[InFuse] intermediate log format / minimal example

README.md

msgpack Logs

This is an example of how to create an InFuse-compatible intermediate log file in the msgpack format.

Setup

Install msgpack: run install.sh.

Compile Example

compile with g++:

g++ main.cpp

Run Example

Write logfile to output.msg:

./a.out

Read logfile from output.msg and print content on stdout:

python3 load.py

msgpack Documentation

• pack functions: https://github.com/msgpack/msgpack-c/wiki/v2_0_c_overview#packer
• C interface: https://github.com/msgpack/msgpack-c/wiki/v2_0_c_overview

install.sh

git clone https://github.com/msgpack/msgpack-c.git
cd msgpack-c
mkdir build
cd build
sudo make install

load.py

import msgpack
log = msgpack.unpack(open("output.msg", "rb"))
print(log)

main.cpp

#include <msgpack.h>
#include <msgpack/fbuffer.h>
#include <cstdlib>
#include <cstring>
#include <string>


int main()
{
    const unsigned NUM_DATASTREAMS = 1;
    const char* STREAM_NAME = "component.port";
    const char* META_STREAM_NAME = "component.port.meta";
    const char* TYPENAME = "int";
    const char* OUTPUT_FILE = "output.msg";
    const unsigned STREAM_LENGTH = 2;  // we have to know the stream length before we write the log...
    int data[2];
    data[0] = 2;
    data[1] = 3;
    int timestamps[2];
    timestamps[0] = 0;
    timestamps[1] = 1;

    FILE* fp = fopen(OUTPUT_FILE, "w");

    msgpack_packer packer;
    msgpack_packer_init(&packer, fp, msgpack_fbuffer_write);

    msgpack_pack_map(&packer, 2 * NUM_DATASTREAMS);

    // Data stream (key)
    msgpack_pack_str(&packer, strlen(STREAM_NAME));
    msgpack_pack_str_body(&packer, STREAM_NAME, strlen(STREAM_NAME));

    // Data stream (content)
    msgpack_pack_array(&packer, STREAM_LENGTH);
    // Write whatever you want here
    for(unsigned i = 0; i < STREAM_LENGTH; i++)
        msgpack_pack_int64(&packer, data[i]);


    // Encode complex objects in maps, e.g.,

    // msgpack_pack_map(&packer, NUM_FIELDS);

    // msgpack_pack_str(&packer, ...);
    // msgpack_pack_str_body(&packer, FIELD_NAME, ...);

    // msgpack_pack_...(&packer, ...);  // field content


    // Meta data (key)
    msgpack_pack_str(&packer, strlen(META_STREAM_NAME));
    msgpack_pack_str_body(&packer, META_STREAM_NAME, strlen(META_STREAM_NAME));

    // Meta data (content)
    msgpack_pack_map(&packer, 2);
    // Timestamps
    const std::string TIME_KEY = "timestamps";
    msgpack_pack_str(&packer, TIME_KEY.size());
    msgpack_pack_str_body(&packer, TIME_KEY.c_str(), TIME_KEY.size());
    msgpack_pack_array(&packer, STREAM_LENGTH);
    for(unsigned i = 0; i < STREAM_LENGTH; i++)
        msgpack_pack_int64(&packer, timestamps[i]);
    // Type name
    const std::string TYPE_KEY = "type";
    msgpack_pack_str(&packer, TYPE_KEY.size());
    msgpack_pack_str_body(&packer, TYPE_KEY.c_str(), TYPE_KEY.size());
    msgpack_pack_str(&packer, strlen(TYPENAME));
    msgpack_pack_str_body(&packer, TYPENAME, strlen(TYPENAME));

    fclose(fp);

    return 0;
}