offload: Use Guile-SSH instead of GNU lsh.

* guix/scripts/offload.scm (<build-machine>)[ssh-options]: Remove.
[host-key, host-key-type]: New fields.
(%lsh-command, %lshg-command, user-lsh-private-key): Remove.
(user-openssh-private-key, private-key-from-file*): New procedures.
(host-key->type+key, open-ssh-session): New procedures.
(remote-pipe): Remove 'mode' parameter.  Rewrite in terms of
'open-ssh-session' etc.  Update users.
(send-files)[missing-files]: Rewrite using the bidirectional channel
port.
Remove call to 'call-with-compressed-output-port'.
(retrieve-files): Remove call to 'call-with-decompressed-port'.
(machine-load): Remove exit status logic.
* doc/guix.texi (Requirements): Mention Guile-SSH.
(Daemon Offload Setup): Document 'host-key' and 'private-key'.  Show the
default value on each @item line.
* m4/guix.m4 (GUIX_CHECK_GUILE_SSH): New macro.
* config-daemon.ac: Use 'GUIX_CHECK_GUILE_SSH'.  Set
'HAVE_DAEMON_OFFLOAD_HOOK' as a function of that.

1 files changed, 18 insertions, 0 deletions

diff --git a/m4/guix.m4 b/m4/guix.m4
index 6d8ec2e4e04..6630598416b 100644
--- a/m4/guix.m4
+++ b/m4/guix.m4
@@ -171,6 +171,24 @@ AC_DEFUN([GUIX_CHECK_UNBUFFERED_CBIP], [
      fi])
 ])
 
+dnl GUIX_CHECK_GUILE_SSH
+dnl
+dnl Check whether a recent-enough Guile-SSH is available.
+AC_DEFUN([GUIX_CHECK_GUILE_SSH], [
+  dnl Check whether 'channel-send-eof' (introduced in 0.10.2) is present.
+  AC_CACHE_CHECK([whether Guile-SSH is available and recent enough],
+    [guix_cv_have_recent_guile_ssh],
+    [GUILE_CHECK([retval],
+      [(and (@ (ssh channel) channel-send-eof)
+            (@ (ssh popen) open-remote-pipe)
+            (@ (ssh dist node) node-eval))])
+     if test "$retval" = 0; then
+       guix_cv_have_recent_guile_ssh="yes"
+     else
+       guix_cv_have_recent_guile_ssh="no"
+     fi])
+])
+
 dnl GUIX_TEST_ROOT_DIRECTORY
 AC_DEFUN([GUIX_TEST_ROOT_DIRECTORY], [
   AC_CACHE_CHECK([for unit test root directory],