Delivering data from an Apache Kafka® queue to PostgreSQL
You can set up data transfer from a Managed Service for Apache Kafka® topic to Managed Service for PostgreSQL using Yandex Data Transfer. To do this:
If you no longer need the resources you created, delete them.
Getting started
-
Prepare the infrastructure:
ManuallyTerraform-
Create a Managed Service for Apache Kafka® source cluster in any availability zone with any suitable configuration and public access.
-
In the source cluster, create a topic named
sensors
. -
In the source cluster, create a user named
mkf-user
with theACCESS_ROLE_PRODUCER
andACCESS_ROLE_CONSUMER
permissions for the created topic. -
In the same availability zone, create a Managed Service for PostgreSQL target cluster with any appropriate configuration,
pg-user
as the admin username, and hosts located in the public domain. -
Make sure that the cluster security groups are set up correctly and allow connecting to them:
-
If you do not have Terraform yet, install it.
-
Get the authentication credentials. You can add them to environment variables or specify them later in the provider configuration file.
-
Configure and initialize a provider. There is no need to create a provider configuration file manually, you can download it
. -
Place the configuration file in a separate working directory and specify the parameter values. If you did not add the authentication credentials to environment variables, specify them in the configuration file.
-
Download the kafka-postgresql.tf
configuration file to the same working directory.This file describes:
- Networks and subnets for hosting the clusters.
- Security groups for making cluster connections.
- Managed Service for Apache Kafka® source cluster.
- Managed Service for PostgreSQL target cluster.
- Target endpoint.
- Transfer.
-
In
kafka-postgresql.tf
, specify:- Apache Kafka® and PostgreSQL versions
- Apache Kafka® and PostgreSQL user passwords
-
Make sure the Terraform configuration files are correct using this command:
terraform validate
If there are any errors in the configuration files, Terraform will point them out.
-
Create the required infrastructure:
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
All the required resources will be created in the specified folder. You can check resource availability and their settings in the management console
. -
-
-
Install the utilities:
-
kafkacat
to read and write data to Apache Kafka® topics.sudo apt update && sudo apt install --yes kafkacat
Check that you can use it to connect to the Managed Service for Apache Kafka® source cluster over SSL.
-
jq
for JSON file stream processing.sudo apt update && sudo apt-get install --yes jq
-
Prepare the test data
Let's assume the Apache Kafka® sensors
topic in the source cluster receives data from car sensors in JSON format.
Create a local sample.json
file with the following test data:
sample.json
{
"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
}
Prepare and activate the transfer
-
Create a source endpoint with the
Apache Kafka®
type and specify the following items for it:- Topic full name:
sensors
. json
conversion rules. In the Data scheme field, selectJSON specification
and copy and paste the following field specification into the form that opens:
sensors-specification
[ { "name": "device_id", "type": "utf8", "key": true }, { "name": "datetime", "type": "utf8" }, { "name": "latitude", "type": "double" }, { "name": "longitude", "type": "double" }, { "name": "altitude", "type": "double" }, { "name": "speed", "type": "double" }, { "name": "battery_voltage", "type": "double" }, { "name": "cabin_temperature", "type": "uint16" }, { "name": "fuel_level", "type": "uint16" } ]
- Topic full name:
-
Create a target endpoint and a transfer:
ManuallyTerraform-
Create a target endpoint of the
PostgreSQL
type and specify the cluster connection parameters in it:- Installation type:
Managed Service for PostgreSQL cluster
. - Managed Service for PostgreSQL cluster:
<name_of_PostgreSQL_target_cluster>
from the drop-down list. - Database:
db1
. - User:
pg-user
. - Password:
<user_password>
.
- Installation type:
-
Create a transfer of the Replication type that will use the created endpoints.
-
Activate the transfer and wait for its status to change to Replicating.
-
In
kafka-postgresql.tf
, specify the following variables:kf_source_endpoint_id
: ID of the source endpoint.transfer_enabled
: Set to1
for creating a target endpoint and transfer.
-
Make sure the Terraform configuration files are correct using this command:
terraform validate
If there are any errors in the configuration files, Terraform will point them out.
-
Create the required infrastructure:
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
-
-
The transfer will be activated automatically. Wait for its status to change to Replicating.
-
Test the transfer
Make sure the data from the topic in the source Managed Service for Apache Kafka® cluster is being moved to the Managed Service for PostgreSQL database:
-
Send data from the
sample.json
file to the Managed Service for Apache Kafka®sensors
topic usingjq
andkafkacat
:jq -rc . sample.json | kafkacat -P \ -b <broker_host_FQDN>:9091 \ -t sensors \ -k key \ -X security.protocol=SASL_SSL \ -X sasl.mechanisms=SCRAM-SHA-512 \ -X sasl.username="mkf-user" \ -X sasl.password="<user_password_in_the_source_cluster>" \ -X ssl.ca.location=/usr/local/share/ca-certificates/Yandex/YandexInternalRootCA.crt -Z
To learn more about setting up an SSL certificate and working with
kafkacat
, see Connecting to an Apache Kafka® cluster from applications. -
Make sure the data from the source Managed Service for Apache Kafka® cluster has been moved to the Managed Service for PostgreSQL database:
-
Check that the
sensors
table contains the sent data:SELECT * FROM sensors;
Delete the resources you created
Note
Before deleting the created resources, deactivate the transfer.
Some resources are not free of charge. To avoid paying for them, delete the resources you no longer need:
-
Delete the other resources depending on how they were created:
ManuallyTerraform-
In the terminal window, go to the directory containing the infrastructure plan.
-
Delete the
kafka-postgresql.tf
configuration file. -
Make sure the Terraform configuration files are correct using this command:
terraform validate
If there are any errors in the configuration files, Terraform will point them out.
-
Confirm updating the resources.
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
This will delete all the resources described in the
kafka-postgresql.tf
configuration file. -
-