amcp

Invoking python code in AutoMod using RPC

~~(Currently only Python 3 is supported since it uses Function Annotations as type hinting. Support of Python 2 will be added soon.)~~

Support of Python 2 is not tested.

Installation

copy include/$ARCH/*.h to $ASI/include
copy bin/$ARCH/*.dll to $ASI/bin
copy bin/$ARCH/*.lib to $ASI/lib

where $ASI is the AutoMod install path. Also, add ASILIBS=amcp.lib in Environment Variables.

The Python module is under python/. Dependencies: pyzmq and msgpack

Example

Step 1: Define functions in Python

For Python 3+

from amcp import RemoteFunction, DataType as dt, AMCPEngine
import pandas as pd

class Test(AMCPEngine):
    @RemoteFunction
    def time_delta(self, ac: dt.INT) -> dt.STR:
        # dt.STR corresponds to bytes in python
        return "Time delta is {}".format(pd.Timedelta(seconds=ac)).encode("utf-8") 


test_server = Test()

For Python 2

from amcp import remote, DataType as dt, AMCPEngine
import pandas as pd

class Test(AMCPEngine):
    @remote([dt.INT], dt.STR)
    def time_delta(self, ac):
        return "Time delta is {}".format(pd.Timedelta(seconds=ac))

test_server = Test()

The method decorated by RemoteFunction (or remote for Python 2) will be invokable from AutoMod. Data types currently supported: VOID, INT, INT_REF, REAL, REAL_REF, STR and STR_REF. *_REF are reference types which can be modified inside the functions (like pointers in C). In Python code, the referred values are accessed by v[0]. For example:

@RemoteFunction
def iadd(self, a: dt.INT_REF, i: dt.INT):
    a[0] += i

for which the corresponding C function signature will be void test_iadd(int32_t* a, int32_t i);.

Step 2: Generate C code

test_server.gen_c(path=None)

will generate C code similar to the following.

#include <amcp.h>

amcp_context* _amcp_ctx_830913;

int32_t test_amcp_connect(const char* addr){
    _amcp_ctx_830913 = amcp_ctx_new( addr);
    return 0;
}

int32_t test_amcp_close(){
    amcp_ctx_destroy(_amcp_ctx_830913);
    return 0;
}

char* test_time_delta(int32_t ac){
    pm_type _pm[] = {DATA_TYPE_INTEGER};
    signature ps = {"time_delta", 1, _pm, DATA_TYPE_STRING};
    char* ret;
    rpc_call(_amcp_ctx_830913, &ps, &ret, ac);
    return ret;
}

We can also use test.gen_c(path="./") to directly write the code to ./test_gen.c (or test.gen_c(path="./", header=True) to write the code to ./test_gen.h).

Step 3: Start the RPC server

test_server.serve_forever("tcp://*:5555")

Note that this module uses ZeroMQ as the underlying network library. Thus, any endpoint supported by ZeroMQ is acceptable as listening address. The server and AutoMod executable need not be on the same host. Refer to http://api.zeromq.org/4-2:zmq-bind for more info.

Step 4: Include the generated C source and declear the functions in AutoMod

Step 5: Connect the server in `model initialization` or `model ready` function

begin model initialization function
  return test_amcp_connect("tcp://{server-ip}:5555")
end

Again, the connecting address is a ZeroMQ endpoint.

Step 6: Then, we can directly call `test_time_delta` from AutoMod source:

begin P_test arriving
  while 1=1 do begin
    print test_time_delta(ac as seconds) to message
    wait for 5 sec
  end
end

Step 7: Close the connection in `model finished` function

begin model finished function
  return test_amcp_close()
end

Tefx/amcp