bug#30939: still relevant

[Robert Vollmert]

This came up again recently, compare the discussion here:

https://lists.gnu.org/archive/html/guix-devel/2019-06/msg00186.html

Here’s some code to wrap an executable manually to capture its output
and send it to syslog:

(define* (logger-wrapper name exec . args)
  "Return a derivation that builds a script to start a process with
standard output and error redirected to syslog via logger."
  (define exp
    #~(begin
        (use-modules (ice-9 popen))
        (let* ((pid    (number->string (getpid)))
               (logger #$(file-append inetutils "/bin/logger"))
               (args   (list "-t" #$name (string-append "--id=" pid)))
               (pipe   (apply open-pipe* OPEN_WRITE logger args)))
          (dup pipe 1)
          (dup pipe 2)
          (execl #$exec #$exec #$@args))))
  (program-file (string-append name "-logger") exp))