upgrade: Add support for --pull-only and --deploy-only

This makes it easier to script downloading updates in the background,
and only do deployments just before rebooting.

Partially addresses https://github.com/ostreedev/ostree/issues/640

Closes: #642
Approved by: jlebon

6 files changed, 125 insertions, 7 deletions

diff --git a/Makefile-tests.am b/Makefile-tests.am
index 8dbd3811..fd755ee1 100644
--- a/Makefile-tests.am
+++ b/Makefile-tests.am
@@ -83,6 +83,7 @@ dist_test_scripts = \
 	tests/test-admin-instutil-set-kargs.sh \
 	tests/test-admin-upgrade-not-backwards.sh \
 	tests/test-admin-pull-deploy-commit.sh \
+	tests/test-admin-pull-deploy-split.sh \
 	tests/test-admin-locking.sh \
 	tests/test-admin-deploy-clean.sh \
 	tests/test-repo-checkout-subpath.sh	\
diff --git a/man/ostree-admin-upgrade.xml b/man/ostree-admin-upgrade.xml
index ddd33dc6..7766c66e 100644
--- a/man/ostree-admin-upgrade.xml
+++ b/man/ostree-admin-upgrade.xml
@@ -57,7 +57,10 @@ Boston, MA 02111-1307, USA.
         <title>Description</title>
 
         <para>
-            Downloads the latest version of the current ref from the build server and deploys it, if it changed.  Reboot the machine for the changes to take effect.
+            Downloads the latest version of the current ref from the build
+            server and deploys it, if it changed. Reboot the machine for the
+            changes to take effect. These phases can be split via
+            <option>--pull-only</option> and <option>--deploy-only</option>.
         </para>
     </refsect1>
 
@@ -74,6 +77,24 @@ Boston, MA 02111-1307, USA.
             </varlistentry>
 
             <varlistentry>
+                <term><option>--pull-only</option></term>
+
+                <listitem><para> Only perform a pull into the repository; do not
+                create a deployment. This option can hence safely be used in a
+                background scheduled job with the assurance of not changing
+                system state.</para></listitem>
+            </varlistentry>
+
+            <varlistentry>
+                <term><option>--deploy-only</option></term>
+
+                <listitem><para>Create a new deployment from the latest commit
+                in the tracked origin refspec.  This option is intended to be used
+                by a scheduled system that detected changes via <option>--pull-only</option>,
+                and is ready to deploy them.</para></listitem>
+            </varlistentry>
+
+            <varlistentry>
                 <term><option>--reboot</option>,<option>-r</option></term>
 
                 <listitem><para>
diff --git a/src/libostree/ostree-sysroot-upgrader.c b/src/libostree/ostree-sysroot-upgrader.c
index daf2445c..232f8435 100644
--- a/src/libostree/ostree-sysroot-upgrader.c
+++ b/src/libostree/ostree-sysroot-upgrader.c
@@ -552,7 +552,8 @@ ostree_sysroot_upgrader_pull_one_dir (OstreeSysrootUpgrader  *self,
   g_assert (self->merge_deployment);
   from_revision = ostree_deployment_get_csum (self->merge_deployment);
 
-  if (self->origin_remote)
+  if (self->origin_remote &&
+      (upgrader_flags & OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_SYNTHETIC) == 0)
     {
       if (!ostree_repo_pull_one_dir (repo, self->origin_remote, dir_to_pull, refs_to_fetch,
                              flags, progress,
diff --git a/src/libostree/ostree-sysroot-upgrader.h b/src/libostree/ostree-sysroot-upgrader.h
index 77bc8a1d..83c4ad32 100644
--- a/src/libostree/ostree-sysroot-upgrader.h
+++ b/src/libostree/ostree-sysroot-upgrader.h
@@ -85,7 +85,8 @@ gboolean ostree_sysroot_upgrader_check_timestamps (OstreeRepo     *repo,
 
 typedef enum {
   OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_NONE = 0,
-  OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_ALLOW_OLDER = (1 << 0)
+  OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_ALLOW_OLDER = (1 << 0),
+  OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_SYNTHETIC = (1 << 1) /* Don't actually do a pull, just check timestamps/changed */
 } OstreeSysrootUpgraderPullFlags;
 
 _OSTREE_PUBLIC
diff --git a/src/ostree/ot-admin-builtin-upgrade.c b/src/ostree/ot-admin-builtin-upgrade.c
index 394b339a..7c710ffc 100644
--- a/src/ostree/ot-admin-builtin-upgrade.c
+++ b/src/ostree/ot-admin-builtin-upgrade.c
@@ -34,6 +34,8 @@
 
 static gboolean opt_reboot;
 static gboolean opt_allow_downgrade;
+static gboolean opt_pull_only;
+static gboolean opt_deploy_only;
 static char *opt_osname;
 static char *opt_override_commit;
 
@@ -42,6 +44,8 @@ static GOptionEntry options[] = {
   { "reboot", 'r', 0, G_OPTION_ARG_NONE, &opt_reboot, "Reboot after a successful upgrade", NULL },
   { "allow-downgrade", 0, 0, G_OPTION_ARG_NONE, &opt_allow_downgrade, "Permit deployment of chronologically older trees", NULL },
   { "override-commit", 0, 0, G_OPTION_ARG_STRING, &opt_override_commit, "Deploy CHECKSUM instead of the latest tree", "CHECKSUM" },
+  { "pull-only", 0, 0, G_OPTION_ARG_NONE, &opt_pull_only, "Do not create a deployment, just download", NULL },
+  { "deploy-only", 0, 0, G_OPTION_ARG_NONE, &opt_deploy_only, "Do not pull, only deploy", NULL },
   { NULL }
 };
 
@@ -64,6 +68,19 @@ ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GErr
                                           &sysroot, cancellable, error))
     goto out;
 
+  if (opt_pull_only && opt_deploy_only)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Cannot simultaneously specify --pull-only and --deploy-only");
+      goto out;
+    }
+  else if (opt_pull_only && opt_reboot)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Cannot simultaneously specify --pull-only and --reboot");
+      goto out;
+    }
+
   if (!ostree_sysroot_load (sysroot, cancellable, error))
     goto out;
 
@@ -104,6 +121,9 @@ ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GErr
         }
     }
 
+  if (opt_deploy_only)
+    upgraderpullflags |= OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_SYNTHETIC;
+
   { g_auto(GLnxConsoleRef) console = { 0, };
     glnx_console_lock (&console);
 
@@ -112,11 +132,23 @@ ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GErr
 
     if (opt_allow_downgrade)
       upgraderpullflags |= OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_ALLOW_OLDER;
-    
+
     if (!ostree_sysroot_upgrader_pull (upgrader, 0, upgraderpullflags,
                                        progress, &changed,
                                        cancellable, error))
-      goto out;
+      {
+        /* In the pull-only case, we do a cleanup here to ensure that if
+         * multiple commits were pulled, we garbage collect any old
+         * partially-pulled intermediate commits before pulling more. This is
+         * really a best practice in general, but for maximum compatiblity, we
+         * only do cleanup if a user specifies the new --pull-only option.
+         * Otherwise, we would break the case of trying to deploy a commit that
+         * isn't directly referenced.
+         */
+        if (opt_pull_only)
+          (void) ostree_sysroot_cleanup (sysroot, NULL, NULL);
+        goto out;
+      }
 
     if (progress)
       ostree_async_progress_finish (progress);
@@ -128,8 +160,11 @@ ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GErr
     }
   else
     {
-      if (!ostree_sysroot_upgrader_deploy (upgrader, cancellable, error))
-        goto out;
+      if (!opt_pull_only)
+        {
+          if (!ostree_sysroot_upgrader_deploy (upgrader, cancellable, error))
+            goto out;
+        }
 
       if (opt_reboot)
         {
diff --git a/tests/test-admin-pull-deploy-split.sh b/tests/test-admin-pull-deploy-split.sh
new file mode 100755
index 00000000..7a6750e2
--- /dev/null
+++ b/tests/test-admin-pull-deploy-split.sh
@@ -0,0 +1,59 @@
+#!/bin/bash
+#
+# Copyright (C) 2017 Colin Walters <walters@verbum.org>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+# See https://github.com/ostreedev/ostree/pull/642
+
+set -euo pipefail
+
+. $(dirname $0)/libtest.sh
+
+echo "1..1"
+
+setup_os_repository "archive-z2" "syslinux"
+
+cd ${test_tmpdir}
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo remote add --set=gpg-verify=false testos $(cat httpd-address)/ostree/testos-repo
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo pull testos testos/buildmaster/x86_64-runtime
+rev=$(${CMD_PREFIX} ostree --repo=sysroot/ostree/repo rev-parse testos/buildmaster/x86_64-runtime)
+parent_rev=$(${CMD_PREFIX} ostree --repo=sysroot/ostree/repo rev-parse ${rev}^)
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo pull testos testos/buildmaster/x86_64-runtime@${parent_rev}
+${CMD_PREFIX} ostree admin deploy --karg=root=LABEL=MOO --karg=quiet --os=testos testos:testos/buildmaster/x86_64-runtime
+assert_has_dir sysroot/ostree/deploy/testos/deploy/${parent_rev}.0
+assert_not_has_dir sysroot/ostree/deploy/testos/deploy/${rev}.0
+# Do a pull, this one should get us new content
+${CMD_PREFIX} ostree admin upgrade --os=testos --pull-only --os=testos > out.txt
+assert_not_file_has_content out.txt 'No update available'
+# And pull again should still tell us we have new content
+${CMD_PREFIX} ostree admin upgrade --os=testos --pull-only --os=testos > out.txt
+assert_not_file_has_content out.txt 'No update available'
+assert_has_dir sysroot/ostree/deploy/testos/deploy/${parent_rev}.0
+assert_not_has_dir sysroot/ostree/deploy/testos/deploy/${rev}.0
+assert_file_has_content sysroot/boot/loader/entries/ostree-testos-0.conf 'TestOS 42 1.0.9'
+assert_streq "${rev}" $(${CMD_PREFIX} ostree --repo=sysroot/ostree/repo rev-parse testos/buildmaster/x86_64-runtime)
+# Now, generate new content upstream; we shouldn't pull it
+os_repository_new_commit
+${CMD_PREFIX} ostree admin upgrade --os=testos --deploy-only --os=testos > out.txt
+assert_not_file_has_content out.txt 'No update available'
+assert_file_has_content sysroot/boot/loader/entries/ostree-testos-0.conf 'TestOS 42 1.0.10'
+assert_has_dir sysroot/ostree/deploy/testos/deploy/${parent_rev}.0
+assert_has_dir sysroot/ostree/deploy/testos/deploy/${rev}.0
+${CMD_PREFIX} ostree admin upgrade --os=testos --deploy-only --os=testos > out.txt
+assert_file_has_content out.txt 'No update available'
+
+echo 'ok upgrade --pull-only + --deploy-only'