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, 13 insertions, 5 deletions

diff --git a/config-daemon.ac b/config-daemon.ac
index 8a3e6d8b601..056c939e390 100644
--- a/config-daemon.ac
+++ b/config-daemon.ac
@@ -128,12 +128,20 @@ if test "x$guix_build_daemon" = "xyes"; then
   dnl 'restore-file-set', which requires unbuffered custom binary input
   dnl ports from Guile >= 2.0.10.)
   GUIX_CHECK_UNBUFFERED_CBIP
-  guix_build_daemon_offload="$ac_cv_guix_cbips_support_setvbuf"
 
-  if test "x$guix_build_daemon_offload" = "xyes"; then
-    AC_DEFINE([HAVE_DAEMON_OFFLOAD_HOOK], [1],
-      [Define if the daemon's 'offload' build hook is being built.])
-  fi
+  dnl Check for Guile-SSH, which is required by 'guix offload'.
+  GUIX_CHECK_GUILE_SSH
+
+  case "x$ac_cv_guix_cbips_support_setvbuf$guix_cv_have_recent_guile_ssh" in
+    xyesyes)
+      guix_build_daemon_offload="yes"
+      AC_DEFINE([HAVE_DAEMON_OFFLOAD_HOOK], [1],
+        [Define if the daemon's 'offload' build hook is being built (requires Guile-SSH).])
+      ;;
+    *)
+      guix_build_daemon_offload="no"
+      ;;
+  esac
 
   dnl Temporary directory used to store the daemon's data.
   GUIX_TEST_ROOT_DIRECTORY