Module metadata_version 

KIP-778 metadata.version feature-level model.

The canonical string<->integer-level table, mirrored byte-for-byte from upstream Kafka’s MetadataVersion enum over the range Krabka advertises ([METADATA_VERSION_MIN, METADATA_VERSION_MAX]). JVM clients call MetadataVersion.fromFeatureLevel(N) and throw on any level their enum does not know, so the levels and X.Y-IVn names here MUST match upstream exactly. Verify against MetadataVersion.java in Kafka’s server-common module on trunk before editing: levels are never reused, so the table must carry every level up to METADATA_VERSION_MAX, reserved ones included.

Structs

MetadataVersion

One metadata.version level: its integer feature level, canonical X.Y-IVn name, short X.Y form, and Kafka’s didMetadataChange flag.

Constants

CIDR_ACL_MIN_LEVEL

Level at which ACL host patterns may be CIDR blocks (4.4-IV1, KIP-1276).

CONTROLLER_UNREGISTRATION_MIN_LEVEL

Level at which a controller may be unregistered (4.4-IV2, KIP-1312): Kafka’s MetadataVersion.isControllerUnregistrationSupported.

CORDONED_LOG_DIRS_MIN_LEVEL

Level at which RegisterBrokerRecord and BrokerRegistrationChangeRecord carry KIP-1066 cordoned log directories (4.3-IV0).

DELEGATION_TOKEN_MIN_LEVEL

Level at which KRaft gained delegation tokens (3.6-IV2).

DIRECTORY_ASSIGNMENT_MIN_LEVEL

Level at which partition directory assignments became part of the KRaft metadata records (3.7-IV2, KIP-858).

ELR_DEFAULT_METADATA_LEVEL

Level at which ELRV_1 becomes the bootstrap default (4.1-IV0, EligibleLeaderReplicasVersion.ELRV_1’s bootstrap metadata version).

ELR_MIN_LEVEL

Level at which partition records gained KIP-966 eligible-leader fields (4.0-IV1).

ELR_VERSION_FEATURE

The eligible.leader.replicas.version feature name (KIP-966). Gates the controller’s maintenance of eligible leader replicas.

ELR_VERSION_MAX

Maximum supported eligible.leader.replicas.version level: 1, ELRV_1, which turns KIP-966 ELR maintenance on.

ELR_VERSION_MIN

Minimum supported eligible.leader.replicas.version level: 0, ELRV_0, the level at which the controller keeps no ELR.

KRAFT_VERSION_FEATURE

KIP-853 Raft protocol and dynamic-membership feature.

METADATA_DOWNGRADE_CAPABILITY_FEATURE

Krabka registration-only marker for KIP-1155 downgrade support.

METADATA_DOWNGRADE_CAPABILITY_LEVEL

The only supported level of METADATA_DOWNGRADE_CAPABILITY_FEATURE.

METADATA_VERSION_FEATURE

The metadata.version feature name (KIP-584 / KIP-778).

METADATA_VERSION_MAX

Maximum supported level: 4.5-IV0, Kafka trunk’s latestTesting (the Kafka 4.5.0 release level, which changes no metadata record format).

METADATA_VERSION_MIN

Minimum supported level: 3.3-IV3 (KRaft GA), the floor that real Kafka 4.0 supports.

ONLINE_DOWNGRADE_MIN_LEVEL

Lowest level that supports controller registrations (3.7-IV0).

SCRAM_MIN_LEVEL

Level at which KRaft gained SCRAM credentials (3.5-IV2).

SHARE_VERSION_2_DEFAULT_METADATA_LEVEL

Level at which share.version 2 becomes the bootstrap default (4.4-IV0, trunk’s ShareVersion.SV_2 bootstrap metadata version, KIP-1191).

SHARE_VERSION_DEFAULT_METADATA_LEVEL

Level at which share.version 1 becomes the bootstrap default (4.2-IV0, ShareVersion.SV_1’s bootstrap metadata version, KIP-932 GA).

SHARE_VERSION_FEATURE

The share.version feature name (KIP-932). Gates share-group membership.

SHARE_VERSION_MAX

Maximum supported share.version level: 2, trunk’s ShareVersion.SV_2 (KIP-1191 dead-letter queues).

SHARE_VERSION_MIN

Minimum supported share.version level: 0 (feature disabled).

STREAMS_VERSION_DEFAULT_METADATA_LEVEL

Level at which streams.version 1 becomes the bootstrap default (4.2-IV1, StreamsVersion.SV_1’s bootstrap metadata version, KIP-1071 GA).

STREAMS_VERSION_FEATURE

The streams.version feature name (KIP-1071). Gates the broker-side Streams rebalance protocol (StreamsGroupHeartbeat / StreamsGroupDescribe).

STREAMS_VERSION_MAX

Maximum supported streams.version level: 1 (KIP-1071 early access).

STREAMS_VERSION_MIN

Minimum supported streams.version level: 0 (feature disabled).

Functions

did_metadata_change

Kafka’s didMetadataChange flag for level, or None for a level outside the supported table.

from_feature_level

Look up a level by integer feature level. None if outside the supported table.

from_version_string

Resolve a version string to a level.

is_supported_level

True if level is within [METADATA_VERSION_MIN, METADATA_VERSION_MAX].

metadata_changed_between

Kafka’s MetadataVersion.checkIfMetadataChanged: whether moving between from and to, in either direction, crosses a level that changed the metadata record format. Equal levels never do.