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matrix-spec/scripts/speculator/main.go

373 lines
8.9 KiB
Go

// speculator allows you to preview pull requests to the matrix.org specification.
// It serves the following HTTP endpoints:
// - / lists open pull requests
// - /spec/123 which renders the spec as html at pull request 123.
// - /diff/rst/123 which gives a diff of the spec's rst at pull request 123.
// - /diff/html/123 which gives a diff of the spec's HTML at pull request 123.
// It is currently woefully inefficient, and there is a lot of low hanging fruit for improvement.
package main
import (
"bytes"
"encoding/json"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"math/rand"
"net/http"
"net/url"
"os"
"os/exec"
"path"
"strconv"
"strings"
"syscall"
"time"
)
type PullRequest struct {
Number int
Base Commit
Head Commit
Title string
User User
HTMLURL string `json:"html_url"`
}
type Commit struct {
SHA string
Repo RequestRepo
}
type RequestRepo struct {
CloneURL string `json:"clone_url"`
}
type User struct {
Login string
HTMLURL string `json:"html_url"`
}
var (
port = flag.Int("port", 9000, "Port on which to listen for HTTP")
allowedMembers map[string]bool
)
func (u *User) IsTrusted() bool {
return allowedMembers[u.Login]
}
const (
pullsPrefix = "https://api.github.com/repos/matrix-org/matrix-doc/pulls"
matrixDocCloneURL = "https://github.com/matrix-org/matrix-doc.git"
)
func gitClone(url string, shared bool) (string, error) {
directory := path.Join("/tmp/matrix-doc", strconv.FormatInt(rand.Int63(), 10))
cmd := exec.Command("git", "clone", url, directory)
if shared {
cmd.Args = append(cmd.Args, "--shared")
}
err := cmd.Run()
if err != nil {
return "", fmt.Errorf("error cloning repo: %v", err)
}
return directory, nil
}
func gitCheckout(path, sha string) error {
cmd := exec.Command("git", "checkout", sha)
cmd.Dir = path
err := cmd.Run()
if err != nil {
return fmt.Errorf("error checking out repo: %v", err)
}
return nil
}
func gitFetch(path string) error {
cmd := exec.Command("git", "fetch")
cmd.Dir = path
err := cmd.Run()
if err != nil {
return fmt.Errorf("error fetching repo: %v", err)
}
return nil
}
func lookupPullRequest(url url.URL, pathPrefix string) (*PullRequest, error) {
if !strings.HasPrefix(url.Path, pathPrefix+"/") {
return nil, fmt.Errorf("invalid path passed: %s expect %s/123", url.Path, pathPrefix)
}
prNumber := url.Path[len(pathPrefix)+1:]
if strings.Contains(prNumber, "/") {
return nil, fmt.Errorf("invalid path passed: %s expect %s/123", url.Path, pathPrefix)
}
resp, err := http.Get(fmt.Sprintf("%s/%s", pullsPrefix, prNumber))
defer resp.Body.Close()
if err != nil {
return nil, fmt.Errorf("error getting pulls: %v", err)
}
dec := json.NewDecoder(resp.Body)
var pr PullRequest
if err := dec.Decode(&pr); err != nil {
return nil, fmt.Errorf("error decoding pulls: %v", err)
}
return &pr, nil
}
func generate(dir string) error {
cmd := exec.Command("python", "gendoc.py", "--nodelete")
cmd.Dir = path.Join(dir, "scripts")
var b bytes.Buffer
cmd.Stderr = &b
err := cmd.Run()
if err != nil {
return fmt.Errorf("error generating spec: %v\nOutput from gendoc:\n%v", err, b.String())
}
return nil
}
func writeError(w http.ResponseWriter, code int, err error) {
w.WriteHeader(code)
io.WriteString(w, fmt.Sprintf("%v\n", err))
}
type server struct {
matrixDocCloneURL string
}
// generateAt generates spec from repo at sha.
// Returns the path where the generation was done.
func (s *server) generateAt(sha string) (dst string, err error) {
err = gitFetch(s.matrixDocCloneURL)
if err != nil {
return
}
dst, err = gitClone(s.matrixDocCloneURL, true)
if err != nil {
return
}
if err = gitCheckout(dst, sha); err != nil {
return
}
err = generate(dst)
return
}
func (s *server) serveSpec(w http.ResponseWriter, req *http.Request) {
var sha string
if strings.ToLower(req.URL.Path) == "/spec/head" {
sha = "HEAD"
} else {
pr, err := lookupPullRequest(*req.URL, "/spec")
if err != nil {
writeError(w, 400, err)
return
}
// We're going to run whatever Python is specified in the pull request, which
// may do bad things, so only trust people we trust.
if err := checkAuth(pr); err != nil {
writeError(w, 403, err)
return
}
sha = pr.Head.SHA
}
dst, err := s.generateAt(sha)
defer os.RemoveAll(dst)
if err != nil {
writeError(w, 500, err)
return
}
b, err := ioutil.ReadFile(path.Join(dst, "scripts/gen/specification.html"))
if err != nil {
writeError(w, 500, fmt.Errorf("Error reading spec: %v", err))
return
}
w.Write(b)
}
func checkAuth(pr *PullRequest) error {
if !pr.User.IsTrusted() {
return fmt.Errorf("%q is not a trusted pull requester", pr.User.Login)
}
return nil
}
func (s *server) serveRSTDiff(w http.ResponseWriter, req *http.Request) {
pr, err := lookupPullRequest(*req.URL, "/diff/rst")
if err != nil {
writeError(w, 400, err)
return
}
// We're going to run whatever Python is specified in the pull request, which
// may do bad things, so only trust people we trust.
if err := checkAuth(pr); err != nil {
writeError(w, 403, err)
return
}
base, err := s.generateAt(pr.Base.SHA)
defer os.RemoveAll(base)
if err != nil {
writeError(w, 500, err)
return
}
head, err := s.generateAt(pr.Head.SHA)
defer os.RemoveAll(head)
if err != nil {
writeError(w, 500, err)
return
}
diffCmd := exec.Command("diff", "-u", path.Join(base, "scripts", "tmp", "full_spec.rst"), path.Join(head, "scripts", "tmp", "full_spec.rst"))
var diff bytes.Buffer
diffCmd.Stdout = &diff
if err := ignoreExitCodeOne(diffCmd.Run()); err != nil {
writeError(w, 500, fmt.Errorf("error running diff: %v", err))
return
}
w.Write(diff.Bytes())
}
func (s *server) serveHTMLDiff(w http.ResponseWriter, req *http.Request) {
pr, err := lookupPullRequest(*req.URL, "/diff/html")
if err != nil {
writeError(w, 400, err)
return
}
// We're going to run whatever Python is specified in the pull request, which
// may do bad things, so only trust people we trust.
if err := checkAuth(pr); err != nil {
writeError(w, 403, err)
return
}
base, err := s.generateAt(pr.Base.SHA)
defer os.RemoveAll(base)
if err != nil {
writeError(w, 500, err)
return
}
head, err := s.generateAt(pr.Head.SHA)
defer os.RemoveAll(head)
if err != nil {
writeError(w, 500, err)
return
}
htmlDiffer, err := findHTMLDiffer()
if err != nil {
writeError(w, 500, fmt.Errorf("could not find HTML differ"))
return
}
cmd := exec.Command(htmlDiffer, path.Join(base, "scripts", "gen", "specification.html"), path.Join(head, "scripts", "gen", "specification.html"))
var b bytes.Buffer
cmd.Stdout = &b
if err := cmd.Run(); err != nil {
writeError(w, 500, fmt.Errorf("error running HTML differ: %v", err))
return
}
w.Write(b.Bytes())
}
func findHTMLDiffer() (string, error) {
wd, err := os.Getwd()
if err != nil {
return "", err
}
differ := path.Join(wd, "htmldiff.pl")
9 years ago
if _, err := os.Stat(differ); err == nil {
return differ, nil
}
return "", fmt.Errorf("unable to find htmldiff.pl")
}
func listPulls(w http.ResponseWriter, req *http.Request) {
resp, err := http.Get(pullsPrefix)
if err != nil {
writeError(w, 500, err)
return
}
defer resp.Body.Close()
dec := json.NewDecoder(resp.Body)
var pulls []PullRequest
if err := dec.Decode(&pulls); err != nil {
writeError(w, 500, err)
return
}
if len(pulls) == 0 {
io.WriteString(w, "No pull requests found")
return
}
s := "<body><ul>"
for _, pull := range pulls {
s += fmt.Sprintf(`<li>%d: <a href="%s">%s</a>: <a href="%s">%s</a>: <a href="spec/%d">spec</a> <a href="diff/html/%d">spec diff</a> <a href="diff/rst/%d">rst diff</a></li>`,
pull.Number, pull.User.HTMLURL, pull.User.Login, pull.HTMLURL, pull.Title, pull.Number, pull.Number, pull.Number)
}
s += `</ul><div><a href="spec/head">View the spec at head</a></div></body>`
io.WriteString(w, s)
}
func ignoreExitCodeOne(err error) error {
if err == nil {
return err
}
if exiterr, ok := err.(*exec.ExitError); ok {
if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
if status.ExitStatus() == 1 {
return nil
}
}
}
return err
}
func main() {
flag.Parse()
// It would be great to read this from github, but there's no convenient way to do so.
// Most of these memberships are "private", so would require some kind of auth.
allowedMembers = map[string]bool{
"dbkr": true,
"erikjohnston": true,
"illicitonion": true,
"Kegsay": true,
"NegativeMjark": true,
}
rand.Seed(time.Now().Unix())
masterCloneDir, err := gitClone(matrixDocCloneURL, false)
if err != nil {
log.Fatal(err)
}
s := server{masterCloneDir}
http.HandleFunc("/spec/", s.serveSpec)
http.HandleFunc("/diff/rst/", s.serveRSTDiff)
http.HandleFunc("/diff/html/", s.serveHTMLDiff)
http.HandleFunc("/healthz", serveText("ok"))
http.HandleFunc("/", listPulls)
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", *port), nil))
}
func serveText(s string) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, req *http.Request) {
io.WriteString(w, s)
}
}