/
gogen.go
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/
gogen.go
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// Copyright (C) 2022 Storj Labs, Inc.
// See LICENSE for copying information.
package apigen
import (
"fmt"
"go/format"
"os"
"path/filepath"
"reflect"
"strings"
"time"
"github.com/zeebo/errs"
"golang.org/x/exp/slices"
"storj.io/common/uuid"
)
// DateFormat is the layout of dates passed into and out of the API.
const DateFormat = "2006-01-02T15:04:05.999Z"
// MustWriteGo writes generated Go code into a file.
// If an error occurs, it panics.
func (a *API) MustWriteGo(path string) {
generated, err := a.generateGo()
if err != nil {
panic(err)
}
rootDir := a.outputRootDir()
fullpath := filepath.Join(rootDir, path)
err = os.MkdirAll(filepath.Dir(fullpath), 0700)
if err != nil {
panic(errs.Wrap(err))
}
err = os.WriteFile(fullpath, generated, 0644)
if err != nil {
panic(errs.Wrap(err))
}
}
// generateGo generates api code and returns an output.
func (a *API) generateGo() ([]byte, error) {
result := &StringBuilder{}
pf := result.Writelnf
if a.PackagePath == "" {
return nil, errs.New("Package path must be defined")
}
packageName := a.PackageName
if packageName == "" {
parts := strings.Split(a.PackagePath, "/")
packageName = parts[len(parts)-1]
}
imports := struct {
All map[importPath]bool
Standard []importPath
External []importPath
Internal []importPath
}{
All: make(map[importPath]bool),
}
i := func(paths ...string) {
for _, path := range paths {
if path == "" || path == a.PackagePath {
continue
}
ipath := importPath(path)
if _, ok := imports.All[ipath]; ok {
continue
}
imports.All[ipath] = true
var slice *[]importPath
switch {
case !strings.Contains(path, "."):
slice = &imports.Standard
case strings.HasPrefix(path, "storj.io"):
slice = &imports.Internal
default:
slice = &imports.External
}
*slice = append(*slice, ipath)
}
}
var getTypePackages func(t reflect.Type) []string
getTypePackages = func(t reflect.Type) []string {
t = getElementaryType(t)
if t.Kind() == reflect.Map {
pkgs := []string{getElementaryType(t.Key()).PkgPath()}
return append(pkgs, getTypePackages(t.Elem())...)
}
return []string{t.PkgPath()}
}
for _, group := range a.EndpointGroups {
for _, method := range group.endpoints {
if method.Request != nil {
i(getTypePackages(reflect.TypeOf(method.Request))...)
}
if method.Response != nil {
i(getTypePackages(reflect.TypeOf(method.Response))...)
}
}
}
for _, group := range a.EndpointGroups {
i("github.com/zeebo/errs")
pf(
"var Err%sAPI = errs.Class(\"%s %s api\")",
capitalize(group.Prefix),
packageName,
strings.ToLower(group.Prefix),
)
for _, m := range group.Middleware {
i(middlewareImports(m)...)
}
}
pf("")
params := make(map[*FullEndpoint][]Param)
for _, group := range a.EndpointGroups {
// Define the service interface
pf("type %sService interface {", capitalize(group.Name))
for _, e := range group.endpoints {
params[e] = append(e.PathParams, e.QueryParams...)
var paramStr string
for i, param := range params[e] {
paramStr += param.Name
if i == len(params[e])-1 || param.Type != params[e][i+1].Type {
paramStr += " " + param.Type.String()
}
paramStr += ", "
}
if e.Request != nil {
paramStr += "request " + a.handleTypesPackage(reflect.TypeOf(e.Request)) + ", "
}
i("context", "storj.io/storj/private/api")
if e.Response != nil {
responseType := reflect.TypeOf(e.Response)
returnParam := a.handleTypesPackage(responseType)
if !isNillableType(responseType) {
returnParam = "*" + returnParam
}
pf("%s(ctx context.Context, "+paramStr+") (%s, api.HTTPError)", e.GoName, returnParam)
} else {
pf("%s(ctx context.Context, "+paramStr+") (api.HTTPError)", e.GoName)
}
}
pf("}")
pf("")
}
for _, group := range a.EndpointGroups {
cname := capitalize(group.Name)
i("go.uber.org/zap", "github.com/spacemonkeygo/monkit/v3")
pf(
"// %sHandler is an api handler that implements all %s API endpoints functionality.",
cname,
group.Name,
)
pf("type %sHandler struct {", cname)
pf("log *zap.Logger")
pf("mon *monkit.Scope")
pf("service %sService", cname)
autodefinedFields := map[string]string{"log": "*zap.Logger", "mon": "*monkit.Scope", "service": cname + "Service"}
for _, m := range group.Middleware {
for _, f := range middlewareFields(a, m) {
if t, ok := autodefinedFields[f.Name]; ok {
if t != f.Type {
panic(
fmt.Sprintf(
"middleware %q has a field with name %q and type %q which clashes with another defined field with the same name but with type %q",
reflect.TypeOf(m).Name(),
f.Name,
f.Type,
t,
),
)
}
continue
}
autodefinedFields[f.Name] = f.Type
pf("%s %s", f.Name, f.Type)
}
}
pf("}")
pf("")
}
for _, group := range a.EndpointGroups {
cname := capitalize(group.Name)
i("github.com/gorilla/mux")
autodedefined := map[string]struct{}{"log": {}, "mon": {}, "service": {}}
middlewareArgs := make([]string, 0, len(group.Middleware))
middlewareFieldsList := make([]string, 0, len(group.Middleware))
for _, m := range group.Middleware {
for _, f := range middlewareFields(a, m) {
if _, ok := autodedefined[f.Name]; !ok {
middlewareArgs = append(middlewareArgs, fmt.Sprintf("%s %s", f.Name, f.Type))
middlewareFieldsList = append(middlewareFieldsList, fmt.Sprintf("%[1]s: %[1]s", f.Name))
}
}
}
if len(middlewareArgs) > 0 {
pf(
"func New%s(log *zap.Logger, mon *monkit.Scope, service %sService, router *mux.Router, %s) *%sHandler {",
cname,
cname,
strings.Join(middlewareArgs, ", "),
cname,
)
} else {
pf(
"func New%s(log *zap.Logger, mon *monkit.Scope, service %sService, router *mux.Router) *%sHandler {",
cname,
cname,
cname,
)
}
pf("handler := &%sHandler{", cname)
pf("log: log,")
pf("mon: mon,")
pf("service: service,")
if len(middlewareFieldsList) > 0 {
pf(strings.Join(middlewareFieldsList, ",") + ",")
}
pf("}")
pf("")
pf(
"%sRouter := router.PathPrefix(\"%s/%s\").Subrouter()",
uncapitalize(group.Prefix),
a.endpointBasePath(),
strings.ToLower(group.Prefix),
)
for _, endpoint := range group.endpoints {
handlerName := "handle" + endpoint.GoName
pf(
"%sRouter.HandleFunc(\"%s\", handler.%s).Methods(\"%s\")",
uncapitalize(group.Prefix),
endpoint.Path,
handlerName,
endpoint.Method,
)
}
pf("")
pf("return handler")
pf("}")
pf("")
}
for _, group := range a.EndpointGroups {
for _, endpoint := range group.endpoints {
i("net/http")
pf("")
handlerName := "handle" + endpoint.GoName
pf("func (h *%sHandler) %s(w http.ResponseWriter, r *http.Request) {", capitalize(group.Name), handlerName)
pf("ctx := r.Context()")
pf("var err error")
pf("defer h.mon.Task()(&ctx)(&err)")
pf("")
pf("w.Header().Set(\"Content-Type\", \"application/json\")")
pf("")
if err := handleParams(result, i, endpoint.PathParams, endpoint.QueryParams); err != nil {
return nil, err
}
if endpoint.Request != nil {
a.handleBody(pf, endpoint.Request)
}
for _, m := range group.Middleware {
pf(m.Generate(a, group, endpoint))
}
pf("")
var methodFormat string
if endpoint.Response != nil {
methodFormat = "retVal, httpErr := h.service.%s(ctx, "
} else {
methodFormat = "httpErr := h.service.%s(ctx, "
}
for _, param := range params[endpoint] {
methodFormat += param.Name + ", "
}
if endpoint.Request != nil {
methodFormat += "payload"
}
methodFormat += ")"
pf(methodFormat, endpoint.GoName)
pf("if httpErr.Err != nil {")
pf("api.ServeError(h.log, w, httpErr.Status, httpErr.Err)")
if endpoint.Response == nil {
pf("}")
pf("}")
continue
}
pf("return")
pf("}")
i("encoding/json")
pf("")
pf("err = json.NewEncoder(w).Encode(retVal)")
pf("if err != nil {")
pf(
"h.log.Debug(\"failed to write json %s response\", zap.Error(Err%sAPI.Wrap(err)))",
endpoint.GoName,
capitalize(group.Prefix),
)
pf("}")
pf("}")
}
}
fileBody := result.String()
result = &StringBuilder{}
pf = result.Writelnf
pf("// AUTOGENERATED BY private/apigen")
pf("// DO NOT EDIT.")
pf("")
pf("package %s", packageName)
pf("")
pf("import (")
all := [][]importPath{imports.Standard, imports.External, imports.Internal}
for sn, slice := range all {
slices.Sort(slice)
for pn, path := range slice {
if r, ok := path.PkgName(); ok {
pf(`%s "%s"`, r, path)
} else {
pf(`"%s"`, path)
}
if pn == len(slice)-1 && sn < len(all)-1 {
pf("")
}
}
}
pf(")")
pf("")
if _, ok := imports.All["time"]; ok {
pf("const dateLayout = \"%s\"", DateFormat)
pf("")
}
result.WriteString(fileBody)
output, err := format.Source([]byte(result.String()))
if err != nil {
return nil, errs.Wrap(err)
}
return output, nil
}
// handleTypesPackage handles the way some type is used in generated code.
// If type is from the same package then we use only type's name.
// If type is from external package then we use type along with its appropriate package name.
func (a *API) handleTypesPackage(t reflect.Type) string {
switch t.Kind() {
case reflect.Array:
return fmt.Sprintf("[%d]%s", t.Len(), a.handleTypesPackage(t.Elem()))
case reflect.Slice:
return "[]" + a.handleTypesPackage(t.Elem())
case reflect.Pointer:
return "*" + a.handleTypesPackage(t.Elem())
}
if t.PkgPath() == a.PackagePath {
return t.Name()
}
return t.String()
}
// handleBody handles request body.
func (a *API) handleBody(pf func(format string, a ...interface{}), body interface{}) {
pf("payload := %s{}", a.handleTypesPackage(reflect.TypeOf(body)))
pf("if err = json.NewDecoder(r.Body).Decode(&payload); err != nil {")
pf("api.ServeError(h.log, w, http.StatusBadRequest, err)")
pf("return")
pf("}")
pf("")
}
// handleParams handles parsing of URL path parameters or query parameters.
func handleParams(builder *StringBuilder, i func(paths ...string), pathParams, queryParams []Param) error {
pf := builder.Writelnf
pErrCheck := func() {
pf("if err != nil {")
pf("api.ServeError(h.log, w, http.StatusBadRequest, err)")
pf("return")
pf("}")
}
for _, params := range []*[]Param{&queryParams, &pathParams} {
for _, param := range *params {
varName := param.Name
if param.Type.Kind() != reflect.String {
varName += "Param"
}
switch params {
case &queryParams:
pf("%s := r.URL.Query().Get(\"%s\")", varName, param.Name)
pf("if %s == \"\" {", varName)
pf("api.ServeError(h.log, w, http.StatusBadRequest, errs.New(\"parameter '%s' can't be empty\"))", param.Name)
pf("return")
pf("}")
pf("")
case &pathParams:
pf("%s, ok := mux.Vars(r)[\"%s\"]", varName, param.Name)
pf("if !ok {")
pf("api.ServeError(h.log, w, http.StatusBadRequest, errs.New(\"missing %s route param\"))", param.Name)
pf("return")
pf("}")
pf("")
}
switch param.Type {
case reflect.TypeOf(uuid.UUID{}):
i("storj.io/common/uuid")
pf("%s, err := uuid.FromString(%s)", param.Name, varName)
pErrCheck()
case reflect.TypeOf(time.Time{}):
i("time")
pf("%s, err := time.Parse(dateLayout, %s)", param.Name, varName)
pErrCheck()
default:
switch param.Type.Kind() {
case reflect.String:
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
i("strconv")
convName := varName
if param.Type.Kind() != reflect.Uint64 {
convName += "U64"
}
bits := param.Type.Bits()
if param.Type.Kind() == reflect.Uint {
bits = 32
}
pf("%s, err := strconv.ParseUint(%s, 10, %d)", convName, varName, bits)
pErrCheck()
if param.Type.Kind() != reflect.Uint64 {
pf("%s := %s(%s)", param.Name, param.Type.String(), convName)
}
default:
return errs.New("Unsupported parameter type \"%s\"", param.Type)
}
}
pf("")
}
}
return nil
}
type importPath string
// PkgName returns the name of the package based of the last part of the import
// path and false if the name isn't a rename, otherwise it returns true.
//
// The package name is renamed when the last part of the path contains hyphen
// (-) or dot (.) and the rename is this part with the hyphens and dots
// stripped.
func (i importPath) PkgName() (rename string, ok bool) {
b := filepath.Base(string(i))
if strings.Contains(b, "-") || strings.Contains(b, ".") {
return strings.ReplaceAll(strings.ReplaceAll(b, "-", ""), ".", ""), true
}
return b, false
}