Schema-registry-statistics

Schema Registry Statistics Tool is a small utility that allows you to easily identify the usage of different schema versions within a topic.
Using this tool, you can consume from a topic, while calculating the percentage of each schema version.

Table of Contents

• Schema-registry-statistics
  • Table of Contents
  • Flags
  • Usage
    • Generate Pie Chart
  • How does it work?
  • Local testing
  • License

Example output:

[sr-stats] 2022/12/28 10:02:12 Starting to consume from payments-topic
[sr-stats] 2022/12/28 10:02:12 Consumer up and running!...
[sr-stats] 2022/12/28 10:02:12 Use SIGINT to stop consuming.
[sr-stats] 2022/12/28 10:02:14 terminating: via signal
[sr-stats] 2022/12/28 10:02:14 Total messages consumed: 81
Schema ID 1 => 77%
Schema ID 3 => 23%

As you can see, in the payments-topic, 77% of the messages are produced using schema ID 1, while the remaining messages are produced using schema ID 3.

You can get the schema by ID:

curl -s http://<SCHEMA_REGISTRY_ADDR>/schemas/ids/1 | jq .

For further offsets analysis, you can store the results into a JSON file:

{"1":[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61],"3":[62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80]}

Flags

Name	Description	Require	Type	default
--bootstrap	The Kafka bootstrap servers.	V	string	"localhost:9092"
--topic	The topic name to consume.	V	string	""
--version	The Kafka client version to be used.		string	"2.1.1"
--group	The consumer group name.		string	schema-stats
--user	The Kafka username for authentication.		string	""
--password	The Kafka authentication password.		string	""
--tls	Use TLS communication.		bool	false
--cert	When TLS communication is enabled, specify the path for the CA certificate.	when tls	string	""
--store	Store results into a file.		bool	false
--chart	Generate pie chart from results.		bool	false
--path	If store flag is set, the path to store the file.		string	"/tmp/results.json"
--oldest	Consume from oldest offset.		bool	true
--limit	Limit consumer to X messages, if different than 0.		int	0
--verbose	Raise the consumer log level.		bool	false

Usage

./schema-registry-statistics --bootstrap kafka1:9092 --group stat-consumer --topic payments-topic --store --path ~/results.json

Consume from payments-topic of kafka1 and store the results. The consumer will run until SIGINT (CMD + C) will be used.

Generate Pie Chart

By using the --chart flag, you can generate an HTML page with a pie chart visualization:

How does it work?

According to the Kafka wire format, has only a couple of components:

Bytes	Area	Description
0	Magic Byte	Confluent serialization format version number; currently always 0.
1-4	Schema ID	4-byte schema ID as returned by the Schema Registry.
5..	Data	Serialized data in the specified schema format (Avro, Protobuf).

The tool leverage this format, and reads the binary format of the each message in order to extract the schema ID and store it.

Local testing

You can use the docker-compose.yml file to create a local environment from scratch.
In the /scripts directory, there are 2 versions of the same schema, and a simple Python Avro producer.

License

This project is licensed under the Apache License - see the LICENSE file for details.