instrumentation: Port dmesg instrument from WA2

wa/instrumentation/dmesg.py

@@ -0,0 +1,67 @@
+#    Copyright 2014-2017 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+import os
+
+from wa import Instrument, Parameter
+from wa.framework.exception import InstrumentError
+from wa.framework.instrumentation import slow
+from wa.utils.misc import ensure_file_directory_exists as _f
+
+class DmesgInstrument(Instrument):
+    # pylint: disable=no-member,attribute-defined-outside-init
+    """
+    Collected dmesg output before and during the run.
+
+    """
+
+    name = 'dmesg'
+
+    parameters = [
+        Parameter('loglevel', kind=int, allowed_values=range(8),
+                  description='Set loglevel for console output.')
+    ]
+
+    loglevel_file = '/proc/sys/kernel/printk'
+
+    def initialize(self, context):
+        self.need_root = self.target.os == 'android'
+        if self.need_root and not self.target.is_rooted:
+            raise InstrumentError('Need root to collect dmesg on Android')
+
+    def setup(self, context):
+        if self.loglevel:
+            self.old_loglevel = self.target.get_sysfile_value(self.loglevel_file)
+            self.target.set_sysfile_value(self.loglevel_file, self.loglevel, verify=False)
+        self.before_file = _f(os.path.join(context.output_directory, 'dmesg', 'before'))
+        self.after_file = _f(os.path.join(context.output_directory, 'dmesg', 'after'))
+
+    @slow
+    def start(self, context):
+        with open(self.before_file, 'w') as wfh:
+            wfh.write(self.target.execute('dmesg', as_root=self.need_root))
+        context.add_artifact('dmesg_before', self.before_file, kind='data')
+        if self.target.is_rooted:
+            self.target.execute('dmesg -c', as_root=True)
+
+    def stop(self, context):
+        with open(self.after_file, 'w') as wfh:
+            wfh.write(self.target.execute('dmesg', as_root=self.need_root))
+        context.add_artifact('dmesg_after', self.after_file, kind='data')
+
+    def teardown(self, context):  # pylint: disable=unused-argument
+        if self.loglevel:
+            self.target.set_sysfile_value(self.loglevel_file, self.old_loglevel, verify=False)