--- /dev/null
+
+--------------------------------------------------------------------------------
+
+ Copyright (c) 2018-2019 AT&T Intellectual Property.
+
+ 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.
+--------------------------------------------------------------------------------
+
+
+
+MC Listener
+
+This directory contains the source for the a simple message listener which
+writes messages received via RMR into a fifo (named pipe) for an external
+process to consume.
+
+Fifos are named MT_xxxxxxxx where the Xs are replaced with the message
+type with up to 7 leading zeros (e.g. MT_00000002). The data written
+to a pipe has the form:
+ <8 bytes><n bytes>
+
+Where the first 8 bytes are the ASCII representation of the length of
+the message (n) (the 8th byte is a zero allowing the bytes to be
+treated as a C string if desired. The next n bytes are the unchanged
+payload which was received. No RMR header information (e.g. source,
+meid, etc.) is communicated.
+
+If the listener is executed with the timestamp extension enabled, then
+the leading 'header' is enhanced such that the time the message was
+received by the listener is added. Additionally, a leading delimiter
+is added to make synchronisation possible. The timestamp is also an
+ASCII string of the form 1570110224356 (milliseconds past the epoch).
+The enhanced header has the format:
+
+ <delimeter><length-bytes><time-bytes>
+
+The <delimeter> is a series of 4 bytes which should always be: '@MCL'.
+It is intended to be used to sequence "frames" in the pipe should there be
+write errors which result in missing data. If the application reading from
+a pipe does not see this delimeter, then it should read byte by byte from
+the pipe until it does in order to synchronise with the stream.
+
+The <length-bytes> are as descrbed previously: 8 byte ASCII string (nil
+terminated).
+
+The <time-bytes> is an ASCII string (nil terminated) with a length of 16
+bytes.
+
+The entire header will require 28 bytes.
+
+
+There are multiple docker files; *.df.
+ mcl_runime.df -- builds an image with the runtime mc_listener binary
+ mcl_dev.df -- builds a development image that can be used to
+ interactively build and test the library and mc_listener
+ application.
+
+Unit testing
+A very small set of unit tests are provided for the library functions in
+mcl.c. Because of the nature of the fanout function, which blocks waiting
+on RMR messages, it is not possible to unit test that bit of code.
+
+FIFO Reader
+The pipe_reader programme is a simple application which uses the mcl.c
+library functions to open and read from a single pipe. If the -e option
+is given it will expect that data in the FIFO has extended headers. Use
+the -? option (or -h) to generate a full usage statement.
Code Review / ric-app / mc.git / blobdiff