comram 0.0.12

shared ram based data distribution lib

README

Project Scope:

ramshare:

Create data structures in shared memory based on a data structure file. Read and write to data structure tag. Data structure tags can be accessed system-wide.

procon:

producer:

Creates a socket server and either connect or create shared data structure. Consumers can connect to producer, and all data from data structure will be transferred to connected consumers periodic.

consumer:

Connects to producer, either creates or connects to shared data structure. Shared data structure will be overwritten periodic, so shared data structure is read only on consumer site.

dmsg

Direct event based messages between producer and consumers. Messages will be serialized with pickle before send, and de-serialized with pickle before message is returned.

Data structure .xml file:

<config>
    <connection_status LENGTH="2" TYPE="int" INIT_VALUE="0" DESCRIPTION="connection of status" > </connection_status>
    <tag_1 LENGTH="10" TYPE="int" > </tag_1>
    <timestamp LENGTH="20" TYPE="float" > </timestamp>
    <status LENGTH="100" TYPE="string" ></status>
</config>

Required tags:

For produced / consumed data structures, "connection_status" is required.

Required members:

tag_1 = reference name, used to read or write from data structure.

LENGTH = tag length in bytes, minimum value is 2

Optional members

TYPE = tag type, INIT_VALUE = initial tag value

DESCRIPTION = description of tag

Usage:

Write to tag:

from comram import ramshare

test = ramshare.RamShare("share_name", data_type="/path_to_structure/test_structure.xml")
test.write_to_tag("tag_1", 99)

Read from tag:

from comram import ramshare

test = ramshare.RamShare("share_name", data_type="/path_to_structure/test_structure.xml")
tag_1 = test.read_tag("tag_1")

Produce data structure:

from comram import procon

producer = procon.Produce("share_name", data_type="/path_to_structure/test_structure.xml", ip="127.0.0.1", port=9980, 
                          send_interval=0.01)
producer.start_produce()

Consume data structure:

from comram import procon

consumer = procon.Consume("share_name", "consumer_name", data_type="/path_to_structure/test_structure.xml",
                          ip="127.0.0.1", port=9980)
consumer.start_consume()

dmsg usage:

produce:

from comram import dmsg

test_producer = dmsg.Produce("127.0.0.1", 9500, debug=True)
test_producer.send_message("test message")
test_producer.close()

consume:

from comram import dmsg

test_consume = dmsg.Consume("test_consumer", "127.0.0.1", 9500)
test_msg = test_consume.get_msg()
test_consume.close()

Known issues

tag length under under 2 byte not possible