.. _thrift-hello-sample:
Thrift sample
#############
.. figure:: thrift-layers.png
:align: center
:alt: Thrift Layers
What is Thrift?
***************
`Apache Thrift`_ is an `IDL`_ specification, `RPC`_ framework, and
`code generator`_. It works across all major operating systems, supports over
27 programming languages, 7 protocols, and 6 low-level transports. Thrift was
originally developed at `Facebook in 2006`_ and then shared with the
`Apache Software Foundation`_. Thrift supports a rich set of types and data
structures, and abstracts away transport and protocol details, which lets
developers focus on application logic.
.. _Apache Thrift:
https://github.com/apache/thrift
.. _IDL:
https://en.wikipedia.org/wiki/Interface_description_language
.. _RPC:
https://en.wikipedia.org/wiki/Remote_procedure_call
.. _code generator:
https://en.wikipedia.org/wiki/Automatic_programming
.. _Facebook in 2006:
https://thrift.apache.org/static/files/thrift-20070401.pdf
.. _Apache Software Foundation:
https://www.apache.org
Overview
********
This sample application includes a client and server implementing the RPC
interface described in :zephyr_file:`samples/modules/thrift/hello/hello.thrift`.
The purpose of this example is to demonstrate how components at different
layers in thrift can be combined to build an application with desired features.
Requirements
************
- Optional Modules
.. code-block:: console
:caption: Download optional modules with west
west config manifest.group-filter -- +optional
west update
- QEMU Networking (described in :ref:`networking_with_qemu`)
- Thrift dependencies installed for your host OS e.g. in Ubuntu
.. code-block:: console
:caption: Install additional dependencies in Ubuntu
sudo apt install -y libboost-all-dev thrift-compiler libthrift-dev
Building and Running
********************
This application can be run on a Linux host, with either the server or the
client in the QEMU environment, and the peer is built and run natively on
the host.
Building the Native Client and Server
=====================================
.. code-block:: console
$ make -j -C samples/modules/thrift/hello/client/
$ make -j -C samples/modules/thrift/hello/server/
Under ``client/``, 3 executables will be generated, and components
used in each layer of them are listed below:
+----------------------+------------+--------------------+------------------+
| hello_client | TSocket | TBufferedTransport | TBinaryProtocol |
+----------------------+------------+--------------------+------------------+
| hello_client_compact | TSocket | TBufferedTransport | TCompactProtocol |
+----------------------+------------+--------------------+------------------+
| hello_client_ssl | TSSLSocket | TBufferedTransport | TBinaryProtocol |
+----------------------+------------+--------------------+------------------+
The same applies for the server. Only the client and the server with the
same set of stacks can communicate.
Additionally, there is a ``hello_client.py`` Python script that can be used
interchangeably with the ``hello_client`` C++ application to illustrate the
cross-language capabilities of Thrift.
+----------------------+------------+--------------------+------------------+
| hello_client.py | TSocket | TBufferedTransport | TBinaryProtocol |
+----------------------+------------+--------------------+------------------+
Running the Zephyr Server in QEMU
=================================
Build the Zephyr version of the ``hello/server`` sample application like this:
.. zephyr-app-commands::
:zephyr-app: samples/modules/thrift/hello/server
:board: board_name
:goals: build
:compact:
To enable advanced features, extra arguments should be passed accordingly:
- TCompactProtocol: ``-DCONFIG_THRIFT_COMPACT_PROTOCOL=y``
- TSSLSocket: ``-DCONF_FILE="prj.conf ../overlay-tls.conf"``
For example, to build for ``qemu_x86_64`` with TSSLSocket support:
.. zephyr-app-commands::
:zephyr-app: samples/modules/thrift/hello/server
:host-os: unix
:board: qemu_x86_64
:conf: "prj.conf ../overlay-tls.conf"
:goals: run
:compact:
In another terminal, run the ``hello_client`` sample app compiled for the
host OS:
.. code-block:: console
$ ./hello_client 192.0.2.1
$ ./hello_client_compact 192.0.2.1
$ ./hello_client_ssl 192.0.2.1 ../native-cert.pem ../native-key.pem ../qemu-cert.pem
You should observe the following in the original ``hello/server`` terminal:
.. code-block:: console
ping
echo: Hello, world!
counter: 1
counter: 2
counter: 3
counter: 4
counter: 5
In the client terminal, run ``hello_client.py`` app under the host OS (not
described for compact or ssl variants for brevity):
.. code-block:: console
$ ./hello_client.py
You should observe the following in the original ``hello/server`` terminal.
Note that the server's state is not discarded (the counter continues to
increase).
.. code-block:: console
ping
echo: Hello, world!
counter: 6
counter: 7
counter: 8
counter: 9
counter: 10
Running the Zephyr Client in QEMU
=================================
In another terminal, run the ``hello_server`` sample app compiled for the
host OS:
.. code-block:: console
$ ./hello_server 0.0.0.0
$ ./hello_server_compact 0.0.0.0
$ ./hello_server_ssl 0.0.0.0 ../native-cert.pem ../native-key.pem ../qemu-cert.pem
Then, in annother terminal, run the corresponding ``hello/client`` sample:
.. zephyr-app-commands::
:zephyr-app: samples/modules/thrift/hello/client
:board: qemu_x86_64
:goals: run
:compact:
The additional arguments for advanced features are the same as
``hello/server``.
You should observe the following in the original ``hello_server`` terminal:
.. code-block:: console
ping
echo: Hello, world!
counter: 1
counter: 2
counter: 3
counter: 4
counter: 5
bc4374b5fe
