kernel plugin: kernel targets depending on debarch (#689)

This allows using the same snapcraft.yaml to build kernels
for different arches as they have different image targets.

LP: #1604801

Signed-off-by: Sergio Schvezov <sergio.schvezov@ubuntu.com>

snapcraft/plugins/kernel.py

@@ -23,8 +23,13 @@
 The following kernel specific options are provided by this plugin:
 
     - kernel-image-target:
-      (string; default: bzImage)
-      the kernel image make target to build; maps to make target.
+      (yaml object or string; default: bzImage)
+      the default target is bzImage and can be set to any specific
+      target.
+      For more complex cases where one would want to use
+      the same snapcraft.yaml to target multiple architectures a
+      yaml object can be used. This yaml object would be a map of
+      debian architecture and kernel image build targets.
 
     - kernel-initrd-modules:
       (array of string)
@@ -77,7 +82,10 @@ def schema(cls):
         schema = super().schema()
 
         schema['properties']['kernel-image-target'] = {
-            'type': 'string',
+            'oneOf': [
+                {'type': 'string'},
+                {'type': 'object'},
+            ],
             'default': 'bzImage',
         }
 
@@ -138,14 +146,7 @@ def compression_cmd(self):
     def __init__(self, name, options, project):
         super().__init__(name, options, project)
 
-        self.make_targets = [self.options.kernel_image_target, 'modules']
-        self.dtbs = ['{}.dtb'.format(i)
-                     for i in self.options.kernel_device_trees]
-        if self.dtbs:
-            self.make_targets.extend(self.dtbs)
-        self.make_install_targets = [
-            'modules_install', 'INSTALL_MOD_PATH={}'.format(self.installdir)]
-        self.make_install_targets.extend(self._get_fw_install_targets())
+        self._set_kernel_targets()
 
         self.os_snap = os.path.join(self.sourcedir, 'os.snap')
         self.kernel_release = ''
@@ -157,6 +158,26 @@ def enable_cross_compilation(self):
             self.project.kernel_arch))
         self.make_cmd.append('CROSS_COMPILE={}'.format(
             self.project.cross_compiler_prefix))
+        # by enabling cross compilation, the kernel_arch and deb_arch
+        # from the project options have effectively changed so we reset
+        # kernel targets.
+        self._set_kernel_targets()
+
+    def _set_kernel_targets(self):
+        if isinstance(self.options.kernel_image_target, str):
+            self.kernel_image_target = self.options.kernel_image_target
+        elif self.project.deb_arch in self.options.kernel_image_target:
+            self.kernel_image_target = \
+                self.options.kernel_image_target[self.project.deb_arch]
+
+        self.make_targets = [self.kernel_image_target, 'modules']
+        self.dtbs = ['{}.dtb'.format(i)
+                     for i in self.options.kernel_device_trees]
+        if self.dtbs:
+            self.make_targets.extend(self.dtbs)
+        self.make_install_targets = [
+            'modules_install', 'INSTALL_MOD_PATH={}'.format(self.installdir)]
+        self.make_install_targets.extend(self._get_fw_install_targets())
 
     def _get_fw_install_targets(self):
         if not self.options.kernel_with_firmware:
@@ -279,9 +300,9 @@ def _get_build_arch_dir(self):
 
     def _copy_vmlinuz(self):
         kernel = '{}-{}'.format(
-            self.options.kernel_image_target, self.kernel_release)
+            self.kernel_image_target, self.kernel_release)
         src = os.path.join(self._get_build_arch_dir(),
-                           self.options.kernel_image_target)
+                           self.kernel_image_target)
         dst = os.path.join(self.installdir, kernel)
         if not os.path.exists(src):
             raise ValueError(

snapcraft/tests/test_plugin_kernel.py

@@ -100,7 +100,8 @@ def test_schema(self):
             self.assertTrue(properties[prop]['uniqueItems'])
 
         self.assertEqual(
-            properties['kernel-image-target']['type'], 'string')
+            properties['kernel-image-target']['oneOf'],
+            [{'type': 'string'}, {'type': 'object'}])
         self.assertEqual(
             properties['kernel-image-target']['default'], 'bzImage')
 
@@ -820,6 +821,39 @@ def test_enable_cross_compilation(self):
             plugin.make_cmd,
             ['make', '-j2', 'ARCH=arm64', 'CROSS_COMPILE=aarch64-linux-gnu-'])
 
+    def test_kernel_image_target_as_map(self):
+        self.options.kernel_image_target = {'arm64': 'Image'}
+        project_options = snapcraft.ProjectOptions(target_deb_arch='arm64')
+        plugin = kernel.KernelPlugin('test-part', self.options,
+                                     project_options)
+
+        self.assertEqual(plugin.make_targets, ['Image', 'modules'])
+
+    def test_kernel_image_target_as_string(self):
+        self.options.kernel_image_target = 'Image'
+        project_options = snapcraft.ProjectOptions(target_deb_arch='arm64')
+        plugin = kernel.KernelPlugin('test-part', self.options,
+                                     project_options)
+
+        self.assertEqual(plugin.make_targets, ['Image', 'modules'])
+
+    def test_kernel_image_target_non_existent(self):
+        class Options:
+            build_parameters = []
+            kconfigfile = None
+            kdefconfig = []
+            kconfigs = []
+            kernel_with_firmware = True
+            kernel_initrd_modules = []
+            kernel_initrd_firmware = []
+            kernel_device_trees = []
+            kernel_initrd_compression = 'gz'
+        project_options = snapcraft.ProjectOptions(target_deb_arch='arm64')
+        plugin = kernel.KernelPlugin('test-part', self.options,
+                                     project_options)
+
+        self.assertEqual(plugin.make_targets, ['bzImage', 'modules'])
+
     @mock.patch.object(storeapi.StoreClient, 'download')
     def test_pull(self, download_mock):
         plugin = kernel.KernelPlugin('test-part', self.options,