(Feat): Initial Commit

scripts/internal/handlers/gen.go

@@ -0,0 +1,183 @@
+//go:build scripts
+
+// This program generates /internal/api/handlers.go.
+// It can be invoked by running go run -tags scripts scripts/handlers/gen_handlers.go
+
+// Supported args:
+// -print-only
+
+package handlers
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"text/template"
+
+	"github.com/rs/zerolog/log"
+
+	"allaboutapps.dev/aw/go-starter/scripts/internal/util"
+)
+
+// https://blog.carlmjohnson.net/post/2016-11-27-how-to-use-go-generate/
+
+var (
+	handlersPackage = "/internal/api/handlers"
+
+	pathProjectRoot  = util.GetProjectRootDir()
+	pathHandlersRoot = pathProjectRoot + handlersPackage
+	pathModFile      = pathProjectRoot + "/go.mod"
+	pathHandlersFile = pathHandlersRoot + "/handlers.go"
+
+	// methodPrefixes defines all keywords that we search for in the handlers sub packages
+	// <methodPrefixes>*<methodSuffix> must be the naming of the route (Capitalized)
+	methodPrefixes = []string{
+		// https://swagger.io/specification/v2/ fixed fields: GET, PUT, POST, DELETE, OPTIONS, HEAD, PATCH
+		"Get", "Put", "Post", "Delete", "Options", "Head", "Patch",
+	}
+	// Match suffixes like 'Route', 'RouteV1', 'RouteV123'
+	methodSuffixPattern = regexp.MustCompile(`Route(V[0-9]*)?$`)
+
+	packageTemplate = template.Must(template.New("").Parse(`// Code generated by go run -tags scripts scripts/handlers/gen_handlers.go; DO NOT EDIT.
+package handlers
+
+import (
+	"allaboutapps.dev/aw/go-starter/internal/api"
+	{{- range .SubPkgs }}
+	"{{ . }}"
+	{{- end }}
+	"github.com/labstack/echo/v4"
+)
+
+func AttachAllRoutes(s *api.Server) {
+	// attach our routes
+	s.Router.Routes = []*echo.Route{
+		{{- range .Funcs }}
+		{{ .PackageName }}.{{ .FunctionName }}(s),
+		{{- end }}
+	}
+}
+`))
+)
+
+type ResolvedFunction struct {
+	FunctionName    string
+	PackageName     string
+	PackageNameFQDN string
+}
+
+type TempateData struct {
+	SubPkgs []string
+	Funcs   []ResolvedFunction
+}
+
+// get all functions in above handler packages
+// that match <methodPrefixes>*<methodSuffix>
+func GenHandlers(printOnly bool) error {
+	funcs := []ResolvedFunction{}
+
+	baseModuleName, err := util.GetModuleName(pathModFile)
+	if err != nil {
+		log.Fatal().Err(err).Msg("Failed to get module name")
+	}
+
+	set := token.NewFileSet()
+
+	err = filepath.Walk(pathHandlersRoot, func(path string, fileInfo os.FileInfo, err error) error {
+		if err != nil {
+			return fmt.Errorf("failed to access path %q: %w", path, err)
+		}
+
+		// ignore handler file to be generated
+		// ignore directories
+		// ignore non go files
+		// ignore test go files
+		if path == pathHandlersFile || fileInfo.IsDir() || !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "test.go") {
+			return nil
+		}
+
+		gofile, err := parser.ParseFile(set, path, nil, 0)
+		if err != nil {
+			return fmt.Errorf("failed to parse package: %q: %w", path, err)
+		}
+
+		fileDir := filepath.Dir(path)
+		packageNameFQDN := strings.Replace(fileDir, pathProjectRoot, baseModuleName, 1)
+
+		for _, d := range gofile.Decls {
+			if fn, isFn := d.(*ast.FuncDecl); isFn {
+				fnName := fn.Name.String()
+
+				for _, prefix := range methodPrefixes {
+					if strings.HasPrefix(fnName, prefix) && methodSuffixPattern.MatchString(fnName) {
+						funcs = append(funcs, ResolvedFunction{
+							FunctionName:    fnName,
+							PackageName:     gofile.Name.Name,
+							PackageNameFQDN: packageNameFQDN,
+						})
+					}
+				}
+			}
+		}
+
+		// fmt.Println(packageNameFQDN, path)
+
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("failed to walk handlers root: %w", err)
+	}
+
+	// stable sort the functions
+	// first PackageName then FunctionName
+	sort.Slice(funcs, func(i, j int) bool {
+		return funcs[i].PackageNameFQDN+funcs[i].FunctionName < funcs[j].PackageNameFQDN+funcs[j].FunctionName
+	})
+
+	// only add subPkg if there was actually a route within it found
+	subPkgs := []string{}
+	for _, fun := range funcs {
+		mustAppend := true
+
+		for _, a := range subPkgs {
+			if a == fun.PackageNameFQDN {
+				mustAppend = false
+			}
+		}
+
+		if mustAppend {
+			subPkgs = append(subPkgs, fun.PackageNameFQDN)
+		}
+	}
+
+	if printOnly {
+		for _, function := range funcs {
+			log.Info().Msgf("%s %s", function.PackageNameFQDN, function.FunctionName)
+		}
+
+		// bailout
+		return nil
+	}
+
+	handlersFile, err := os.Create(pathHandlersFile)
+	if err != nil {
+		return fmt.Errorf("failed to create handlers file: %w", err)
+	}
+
+	defer handlersFile.Close()
+
+	if err = packageTemplate.Execute(handlersFile, TempateData{
+		SubPkgs: subPkgs,
+		Funcs:   funcs,
+	}); err != nil {
+		return fmt.Errorf("failed to execute package template: %w", err)
+	}
+
+	return nil
+}