SBC pod launcher JSON based configuration parser

[walidbarakat]

Description :

• A library to be plugged to gRPC service executable. currently the expected behavior is that the client sends NMOS configuration and once the service receives this info, this library being invoked to read a JSON configuration file, process the configuration data, and constructs a command string. then the returned string to the main thread to execute the ffmpeg command-line tool with the specified parameters. The application is designed to handle various configuration keys dynamically and includes error handling mechanisms to ensure robustness.

Prerequisite :
before launching the pod service, an environment variable CONFIG_FILE is expected to be set to hold the absolute path for the json configuration file i.e /tmp/config.json

Functionality :
1 - Reading the Configuration File:

• The application takes a single command-line argument, which is the path to the JSON configuration file.
  It opens and reads the content of the specified JSON configuration file.

2- Parsing the JSON Configuration:

• The application parses the JSON content using nlohmann library.
  It extracts the appParams section from the ffmpegPipelineDefinition object within the JSON structure.

3 - Processing Configuration Parameters:

• The application defines a set of handler functions to process specific keys in the appParams section.
  Each handler function prints the key and value, performs any necessary processing, and returns a formatted string in the format "-key value".

• The handleKeyValue function handles generic key-value pairs, while the handleFrameRate function specifically handles the frame_rate key by calculating the frame rate from its numerator and denominator values.

4 - Constructing the Command String:

• The application collects the formatted strings returned by the handler functions and constructs a single command string by joining them with spaces.

6 - Error Handling:

• The application includes error handling mechanisms to handle various error conditions, such as missing keys, invalid values, and command execution failures. It logs fatal error messages and exits gracefully if any error occurs during the execution.

Compilation and usage :
it compiles as part of the whole cmake project in gRPC folder. so just compiling gRPC service will be enough for compilation and linking : ./compile.sh

Example JSON file :

{
    "ffmpegPipelineDefinition" : {
        "appParams" : {
            "codec" : "rawvideo",
            "pixel_format" : "yuv420p",
            "height" : "1080",
            "width" : "1920",
            "frame_rate" : {
                "numerator" : 60,
                "denominator" : 1
            },
            "socket_name" : "NULL",
            "ip_addr" : "192.168.10.1",
            "port" : "9001",
            "payload_type" : "st20",
            "protocol_type" : "auto",
            "video_size" : "1920x1080",
            "interface_id" : "0"
        }
    }
}

[awilczyns]

Building with ./compile.sh --unit_testing is resulting in missing include errors. Please investigate and resolve the issue.

[awilczyns]

Please provide a usage example demonstrating how to run the full pipeline, starting from the Dockerfile entrypoint (ffmpeg_wrapper_service)

[walidbarakat]

Please provide a usage example demonstrating how to run the full pipeline, starting from the Dockerfile entrypoint (ffmpeg_wrapper_service)

This change doesn't affect the way of running the full pipeline. so from Dockerfile entrypoint still need just to run as it is docker <image_name> <ip> <port> as we know implicitly once the NMOS configuration is sent - which contains an IP and PORT for transmission - the functionality added here will be triggered and processing the json configuration can be considered as a sub-process of processing the incoming message - NMOS configuration -.

in short words, the pipeline can run the same with and without this change.