Fetching data from RabbitMQ to Managed Service for ClickHouse®

A Managed Service for ClickHouse® cluster can get data from RabbitMQ in real time. Managed Service for ClickHouse® automatically inserts data sent to specific RabbitMQ queue exchanges into a table run on the RabbitMQ engine.

To set up data delivery from RabbitMQ to Managed Service for ClickHouse®:

1. Set up integration with RabbitMQ for the Managed Service for ClickHouse® cluster.
2. In the Managed Service for ClickHouse® cluster, create a table on the RabbitMQ engine.
3. Send the test data to the RabbitMQ queue.
4. Check that the test data is present in the Managed Service for ClickHouse® cluster table.

If you no longer need the resources you created, delete them.

Getting startedGetting started

Prepare the infrastructurePrepare the infrastructure

Configure additional settingsConfigure additional settings

1. Connect to a virtual machine over SSH.

   1. Install RabbitMQ:

      sudo apt update && sudo apt install rabbitmq-server --yes
      

   2. Create a user for RabbitMQ:

      sudo rabbitmqctl add_user <username> <password>
      

   3. Grant this user permissions to connect to the server:

      sudo rabbitmqctl set_permissions -p / <username> ".*" ".*" ".*" && \
      sudo rabbitmqctl set_topic_permissions -p / <username> amq.topic "cars" "cars"
      

2. Install the amqp-publish and amqp-declare-queue utilities to work with RabbitMQ and jq for stream processing JSON files:

   sudo apt update && sudo apt install amqp-tools --yes && sudo apt-get install jq --yes
   

3. Check if you can create a queue named cars in RabbitMQ using amqp-declare-queue:

   amqp-declare-queue \
       --url=amqp://<username>:<password>@<IP_address_or_FQDN_of_the_RabbitMQ_server>:5672 \
       --queue=cars
   

4. Install the clickhouse-client utility to connect to the database in the Managed Service for ClickHouse® cluster.

   1. Connect the DEB repository ClickHouse®:

      sudo apt update && sudo apt install --yes apt-transport-https ca-certificates dirmngr && \
      sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv E0C56BD4 && \
      echo "deb https://packages.clickhouse.com/deb stable main" | sudo tee \
      /etc/apt/sources.list.d/clickhouse.list
      

   2. Install the dependencies:

      sudo apt update && sudo apt install clickhouse-client --yes
      

   3. Download the configuration file for clickhouse-client:

      mkdir -p ~/.clickhouse-client && \
      wget "https://storage.yandexcloud.net/doc-files/clickhouse-client.conf.example" \
        --output-document ~/.clickhouse-client/config.xml
      

   Check that you can use clickhouse-client to connect to the Managed Service for ClickHouse® cluster over SSL.

Set up integration with RabbitMQ for the Managed Service for ClickHouse® clusterSet up integration with RabbitMQ for the Managed Service for ClickHouse® cluster

resource "yandex_mdb_clickhouse_cluster" "clickhouse-cluster" {
  ...
  clickhouse {
    ...
    config {
      rabbitmq {
        username = "<username>"
        password = "<password>"
      }
    }
    ...
  }
}

In the Managed Service for ClickHouse® cluster, create a table on the RabbitMQ engineIn the Managed Service for ClickHouse® cluster, create a table on the RabbitMQ engine

Let's assume there is a cars queue in RabbitMQ, where you input the following JSON data from the car sensors at the RabbitMQ exchange point called exchange:

• device_id: String ID of the device.

• datetime: Date and time when the data was generated, in YYYY-MM-DD HH:MM:SS format.

• Car coordinates:

  • latitude: Latitude.
  • longitude: Longitude.
  • altitude: Altitude above sea level.

• speed: Current speed.

• battery_voltage: Battery voltage (used for electric cars. For cars with internal combustion engine, this parameter is null).

• cabin_temperature: Temperature inside the car.

• fuel_level: Fuel level (used for cars with internal combustion engine. For electric cars, this parameter is null).

This data will be transmitted as RabbitMQ messages. Each message will contain a JSON object as a string in the following format:

{"device_id":"iv9a94th6rzt********","datetime":"2020-06-05 17:27:00","latitude":"55.70329032","longitude":"37.65472196","altitude":"427.5","speed":"0","battery_voltage":"23.5","cabin_temperature":"17","fuel_level":null}

The Managed Service for ClickHouse® cluster will insert data into a table in JSONEachRow format which converts strings from RabbitMQ messages to the appropriate column values.

Create a table in the Managed Service for ClickHouse® cluster to accept data from RabbitMQ:

1. Connect to the db1 database of the Managed Service for ClickHouse® cluster using clickhouse-client.

2. Run the following query:

   CREATE TABLE IF NOT EXISTS db1.cars (
       device_id String,
       datetime DateTime,
       latitude Float32,
       longitude Float32,
       altitude Float32,
       speed Float32,
       battery_voltage Nullable(Float32),
       cabin_temperature Float32,
       fuel_level Nullable(Float32)
   ) ENGINE = RabbitMQ
   SETTINGS
       rabbitmq_host_port = '<Internal_IP_address_of_VM_with_RabbitMQ>:5672',
       rabbitmq_routing_key_list = 'cars',
       rabbitmq_exchange_name = 'exchange',
       rabbitmq_format = 'JSONEachRow';
   

This table will be automatically filled with messages read from the cars queue at the exchange of RabbitMQ. When reading the data, Managed Service for ClickHouse® uses the authentication credentials provided earlier.

Send the test data to the RabbitMQ queueSend the test data to the RabbitMQ queue

1. Create a sample.json file with the following test data:

   {
        "device_id": "iv9a94th6rzt********",
        "datetime": "2020-06-05 17:27:00",
        "latitude": 55.70329032,
        "longitude": 37.65472196,
        "altitude": 427.5,
        "speed": 0,
        "battery_voltage": 23.5,
        "cabin_temperature": 17,
        "fuel_level": null
    }
   
    {
        "device_id": "rhibbh3y08qm********",
        "datetime": "2020-06-06 09:49:54",
        "latitude": 55.71294467,
        "longitude": 37.66542005,
        "altitude": 429.13,
        "speed": 55.5,
        "battery_voltage": null,
        "cabin_temperature": 18,
        "fuel_level": 32
    }
   
    {
        "device_id": "iv9a94th6rzt********",
        "datetime": "2020-06-07 15:00:10",
        "latitude": 55.70985913,
        "longitude": 37.62141918,
        "altitude": 417.0,
        "speed": 15.7,
        "battery_voltage": 10.3,
        "cabin_temperature": 17,
        "fuel_level": null
    }
   

2. Send the data from the sample.json file to the previously created cars queue of the exchange point using jq and amqp-publish.

   jq \
   --raw-output \
   --compact-output . ./sample.json |\
   amqp-publish \
   --url=amqp://<RabbitMQ_username>:<password>@<IP_address_or_FQDN_of_the_RabbitMQ_server>:5672 \
   --routing-key=cars \
   --exchange=exchange
   

Check that the test data is present in the Managed Service for ClickHouse® cluster tableCheck that the test data is present in the Managed Service for ClickHouse® cluster table

To access the data, use a materialized view (MATERIALIZED VIEW). When a materialized view is added to a table on the RabbitMQ engine, it starts collecting data in the background. This allows you to continuously receive messages from RabbitMQ and convert them to the required format using SELECT.

To create a materialized view for the db1.cars table:

1. Connect to the db1 database of the Managed Service for ClickHouse® cluster using clickhouse-client.

2. Run the following queries:

   CREATE TABLE IF NOT EXISTS db1.cars_data_source (
        device_id String,
        datetime DateTime,
        latitude Float32,
        longitude Float32,
        altitude Float32,
        speed Float32,
        battery_voltage Nullable(Float32),
        cabin_temperature Float32,
        fuel_level Nullable(Float32)
   ) ENGINE MergeTree()
     ORDER BY device_id;
   
   CREATE MATERIALIZED VIEW db1.cars_view TO db1.cars_data_source
     AS SELECT * FROM db1.cars;
   

To get all the data from the db1.cars_view materialized view:

1. Connect to the db1 database of the Managed Service for ClickHouse® cluster using clickhouse-client.

2. Run the following query:

   SELECT * FROM db1.cars_view;
   

The query will return a table with data sent to RabbitMQ.

Delete the resources you createdDelete the resources you created

Delete the resources you no longer need to avoid paying for them:

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