issue-#419 Add Packet Padder Plugin

ait/core/server/plugins/PacketPadder.py

@@ -0,0 +1,19 @@
+from ait.core.server.plugins import Plugin
+from ait.core import log
+
+
+class PacketPadder(Plugin):
+    def __init__(self, inputs=None, outputs=None, zmq_args=None, pad_octets=0, **kwargs):
+        if pad_octets >= 0:
+            self.size_pad_octets = pad_octets
+        else:
+            self.size_pad_octets = 0
+            log.error(f"PacketPadder -> Pad value{pad_octets} octets must be a \
+                        positive integer! Bypassing padding!")
+        super().__init__(inputs, outputs, zmq_args)
+
+    def process(self, data, topic=None):
+        if len(data) < self.size_pad_octets:
+            fill = bytearray(self.size_pad_octets - len(data))
+            data = data + fill
+        self.publish(data)

doc/source/plugin_PacketPadder.rst

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+Packet Padder Plugin
+========================
+The packet padder plugin pads command processing pipeline data to a user configured size in octets.
+
+If the size of pipeline data in octets is less than the user specified value, the pipline will pad 0s to achieve the specified size.
+
+Configuration
+-------------
+
+Add and customize the following template in your config.yaml
+
+.. code-block:: none
+	- plugin:
+          name: ait.core.server.plugins.PacketPadder.PacketPadder
+          inputs:
+	          - PacketAccumulator
+          pad_octets: 987
+
+The *pad_octets* option specifies the minimum size to pad the data to. The plugin will not modify the data if its size already meets or exceeds this value. A negative, 0, or missing value will bypass the plugin.
+
+Use *inputs* to specify which PUB/SUB topic the plugin should receive pipeline data from.