package helloworld
import (
"fmt"
"net/http"
"appengine"
"appengine/user"
)
func init() {
fmt.Print("hello")
http.HandleFunc("/", handler)
}
func handler(w http.ResponseWriter, r *http.Request) {
c := appengine.NewContext(r)
u := user.Current(c)
if u == nil {
url, err := user.LoginURL(c, r.URL.String())
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Location", url)
w.WriteHeader(http.StatusFound)
return
}
fmt.Fprintf(w, "Hello, %v!", u)
}
Throw the following error in goapp serve output
(saucy)adam@localhost:~/projects/ringed-land-605/default$ goapp serve -host 0.0.0.0 .
INFO 2014-06-08 23:57:47,862 devappserver2.py:716] Skipping SDK update check.
INFO 2014-06-08 23:57:47,877 api_server.py:171] Starting API server at: http://localhost:48026
INFO 2014-06-08 23:57:47,923 dispatcher.py:182] Starting module "default" running at: http://0.0.0.0:8080
INFO 2014-06-08 23:57:47,925 admin_server.py:117] Starting admin server at: http://localhost:8000
ERROR 2014-06-08 23:57:48,759 http_runtime.py:262] bad runtime process port ['hello46591
']
Removing the fmt.Print() fixes the issue. My question is why does that happen?
When starting the runtime process, the Go Development Server (in the App Engine Go SDK) is reading the single line response found in your helloworld's init.
This modifies the _start_process_flavor flag in http_runtime.py; consequently, the HTTP runtime attempts to read the line for direction on which port to listen to.
Read the single line response expected in the start process file. [...] The START_PROCESS_FILE flavor uses a file for the runtime instance to report back the port it is listening on.
In this case, hello isn't a valid port to listen on.
Try using Go's log package instead:
log.Print("hello")