Stream command output as a response

internal/hook/hook.go

@@ -531,6 +531,7 @@ type Hook struct {
  ResponseMessage string `json:"response-message,omitempty"`
  ResponseHeaders ResponseHeaders `json:"response-headers,omitempty"`
  CaptureCommandOutput bool `json:"include-command-output-in-response,omitempty"`
+ StreamCommandOutput bool `json:"stream-command-output,omitempty"`
  CaptureCommandOutputOnError bool `json:"include-command-output-in-response-on-error,omitempty"`
  PassEnvironmentToCommand []Argument `json:"pass-environment-to-command,omitempty"`
  PassArgumentsToCommand []Argument `json:"pass-arguments-to-command,omitempty"`

webhook.go

@@ -6,6 +6,7 @@ import (
  "encoding/json"
  "flag"
  "fmt"
+ "io"
  "io/ioutil"
  "log"
  "net"
@@ -67,6 +68,19 @@ var (
  pidFile *pidfile.PIDFile
 )
 
+type flushWriter struct {
+ f http.Flusher
+ w io.Writer
+}
+
+func (fw *flushWriter) Write(p []byte) (n int, err error) {
+ n, err = fw.w.Write(p)
+ if fw.f != nil {
+ fw.f.Flush()
+ }
+ return
+}
+
 func matchLoadedHook(id string) *hook.Hook {
  for _, hooks := range loadedHooksFromFiles {
  if hook := hooks.Match(id); hook != nil {
@@ -535,8 +549,10 @@ func hookHandler(w http.ResponseWriter, r *http.Request) {
  w.Header().Set(responseHeader.Name, responseHeader.Value)
  }
 
- if matchedHook.CaptureCommandOutput {
- response, err := handleHook(matchedHook, rid, &headers, &query, &payload, &body)
+ if matchedHook.StreamCommandOutput {
+ handleHook(matchedHook, rid, &headers, &query, &payload, &body, w)
+ } else if matchedHook.CaptureCommandOutput {
+ response, err := handleHook(matchedHook, rid, &headers, &query, &payload, &body, nil)
 
  if err != nil {
  w.WriteHeader(http.StatusInternalServerError)
@@ -554,7 +570,7 @@ func hookHandler(w http.ResponseWriter, r *http.Request) {
  fmt.Fprint(w, response)
  }
  } else {
- go handleHook(matchedHook, rid, &headers, &query, &payload, &body)
+ go handleHook(matchedHook, rid, &headers, &query, &payload, &body, nil)
 
  // Check if a success return code is configured for the hook
  if matchedHook.SuccessHttpResponseCode != 0 {
@@ -577,7 +593,7 @@ func hookHandler(w http.ResponseWriter, r *http.Request) {
  fmt.Fprint(w, "Hook rules were not satisfied.")
 }
 
-func handleHook(h *hook.Hook, rid string, headers, query, payload *map[string]interface{}, body *[]byte) (string, error) {
+func handleHook(h *hook.Hook, rid string, headers, query, payload *map[string]interface{}, body *[]byte, w http.ResponseWriter) (string, error) {
  var errors []error
 
  // check the command exists
@@ -646,12 +662,31 @@ func handleHook(h *hook.Hook, rid string, headers, query, payload *map[string]in
 
  log.Printf("[%s] executing %s (%s) with arguments %q and environment %s using %s as cwd\n", rid, h.ExecuteCommand, cmd.Path, cmd.Args, envs, cmd.Dir)
 
- out, err := cmd.CombinedOutput()
+ var out []byte
 
- log.Printf("[%s] command output: %s\n", rid, out)
+ if w != nil {
+ log.Printf("[%s] command output will be streamed to response", rid)
 
- if err != nil {
- log.Printf("[%s] error occurred: %+v\n", rid, err)
+ // Implementation from https://play.golang.org/p/PpbPyXbtEs
+ // as described in https://stackoverflow.com/questions/19292113/not-buffered-http-responsewritter-in-golang
+ fw := flushWriter{w: w}
+ if f, ok := w.(http.Flusher); ok {
+ fw.f = f
+ }
+ cmd.Stderr = &fw
+ cmd.Stdout = &fw
+
+ if err := cmd.Run(); err != nil {
+ log.Printf("[%s] error occurred: %+v\n", rid, err)
+ }
+ } else {
+ out, err = cmd.CombinedOutput()
+
+ log.Printf("[%s] command output: %s\n", rid, out)
+
+ if err != nil {
+ log.Printf("[%s] error occurred: %+v\n", rid, err)
+ }
  }
 
  for i := range files {

webhook_test.go

@@ -53,7 +53,7 @@ func TestStaticParams(t *testing.T) {
  b := &bytes.Buffer{}
  log.SetOutput(b)
 
- _, err = handleHook(spHook, "test", &spHeaders, &map[string]interface{}{}, &map[string]interface{}{}, &[]byte{})
+ _, err = handleHook(spHook, "test", &spHeaders, &map[string]interface{}{}, &map[string]interface{}{}, &[]byte{}, nil)
  if err != nil {
  t.Fatalf("Unexpected error: %v\n", err)
  }