kafkaer

Template based Kafka topic/cluster/ACL management

navdeepsekhon
27
2
Java

kafkaer

CircleCI
Maven Central

Table of Contents

Overview

Kafkaer is a deployment and configuration tool for Apache Kafka. It allows you to automate creation/update of topics and brokers across multiple environments. Create one template configration file and control using different properties files.

Current features:

  • Create topics
  • Update configurations and partitions for existing topics
  • Update configs for a specific broker
  • Update configs for entire kafka cluster
  • Create/update Access control lists (ACLs)
  • Delete all topics created by tool
  • Delete all schemas from schema registry when deleting topics

Two ways to use:

Executable jar

Get the jar from releases

java -jar kafkaer.jar --properties propertiesLocation --config configLocation

Include jar as dep in project from maven central

Gradle:

compile "co.navdeep:kafkaer:1.1"

Maven:

<dependency>
    <groupId>co.navdeep</groupId>
    <artifactId>kafkaer</artifactId>
    <version>1.1</version>
</dependency>

And use it:

Configurator configurator = new Configurator("src/main/resources/your.properties", "src/main/resources/kafka-config.json");
configurator.applyConfig();
The jar published to maven is also an executable.

kafka-config.json

Example:

{
  "topics": [
    {
      "name": "withSuffix-${topic.suffix}",
      "partitions": 3,
      "replicationFactor": 3,
      "description": "This description is just for documentation. It does not affect the kafka cluster.",
      "configs": {
        "compression.type": "gzip",
        "cleanup.policy": "delete",
        "delete.retention.ms": "86400000"
      }
    },
    {
      "name": "test",
      "partitions": 1,
      "replicationFactor": 1,
      "configs": {
        "compression.type": "gzip",
        "cleanup.policy": "compact"
      }
    }
  ],
    "brokers": [
      {
        "id": "1",
        "config": {
          "sasl.login.refresh.window.jitter": "0.05"
        }
      }
    ],
    "aclStrings": [
        "User:joe,Topic,LITERAL,test,Read,Allow,*",
        "User:jon,Cluster,LITERAL,kafka-cluster,Create,Allow,*"
      ]
}

Topics:

A list of topics. Required for each topic:

name,
partitions,
replicationFactor

Rest of all the configs go inside the configs map. You can specify any/all of the topic configurations listed in the kafka documentation

description is optional. It is just for documentation purpose and is ignored by kafkaer.

What if the topic already exists:

Partitions:

If the partitions listed in the config are more than the existing partitions - topic partitions will be increased to the number.

If the partitions listed in config are less than the existing - an exception will be thrown.

If they are same - nothing.

If flag --preserve-partition-count is used, partitions will not be updated.

All other configs:

All other configs will be updated to the new values from config.

Brokers

A list of broker configs.

NOTE: If a broker id is provided, the update is made only on that broker. If no broker id is provided update is sent to each broker in the cluster. See kafka documentation for all broker configs

Cluster-wide configs must be without an id.

ACLs

You can provide the ACLs to create in one of two formats:

Structured list:

"acls" : [
    {
      "principal": "User:joe",
      "resourceType": "Topic",
      "patternType": "LITERAL",
      "resourceName": "test",
      "operation": "Read",
      "permissionType": "Allow",
      "host": "*"
    },
    {
          "principal": "User:jon",
          "resourceType": "Cluster",
          "patternType": "LITERAL",
          "resourceName": "kafka-cluster",
          "operation": "Create",
          "permissionType": "Allow",
          "host": "*"
        }
  ]

As a list of strings:

//Format: "principal,resourceType,patternType,resourceName,operation,permissionType,host"

"aclStrings": [
    "User:joe,Topic,LITERAL,test,Read,Allow,*",
    "User:jon,Cluster,LITERAL,kafka-cluster,Create,Allow,*"
  ]

All the values are case insensitive.

Variables in kafka-config.json

To allow for deployments across different environments, kafka-config.json allows you to specify variables for values that will be replaced with values from the properties file. In the example above the topic name withSuffix-${topic.suffix} will be replaced with withSuffix-iamasuffix using the value of topic.suffix from props.

Why is it useful?

Use case 1: You want to setup multiple instances of your application on same kafka cluster. You can name all your topics with ${topic.suffix} and use different value for each instance john, jane etc.

Use case 2: You might need 50 partitions for your topics in production but only 3 for dev. You create two properties files with different values and use the same kafka-config.json.

Properties file

Standard java properties file.

#admin client configs
kafkaer.bootstrap.servers=localhost:29092
kafkaer.client.id=kafkaer

#variables
topic.suffix=iamasuffix

Admin Client configs

Kafkaer uses AdminClient API to connect to Kafka.
All the admin client configs can be provided in the same properties file. Property name must have prefix kafkaer. followed by one of AdminClientConfig. For example, to specify bootstrap.servers add a property called kafkaer.bootstrap.servers. All the admin client configs are supported. See the list of configs here

Delete created topics

Provide the --wipe flag to delete all the topics listed in the config.json

Delete Schemas

If you’re using confluent schema registry or other compatible schema registry to store topic schemas, kafkaer can delete the associated schemas when deleting the topics.

Use flag --wipe-schemas with --wipe to delete schemas.

Provide the schema registry url with property kafkaer.schema.registry.url. Other schema registry properties can be provided by prefixing kafkaer..

kafkaer.schema.registry.security.protocol=SSL
kafkaer.schema.registry.ssl.truststore.location=...
...

Debug

Use flag --debug for detailed logging

Preserve Partition Count

If a topic already exists and it’s partition count is different from what is defined in the config, kafkaer will try update the partitions as described above. In order to ignore the partition count and keep the existing partitions, --preserve-partition-count flag can be used. When used, the difference is partition count will only be logged.

Contributions

Merge requests welcome. Please create an issue with change details and link it to your merge request.

Note: This project uses lombok. Please install the plugin for your IDE to avoid compilation errors.