blob: c0418bcfb0c18a5975f332517c4e47f790b9bfdc [file] [log] [blame]
package engine
import (
// ServeHTTP executes a job as specified by the http request `r`, and sends the
// result as an http response.
// This method allows an Engine instance to be passed as a standard http.Handler interface.
// Note that the protocol used in this methid is a convenience wrapper and is not the canonical
// implementation of remote job execution. This is because HTTP/1 does not handle stream multiplexing,
// and so cannot differentiate stdout from stderr. Additionally, headers cannot be added to a response
// once data has been written to the body, which makes it inconvenient to return metadata such
// as the exit status.
func (eng *Engine) ServeHTTP(w http.ResponseWriter, r *http.Request) {
var (
jobName = path.Base(r.URL.Path)
jobArgs, exists = r.URL.Query()["a"]
if !exists {
jobArgs = []string{}
w.Header().Set("Job-Name", jobName)
for _, arg := range jobArgs {
w.Header().Add("Job-Args", arg)
job := eng.Job(jobName, jobArgs...)
// FIXME: distinguish job status from engine error in Run()
// The former should be passed as a special header, the former
// should cause a 500 status
// The exit status cannot be sent reliably with HTTP1, because headers
// can only be sent before the body.
// (we could possibly use http footers via chunked encoding, but I couldn't find
// how to use them in net/http)