/
main.go
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/
main.go
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package main
import (
"bytes"
"encoding/json"
"flag"
"fmt"
"go/format"
"io/ioutil"
"log"
"os"
"path/filepath"
"reflect"
"regexp"
"sort"
"strings"
"text/template"
"time"
"unicode"
)
var dir = flag.String("dir", "", "directory with json files")
var files = flag.String("files", "", "comma-seperated json filepaths")
var tags = flag.String("tags", "", "comma-seperated tags for structs. Note - json is forced")
var fieldTypes = flag.String("types", "", "comma-seperated forced types eg. 'created_at:Time'")
var output = flag.String("o", "stdout", "")
var pkgOpt = flag.String("pkg", "", "package name")
type tagType struct {
Package string
Name string
Extra []string
}
func (t *tagType) String() string {
if t.Extra != nil {
return fmt.Sprintf("%s:\"%s,%s\"", t.Package, t.Name, strings.Join(t.Extra, ","))
}
return fmt.Sprintf("%s:\"%s\"", t.Package, t.Name)
}
type rawEvent struct {
Name string
PayloadJSON string
}
type member struct {
Name string
Typ string
Tags []tagType
}
type object struct {
Name string
Members []member
}
type rawEventSlice []rawEvent
func (p rawEventSlice) Len() int { return len(p) }
func (p rawEventSlice) Less(i, j int) bool { return p[i].Name < p[j].Name }
func (p rawEventSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
func (p rawEventSlice) Sort() { sort.Sort(p) }
func (p rawEventSlice) Contains(event string) bool {
i := sort.Search(len(p), func(i int) bool { return p[i].Name >= event })
return i != len(p) && p[i].Name == event
}
func unique(events []rawEvent) []string {
var unique = make(map[string]struct{})
for i := range events {
unique[events[i].Name] = struct{}{}
}
s := make([]string, 0, len(unique))
for k := range unique {
s = append(s, k)
}
sort.Strings(s)
return s
}
type memberSet []member
func (ms memberSet) Search(name string) int {
return sort.Search(len(ms), func(i int) bool { return ms[i].Name >= name })
}
func (ms *memberSet) Add(m member) {
// Member's type can be empty, when it duplicates type of its parent;
// ignore it as recursive types are not supported.
if m.Typ == "" {
return
}
switch i := ms.Search(m.Name); {
case i == len(*ms):
*ms = append(*ms, m)
case (*ms)[i].Name == m.Name:
if typ := (*ms)[i].Typ; typ != m.Typ {
// The "created_at" and "pushed_at" keys storing timestamps instead
// of RFC3339 time for PushEvent looks like a bug. Force use of
// the Time type.
if m.Name == "CreatedAt" || m.Name == "PushedAt" {
(*ms)[i].Typ = "Time"
break
}
(*ms)[i].Typ = "interface{}"
fmt.Fprintf(os.Stderr, "different types for %s member: %s and %s, using interface{}\n", m.Name, typ, m.Typ)
}
default:
*ms = append(*ms, member{})
copy((*ms)[i+1:], (*ms)[i:])
(*ms)[i] = m
}
}
type objectSet []object
func (os objectSet) Search(name string) int {
return sort.Search(len(os), func(i int) bool { return os[i].Name >= name })
}
func (os *objectSet) Add(o object) {
switch i := os.Search(o.Name); {
case i == len(*os):
*os = append(*os, o)
case (*os)[i].Name == o.Name:
for _, m := range o.Members {
// Ignore members which are named after structs to not create
// invalid recursive types.
if o.Name == m.Name && m.Name == m.Typ {
continue
}
(*memberSet)(&(*os)[i].Members).Add(m)
}
default:
*os = append(*os, object{})
copy((*os)[i+1:], (*os)[i:])
(*os)[i] = o
}
}
type typeTree struct {
m map[string]interface{}
tags []string
types map[string]string
}
func newTypeTree(events []rawEvent, types map[string]string, tags ...string) typeTree {
t := typeTree{
make(map[string]interface{}, len(events)),
tags,
types,
}
for _, e := range events {
t.push(e)
}
return t
}
func (t typeTree) push(e rawEvent) {
type node struct {
typ, v map[string]interface{}
}
var v map[string]interface{}
if err := json.Unmarshal([]byte(e.PayloadJSON), &v); err != nil {
die(err)
}
typ, ok := t.m[e.Name].(map[string]interface{})
if !ok {
t.m[e.Name] = v
return
}
nd, stack := node{}, []node{{typ: typ, v: v}}
for n := len(stack); n != 0; n = len(stack) {
nd, stack = stack[n-1], stack[:n-1]
for k, v := range nd.v {
typ, ok := nd.typ[k]
if !ok {
nd.typ[k] = v
continue
}
switch rtyp, rv := reflect.TypeOf(typ), reflect.TypeOf(v); {
case rtyp == nil && rv != nil && rv.Kind() == reflect.Map:
typ = make(map[string]interface{})
nd.typ[k] = typ
case rtyp != nil && rv != nil && rtyp != rv:
die(fmt.Sprintf("merge: incompatible types for %s: %T vs %v", k, v, typ))
default:
if v, ok := v.(map[string]interface{}); ok {
stack = append(stack, node{typ: typ.(map[string]interface{}), v: v})
}
}
}
}
}
func (t typeTree) objects() (obj []object) {
var stack = make([]node, 0, len(t.m))
for k, v := range t.m {
v, ok := v.(map[string]interface{})
if !ok {
die(fmt.Sprintf("%s is not a JSON object", k))
}
stack = append(stack, node{name: k, nodes: v})
}
var nd node
for n := len(stack); n != 0; n = len(stack) {
nd, stack = stack[n-1], stack[:n-1]
o := object{Name: nd.name, Members: make([]member, 0, len(nd.nodes))}
for k, v := range nd.nodes {
// Ignore "_links" member as it's redundant and it pollutes a number
// of structs with a "href" member.
if k == "_links" {
continue
}
var tags = []tagType{{Package: "json", Name: k}}
for _, tag := range t.tags {
if tag == "json" {
continue
}
tags = append(tags, tagType{Package: tag, Name: k})
}
m := member{Name: camelCase(k), Tags: tags}
t.setType(&m, v, nd.name, &stack)
(*memberSet)(&o.Members).Add(m)
}
(*objectSet)(&obj).Add(o)
}
return obj
}
const header = `// Created by go generate; DO NOT EDIT
package {{pkg}}
`
const types = `{{range $_, $o := .}}// {{$o.Name}} was autogenerated by go generate.
type {{$o.Name}} struct {
{{range $_, $m := $o.Members}} {{$m.Name}} {{$m.Typ}} ` + "`{{join $m.Tags}}`" + `
{{end}}
}
{{end}}
`
var tmplHeader = template.Must(template.New("payloads").Funcs(map[string]interface{}{"snakeCase": snakeCase, "pkg": pkg}).Parse(header))
var tmplTypes = template.Must(template.New("payloads").Funcs(map[string]interface{}{"join": joinTags}).Parse(types))
var idiomaticReplacer = strings.NewReplacer("Url", "URL", "Id", "ID", "Html", "HTML", "Sha", "SHA", "Ssh", "SSH")
func joinTags(t []tagType) string {
str := ""
for _, tag := range t {
str += tag.String() + " "
}
return strings.TrimRight(str, " ")
}
func pkg() string {
if *pkgOpt == "" {
flag.PrintDefaults()
os.Exit(1)
}
return *pkgOpt
}
func nonil(err ...error) error {
for _, err := range err {
if err != nil {
return err
}
}
return nil
}
func die(v interface{}) {
fmt.Fprintln(os.Stderr, v)
os.Exit(1)
}
func snakeCase(s string) (t string) {
if i := strings.Index(s, "Event"); i != -1 {
s = s[:i]
}
for _, c := range s {
if unicode.IsUpper(c) {
t = t + "_" + string(unicode.ToLower(c))
} else {
t = t + string(c)
}
}
return strings.Trim(t, "_")
}
func camelCase(s string) (t string) {
up := true
for _, r := range s {
switch r {
case ' ', '-', '_':
up = true
default:
if up {
t = t + string(unicode.ToUpper(r))
up = false
} else {
t = t + string(r)
}
}
}
return idiomaticReplacer.Replace(t)
}
type node struct {
name string
nodes map[string]interface{}
}
func (t typeTree) hardcodedType(m *member) (string, bool) {
if m.Tags == nil {
panic("Tags field must not be empty!")
}
typ, ok := t.types[m.Tags[0].Name]
return typ, ok
}
func (t typeTree) setType(m *member, v interface{}, parent string, stack *[]node) {
var setType func(*member, interface{}, string, *[]node)
setType = func(m *member, v interface{}, parent string, stack *[]node) {
if typ, ok := t.hardcodedType(m); ok {
m.Typ = typ
return
}
switch v := v.(type) {
case map[string]interface{}:
if parent == m.Name {
// Ignore members which are named after structs to not create
// invalid recursive types.
break
}
m.Typ = m.Name
// Files is a member of a gist object, it's handled separately since
// it's a map.
//
// https://developer.github.com/v3/gists/
if m.Typ != "Files" {
*stack = append(*stack, node{name: m.Name, nodes: v})
}
case bool:
m.Typ = "bool"
case float64:
m.Typ = "float64"
case []interface{}:
if len(v) == 0 {
m.Typ = "[]string"
break
}
var prev = *m
var cur = *m
for _, v := range v {
setType(&cur, v, "", stack)
if prev.Typ != "" && cur.Typ != prev.Typ {
die(fmt.Sprintf("heterogeneous arrays not supported: %s, %s", prev.Typ, cur.Typ))
}
prev = cur
}
m.Typ = "[]" + cur.Typ
case string:
switch err := (&time.Time{}).UnmarshalText([]byte(v)); err {
case nil:
m.Typ = "Time"
default:
m.Typ = "string"
}
default:
die(fmt.Sprintf("unable to guess type for %s: %T", m.Name, v))
}
}
setType(m, v, parent, stack)
}
func readData(dir string, fis ...os.FileInfo) (events []rawEvent) {
for _, fi := range fis {
event := strings.ToLower(fi.Name())
if !strings.HasSuffix(event, ".json") {
log.Println("webhook: ignoring", fi.Name())
continue
}
if i := strings.IndexRune(event, '-'); i != -1 {
event = event[:i]
} else {
event = event[:len(event)-len(".json")]
}
event = camelCase(event)
log.Printf("webhook: reading %s (%s) . . .", fi.Name(), event)
if (*rawEventSlice)(&events).Contains(event) {
fmt.Fprintf(os.Stderr, "merging duplicate JSON file for %q event . . .\n", event)
}
body, err := ioutil.ReadFile(filepath.Join(dir, fi.Name()))
if err != nil {
die(err)
}
events = append(events, rawEvent{Name: event, PayloadJSON: string(body)})
}
return events
}
func statFiles(files string) ([]os.FileInfo, error) {
var fis []os.FileInfo
fs := strings.Split(files, ",")
for _, f := range fs {
fi, err := os.Stat(f)
if err != nil {
return nil, err
}
fis = append(fis, fi)
}
return fis, nil
}
var reTypes = regexp.MustCompile("(\\S+):(\\S+)")
func parseTypes(types string) map[string]string {
m := make(map[string]string)
ts := strings.Split(types, ",")
for _, t := range ts {
match := reTypes.FindStringSubmatch(t)
if match == nil {
return nil
}
m[match[1]] = match[2]
}
return m
}
func main() {
flag.Parse()
var events []rawEvent
var fis []os.FileInfo
if *dir == "" {
flag.PrintDefaults()
os.Exit(1)
}
fis, err := ioutil.ReadDir(*dir)
if err != nil {
die(err)
}
events = readData(*dir, fis...)
rawEventSlice(events).Sort()
for i := range events {
if events[i].PayloadJSON == "" {
die(fmt.Sprintf("empty payload for %q event (i=%d)", events[i].Name, i))
}
}
buf := bytes.NewBuffer([]byte(""))
if err := tmplHeader.Execute(buf, unique(events)); err != nil {
die(err)
}
typeMap := parseTypes(*fieldTypes)
if err := tmplTypes.Execute(buf,
newTypeTree(events, typeMap, strings.Split(*tags, ",")...).objects()); err != nil {
die(err)
}
b, err := format.Source(buf.Bytes())
if err != nil {
die(err)
}
if *output == "stdout" {
fmt.Fprintln(os.Stdout, string(b))
os.Exit(0)
}
if err = ioutil.WriteFile(*output, b, 0655); err != nil {
die(err)
}
}