Message passing practise using Google's Protobuf

This repository is created for our team members to get familiar with Google's protobuf library which is a extremely good library for creating structured data. The Swarm Project intends to use Google's protobuf to send structured data (messages) for their communication infrastructure to have a proper protocol to send/receive messages to the bots.

Platform

Please make sure you are running Ubuntu systems. If you are using other linux systems, then it would be a little more pain to configure this. Just try and avoid using any unix system for this development. Windows is a big NO NO!

Note: There are two versions of protobuf ie. v2 and v3. We will be using the v3 and not v2. Please make sure you have that version otherwise it will cause unnecessary problems.

Also we will be using mainly C++ for all of our communications system so we will try to only support this and not other languages.

Installing Google's Protobuf

Firstly you would need some packages for the build systems to work. To install those things in Ubuntu, type this:

$ sudo apt-get install autoconf automake libtool curl make g++ unzip

On other platforms, you would need to use their own package management system to install dependencies.

The methods to install protobuf are:

• Using apt-get: This is a bad method since the Ubuntu packages are not updated and currently they are on protobuf v2 while we would be using v3.

• Cloning their github repo and build the latest tip of master: This is a good method if you are really desperate to get the latest commits. Unfortunately their bazel build system isn't that robust and is failing on some machines, so just try and avoid this. And on top of that you will also have to download and configure gmock source and then generate various template Makefiles and configure script. Not worth the effort!

• Get the stable v3: This is the most reliable method. Get the source code for the v3 tag. Here is the release tag for the same. You can get a zipped source code from here.

Now let's come to how to actually install. These steps need to be followed:

$ ./configure
$ make
$ make check
$ sudo make install
$ sudo ldconfig                         #refresh the shared library cache

Note: If make check fails, you can still install, but some features of the library won't work.

A very detailed installation documentation can be found here. It also contains how to configure protobuf on all systems. If you are able to configure it all by yourself, well and good!

Compiling the source code

Our build process is quite simple and we have avoided the use of fancy tools as much as we can. We simply use Makefiles.

To compile:

$ make

Binaries

There should be two binaries created read and write and it is self explanatory as to what they would be doing.

write: reads the various values from standard input stream and writes the protobuf message to a file passed in the arguments.

read: reads the protobuf values from a file passed in the arguments and outputs the various values to the standout output stream.

Running

To run the write program, use:

$ ./write hi.txt

where hi.txt is the file name where the protobuf message will be stored.

Other binaries should follow the same convention.

Learning about Protobuf

To learn about protobuf, nothing can be better than Google's own documentation. Clone the protobuf's github repo and read the examples in the directory examples/ and docs/.

For a proper tutorial please refer here.