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|
package main
import (
"bytes"
"errors"
"flag"
"fmt"
"io/ioutil"
"log"
"net"
"net/http"
"net/url"
"regexp"
"strconv"
"strings"
"text/template"
"time"
"github.com/coreos/go-semver/semver"
)
var (
addrFlag = flag.String("addr", ":8080", "Serve HTTP at given address")
socketFlag = flag.String("socket", "", "Serve HTTP at given UNIX socket")
vanityRootFlag = flag.String("vanity-root", "", "Vanity root URL (e.g.: https://upper.io).")
repoRootFlag = flag.String("repo-root", "", "Git repository root URL (e.g.: https://github.com/upper).")
)
var packagePattern = regexp.MustCompile(`^/([-a-zA-Z0-9]+)\.?(v([0-9]*))?(.*)$`)
var httpClient = &http.Client{Timeout: 10 * time.Second}
const refsSuffix = ".git/info/refs?service=git-upload-pack"
// Error messages.
var (
ErrNoRepo = errors.New("repository not found")
ErrNoVersion = errors.New("version reference not found")
)
func main() {
if err := run(); err != nil {
log.Fatalf("Could not start server: %q", err)
}
}
func run() error {
flag.Parse()
if *addrFlag == "" && *socketFlag == "" {
return fmt.Errorf("must provide -addr")
}
if *repoRootFlag == "" {
return fmt.Errorf("must provide -repo-root")
}
if *vanityRootFlag == "" {
return fmt.Errorf("must provide -vanity-root")
}
repoRoot, err := NewRepoRoot(*repoRootFlag, *vanityRootFlag)
if err != nil {
return fmt.Errorf("could not parse -repo-root: %q", err)
}
var listenAddr, listenNet string
if *socketFlag != "" {
listenNet, listenAddr = "unix", *socketFlag
} else {
listenNet, listenAddr = "tcp", *addrFlag
}
li, err := net.Listen(listenNet, listenAddr)
if err != nil {
return fmt.Errorf("Failed to bind to %s %s: %v", listenNet, listenAddr, err)
}
http.HandleFunc("/", newHandler(repoRoot))
log.Printf("Listening at %s. %s -> %s", listenAddr, *vanityRootFlag, *repoRootFlag)
return http.Serve(li, nil)
}
var gogetTemplate = template.Must(template.New("").Parse(`
<html>
<head>
<meta name="go-import" content="{{.VanityPath}} git {{.VanityURL}}">
<meta name="go-source" content="{{.VanityPath}} _ {{.RepoRootURL}}/tree/{{.GitTree}}{/dir} {{.RepoRootURL}}/blob/{{.GitTree}}{/dir}/{file}#L{line}">
</head>
<body>
go get {{.VanityPath}}
</body>
</html>
`))
// RepoRoot represents a real repository and vanity name pair.
type RepoRoot struct {
vanityURL *url.URL
repoURL *url.URL
RepoHostPath string
VanityHostPath string
}
func parseRepoURL(in string) (*url.URL, error) {
u, err := url.Parse(in)
if err != nil {
return nil, err
}
if u.Scheme == "" {
u.Scheme = "https"
}
return u, err
}
// NewRepoRoot creates a RepoRoot
func NewRepoRoot(repoURL string, vanityURL string) (*RepoRoot, error) {
u, err := parseRepoURL(repoURL)
if err != nil {
return nil, err
}
v, err := parseRepoURL(vanityURL)
if err != nil {
return nil, err
}
return &RepoRoot{
repoURL: u,
vanityURL: v,
RepoHostPath: u.Host + u.Path,
VanityHostPath: v.Host + v.Path,
}, nil
}
// NewRepo creates a new repository.
func (root *RepoRoot) NewRepo(name string) *Repo {
return &Repo{
Root: root,
Name: name,
}
}
// Repo represents a source code repository on GitHub.
type Repo struct {
Root *RepoRoot
Name string
Major string
RequestedVersion semver.Version
// FullVersion is the best version in AllVersions that matches MajorVersion.
// It defaults to InvalidVersion if there are no matches.
FullVersion *semver.Version
// AllVersions holds all versions currently available in the repository,
// either coming from branch names or from tag names. Version zero (v0)
// is only present in the list if it really exists in the repository.
AllVersions semver.Versions
}
// SetVersions records in the relevant fields the details about which
// package versions are available in the repository.
func (repo *Repo) SetVersions(all semver.Versions) {
repo.AllVersions = all
for _, v := range repo.AllVersions {
if v.Major == repo.RequestedVersion.Major && (repo.FullVersion == nil || repo.FullVersion.LessThan(*v)) {
repo.FullVersion = v
}
}
}
// RepoRoot returns the repository root, without a schema.
func (repo *Repo) RepoRoot() string {
return repo.Root.RepoHostPath + "/" + repo.Name
}
// VanityRoot returns the vanity repository root, without a schema.
func (repo *Repo) VanityRoot() string {
return repo.Root.VanityHostPath + "/" + repo.Name
}
// GitTree returns the repository tree name for the selected version.
func (repo *Repo) GitTree() string {
if repo.FullVersion == nil || repo.Major == "" {
return "master"
}
return repo.FullVersion.String()
}
// VanityPath returns the real package path, without a schema.
func (repo *Repo) VanityPath() string {
if repo.Major == "" {
return repo.VanityRoot()
}
return repo.VanityRoot() + ".v" + repo.Major
}
// VanityURL returns the vanity package's URL.
func (repo *Repo) VanityURL() string {
return repo.Root.vanityURL.Scheme + "://" + repo.VanityPath()
}
// RepoRootURL returns the real package's URL.
func (repo *Repo) RepoRootURL() string {
return repo.Root.repoURL.Scheme + "://" + repo.RepoRoot()
}
func newHandler(repoRoot *RepoRoot) func(http.ResponseWriter, *http.Request) {
return func(resp http.ResponseWriter, req *http.Request) {
if req.URL.Path == "/health-check" {
resp.Write([]byte("ok"))
return
}
log.Printf("%s requested %s", req.RemoteAddr, req.URL)
if req.URL.Path == "/" {
sendNotFound(resp, "Missing package name.")
return
}
u, err := url.Parse(req.URL.Path)
if err != nil {
sendError(resp, "Failed to parse request path")
return
}
p := packagePattern.FindStringSubmatch(u.Path)
pkgName, _, version, extra := p[1], p[2], p[3], p[4]
repo := repoRoot.NewRepo(pkgName)
var requestedVersion semver.Version
if version != "" {
repo.Major = version
repo.RequestedVersion.Major, _ = strconv.ParseInt(repo.Major, 10, 64)
}
var changed []byte
var versions semver.Versions
original, err := fetchRefs(repo)
if err == nil {
changed, versions, err = changeRefs(original, &repo.RequestedVersion)
repo.SetVersions(versions)
}
switch err {
case nil:
// all ok
case ErrNoRepo:
sendNotFound(resp, "Git repository not found at https://%s", repo.RepoRoot())
return
case ErrNoVersion:
sendNotFound(resp, `Git repository at https://%s has no tag %v`, repo.RepoRoot(), requestedVersion)
return
default:
resp.WriteHeader(http.StatusBadGateway)
resp.Write([]byte(fmt.Sprintf("Cannot obtain refs from Git: %v", err)))
return
}
switch extra {
case `/git-upload-pack`:
proxyURL := "https://" + repo.RepoRoot() + "/git-upload-pack"
proxyReq, err := http.NewRequest(req.Method, proxyURL, req.Body)
if err != nil {
resp.WriteHeader(http.StatusInternalServerError)
return
}
for k, v := range req.Header {
proxyReq.Header[k] = v
}
proxyRes, err := http.DefaultClient.Do(proxyReq)
if err != nil {
log.Printf("Proxy: %v", err)
resp.WriteHeader(http.StatusServiceUnavailable)
return
}
defer proxyRes.Body.Close()
for k, v := range proxyRes.Header {
resp.Header()[k] = v
}
buf, err := ioutil.ReadAll(proxyRes.Body)
if err != nil {
log.Printf("Proxy: %v", err)
resp.WriteHeader(http.StatusBadGateway)
return
}
if _, err = resp.Write(buf); err != nil {
log.Printf("Proxy: %v", err)
resp.WriteHeader(http.StatusInternalServerError)
return
}
return
case `/info/refs`:
resp.Header().Set("Content-Type", "application/x-git-upload-pack-advertisement")
resp.Write(changed)
return
}
resp.Header().Set("Content-Type", "text/html")
if req.FormValue("go-get") == "1" {
// execute simple template when this is a go-get request
err = gogetTemplate.Execute(resp, repo)
if err != nil {
log.Printf("error executing go get template: %s\n", err)
}
return
}
sendNotFound(resp, "Missing ?go-get=1 parameter.")
}
}
func sendError(resp http.ResponseWriter, msg string, args ...interface{}) {
if len(args) > 0 {
msg = fmt.Sprintf(msg, args...)
}
resp.WriteHeader(http.StatusInternalServerError)
resp.Write([]byte(msg))
}
func sendNotFound(resp http.ResponseWriter, msg string, args ...interface{}) {
if len(args) > 0 {
msg = fmt.Sprintf(msg, args...)
}
resp.WriteHeader(http.StatusNotFound)
resp.Write([]byte(msg))
}
func fetchRefs(repo *Repo) (data []byte, err error) {
repoURL := repo.RepoRootURL() + refsSuffix
resp, err := httpClient.Get(repoURL)
if err != nil {
return nil, fmt.Errorf("cannot talk to git repository: %v", err)
}
defer resp.Body.Close()
switch resp.StatusCode {
case 200:
// ok
case 401, 404:
return nil, ErrNoRepo
default:
return nil, fmt.Errorf("error from git repository: %v", resp.Status)
}
data, err = ioutil.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("error reading from git: %v", err)
}
return data, err
}
func changeRefs(data []byte, major *semver.Version) (changed []byte, versions semver.Versions, err error) {
var hlinei, hlinej int // HEAD reference line start/end
var mlinei, mlinej int // master reference line start/end
var vrefhash string
var vrefname string
var vrefv *semver.Version
// Record all available versions, the locations of the master and HEAD lines,
// and details of the best reference satisfying the requested major version.
versions = semver.Versions{}
sdata := string(data)
for i, j := 0, 0; i < len(data); i = j {
size, err := strconv.ParseInt(sdata[i:i+4], 16, 32)
if err != nil {
return nil, nil, fmt.Errorf("cannot parse refs line size: %s", string(data[i:i+4]))
}
if size == 0 {
size = 4
}
j = i + int(size)
if j > len(sdata) {
return nil, nil, fmt.Errorf("incomplete refs data received from GitHub")
}
if sdata[0] == '#' {
continue
}
hashi := i + 4
hashj := strings.IndexByte(sdata[hashi:j], ' ')
if hashj < 0 || hashj != 40 {
continue
}
hashj += hashi
namei := hashj + 1
namej := strings.IndexAny(sdata[namei:j], "\n\x00")
if namej < 0 {
namej = j
} else {
namej += namei
}
name := sdata[namei:namej]
if name == "HEAD" {
hlinei = i
hlinej = j
}
if name == "refs/heads/master" {
mlinei = i
mlinej = j
}
if strings.HasPrefix(name, "refs/tags/v") {
if !strings.HasSuffix(name, "^{}") {
continue // Only accept annotated tags.
}
// Annotated tag is peeled off and overrides the same version just parsed.
name = name[:len(name)-3]
v, err := semver.NewVersion(name[strings.IndexByte(name, 'v')+1:])
if err == nil {
versions = append(versions, v)
if major.Major == v.Major && (vrefv == nil || v == vrefv || vrefv.LessThan(*v)) {
vrefv = v
vrefhash = sdata[hashi:hashj]
vrefname = name
}
}
}
}
// If the file has no HEAD line or the version was not found, report as unavailable.
if hlinei == 0 || vrefhash == "" {
return nil, nil, ErrNoVersion
}
var buf bytes.Buffer
buf.Grow(len(data) + 256)
// Copy the header as-is.
buf.Write(data[:hlinei])
// Extract the original capabilities.
caps := ""
if i := strings.Index(sdata[hlinei:hlinej], "\x00"); i > 0 {
caps = strings.Replace(sdata[hlinei+i+1:hlinej-1], "symref=", "oldref=", -1)
}
// Insert the HEAD reference line with the right hash and a proper symref capability.
var line string
if strings.HasPrefix(vrefname, "refs/heads/") {
if caps == "" {
line = fmt.Sprintf("%s HEAD\x00symref=HEAD:%s\n", vrefhash, vrefname)
} else {
line = fmt.Sprintf("%s HEAD\x00symref=HEAD:%s %s\n", vrefhash, vrefname, caps)
}
} else {
if caps == "" {
line = fmt.Sprintf("%s HEAD\n", vrefhash)
} else {
line = fmt.Sprintf("%s HEAD\x00%s\n", vrefhash, caps)
}
}
fmt.Fprintf(&buf, "%04x%s", 4+len(line), line)
// Insert the master reference line.
line = fmt.Sprintf("%s refs/heads/master\n", vrefhash)
fmt.Fprintf(&buf, "%04x%s", 4+len(line), line)
// Append the rest, dropping the original master line if necessary.
if mlinei > 0 {
buf.Write(data[hlinej:mlinei])
buf.Write(data[mlinej:])
} else {
buf.Write(data[hlinej:])
}
return buf.Bytes(), versions, nil
}
|
