Cloud Stream Client

Cloud Stream Client is designed to showcase of connectivity between client application through WebSocket communication with Cloud Stream. The project utilizes Protocol Buffers (protobuf) as a language-neutral data serialization mechanism to efficiently exchange messages between the client and the cloud stream service.

This README provides a brief overview of the project structure, dependencies, and instructions on how to build and run the client program.

Table of Contents

• Python client
• Docker based
  • Dependencies
  • Project Structure
  • Build Instructions
  • Running the Client
  • List of Parameters

Python client

A Python client can be run with minimum effort. It is the same as the one used in Docker

First we need to make sure python3 is available.

myuser:~/Cloud.Stream.Client$ $ python3 --version

Second we need to install the modules required

myuser:~/Cloud.Stream.Client$ pip3 install --user -r python/requirements.txt

Export the password as STREAMUSER and STREAMPASS environment variables

Clone the repo and go to the root folder of the repo to run the command to start the python client and subscribe to your desired subject. For example:

myuser:~/Cloud.Stream.Client$ python3 python/src/client/client.py --websocket-server md.deutsche-boerse.com --subject md-tradegate --username $STREAMUSER --password $STREAMPASS --msgFormat json

The messages are logged by default into streamclient.log The message format is proto by default, the above example uses json but proto is recommended. The https_proxy variable must be exported if you run this from behind a proxy.

Generally, feel free to modify the client.py before you run or other purposes

myuser:~/Cloud.Stream.Client$ head -2 streamclient.log
{'subs': 'md-tradegate', 'messages': [{'@type': 'type.googleapis.com/Client.Response', 'requestId': '123456789', 'subscription': {'statusCode': 200}}]},
{'subs': 'md-tradegate', 'seq': '356857164', 'messages': [{'@type': 'type.googleapis.com/dbag.cef.MarketData', 'Seq': {'ApplID': 2150, 'ApplSeqNum': '7255305109391986657'}, 'Instrmt': {'MktID': 'XGAT', 'Sym': 'LU1291109616', 'SecTyp': 'FUN'}, 'Dat': {'Bid': {'Px': {'m': '133401', 'e': -4}, 'Sz': {'m': '2000'}, 'MDQteTyp': {'Value': 'TRADEABLE'}, 'Typ': {}}, 'Offer': {'Px': {'m': '133519', 'e': -4}, 'Sz': {'m': '2000'}, 'MDQteTyp': {'Value': 'TRADEABLE'}, 'Typ': {'Value': 'OFFER'}}, 'Status': {'Value': 'ACTIVE'}, 'TrdgStat': {'Value': 'CONTINUOUS'}, 'Tm': '1689257358134000000'}}]}

Docker based

One can docker in case you're restricted on the machine you're running the client.

Dependencies

The project includes a Dockerfile containing all necessary dependencies. To build the image simply run make build-image, which will genearte an image with all required dependecies. Alternatively, if you prefer building from source code, the following dependencies are required.

• mdstream-client-cpp:

  • C++ compiler with C++17 support (e.g., GCC, Clang)
  • Protobuf 3.21 or later
  • IXWebSocket 11.4 or later
  • nlohmann/json

• mdstream-client-python:

  • Python 3.6 or later
  • websockets
  • pyjwt
  • pprint
  • protobuf
  • requests
  • urllib

Project Structure

The project is organized as follows.

Cloud.Stream.Client
├── Makefile
├── README.md
├── build-image
├── proto
|   ├── README.md
|   ├── rules.mk
|   └── src
|       ├── client.proto
|       ├── md_cef.proto
|       ├── md_crypto.proto
|       └── md_energy.proto
├── cpp
|   ├── README.md
|   ├── rules.mk
|   └── src
|       ├── client
|       |   └── ...
|       └── utils
|           └── ...
└── python
    ├── README.md
    ├── requirements.txt
    ├── rules.mk
    └── src
        ├── client
        |   └── ...
        └── interpreter
            └── ...

• cpp/: Contains the C++ client code.
• python/: Contains the Python Client and requirements.
• proto/: Contains the Protocol Buffer definition files (.proto) for message serialization
• .devcontainer/: Contains Dockerfile for building an image with all dependencies.
• Makefile: A Makefile containinng build targets and commands.

Build Instructions

1. Clone the repository:

git clone https://github.com/deutsche-boerse/Cloud.Stream.Client.git
cd Cloud.Stream.Client

2. Build the Docker image. (optional)

make build-image
make run-container

mdstream-client-cpp

3. Generate C++ files and headers from protobuf files.

make proto-cpp

4. Compile and link the C++ client.

make mdstream-client-cpp

mdstream-client-python

3. Generate Python sources from protobuf files

make proto-python

4. Generate Python sources for the client.

make mdstream-client-python

Running the Client

Here's an example how to run mdstream-client-cpp

./build/cpp/mdstream-client-cpp --websocket-server [CLOUD_STREAM_SERVER]  \
    --subject [STREAM] --username [USER] --password [PASSOWRD]

Here's an example how to run mdstream-client-python

python3 ./build/python/client.py --websocket-server [CLOUD_STREAM_SERVER] \   
    --subject [STREAM] --username [USER] --password [PASSWORD]

List of Parameters

Parameter	type	Description
--login-server	String (URL)	login server URL to get jwt authentication key
--websocket-server	String (URL)	WebSocket address of Cloud Stream interface
--username	String	Username
--password	String	Password
--token	String	Authentication token
--subject	String	Requested subjects. Multiple subjects can be selected.
--log-file	String (Path)	Write messages to specified file or stdout if no file is given
--recover-by-seq-id	Integer	Recover message starting from ID
--recover-by-timestamp	Integer	Recover message from timestamp in nanosecond
--msgFormat	String	proto or json as message format delivered to client