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package main
import (
"bytes"
"crypto/tls"
"encoding/json"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"math/rand"
"net/http"
"net/url"
"os"
"os/exec"
"path"
"sort"
"strings"
"time"
"gopkg.in/yaml.v2"
)
var flags struct {
addr string
proxyURL string
proxyClientCert string
proxyClientKey string
proxyMinikube bool
cache bool
}
func init() {
flag.StringVar(&flags.addr, "addr", "localhost:8080", "Address to listen on")
flag.StringVar(&flags.proxyURL, "proxy-url", "", "Proxy requests to this URL")
flag.StringVar(&flags.proxyClientCert, "proxy-client-cert", "", "Client certificate to use when connecting to proxy")
flag.StringVar(&flags.proxyClientKey, "proxy-client-key", "", "Client key to use when connecting to proxy")
flag.BoolVar(&flags.proxyMinikube, "proxy-minikube", false, "Shortcut for -proxy-url https://$(minikube ip):8443 -proxy-client-cert ~/.minikube/client.crt -proxy-client-key ~/.minikube/client.key")
flag.BoolVar(&flags.cache, "cache", false, "Cache all requests")
}
func main() {
flag.Parse()
if flags.proxyMinikube {
err := proxyMinikube()
if err != nil {
log.Fatalf("Error: Setting up Minikube proxy: %s", err)
}
}
cert := tls.Certificate{}
if flags.proxyClientCert != "" && flags.proxyClientKey != "" {
var err error
cert, err = tls.LoadX509KeyPair(flags.proxyClientCert, flags.proxyClientKey)
if err != nil {
log.Fatalf("Error: parsing client cert and key: %s", err)
}
}
var responsesPath string
if flag.NArg() == 1 {
responsesPath = flag.Arg(0)
}
var responses Responses
requestLog := Log(make([]LogEntry, 0))
http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
responses.Load(responsesPath)
stub := responses.Match(req)
haveCachedStub := flags.cache && stub != nil
var resp *http.Response
if flags.proxyURL != "" && !haveCachedStub {
resp = respondWithProxy(flags.proxyURL, &cert, w, req)
} else {
resp = respondWithStub(stub, w, req)
}
if resp == nil {
return
}
e := requestLog.Log(req, resp)
if flags.cache {
responses.Add(e.AsResponse())
}
})
http.HandleFunc("/_log", func(w http.ResponseWriter, req *http.Request) {
showCache := flags.cache && req.URL.Query().Get("cache") == "true"
if showCache || strings.Contains(req.Header.Get("Accept"), "application/yaml") {
var rs []Response
if showCache {
rs = responses.responses
} else {
rs = requestLog.AsResponses()
}
err := renderYAML(w, rs)
if err != nil {
log.Printf("Error: Render log: %s", err)
}
return
}
for i := len(requestLog) - 1; i >= 0; i-- {
w.Write([]byte("------------------------------------------------------\n"))
requestLog[i].Request().Write(w)
w.Write([]byte("\n"))
requestLog[i].Response().Write(w)
w.Write([]byte("\n"))
}
})
http.HandleFunc("/_help", func(w http.ResponseWriter, req *http.Request) {
urls := []struct {
URL string
Summary string
}{
{URL: "/_log", Summary: "View all received requests with responses"},
{URL: "/_help", Summary: "This help"},
}
fmt.Fprint(w, `<!doctype html>
<html>
<head>
<title>/_help</title>
</head>
<body>
<ul>`)
for _, url := range urls {
fmt.Fprintf(w, "<li><pre><a href=\"%s\">%s</a> - %s</pre></li>", url.URL, url.URL, url.Summary)
}
fmt.Fprint(w, `
</ul>
</body>
</html`)
})
log.Printf("Listening on http://%s", flags.addr)
log.Printf("See http://%s/_help", flags.addr)
log.Fatal(http.ListenAndServe(flags.addr, nil))
}
func proxyMinikube() error {
out, err := exec.Command("minikube", "ip").Output()
if err != nil {
return err
}
flags.proxyURL = fmt.Sprintf("https://%s:8443", strings.TrimSpace(string(out)))
homeDir := os.Getenv("HOME")
flags.proxyClientCert = path.Join(homeDir, ".minikube/client.crt")
flags.proxyClientKey = path.Join(homeDir, ".minikube/client.key")
return nil
}
func respondWithStub(resp *Response, w http.ResponseWriter, req *http.Request) *http.Response {
time.Sleep(resp.Delay)
if resp.RandomDelay > 0 {
time.Sleep(time.Duration(rand.Intn(int(resp.RandomDelay))))
}
for _, header := range resp.Headers {
w.Header().Set(header.Name, header.Value)
}
if resp.Status == 0 {
resp.Status = 200
}
w.WriteHeader(resp.Status)
w.Write([]byte(resp.Body))
return resp.AsHTTP()
}
func respondWithProxy(proxyURL string, cert *tls.Certificate, w http.ResponseWriter, req *http.Request) *http.Response {
proxyTransport := &http.Transport{
TLSClientConfig: &tls.Config{
GetClientCertificate: func(info *tls.CertificateRequestInfo) (*tls.Certificate, error) {
return cert, nil
},
InsecureSkipVerify: true,
},
}
proxyClient := &http.Client{Transport: proxyTransport}
u, err := url.Parse(proxyURL)
if err != nil {
log.Printf("Error: Parsing proxy url: %s", err)
return nil
}
req.URL.Scheme = u.Scheme
req.URL.Host = u.Host
req.RequestURI = ""
resp, err := proxyClient.Do(req)
if err != nil {
log.Printf("Error: Proxying %s: %s", req.URL.Path, err)
return nil
}
defer resp.Body.Close()
for name, vals := range resp.Header {
w.Header()[name] = vals
}
w.WriteHeader(resp.StatusCode)
buf := new(bytes.Buffer)
io.Copy(buf, resp.Body)
resp.Body = ioutil.NopCloser(bytes.NewReader(buf.Bytes()))
io.Copy(w, buf)
return resp
}
func prettyfyJSON(r io.Reader) ([]byte, error) {
dec := json.NewDecoder(r)
var val interface{}
err := dec.Decode(&val)
if err != nil {
return nil, err
}
return json.MarshalIndent(val, "", " ")
}
func renderYAML(w http.ResponseWriter, responses []Response) error {
out, err := yaml.Marshal(responses)
if err != nil {
return err
}
w.Write(out)
return nil
}
// Log collects HTTP requests/responses for later display and
// processing.
type Log []LogEntry
// Log logs the request/response pair.
func (l *Log) Log(req *http.Request, resp *http.Response) *LogEntry {
userAgent := req.Header.Get("User-Agent")
log.Printf("%s %s - %d (%s, %q)", req.Method, req.URL, resp.StatusCode, req.RemoteAddr, userAgent)
e := LogEntry{
request: req,
requestBody: new(bytes.Buffer),
response: resp,
responseBody: new(bytes.Buffer),
}
io.Copy(e.requestBody, req.Body)
if resp.Header.Get("Content-Type") == "application/json" {
pretty, err := prettyfyJSON(resp.Body)
if err != nil {
log.Printf("Error: Prettyfying JSON: %s", err)
} else {
resp.ContentLength = int64(len(pretty))
resp.Body = ioutil.NopCloser(bytes.NewReader(pretty))
}
}
io.Copy(e.responseBody, resp.Body)
*l = append(*l, e)
return &e
}
// AsResponses returns the log as a list of response definition.
func (l *Log) AsResponses() []Response {
rs := make([]Response, len(*l))
for i, log := range *l {
rs[i] = log.AsResponse()
}
return rs
}
// LogEntry is a request/response pair for logging.
type LogEntry struct {
request *http.Request
requestBody *bytes.Buffer
response *http.Response
responseBody *bytes.Buffer
}
type byHeaderName []Header
func (hs byHeaderName) Len() int { return len(hs) }
func (hs byHeaderName) Swap(i, j int) { hs[i], hs[j] = hs[j], hs[i] }
func (hs byHeaderName) Less(i, j int) bool { return hs[i].Name < hs[j].Name }
// AsResponse returns a Response representation of the entry.
func (e LogEntry) AsResponse() Response {
headers := make([]Header, 0, len(e.response.Header))
for name, vals := range e.response.Header {
for _, val := range vals {
headers = append(headers, Header{Name: name, Value: val})
}
}
sort.Sort(byHeaderName(headers))
return Response{
Method: e.request.Method,
Path: e.request.URL.Path,
Status: e.response.StatusCode,
Headers: headers,
Body: e.responseBody.String(),
}
}
// Request returns the stored http.Request.
func (e LogEntry) Request() *http.Request {
e.request.Body = ioutil.NopCloser(bytes.NewReader(e.requestBody.Bytes()))
return e.request
}
// Response returns the stored http.Response.
func (e LogEntry) Response() *http.Response {
e.response.Body = ioutil.NopCloser(bytes.NewReader(e.responseBody.Bytes()))
e.response.ContentLength = int64(e.responseBody.Len())
return e.response
}
// Response is a mocked HTTP response.
type Response struct {
Method string `yaml:"method"`
Path string `yaml:"path"`
Status int `yaml:"status"`
Headers []Header `yaml:"headers"`
Body string `yaml:"body"`
Delay time.Duration `yaml:"delay,omitempty"`
RandomDelay time.Duration `yaml:"randomDelay,omitempty"`
}
// AsHTTP returns a http.Response representation.
func (resp Response) AsHTTP() *http.Response {
headers := make(map[string][]string)
for _, header := range resp.Headers {
h, ok := headers[header.Name]
if !ok {
h = []string{}
}
h = append(h, header.Value)
headers[header.Name] = h
}
return &http.Response{
ProtoMajor: 1,
ProtoMinor: 1,
StatusCode: resp.Status,
Header: headers,
Body: ioutil.NopCloser(strings.NewReader(resp.Body)),
}
}
// Header is a single-valued HTTP header name and value
type Header struct {
Name string `yaml:"name"`
Value string `yaml:"value"`
}
// Responses is a list of responses that will be stubbed/faked.
type Responses struct {
responses []Response
seen map[string]bool
}
// Match returns a response definition matching the request.
func (rs *Responses) Match(req *http.Request) *Response {
for _, resp := range rs.responses {
if req.Method == resp.Method && req.URL.String() == resp.Path {
return &resp
}
}
return nil
}
// Add adds the response to the log, to include it in future Match
// calls.
func (rs *Responses) Add(r Response) {
if rs.seen[r.Method+" "+r.Path] {
return
}
rs.responses = append(rs.responses, r)
if rs.seen == nil {
rs.seen = make(map[string]bool)
}
rs.seen[r.Method+" "+r.Path] = true
}
// Load loads responses from the YAML file at path.
func (rs *Responses) Load(path string) {
if path == "" {
return
}
responses, err := rs.loadFile(path)
if err != nil {
log.Printf("Error: Parsing %s: %s", path, err)
}
rs.responses = responses
}
func (rs *Responses) loadFile(path string) ([]Response, error) {
out, err := ioutil.ReadFile(path)
if err != nil {
return nil, err
}
var responses []Response
err = yaml.Unmarshal(out, &responses)
if err != nil {
return nil, err
}
return responses, nil
}
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