Use buildroot from container image

For now as:
--config-opts buildroot_image=registry.fedoraproject.org/fedora:41

Fixes: #1159

mock/py/mockbuild/buildroot.py

@@ -110,8 +110,18 @@ def __init__(self, config, uid_manager, state, plugins, bootstrap_buildroot=None
         self.env.update(proxy_env)
         os.environ.update(proxy_env)
 
-        self.use_chroot_image = self.config['use_bootstrap_image']
-        self.chroot_image = self.config['bootstrap_image']
+        if is_bootstrap:
+            self.use_chroot_image = self.config['use_bootstrap_image']
+            self.chroot_image = self.config['bootstrap_image']
+            self.image_skip_pull = self.config["bootstrap_image_skip_pull"]
+            self.image_assert_digest = self.config.get("bootstrap_image_assert_digest", None)
+            self.image_keep_getting = self.config["bootstrap_image_keep_getting"]
+        else:
+            self.use_chroot_image = self.config["use_buildroot_image"]
+            self.chroot_image = self.config["buildroot_image"]
+            self.image_skip_pull = self.config["buildroot_image_skip_pull"]
+            self.image_assert_digest = self.config.get("buildroot_image_assert_digest", None)
+            self.image_keep_getting = self.config["buildroot_image_keep_getting"]
 
         self.pkg_manager = None
         self.mounts = mounts.Mounts(self)
@@ -239,7 +249,10 @@ def _init_locked(self):
 
     @traceLog()
     def _load_from_container_image(self):
-        if not self.uses_bootstrap_image or self.chroot_was_initialized:
+        if self.chroot_was_initialized:
+            return
+
+        if not self.use_chroot_image:
             return
 
         if util.mock_host_environment_type() == "docker":
@@ -269,15 +282,15 @@ def _fallback(message):
                 podman = Podman(self, self.chroot_image)
 
             with _fallback("Can't initialize from container image"):
-                if not self.config["image_skip_pull"]:
-                    podman.retry_image_pull(self.config["image_keep_getting"])
+                if not self.image_skip_pull:
+                    podman.retry_image_pull(self.image_keep_getting)
                 else:
                     podman.read_image_id()
                     getLog().info("Using local image %s (%s)",
                                   self.chroot_image, podman.image_id)
                 podman.tag_image()
 
-                digest_expected = self.config.get("image_assert_digest", None)
+                digest_expected = self.image_assert_digest
                 if digest_expected:
                     getLog().info("Checking image digest: %s",
                                   digest_expected)

mock/py/mockbuild/config.py

@@ -105,6 +105,14 @@ def setup_default_config_opts():
     config_opts['bootstrap_image_keep_getting'] = 120
     config_opts['bootstrap_image_assert_digest'] = None
 
+    config_opts['use_buildroot_image'] = False
+    config_opts['buildroot_image'] = None
+    config_opts['buildroot_image_skip_pull'] = True
+    config_opts['buildroot_image_ready'] = False
+    config_opts['buildroot_image_fallback'] = True
+    config_opts['buildroot_image_keep_getting'] = 120
+    config_opts['buildroot_image_assert_digest'] = None
+
     config_opts['internal_dev_setup'] = True
 
     # cleanup_on_* only take effect for separate --resultdir
@@ -672,6 +680,9 @@ def set_config_opts_per_cmdline(config_opts, options, args):
     if config_opts["calculatedeps"]:
         config_opts["plugin_conf"]["buildroot_lock_enable"] = True
 
+    if config_opts["buildroot_image"]:
+        config_opts["use_buildroot_image"] = True
+
 def check_config(config_opts):
     if 'root' not in config_opts:
         raise exception.ConfigError("Error in configuration "