Ktsllex

Kafka Topic and Schema creator

Setup

Add ktsllex to your deps list :

 {:ktsllex, "~> 0.0.2"},

Run mix do deps.get, deps.compile

Auto migrations

To have it run schema migrations at application boot time.

Add ktsllex to your app boot sequence. After logger, and before any schema reading apps.

      extra_applications: [
        :logger,
        ...
        :ktsllex,
        ...
        :event_serializer

And update config.exs

  config :ktsllex,
    # Should it run the migration when called? Default: false
    run_migrations: false,
    schema_registry_host: {:system, "AVLIZER_CONFLUENT_SCHEMAREGISTRY_URL", "http://localhost:8081"},
    # Reads the yaml schema file from :
    base_path: {:system, "KAFKA_SCHEMA_BASE_PATH", "./schemas"},
    schema_name: {:system, "KAFKA_SCHEMA_NAME", "schema_name"},
    app_name: :app,
    lenses_host: {:system, "LENSES_HOST", "http://localhost:3030"},
    lenses_user: {:system, "LENSES_USER", "admin"},
    lenses_pass: {:system, "LENSES_PASS", "admin"},
    lenses_topic: {:system, "LENSES_TOPIC", "topic_name"}

• base_path - needs to be relitive to a path that is releasted with your app, eg priv

Usage

You have access to create_schemas and create_topics mix tasks, eg:

$ mix create_schemas --host=localhost:8081 --schema=schema_name --base=./path/to/schemas/json
$ mix create_topics --host=localhost:3030 --user=admin --password=admin --topic=topic_name

Options

• --base

The path to the schema files is passed into mix create_schemas via --base=./path/to/schemas/json.

It expects to find two files there, one ending -key.json and one -value.json.

Example: If this command was used:

mix create_schemas --base=./schemas/users

Then there should be two flies in ./schemas:

• ./schemas-key.json

• ./schemas-value.json

• --schema

The -key and -value schemas get updated based on the schema parameter

Example: Given this myschema command :

mix create_schemas --schema=myschema

And if this is the schemas-key.json file :

{
  "type": "record",
  "name": "Key",
  "namespace": "anything",
  "connect.name": "anything.Key"
}

Then it would be updated to

{
  "type": "record",
  "name": "Key",
  "namespace": "myschema",
  "connect.name": "myschema.Key"
}

Compatibility Config

To get or set compatibility config :

# Get global
iex> Ktsllex.Config.get("http://localhost:8081")
%{"compatibilityLevel" => "BACKWARD"}

# Set global
iex> Ktsllex.Config.set("http://localhost:8081", "BACKWARD")
%{"compatibilityLevel" => "BACKWARD"}

# Get for a given topic name
iex> Ktsllex.Config.get("http://localhost:8081", "topic-name")
%{"compatibilityLevel" => "BACKWARD"}

# Set for a given topic name
iex> Ktsllex.Config.set("http://localhost:8081", "BACKWARD", "topic-name")
%{"compatibilityLevel" => "BACKWARD"}

If getting a topic that does not have a compatibility set, it will return this:

%{"error_code" => 40401, "message" => "Subject not found."}

Development

• mix deps.get
• mix test

License

Copyright (c) 2018 Quiqup LTD, MIT License. See LICENSE.txt for further details.