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Architecture and Design Docs
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Add metadata ADR #194

Closed Jarema closed 1 year ago

Jarema commented 1 year ago

Metadata for Stream and Consumer

Metadata Value
Date 2023-01-23
Author @Jarema
Tags jetstream, client, server

Context and Problem Statement

Until now, there was no way to easily add additional information about Stream or Consumer. The only solution was using Description field, which is a ugly workaround.

Server PR

https://github.com/nats-io/nats-server/pull/3797

Design

The solution is to add new metadata field to both Consumer and Stream config. The metadata field would by a map of string keys and string values.

The map would be represented in json as object with nested key/value pairs, which is a default way to marshal maps/hashmaps in most languages.

Example

{
  "durable_name": "consumer",
  ... // other consumer/stream fields
  "metadata": {
    "owner": "nack",
    "domain": "product"
  }
}

Open questions

Do we want to limit the size of metadata?

Signed-off-by: Tomasz Pietrek tomasz@nats.io

Jarema commented 1 year ago

Improved ADR after discussions:

  1. Set limit to 128kB
  2. Added reserved prefix for internals _nats.
Jarema commented 1 year ago

@ripienaar @wallyqs ADR updated, PR updated.