := strings.SplitSeq(string(file), "\n")
+
+		for line := range lines {
+			if !strings.HasPrefix(strings.TrimSpace(line), "//context:ignore") {
+				continue
+			}
+
+			path, methods, ok := parseContextIgnoreLine(line)
+
+			if !ok {
+				fmt.Printf("Failed to parse %s rule, ignore", line)
+				continue
+			}
+
+			for _, m := range methods {
+				contextIgnorePaths = append(contextIgnorePaths, m+" "+path)
+			}
+		}
+	}
+
+	// generate out
+	type tmplData struct {
+		IgnorePaths []string
+	}
+
+	var buf bytes.Buffer
+
+	if err := pathsTmpl.Execute(&buf, tmplData{
+		IgnorePaths: contextIgnorePaths,
+	}); err != nil {
+		return err
+	}
+
+	formatted, err := format.Source(buf.Bytes())
+
+	if err != nil {
+		return fmt.Errorf("gofmt failed: %w", err)
+	}
+
+	// write out
+	err = os.WriteFile("context_paths.go", formatted, 0666)
+
+	if err != nil {
+		return fmt.Errorf("failed to write out: %w", err)
+	}
+
+	return nil
+}
+
+func parseContextIgnoreLine(line string) (string, []string, bool) {
+	line = strings.TrimPrefix(line, "//context:ignore ")
+	path, methodStr, ok := strings.Cut(line, " ")
+	if !ok {
+		return "", []string{}, false
+	}
+	var methodsParsed []string
+	methodParts := strings.SplitSeq(methodStr, ",")
+	for m := range methodParts {
+		if strings.TrimSpace(m) == "" {
+			continue
+		}
+		m = strings.ToUpper(m)
+		methodsParsed = append(methodsParsed, m)
+	}
+	return path, methodsParsed, true
+}