Table of Contents

Status

Current state: Under discussionAccepted - 2.6.0 contains describe and alter functionality, resolve is pending for a future release.

Discussion thread: here

JIRA: KAFKA-7740

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

Quota management via Admin Client has gone through a couple drafts of proposals (KIP -248, KIP-422). While improvements have been made to the Admin interface for configuration handling, fitting quotas into the API is awkward as they don't fit the natural key-value pairing, nor is the configuration output expressive enough to return all useful information. Therefore, it'd be beneficial to have a quota-native API for managing quotas, which would offer an intuitive and less error-prone interface, convey additional information beyond what the configuration APIs provide, and enable for future extensibility as quotas types are added or evolved.

Background

By default, quotas are defined in terms of a user and client ID, where the user acts as an opaque principal name, and the client ID as a generic group identifier. When setting quotas, an administrator has flexibility in how it specifies the user and client ID for which the quota applies, where the user and client ID may be specifically named, indicated as a default, or omitted entirely. Since quotas have flexible configurations, there is a method for resolving the quotas that apply to a request: a hierarchy structure is used, where the most specific defined quota will be matched to a request's user and client ID.

...

As such, reasoning around quotas can be complex, as it's not immediately obvious which quotas may apply to a given user and/or client ID. Providing descriptive information about how quotas are matched is the first goal of this KIP. Likewise, retrieving and modifying quota values can be done in a more expressive and robust way, which is the second goal of the KIP.

APIs

In order to clearly specify the APIs, let's first disambiguate some terminology: Every client request that is processed is associated with a quota entity, which is a map of entity types to their corresponding entity names for the request. Using the current entity types, an entity is of the form {user=test-user, client-id=test-client}, where user and client-id are the types, and test-user and test-client are the names. However, when specifying a quota configuration entry, only a subset of the entity types need to be provided, which is referred to as an entity match, for example, {user=<default>}.

...

Altering quotas only works on a config-centric manner, and therefore doesn't need distinguishing. For a given entity match, the administrator should be able to specify which quotas apply, or alternatively remove existing quotas so they no longer match. This is AlterClientQuotas.

The quota values are of type Double, which presents a complication in that the RPC protocol doesn't support floating point values. To accommodate this, RPC protocol message type 'double' will be added, which will serialize doubles according to the IEEE 754 floating-point "double format" bit layout.

Types Rationale

While there's two defined entity types in AK, a server-side plugin mechanism allows for further expansion. Likewise, as use cases evolve, finer-grained quota control may be necessary. Therefore, entity types should not be statically bound to publicly defined constants, and instead the API should support flexible entity types by interpreting them as a String identifier. Any entity types that the broker doesn't understand should throw an IllegalArgumentException back to the client.

...

Since a fixed set of entity types aren't defined, an entity should be represented by a Map<String, String>, which maps an entity type to the entity name.

Public Interfaces

Admin client calls will be added to correspond to DescribeClientQuotas, ResolveClientQuotas, and AlterClientQuotas, with supporting types defined in the common.quotas package.

Common types in package org.apache.kafka.common.quota

...

(2.6.0)

Code Block

language	java

/**
 * Describes a client fully-qualifiedquota entity.
 */
public class QuotaEntity, which is a mapping of entity types to their names.
 */
public class ClientQuotaEntity {

    /**
     * The Typetype of an entity entry.
     */
    public static final String USER = "user";
    public static final String CLIENT_ID = "client-id";

    /**
     * RepresentsConstructs thea defaultquota nameentity for the given antypes entity,and inames.e. If thea entityname that's matchedis null,
     * when an exact match isn't found then it is mapped to the built-in default entity name.
     */
     * public@param staticentries finalmaps String QUOTA_ENTITY_NAME_DEFAULT = // implementation definedentity type to its name
     */
    public ClientQuotaEntity(Map<String, String> entries);

    /**
     * `entries`@return describesmap theof fully-qualified entity. The key is a {@code Type} string, howeverentity type to its name
     */
    public *Map<String, there may also exist keys that are not enumerated by {@code Type} that still apply, e.g.String> entries();
}

/**
 * Describes a component for applying a client quota filter.
 */
public class ClientQuotaFilterComponent {

     /**
 the server may internally associate* anotherConstructs type.and Whenreturns queryinga entities, it's necessary
     * to return all quota types because quota values for these types may influence the effectivefilter component that exactly matches the provided entity
     * name for the entity type.
     *
     * @param entityType quotathe value.entity However,type whenthe alteringfilter acomponent quota,applies anyto
 types that aren't specified must be able   * @param entityName the entity name that's matched exactly
     */
 to   bepublic inferredstatic byClientQuotaFilterComponent theofEntity(String serverentityType, otherwise an error is returned. String entityName);

    /**
     *
 Constructs and returns a filter *component Forthat example, {("CLIENT_ID" -> "test-client"),matches the built-in default entity name
     * for the entity type.
     *
     * ("USER" -> "test-user"),
     *  @param entityType the entity type the filter component applies to
     */
    public static ClientQuotaFilterComponent  ofDefaultEntity("GROUP" -> "internal-group")}.String entityType);

     /**/
    public QuotaEntity(Map<String, String> entries);
}

/**
 * Describes a quota entity filter.
 */
public class QuotaFilter {
    /*** Constructs and returns a filter component that matches any specified name for the
     * A filter to be appliedentity type.
     *
     * @param entityType the entity type the filter component applies to
     */
 @param match the non-nullpublic stringstatic that's matched exactlyClientQuotaFilterComponent ofEntityType(String entityType);

     /**/
     * public@return QuotaFilter(String entityType, String match);
}

DescribeClientQuotas:

Code Block

language	java

public class DescribeClientQuotasOptions extends AbstractOptions<DescribeClientQuotasOptions> {the component's entity type
     */
    public // Empty.
}

String entityType();

    /**
  *  The result* of@return the {@link Admin#DescribeClientQuotas(Collection<QuotaFilter>, DescribeClientQuotasOptions)} call.
 */
public class DescribeClientQuotasResult {

    /**optional match string, where:
     *         if present, the name that's matched exactly
     * Maps an entity to its configured quota value(s). Note if noempty, valuematches isthe defined for a quotadefault name
     * type for that entity's config, then it is not includedif innull, thematches resultingany valuespecified map.name
     */
    public Optional<String> match();
}

/**
 @param* entitiesDescribes thea collectionclient ofquota entities that matched the filter
     entity filter.
 */
    public DescribeClientQuotasResult(KafkaFuture<Map<QuotaEntity, Map<String, Long>>> entities);class ClientQuotaFilter {

    /**
     * A Returnsfilter ato mapbe fromapplied quotato entitymatching toclient aquotas.
 future which can be used*
 to check the status of* the@param operation.
components the components to filter */on
    public KafkaFuture<Map<QuotaEntity, Map<String, Long>>> entities();
}

public interface Admin extends AutoCloseable {
    ...* @param strict whether the filter only includes specified components
     */
    private ClientQuotaFilter(Collection<ClientQuotaFilterComponent> components, boolean strict);

    /**
     * DescribesConstructs alland entitiesreturns matchinga allquota providedfilter filtersthat (logicalmatches AND)all thatprovided havecomponents. atMatching least oneentities
     * quotawith valueentity defined.
types that are not specified *
by a component will also *be @paramincluded filters filters to apply to matching entitiesin the result.
     *
     * @param optionscomponents the optionscomponents tofor use
     * @return result containing all matching entitiesthe filter
     */
    DescribeClientQuotasResultpublic describeClientQuotas(Collection<QuotaFilter> filters, DescribeClientQuotasOptions options);
}

ResolveClientQuotas:

Code Block

language	java

public class ResolveClientQuotasOptions extends AbstractOptions<ResolveClientQuotasOptions> {static ClientQuotaFilter contains(Collection<ClientQuotaFilterComponent> components);

    /**
     * WhetherConstructs toand excludereturns thea listquota offilter overriddenthat valuesmatches forall everyprovided quotacomponents. type in the result.
     */
    public ResolveClientQuotasOptions setOmitOverriddenValues(boolean omitOverriddenValues);
}

/**
 * The result of the {@link Admin#ResolveClientQuotas(Collection<QuotaEntity>, ResolveClientQuotasOptions)} call.
 */
public class ResolveClientQuotasResult {
    /**Matching entities
     * with entity types that are not specified by a component will *not* be included in the result.
     *
     * Information@param aboutcomponents athe specificcomponents quotafor configurationthe entry.filter
     */
    public static classClientQuotaFilter Entry {
  containsOnly(Collection<ClientQuotaFilterComponent> components);

      /**
     * Constructs and returns *a @paramquota sourcefilter thethat entitymatches sourceall for the valueconfigured entities.
     */
    * @param value the non-null valuepublic static ClientQuotaFilter all();

    /**
     * @return the filter's */components
     */
    public Collection<ClientQuotaFilterComponent> Entry(QuotaEntity source, Long value);
    }components();

    /**
     * Information@return aboutwhether the value for a quota type.filter is strict, i.e. only includes specified components
     */
    public boolean strict();
}

/**
 NOTE:* WeDescribes maintain a `Value`configuration classalteration because additional information may to be added, e.g.,
     *       a list of overridden entries.
     */made to a client quota entity.
 */
public class ClientQuotaAlteration {

    public static class ValueOp {

        /**
         * @param entrykey the quota type entryto alter
         */
 @param value if set then the existing publicvalue Value(Entry entry);
is updated,
     }

    /**
     * Maps a collection of entities to their effective quotaotherwise values.
if null, the existing value is *cleared
     * @param config the quota configuration for the requested entities */
     */
    public ResolveClientQuotasResultOp(Map<QuotaEntity,String KafkaFuture<Map<Stringkey, Value>>>Double configvalue);

    /**
     /**
 Returns a map from quota entity to a future* which@return canthe bequota usedtype to checkalter
 the status of the operation.
     */
    public Map<QuotaEntity, KafkaFuture<Map<String, Value>>> config   public String key();

        /**
     *   Returns a* future@return whichif succeedsset onlythen ifthe allexisting quotavalue descriptionsis succeed.updated,
      */
   * public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
 otherwise if  ...

    /**
null, the existing value is cleared
      * Describes the effective*/
 quotas for the provided entities.
   public Double *value();
    }

 * @param entities the entities to describe the effective quotas for  private final ClientQuotaEntity entity;
    private final Collection<Op> ops;

    /**
     * @param optionsentity the options to use entity whose config will be modified
     * @return@param ops the effectivealteration quotas for the entitiesto perform
     */
    ResolveClientQuotasResultpublic resolveClientQuotasClientQuotaAlteration(Collection<QuotaEntity>ClientQuotaEntity entitiesentity, ResolveClientQuotasOptionsCollection<Op> optionsops);
}

AlterClientQuotas

Code Block

language	java
title	AlterQuotas

public class AlterClientQuotasEntry {
    /**
    public class* Op@return {
the entity whose config will be   /**modified
         */
 @param key the quotapublic type to alterClientQuotaEntity entity();

    /**
     * @param@return valuethe ifalteration setto thenperform
 the existing value is updated,*/
    public Collection<Op> ops();
}

DescribeClientQuotas (2.6.0)

Code Block

language	java

public class DescribeClientQuotasOptions *extends AbstractOptions<DescribeClientQuotasOptions> {
    // Empty.
}

/**
 * The result of the  otherwise if null, the existing value is cleared{@link Admin#describeClientQuotas(Collection, DescribeClientQuotasOptions)} call.
 */
public class DescribeClientQuotasResult {

    /**
     */
 Maps an entity to its configured quota public Op(String key, Long value);
    }

value(s). Note if no value is defined for a quota
     /**
 type for that entity's config, *then @paramit entityis thenot entityincluded whosein configthe willresulting bevalue modifiedmap.
     *
 @param ops the alteration to perform - if value is set, then the existing value is updated,
     *            otherwise if null, the existing value is cleared  * @param entities future for the collection of entities that matched the filter
     */
    public DescribeClientQuotasResult(KafkaFuture<Map<ClientQuotaEntity, Map<String, Double>>> entities);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public AlterClientQuotasEntry(QuotaEntity entityKafkaFuture<Map<ClientQuotaEntity, Map<String, Collection<Op>Double>>> opsentities();
}

public classinterface AlterClientQuotasOptionsAdmin extends AbstractOptions<AlterClientQuotasOptions>AutoCloseable {
    ...

    /**
     * SetsDescribes whetherall theentities requestmatching shouldthe beprovided validatedfilter withoutthat alteringhave theat configs.
least one client quota  */configuration
    public AlterClientQuotasOptions* validateOnly(boolean validateOnly);
}

/**
 * The result of the {@link Admin#AlterClientQuotas(Collection<AlterClientQuotasEntry>, AlterClientQuotasOptions)} call.
 *
value defined.
     * <p>
     * The APIfollowing ofexceptions thiscan classbe isanticipated evolving,when seecalling {@link@code Adminget()} foron details.
 */
public class AlterClientQuotasResult {
the future from the
     public AlterClientQuotasResult(Map<QuotaEntity, KafkaFuture<Void>> futures);

* returned {@link DescribeClientQuotasResult}:
     /** <ul>
     *   Returns a map from quota entity to a future which can be used to check the status of the operation.<li>{@link org.apache.kafka.common.errors.ClusterAuthorizationException}
     *   If the authenticated user didn't have describe access to the cluster.</li>
     */
    public Map<QuotaEntity, KafkaFuture<Void>> values();

<li>{@link org.apache.kafka.common.errors.InvalidRequestException}
      /**
   If the *request Returnsdetails aare future which succeeds only if all quota alterations succeed.invalid. e.g., an invalid entity type was specified.</li>
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Alters the quotas as specified for the entries.<li>{@link org.apache.kafka.common.errors.TimeoutException}
     *   If the request timed out before the describe could finish.</li>
     * </ul>
     * <p>
     * This operation is supported by brokers with version 2.6.0 or higher.
     *
     * @param filter the filter to apply to match entities
     * @param alterationsoptions the alterationsoptions to performuse
     * @return the resultDescribeClientQuotasResult ofcontaining the alterationsresult
     */
    AlterClientQuotasResultDescribeClientQuotasResult alterClientQuotasdescribeClientQuotas(Collection<AlterClientQuotasEntry>ClientQuotaFilter entriesfilter, AlterClientQuotasOptionsDescribeClientQuotasOptions options);
}

kafka-client-quotas.sh/ClientQuotasCommand:

A ClientQuotasCommand would be constructed with an associated bin/kafka-client-quotas.sh script for managing quotas via command line, and would have three modes of operation, roughly correlating to each of the API calls:

List: Lists the quota entities for the given entity specification and their corresponding quota values, as explicitly specified in the configuration. The user may provide explicit entity types+names, or a pattern to apply to an entity type find matching entity names. If an entity type is omitted from the input, it is treated as a wildcard.
Describe: Describes the effective quotas for an entity, including contextual information about how those quotas were derived. This includes what configuration entries matched to the entity and, if requested, the overridden, less-specific matches for the entity.
Alter: Modifies a quota configuration entry in an incremental manner, i.e. specify which entries to add, update, and/or remove.

Flags

Various flags will be used to accomplish these operations.

Common flags:
--bootstrap-server: The standard bootstrap server.
--command-config: Property file for the Admin client.

Operations (mutually exclusive):
--list: Lists the entities that match the given specification, and prints out their configuration values.
--describe: Describes the effective quota values for an entity.
--alter: Alters the configuration for the given specification.

Entity specification flags (common to all):
--names: Comma-separated list of type=name pairs, e.g. "user=some-user,client-id=some-client-id"
--defaults: Comma-separated list of entity types with the default name, e.g. "defaults=user,client-id" (Note a separate flag is necessary since names are opaque.)

Exclusive to --describe: None.

Exclusive to --resolve: None.

Exclusive to --alter:
--add: Comma-separated list of entries to add or update to the configuration, in format "name=value".
--delete: Comma-separated list of entries to remove from the configuration, in format "name".
--validate-only: If set, validates the alteration but doesn't perform it.

Input

When specifying configuration entries, the form: quota-name[=quota-value] is used.

Output

In general, the output of the entities will be of the form: {entity-type=entity-name, ...}, where entity-name is sanitized for output since it is an opaque string. When displaying configuration values, the form: quota-name=quota-value.

When describing overridden entries in the ResolveClientQuotas, the entry is prefixed by a * to denote it's not effective.

Describe:

ResolveClientQuotas (pending future release)

Code Block

language	java

public class ResolveClientQuotasOptions extends AbstractOptions<ResolveClientQuotasOptions> {
    // Empty.
}

/**
 * The result of the {@link Admin#resolveClientQuotas(Collection, ResolveClientQuotasOptions)} call.
 */
public class ResolveClientQuotasResult {
    /**
     * Information about a specific quota configuration entry.
     */
    public class Entry {
        /**
         * @param source the entity source for the value
         * @param value the non-null value
         */
        public Entry(QuotaEntity source, Double value);
    }

    /**
     * Information about the value for a quota type.
     *
     * NOTE: We maintain a `Value` class because additional information may be added, e.g.,
     *       a list of overridden entries.
     */
    public class Value {
        /**
         * @param entry the quota entry
         */
        public Value(Entry entry);
    }

    /**
     * Maps a collection of entities to their resolved quota values.
     *
     * @param config the quota configuration for the requested entities
     */
    public ResolveClientQuotasResult(Map<QuotaEntity, KafkaFuture<Map<String, Value>>> config);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public Map<QuotaEntity, KafkaFuture<Map<String, Value>>> config();

    /**
     * Returns a future which succeeds only if all quota descriptions succeed.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Resolves the effective quota values for the provided entities.
     *
     * @param entities the entities to describe the resolved quotas for
     * @param options the options to use
     * @return the resolved quotas for the entities
     */
    ResolveClientQuotasResult resolveClientQuotas(Collection<QuotaEntity> entities, ResolveClientQuotasOptions options);
}

AlterClientQuotas (2.6.0)

Code Block

language	java
title	AlterQuotas

/**
 * Options for {@link Admin#alterClientQuotas(Collection, AlterClientQuotasOptions)}.
 *
 * The API of this class is evolving, see {@link Admin} for details.
 */
public class AlterClientQuotasOptions extends AbstractOptions<AlterClientQuotasOptions> {

    /**
     * Returns whether the request should be validated without altering the configs.
     */
    public boolean validateOnly();

    /**
     * Sets whether the request should be validated without altering the configs.
     */
    public AlterClientQuotasOptions validateOnly(boolean validateOnly);
}

/**
 * The result of the {@link Admin#alterClientQuotas(Collection, AlterClientQuotasOptions)} call.
 *
 * The API of this class is evolving, see {@link Admin} for details.
 */
@InterfaceStability.Evolving
public class AlterClientQuotasResult {

    /**
     * Maps an entity to its alteration result.
     *
     * @param futures maps entity to its alteration result
     */
    public AlterClientQuotasResult(Map<ClientQuotaEntity, KafkaFuture<Void>> futures);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public Map<ClientQuotaEntity, KafkaFuture<Void>> values();

    /**
     * Returns a future which succeeds only if all quota alterations succeed.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Alters client quota configurations with the specified alterations.
     * <p>
     * Alterations for a single entity are atomic, but across entities is not guaranteed. The resulting
     * per-entity error code should be evaluated to resolve the success or failure of all updates.
     * <p>
     * The following exceptions can be anticipated when calling {@code get()} on the futures obtained from
     * the returned {@link AlterClientQuotasResult}:
     * <ul>
     *   <li>{@link org.apache.kafka.common.errors.ClusterAuthorizationException}
     *   If the authenticated user didn't have alter access to the cluster.</li>
     *   <li>{@link org.apache.kafka.common.errors.InvalidRequestException}
     *   If the request details are invalid. e.g., a configuration key was specified more than once for an entity.</li>
     *   <li>{@link org.apache.kafka.common.errors.TimeoutException}
     *   If the request timed out before the alterations could finish. It cannot be guaranteed whether the update
     *   succeed or not.</li>
     * </ul>
     * <p>
     * This operation is supported by brokers with version 2.6.0 or higher.
     *
     * @param entries the alterations to perform
     * @return the AlterClientQuotasResult containing the result
     */
    AlterClientQuotasResult alterClientQuotas(Collection<ClientQuotaAlteration> entries, AlterClientQuotasOptions options);
}

kafka-configs.sh/ConfigCommand (2.6.0)

As a result of introducing the APIs, the ConfigCommand will be updated to support the users and clients entity types when using the --bootstrap-server option. The modification to ConfigCommand was adopted in KIP-543, and usage will remain unchanged from the original --zookeeper functionality.

kafka-client-quotas.sh/ClientQuotasCommand (pending future release)

A ClientQuotasCommand would be constructed with an associated bin/kafka-client-quotas.sh script for managing quotas via command line, and would have three modes of operation, roughly correlating to each of the API calls:

Describe: Describes the quota entities for the given entity specification and their corresponding quota values, as explicitly specified in the configuration. The user may provide explicit entity types+names, or a pattern to apply to an entity type find matching entity names. If an entity type is omitted from the input, it is treated as a wildcard.
Resolve: Resolves the effective quotas for an entity, including contextual information about how those quotas were derived. This includes what configuration entries matched to the entity.
Alter: Modifies a quota configuration entry in an incremental manner, i.e. specify which entries to add, update, and/or remove.

Flags

Various flags will be used to accomplish these operations.

Common flags:
--bootstrap-server: The standard bootstrap server.
--command-config: Property file for the Admin client.

Operations (mutually exclusive):
--describe: Describes the entities that match the given specification, and prints out their configuration values.
--resolve: Resolves the effective quota values for an entity.
--alter: Alters the configuration for the given specification.

Entity specification flags (common to all):
--names: Comma-separated list of type=name pairs, e.g. "user=some-user,client-id=some-client-id"
--defaults: Comma-separated list of entity types with the default name, e.g. "defaults=user,client-id" (Note a separate flag is necessary since names are opaque.)

Exclusive to --describe: None.

Exclusive to --resolve: None.

Exclusive to --alter:
--add: Comma-separated list of entries to add or update to the configuration, in format "name=value".
--delete: Comma-separated list of entries to remove from the configuration, in format "name".
--validate-only: If set, validates the alteration but doesn't perform it.

Input

When specifying configuration entries, the form: quota-name[=quota-value] is used.

Output

In general, the output of the entities will be of the form: {entity-type=entity-name, ...}, where entity-name is sanitized for output since it is an opaque string. When displaying configuration values, the form: quota-name=quota-value.

Describe:

Code Block

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --describe \
                              --names=client-id=my-client

{user=user-one, client-id=my-client}
consumer_byte_rate=4000000
producer_byte_rate=1000000

{user=user-two, client-id=my-client}
producer_byte_rate=2000000

{user=<default>, client-id=my-client}
consumer_byte_rate=1000000
producer_byte_rate=500000

Resolve:

Code Block

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --resolve \
                              --names=user=user-two,client-id=my-client

consumer_byte_rate=2000000 {user=user-two, client-id=my-client}
producer_byte_rate=500000 {user=<default>, client-id=my-client}

Alter:

Code Block

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --alter   \
                              --names=client-id=my-client --defaults=user \
                              --add=consumer_byte_rate=2000000            \
                              --delete=producer_byte_rate

<no output on success>

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --describe \
                              --names=client-id=my-client --defaults=user

{user=<default>, client-id=my-client}
consumer_byte_rate=2000000

Proposed Changes

In addition to the API changes above, the following write protocol would be implemented:

DescribeClientQuotas (2.6.0)

Code Block

{
  "apiKey": 48,
  "type": "request",
  "name": "DescribeClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "Components", "type": "[]ComponentData", "versions": "0+",
      "about": "Filter components to apply to quota entities.", "fields": [
      { "name": "EntityType", "type": "string", "versions": "0+",
        "about": "The entity type that the filter component applies to." },
      { "name": "MatchType", "type": "int8", "versions": "0+",
        "about": "How to match the entity {0 = exact name, 1 = default name, 2 = any specified name}." },
      { "name": "Match", "type": "string", "versions": "0+", "nullableVersions": "0+",
        "about": "The string to match against, or null if unused for the match type." }
    ]},
    { "name": "Strict", "type": "bool", "versions": "0+",
      "about": "Whether the match is strict, i.e. should exclude entities with unspecified entity types." }
  ]
}

{
  "apiKey": 48,
  "type": "response",
  "name": "DescribeClientQuotasResponse",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "ErrorCode", "type": "int16", "versions": "0+",
      "about": "The error code, or `0` if the quota description succeeded." },
    { "name": "ErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+",
      "about": "The error message, or `null` if the quota description succeeded." },
    { "name": "Entries", "type": "[]EntryData", "versions": "0+", "nullableVersions": "0+",
      "about": "A result entry.", "fields": [
      { "name": "Entity", "type": "[]EntityData", "versions": "0+",
        "about": "The quota entity description.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+", "nullableVersions": "0+",

Code Block

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --describe \
                "about": "The entity name, or null if the default." }
     --names=client-id=my-client

{user=user-one, client-id=my-client}
consumer_byte_rate=4000000
producer_byte_rate=1000000

{user=user-two, client-id=my-client}
producer_byte_rate=2000000

{user=<default>, client-id=my-client}
consumer_byte_rate=1000000
producer_byte_rate=500000

Resolve:

Code Block

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --resolve \
         ]},
      { "name": "Values", "type": "[]ValueData", "versions": "0+",
	"about": "The quota values for the entity.", "fields": [
                { "name": "Key", "type": "string", "versions": "0+",
      --names=user=user-two,client-id=my-client

consumer_byte_rate=2000000 {user=user-two, client-id=my-client}
producer_byte_rate=500000 {user=<default>, client-id=my-client}

Alter:

Code Block

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --alter   \ "about": "The quota configuration key." },
        { "name": "Value", "type": "float64", "versions": "0+",
          "about": "The quota configuration value." }
    --names=client-id=my-client --defaults=user \ ]}
    ]}
                     ]
}

ResolveClientQuotas (pending future release)

Code Block

{
  "apiKey": 50,
  "type": "request",
  "name": "ResolveClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
     --add=consumer_byte_rate=2000000     { "name": "Entity", "type": "[]QuotaEntityData", "versions": "0+",
       \
      "about": "The quota entity description.", "fields": [
      { "name": "EntityType", "type": "string", "versions": "0+",
        "about": "The entity  --delete=producer_byte_rate

<no output on success>

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --describe \
       type." },
      { "name": "EntityName", "type": "string", "versions": "0+",
        "about": "The entity name." }
    ]}
  ]
}

{
  "apiKey":   --names=client-id=my-client --defaults=user

{user=<default>, client-id=my-client}
consumer_byte_rate=2000000

...

In addition to the API changes above, the following write protocol would be implemented:

DescribeClientQuotas:

Code Block

{
  "apiKey": 4850,
  "type": "response",
  "name": "ResolveClientQuotasResponse",
  "validVersions": "0",
  "typeflexibleVersions": "requestnone",
  "fields": [
    { "name": "DescribeClientQuotasRequestThrottleTimeMs",
 "type": "validVersionsint32", "versions": "0",
  "flexibleVersions": "none",
  "fields": [+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "FilterEntry", "type": "[]QuotaFilterDataQuotaEntryData", "versions": "0+",
      "about": "Filters to apply to Resolved quota entitiesentries.", "fields": [
      { "name": "EntityTypeErrorCode", "type": "stringint16", "versions": "0+",
        "about": "The entity type that error code, or `0` if the filterresolved quota appliesdescription tosucceeded." },
      { "name": "MatchErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+",
        "about": "The string to match against." }
    ]}
  ]
}

{
  "apiKey": 48,
  "type": "response",
  "name": "DescribeClientQuotasResponse",
  "validVersionserror message, or `null` if the resolved quota description succeeded." },
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+",
  "flexibleVersions      "about": "noneResolved quota entries.",
  "fields": [
        { "name": "ThrottleTimeMsEntityType", "type": "int32string", "versions": "0+",
          "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
 entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The entity name." }
      ]},
      { "name": "EntryQuotaValues", "type": "[]EntryDataQuotaValueData", "versions": "0+",
        "about": "AQuota resultconfiguration entryvalues.", "fields": [
        { "name": "ErrorCodeType", "type": "int16string", "versions": "0+",
          "about": "The error code, or `0` if the quota description succeededtype." },
        { "name": "ErrorMessageEntry", "type": "string[]ValueEntryData", "versions": "0+",
 "nullableVersions": "0+",
        "about": "TheQuota errorvalue message, or `null` if the quota description succeeded." },
entries.", "fields": [
          { "name": "EntityQuotaEntity", "type": "[]QuotaEntityDataValueQuotaEntity", "versions": "0+",
            "about": "TheResolved quota entity descriptionentries.", "fields": [
            { "name": "EntityType", "type": "string", "versions": "0+",
              "about": "The entity type." },
            { "name": "EntityName", "type": "string", "versions": "0+",
              "about": "The entity name." }
          ]},
          { "name": "TypeValue", "type": "stringdouble", "versions": "0+",
            "about": "The quota configuration typevalue." },
      { "name": "Value", "type": "int64", "versions": "0+",
        "about": "The quota value."  ]}
      ]}
    ]}
  ]
}

...

AlterClientQuotas (2.6.0)

Code Block

{
  "apiKey": 49,
  "type": "request",
  "name": "ResolveClientQuotasRequestAlterClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "Entries", "type": "[]EntryData", "versions": "0+",
      "about": "The quota configuration entries to alter.", "fields": [
      { "name": "Entity", "type": "[]QuotaEntityDataEntityData", "versions": "0+",

        "about": "The quota entity to descriptionalter.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+", "nullableVersions": "0+",
          "about": "The name of the entity name, or null if the default." }
      ]},
  ]
}

{
  "apiKey": 49,
 { "typename": "responseOps",
  "nametype": "ResolveClientQuotasResponse[]OpData",
  "validVersionsversions": "0+",
        "flexibleVersionsabout": "noneAn individual quota configuration entry to alter.",
  "fields": [

        { "name": "ThrottleTimeMsKey", "type": "int32string", "versions": "0+",
          "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quotaquota configuration key." },
        { "name": "EntryValue", "type": "[]QuotaEntryDatafloat64", "versions": "0+",
          "about": "Effective quota entries.", "fields": [
The value to set, otherwise ignored if the value is to be removed." },
        { "name": "ErrorCodeRemove", "type": "int16bool", "versions": "0+",
          "about": "The error code, or `0` if the effective quota description succeeded." },Whether the quota configuration value should be removed, otherwise set." }
      ]}
    ]},
    { "name": "ErrorMessageValidateOnly", "type": "stringbool", "versions": "0+", "nullableVersions": "0+",
        "about": "The error message, or `null` if the effective quota description succeeded." },
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versionsWhether the alteration should be validated, but not performed." }
  ]
}

{
  "apiKey": 49,
  "type": "response",
  "name": "AlterClientQuotasResponse",
  "validVersions": "0+",
        "aboutflexibleVersions": "Effective quota entries.none",
  "fields": [
        { "name": "EntityTypeThrottleTimeMs", "type": "stringint32", "versions": "0+",
          "about": "The entityduration type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The entity name." }
      ]}in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
      { "name": "QuotaValuesEntries", "type": "[]QuotaValueDataEntryData", "versions": "0+",
        "about": "QuotaThe quota configuration entries valuesto alter.", "fields": [
        { "name": "TypeErrorCode", "type": "stringint16", "versions": "0+",
          "about": "The error code, or `0` if the quota typealteration succeeded." },
        { "name": "EntryErrorMessage", "type": "[]ValueEntryDatastring", "versions": "0+",
 "nullableVersions": "0+",
        "about": "Quota value entries.", "fields": [
    The error message, or `null` if the quota alteration succeeded." },
      { "name": "QuotaEntityEntity", "type": "[]ValueQuotaEntityEntityData", "versions": "0+",
            "about": "EffectiveThe quota entriesentity to alter.", "fields": [
            { "name": "EntityType", "type": "string", "versions": "0+",
              "about": "The entity type." },
            { "name": "EntityName", "type": "string", "versions": "0+",
              "about"nullableVersions": "The entity name." }
          ]}0+",
          { "name": "Value", "type": "int64", "versionsabout": "0+",The name of the entity, or null if the default." }
            "about": "The quota configuration value." }
        ]}
      ]}
    ]}
  ]
}

AlterClientQuotas:

]}
    ]}
  ]
}

Kafka RPC 'double' support (2.6.0)

Note that, while the ByteBuffer natively supports serializing a Double, the format in which the value is serialized is not strongly specified, so the preference is to explicitly ensure a standard representation of double-precision 64-bit IEEE 754 format. This is achieved in Java using Double.doubleToRawLongBits() and Double.longBitsToDouble() and should be easily portable to other languages.

Code Block

title	clients/src/main/java/org/apache/kafka/common/utils/ByteUtils.java

    /**
     * Read a double-precision 64-bit format IEEE 754 value.
     *
     * @param buffer The buffer to read from
     * @return The long value read
     */
    public static double readDouble(ByteBuffer buffer) {
        return Double.longBitsToDouble(buffer.getLong());
    }

    /**
     * Write the given double following the double-precision 64-bit format IEEE 754 value into the buffer.
     *
     * @param value The value to write
     * @param buffer The buffer to write to
     */
    public static void writeDouble(double value, ByteBuffer buffer) {
        buffer.putLong(Double.doubleToRawLongBits(value));
    }

The protocol type definition:

Code Block

title	clients/src/main/java/org/apache/kafka/common/protocol/types/Type.java

    public static final DocumentedType DOUBLE = new DocumentedType() {

Code Block

{
  "apiKey": 50,
  "type": "request",
  "name": "AlterClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "Entry", "type": "[]EntryData", "versions": "0+",
      "about": "The quota configuration entries to alter.", "fields": [
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+",
        "about": "The quota entity to alter.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The name of the entity." }
      ]},
      { "name": "Op", "type": "[]OpData", "versions": "0+",
        "about": "An individual quota configuration entry to alter.", "fields": [
        { "name": "Type", "type": "string", "versions": "0+",
        @Override
  "about": "The quota type." },
        { "name": "Value", "type": "int64", "versions": "0+",
      public void write(ByteBuffer buffer, Object o) {
            ByteUtils.writeDouble((Double) o, buffer);
  "about": "The value to set, otherwise ignored}

 if the value is to be removed." },@Override
        { "name": "Remove", "type": "bool", "versions": "0+",public Object read(ByteBuffer buffer) {
          "about": "Whether the quota configuration value should be removed, otherwise set." }return ByteUtils.readDouble(buffer);
        }

      ]}
  @Override
  ]},
    { "name": "ValidateOnly", "type": "bool", "versions": "0+",
      "about": "Whether the alteration should be validated, but not performed." }
  ]
}

{
  "apiKey": 50,
  "type": "response",
  "name": "AlterClientQuotasResponse",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "Entry", "type": "[]EntryData", "versions": "0+",
      "about": "The quota configuration entries to alter.", "fields": [
      { "name": "ErrorCode", "type": "int16", "versions": "0+", public int sizeOf(Object o) {
            return 8;
        }

        @Override
        public String typeName() {
            return "DOUBLE";
        }

        @Override
        public Double validate(Object item) {
            if (item instanceof Double)
                return (Double) item;
        "about": "The error code, orelse
 `0` if the quota alteration succeeded." },
      { "name": "ErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+",
    throw new SchemaException(item + " is not a Double.");
     "about": "The error message,}

 or `null` if the quota alteration succeeded." },@Override
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+", public String documentation() {
        "about": "The quota entity toreturn alter.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
"Represents a double-precision 64-bit format IEEE 754 value. " +
                   "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The name of the entity." }
      ]}
    ]}
  ]
} values are encoded using eight bytes in network byte order (big-endian).";
        }
    };

In generator/src/main/java/org/apache/kafka/message/MessageGenerator.java, the following operations will be used (code omitted for brevity):

Code Block

title	generator/src/main/java/org/apache/kafka/message/MessageGenerator.java

Hash code: Double.hashCode(value)

Empty value: (double) 0

Parsing a default value string: Double.parseDouble(defaultValue)

Compatibility, Deprecation, and Migration Plan

All changes would be are forward-compatible, and no migration plan is necessary. It's outside the scope of this KIP to deprecate any functionality.

Rejected Alternatives

Use existing describeConfigs/incrementalAlterConfigs for quota functionality. This falls short for a couple reasons. First, quotas entity names are more dynamic than brokers and tasks which makes them awkward to fit into generic tools which expect a single unique, distinct key, e.g. ConfigCommand. Second, there's no tool that expresses a way to get the effective quota resolved quota for an entity without some heavy engineering on the client side, which lacks extensibility and is more expensive to perform, especially over large collection of entities. Therefore, it makes sense to approach quotas as a standalone set of APIs that provide more targeted information and can properly support future extensibility.

...

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Old Version 51

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Key

Status

Motivation

Background

APIs

Types Rationale

Public Interfaces

Common types in package org.apache.kafka.common.quota

(2.6.0)

ResolveClientQuotas:

AlterClientQuotas

DescribeClientQuotas (2.6.0)

Flags

Input

Output

ResolveClientQuotas (pending future release)

AlterClientQuotas (2.6.0)

kafka-configs.sh/ConfigCommand (2.6.0)

kafka-client-quotas.sh/ClientQuotasCommand (pending future release)

Flags

Input

Output

Proposed Changes

DescribeClientQuotas (2.6.0)

ResolveClientQuotas (pending future release)

AlterClientQuotas (2.6.0)

Kafka RPC 'double' support (2.6.0)

Compatibility, Deprecation, and Migration Plan

Rejected Alternatives

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Versions Compared

Old Version 51

New Version Current

Key

Status

Motivation

Background

APIs

Types Rationale

Public Interfaces

Common types in package org.apache.kafka.common.quota

(2.6.0)

ResolveClientQuotas:

AlterClientQuotas

DescribeClientQuotas (2.6.0)

Flags

Input

Output

ResolveClientQuotas (pending future release)

AlterClientQuotas (2.6.0)

kafka-configs.sh/ConfigCommand (2.6.0)

kafka-client-quotas.sh/ClientQuotasCommand (pending future release)

Flags

Input

Output

Proposed Changes

DescribeClientQuotas (2.6.0)

ResolveClientQuotas (pending future release)

AlterClientQuotas (2.6.0)

Kafka RPC 'double' support (2.6.0)

Compatibility, Deprecation, and Migration Plan

Rejected Alternatives