Allow commits to mark refs as EOL, replaced by others

A commit can now include a "ostree.endoflife-rebase" metadata key
pointing to a new ref.

When updating, the sysroot upgrader will see this and proceed to
pull and deploy the new ref instead. The origin file in the new
deployment will point to the new ref.

This functionality is planned to be used in Endless OS. We will create
a lesser tested branch for brand new, cutting edge hardware support,
and ship that on hardware platforms that require the latest drivers.
However, once our slower-moving official release is later updated to
support the new hardware, we will use this functionality to migrate
those bleeding-edge users over to the official release.

Closes: #874
Approved by: cgwalters

Makefile-tests.am

@@ -82,6 +82,7 @@ _installed_or_uninstalled_test_scripts = \
 	tests/test-local-pull-depth.sh \
 	tests/test-gpg-signed-commit.sh \
 	tests/test-admin-upgrade-unconfigured.sh \
+	tests/test-admin-upgrade-endoflife.sh \
 	tests/test-admin-deploy-syslinux.sh \
 	tests/test-admin-deploy-2.sh \
 	tests/test-admin-deploy-karg.sh \

src/libostree/ostree-sysroot-upgrader.c

@@ -512,6 +512,10 @@ ostree_sysroot_upgrader_pull_one_dir (OstreeSysrootUpgrader  *self,
   char *refs_to_fetch[] = { NULL, NULL };
   const char *from_revision = NULL;
   g_autofree char *origin_refspec = NULL;
+  g_autofree char *new_revision = NULL;
+  g_autoptr(GVariant) new_variant = NULL;
+  g_autoptr(GVariant) new_metadata = NULL;
+  g_autoptr(GVariant) rebase = NULL;
 
   if (self->override_csum != NULL)
     refs_to_fetch[0] = self->override_csum;
@@ -541,6 +545,48 @@ ostree_sysroot_upgrader_pull_one_dir (OstreeSysrootUpgrader  *self,
         ostree_async_progress_finish (progress);
     }
 
+  /* Check to see if the commit marks the ref as EOL, redirecting to
+   * another. */
+  if (!ostree_repo_resolve_rev (repo, origin_refspec, FALSE,
+                                &new_revision, error))
+    return FALSE;
+
+  if (!ostree_repo_load_variant (repo,
+                                 OSTREE_OBJECT_TYPE_COMMIT,
+                                 new_revision,
+                                 &new_variant,
+                                 error))
+    return FALSE;
+
+  g_variant_get_child (new_variant, 0, "@a{sv}", &new_metadata);
+  rebase = g_variant_lookup_value (new_metadata, "ostree.endoflife-rebase", G_VARIANT_TYPE_STRING);
+  if (rebase)
+    {
+      const char *new_ref = g_variant_get_string (rebase, 0);
+
+      /* Pull the new ref */
+      if (self->origin_remote &&
+          (upgrader_flags & OSTREE_SYSROOT_UPGRADER_PULL_FLAGS_SYNTHETIC) == 0)
+        {
+          refs_to_fetch[0] = (char *) new_ref;
+          if (!ostree_repo_pull_one_dir (repo, self->origin_remote, dir_to_pull, refs_to_fetch,
+                                         flags, progress, cancellable, error))
+            return FALSE;
+        }
+
+        /* Use the new ref for the rest of the update process */
+        g_free (self->origin_ref);
+        self->origin_ref = g_strdup(new_ref);
+        g_free (origin_refspec);
+
+        if (self->origin_remote)
+          origin_refspec = g_strconcat (self->origin_remote, ":", new_ref, NULL);
+        else
+          origin_refspec = g_strdup (new_ref);
+
+        g_key_file_set_string (self->origin, "origin", "refspec", origin_refspec);
+    }
+
   if (self->override_csum != NULL)
     {
       if (!ostree_repo_set_ref_immediate (repo,

tests/test-admin-upgrade-endoflife.sh

@@ -0,0 +1,72 @@
+#!/bin/bash
+#
+# Copyright (C) 2014 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.
+
+set -euo pipefail
+
+. $(dirname $0)/libtest.sh
+
+# Exports OSTREE_SYSROOT so --sysroot not needed.
+setup_os_repository "archive-z2" "syslinux"
+# This does:
+# - init ostree repo in testos-repo
+# - create system files in osdata and commit twice those contents into testos-repo
+# - copy osdata to osdata-devel and make another change then commit
+# - create sysroot with init-fs and os-init and syslinux
+# sysroot has /ostree basics (but no contents), syslinux cfg and empty root dirs
+
+echo "1..3"
+
+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)
+echo "rev=${rev}"
+
+# Now sysroot/ostree has the objects from the testos-repo (obtained over http
+# and kept in remote "testos"), but there is no deployment
+
+# This initial deployment gets kicked off with some kernel arguments
+${CMD_PREFIX} ostree admin deploy --karg=root=LABEL=MOO --karg=quiet --os=testos testos:testos/buildmaster/x86_64-runtime
+assert_has_dir sysroot/boot/ostree/testos-${bootcsum}
+
+echo "ok deploy"
+
+# Create a new branch which we want to migrate to
+os_repository_new_commit 1 1 testos/buildmaster/newbranch
+# bootcsum now refers to this new commit
+
+# Create a new commit with an empty tree, which marks the original branch as
+# EOL, redirecting to the new one.
+mkdir empty
+${CMD_PREFIX} ostree --repo=${test_tmpdir}/testos-repo commit --tree=dir=$(pwd)/empty  --add-metadata-string "ostree.endoflife=Product discontinued" --add-metadata-string "ostree.endoflife-rebase=testos/buildmaster/newbranch" -b testos/buildmaster/x86_64-runtime -s "EOL redirect to new branch"
+
+echo "ok new branch"
+
+# Upgrade existing checkout
+${CMD_PREFIX} ostree admin upgrade --os=testos --pull-only
+${CMD_PREFIX} ostree admin upgrade --os=testos --deploy-only
+
+# Check we got redirected to the new branch
+assert_file_has_content sysroot/boot/loader/entries/ostree-testos-0.conf "${bootcsum}"
+rev=$(${CMD_PREFIX} ostree --repo=${test_tmpdir}/testos-repo rev-parse testos/buildmaster/newbranch)
+assert_file_has_content sysroot/ostree/deploy/testos/deploy/${rev}.0/usr/bin/content-iteration "1"
+
+assert_file_has_content sysroot/ostree/deploy/testos/deploy/${rev}.0.origin "newbranch"
+
+echo "ok update and redirect"