WIP: Add rpm-ostree compose container command

This command takes a *derivation* treefile and applies necessary changes
to the live container to make it true.

Currently, only `packages` is supported. But this paves the way for
supporting more derivation fields as well as making currently "base"
fields only become valid derivation fields too (by promoting it from the
`BaseComposeConfigFields` struct to `TreeComposeConfig`).

I think this also helps the move towards coreos#2326 by formalizing "client"
or "derivation" treefiles more and introducing code which consumes them.

What we're doing here is providing a "container" backend for derivation
treefiles, but coreos#2326 will provide a "client" backend which uses the core
more fully. But the input file itself is the exact same, hence providing
symmetry between the two flows. (See also discussions about this in
coreos/fedora-coreos-tracker#1054).

This will also allow us to drop the `microdnf` dependency, though I
haven't yet done that.

src/app/rpmostree-builtin-compose.cxx

@@ -44,6 +44,12 @@ static RpmOstreeCommand compose_subcommands[] = {
   { "extensions", RPM_OSTREE_BUILTIN_FLAG_LOCAL_CMD,
     "Download RPM packages guaranteed to depsolve with a base OSTree",
     rpmostree_compose_builtin_extensions },
+  { "container", (RpmOstreeBuiltinFlags)
+    (RPM_OSTREE_BUILTIN_FLAG_LOCAL_CMD |
+     RPM_OSTREE_BUILTIN_FLAG_HIDDEN |
+     RPM_OSTREE_BUILTIN_FLAG_REQUIRES_ROOT),
+    "Compose container from derivation treefile",
+    rpmostree_compose_builtin_container },
   { NULL, (RpmOstreeBuiltinFlags)0, NULL, NULL }
 };
 

src/app/rpmostree-compose-builtin-tree.cxx

@@ -1661,3 +1661,93 @@ rpmostree_compose_builtin_extensions (int             argc,
 
   return TRUE;
 }
+
+static void
+state_action_changed_cb (DnfState       *state,
+                         DnfStateAction  action,
+                         const gchar    *action_hint)
+{
+  switch (action)
+    {
+      case DNF_STATE_ACTION_INSTALL:
+        if (action_hint)
+          {
+            g_auto(GStrv) split = g_strsplit (action_hint, ";", 0);
+            if (g_strv_length (split) == 4)
+              g_print ("Installing: %s-%s.%s (%s)\n", split[0], split[1], split[2], split[3]);
+            else
+              g_print ("Installing: %s\n", action_hint);
+          }
+        break;
+      default:
+        break;
+    }
+}
+
+gboolean
+rpmostree_compose_builtin_container (int             argc,
+                                     char          **argv,
+                                     RpmOstreeCommandInvocation *invocation,
+                                     GCancellable   *cancellable,
+                                     GError        **error)
+{
+  g_printerr ("NOTICE: This command is experimental and subject to change.\n");
+  g_autoptr(GOptionContext) context = g_option_context_new ("TREEFILE");
+
+  if (!rpmostree_option_context_parse (context,
+                                       NULL,
+                                       &argc, &argv,
+                                       invocation,
+                                       cancellable,
+                                       NULL, NULL, NULL,
+                                       error))
+    return FALSE;
+
+  /* In practice, nothing stops us from running in a regular container today.
+   * But in the future we'll likely have more binding between OSTree container
+   * peculiarities and this code. And we don't want to support more than we need
+   * to.*/
+  auto is_ostree_container = CXX_TRY_VAL(is_ostree_container(), error);
+  if (!is_ostree_container)
+    return glnx_throw (error, "This command can only run in an OSTree container.");
+
+  if (argc < 2)
+    {
+      rpmostree_usage_error (context, "TREEFILE must be specified", error);
+      return FALSE;
+    }
+
+  const char *treefile_path = argv[1];
+  auto basearch = rpmostreecxx::get_rpm_basearch();
+  auto treefile = CXX_TRY_VAL(treefile_new_client (treefile_path, basearch, -1), error);
+  auto packages = treefile->get_packages();
+
+  /* for now, we only support package installs */
+  if (packages.empty())
+    return TRUE;
+
+  g_autoptr(RpmOstreeContext) ctx = rpmostree_context_new_container ();
+  rpmostree_context_set_treefile (ctx, *treefile);
+
+  if (!rpmostree_context_setup (ctx, "/", "/", cancellable, error))
+    return FALSE;
+
+  if (!rpmostree_context_prepare (ctx, cancellable, error))
+    return FALSE;
+
+  if (!rpmostree_context_download (ctx, cancellable, error))
+    return FALSE;
+
+  DnfContext *dnfctx = rpmostree_context_get_dnf (ctx);
+  DnfState *state = dnf_context_get_state (dnfctx);
+  g_signal_connect (state, "action-changed",
+                    G_CALLBACK (state_action_changed_cb),
+                    NULL);
+
+  /* can't use cancellable here because it wants to re-set it on the state,
+   * which will trigger an assertion; XXX: tweak libdnf */
+  if (!dnf_context_run (dnfctx, NULL, error))
+    return FALSE;
+
+  return TRUE;
+}

src/app/rpmostree-compose-builtins.h

@@ -31,6 +31,7 @@ gboolean rpmostree_compose_builtin_install (int argc, char **argv, RpmOstreeComm
 gboolean rpmostree_compose_builtin_postprocess (int argc, char **argv, RpmOstreeCommandInvocation *invocation, GCancellable *cancellable, GError **error);
 gboolean rpmostree_compose_builtin_commit (int argc, char **argv, RpmOstreeCommandInvocation *invocation, GCancellable *cancellable, GError **error);
 gboolean rpmostree_compose_builtin_extensions (int argc, char **argv, RpmOstreeCommandInvocation *invocation, GCancellable *cancellable, GError **error);
+gboolean rpmostree_compose_builtin_container (int argc, char **argv, RpmOstreeCommandInvocation *invocation, GCancellable *cancellable, GError **error);
 
 G_END_DECLS