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Prerequisites:
- DeepStreamSDK 6.0
- Python 3.6
- Gst-python

#Deepstream msgbroker supports sending messages to Azure(mqtt) IOThub, kafka and AMQP broker(rabbitmq)

Dependencies
------------
 $ sudo apt-get update

 Azure Iot:
 ----------
    $ sudo apt-get install -y libcurl4-openssl-dev libssl-dev uuid-dev libglib2.0 libglib2.0-dev

    #If your host machine is x86 and using Ubuntu 18.04, additionally install the below
    $ sudo apt-get install -y libcurl3


 Kafka:
 ------
    $ sudo apt-get install libglib2.0 libglib2.0-dev
    $ sudo apt-get install libjansson4  libjansson-dev
    $ sudo apt-get install librdkafka1=0.11.3-1build1

 AMQP (rabbitmq):
 ----------------
    Install rabbitmq-c library
    --------------------------
    $ git clone -b v0.8.0  --recursive https://github.com/alanxz/rabbitmq-c.git
    $ cd rabbitmq-c
    $ mkdir build && cd build
    $ cmake ..
    $ cmake --build .
    $ sudo cp librabbitmq/librabbitmq.so.4 /opt/nvidia/deepstream/deepstream-<version>/lib/
    $ sudo ldconfig

SETUP:
  1.Use --proto-lib or -p command line option to set the path of adaptor library.
    Adaptor library can be found at /opt/nvidia/deepstream/deepstream-<version>/lib

    kafka lib           - libnvds_kafka_proto.so
    azure device client - libnvds_azure_proto.so
    AMQP lib            - libnvds_amqp_proto.so

  2.Use --conn-str command line option as required to set connection to backend server.
    For Azure           - Full Azure connection string
    For Kafka           - Connection string of format:  host;port;topic
    For Amqp            - Connection string of format:  host;port;username. Password to be provided in cfg_amqp.txt

    Provide connection string under quotes. e.g. --conn-str="host;port;topic"

  3.Use --topic or -t command line option to provide message topic (optional).
    Kafka message adaptor also has the topic param embedded within the connection string format
    In that case, "topic" from command line should match the topic within connection string

  4.Use --schema or -s command line option to select the message schema (optional).
    Json payload to send to cloud can be generated using different message schemas.
    schema = 0; Full message schema with separate payload per object (Default)
    schema = 1; Minimal message with multiple objects in single payload.
    Refer user guide to get more details about message schema.

  5.Use --no-display to disable display.

  6.Use --cfg-file or -c command line option to set adaptor configuration file.
    This is optional if connection string has all relevent information.

    For kafka: use cfg_kafka.txt as a reference.
    This file is used to define the parition key field to be used while sending messages to the
    kafka broker. Refer Kafka Protocol Adaptor section in the DeepStream 4.0 Plugin Manual for
    more details about using this config option. The partition-key setting within the cfg_kafka.txt
    should be set based on the schema type selected using the --schema option. Set this to
    "sensor.id" in case of Full message schema, and to "sensorId" in case of Minimal message schema


    For Azure , use the cfg_azure.txt as a reference. It has the following section:
        [message-broker]
        #connection_str = HostName=<my-hub>.azure-devices.net;DeviceId=<device_id>;SharedAccessKey=<my-policy-key>
        #shared_access_key = <my-policy-key>


        Azure device connection string:
        -------------------------------
        You can provide the connection_str within cfg_azure.txt of format:
        connection_str = HostName=<my-hub>.azure-devices.net;DeviceId=<device_id>;SharedAccessKey=<my-policy-key>

        OR

        optionally, you can pass in part of the required connection string with --conn-str option in format: "url;port;device-id"
        AND provide the shared_access_key within cfg_azure.txt
        shared_access_key = <my-policy-key>

    For AMQP, use cfg_amqp.txt as reference. It has the following default options:
        [message-broker]
        password = guest
        #optional
        hostname = localhost
        username = guest
        port = 5672
        exchange = amq.topic
        topic = topicname

        AMQP connection string:
        ----------------------
        Provide hostname, username, password details in the cfg_amqp.txt

        OR

        optionally, you can pass in part of the required connection string with --conn-str option in format: "hostname;port;username"
        AND provide  password within cfg_amqp.txt
        password = <your_amqp_broker_password>

  NOTE:
    - DO NOT delete the line [message-broker] in cfg file. Its the section identifier used for parsing
    - For Azure & AMQP:
        If you use --conn-str commandline option as in step 2), make sure to provide password details in cfg file
        OR
        You can ignore --conn-str commandline option and provide full connection details within cfg file

  7. Enable logging:
       Go through the README to setup & enable logs for the messaging libraries(kafka, azure, amqp)
         $ cat ../../../tools/nvds_logger/README

To run:
  $ python3 deepstream_test_4.py -i <H264 filename> -p <Proto adaptor library> --conn-str=<Connection string> -s <0/1>

NOTE: More details about the message adapters can be found at README inside DS_PACKAGE_DIR/sources/libs/*_protocol_adaptor

This document shall describe about the sample deepstream-test4 application.

This sample builds on top of the deepstream-test1 sample to demonstrate how to:

* Use "nvmsgconv" and "nvmsgbroker" plugins in the pipeline.
* Create NVDS_META_EVENT_MSG type of meta and attach to buffer.
* Use NVDS_META_EVENT_MSG for different types of objects e.g. vehicle, person etc.
* Provide copy / free functions if meta data is extended through "extMsg" field.

"nvmsgconv" plugin uses NVDS_META_EVENT_MSG type of metadata from the buffer
and generates the "DeepStream Schema" payload in Json format. Static properties
of schema are read from configuration file in the form of key-value pair.
Check dstest4_msgconv_config.txt for reference. Generated payload is attached
as NVDS_META_PAYLOAD type metadata to the buffer.

"nvmsgbroker" plugin extracts NVDS_META_PAYLOAD type of metadata from the buffer
and sends that payload to the server using protocol adaptor APIs.

Generating custom metadata for different type of objects:
In addition to common fields provided in NvDsEventMsgMeta structure, user can
also create custom objects and attach to buffer as NVDS_META_EVENT_MSG metadata.
To do that NvDsEventMsgMeta provides "extMsg" and "extMsgSize" fields. User can
create custom structure, fill that structure and assign the pointer of that
structure as "extMsg" and set the "extMsgSize" accordingly.
If custom object contains fields that can't be simply mem copied then user should
also provide function to copy and free those objects.

Refer generate_event_msg_meta() to know how to use "extMsg" and "extMsgSize"
fields for custom objects and how to provide copy/free function and attach that
object to buffer as metadata.

NOTE: This app by default sends message for first object of every 30th frame. To
change the frequency of messages, modify the following line in source code accordingly.
if(is_first_object and not (frame_number%30)) should be changed to:
if (not (frame_number % 30))  #To get all objects of a single frame