[python] [measurement] 1st draft for Python Measurement Writer. (#1337)

lang/python/ecalhdf5/ecal/measurement/writer.py

@@ -0,0 +1,120 @@
+# ========================= eCAL LICENSE =================================
+#
+# Copyright (C) 2016 - 2019 Continental Corporation
+#
+# 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.
+#
+# ========================= eCAL LICENSE =================================
+
+import ecal.measurement.hdf5 as ecalhdf5
+
+import ecal.proto.helper as pb_helper
+
+from enum import Enum
+
+def combine_encoding_and_type(encoding, type):
+  return encoding + ":" + type
+
+class ProtobufChannelWriter:
+    """Class to create Protobuf Channels
+
+    This API is not considered stable and might break in future eCAL Versions
+    """
+
+    def __init__(self, channel_name: str, protobuf_type, meas: ecalhdf5.Meas):
+        self._protobuf_type = protobuf_type
+        self._binary_writer = BinaryChannelWriter(channel_name, meas=meas, encoding = self.encoding, type = self.type, descriptor = self.descriptor)
+
+    def write_entry(self, data, rcv_timestamp: int, snd_timestamp: int):
+        self._binary_writer.write_entry(data.SerializeToString(), rcv_timestamp, snd_timestamp)
+
+    @property
+    def name(self):
+        return self._channel_name
+
+    @property
+    def descriptor(self):
+        return pb_helper.get_descriptor_from_type(self._protobuf_type)
+
+    @property
+    def encoding(self):
+        return "proto"
+
+    @property
+    def type(self):
+        return self._protobuf_type.DESCRIPTOR.full_name
+
+class BinaryChannelWriter:
+    """Class to create Binary Channels
+    
+    This API is not considered stable and might break in future eCAL Versions
+    """
+
+    def __init__(self, channel_name: str, meas: ecalhdf5.Meas, encoding = "", type = "", descriptor = ""):
+        self._meas = meas
+        self._channel_name = channel_name
+        self._encoding = encoding
+        self._type = type
+        self._descriptor = descriptor
+
+        self._meas.set_channel_description(channel_name, descriptor)
+        self._meas.set_channel_type(channel_name, combine_encoding_and_type(encoding, type))
+
+    def write_entry(self, data, rcv_timestamp: int, snd_timestamp: int):
+        self._meas.add_entry_to_file(data, rcv_timestamp, snd_timestamp, self._channel_name)
+
+    @property
+    def name(self):
+        return self._channel_name
+
+    @property
+    def encoding(self):
+        return self._encoding
+
+    @property
+    def type(self):
+        return self._type
+
+    @property
+    def descriptor(self):
+        return self._descriptor
+
+
+class Encoding(Enum):
+    BINARY = 0
+    PROTOBUF = 1
+
+class MeasurementWriter:
+    """Write an eCAL Measurement
+    
+    This API is not considered stable and might break in future eCAL Versions
+    """
+
+    def __init__(self, output_dir: str, file_name: str, max_size_per_file: int):
+        self._output_dir = output_dir
+        self._file_name = file_name
+        self._max_size_per_file = max_size_per_file
+        self._channels = {}
+
+        self._meas = ecalhdf5.Meas(output_dir, 1)
+        self._meas.set_file_base_name(file_name)
+        self._meas.set_max_size_per_file(max_size_per_file)
+
+    def create_channel(self, channel_name: str, channel_encoding: Encoding, datatype):
+        if channel_encoding == Encoding.PROTOBUF:
+            channel = ProtobufChannelWriter(channel_name = channel_name, protobuf_type = datatype, meas = self._meas)
+        self._channels[channel_name] = channel
+        return channel
+
+    def __del__(self):
+        self._meas.close()