Table of Contents |
---|
Status
Current state: Under DiscussionAccepted
Discussion thread: here
JIRA: https://issues.apache.org/jira/browse/ Jira server ASF JIRA serverId 5aa69414-a9e9-3523-82ec-879b028fb15b key KAFKA-9494
PR:
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
...
This KIP proposes to include 2 additional metadata information - dataType
, and documentation
for the individual config entries.
The motivation behind extending the schema to include dataType
of the configuration entry including dataType
is to enable the client to provide better validation to the user. In the absence of dataType
the only way to know if the user specified value is correct is to make an `alter` call and check if there is no error, which is a suboptimal sub-optimal experience. Including the dataType
could open up potentially other use cases as well.
...
Public Interfaces
Network protocol
Request
There is no change in the request schema except The changes to the Request schema include
- Bump up the valid versions range
- New field
IncludeDocumentation
- with default value of false
Code Block |
---|
{
"apiKey": 32,
"type": "request",
"name": "DescribeConfigsRequest",
// Version 1 adds IncludeSynoyms.
// Version 2 is the same as version 1.
// Version 3 is the same as version 2.
"validVersions": "0-3", <--- Updated Field
"flexibleVersions": "none",
"fields": [
{ "name": "Resources", "type": "[]DescribeConfigsResource", "versions": "0+",
"about": "The resources whose configurations we want to describe.", "fields": [
{ "name": "ResourceType", "type": "int8", "versions": "0+",
"about": "The resource type." },
{ "name": "ResourceName", "type": "string", "versions": "0+",
"about": "The resource name." },
{ "name": "ConfigurationKeys", "type": "[]string", "versions": "0+", "nullableVersions": "0+",
"about": "The configuration keys to list, or null to list all configuration keys." }
]},
{ "name": "IncludeSynoyms", "type": "bool", "versions": "1+", "default": "false", "ignorable": false,
"about": "True if we should include all synonyms." }
]
} |
Response
The changes to the Response schema include
- Bump valid versions range
- Add new Fields -
ConfigValueType, and Documentation
Code Block |
---|
{ "apiKey": 32, { "name": "IncludeDocumentation", "type": "responsebool", "nameversions": "DescribeConfigsResponse1+", "default": "validVersionsfalse":, "0-3"ignorable": false, <--- UpdatedNew Field "flexibleVersions": "none", "fieldsabout": [ "True if we should include configuration documentation." } ] } |
Response
The changes to the Response schema include
- Bump valid versions range
- Add new Fields -
ConfigValueType and Documentation
Code Block |
---|
{ "apiKey": 32, "type": "response", "name": "DescribeConfigsResponse", "validVersions": "0-3", <--- Updated Field "flexibleVersions": "none", "fields": [ { "name": "ThrottleTimeMs{ "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": "Results", "type": "[]DescribeConfigsResultint32", "versions": "0+", "about": "The resultsduration forin each resource.", "fields": [ milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." }, { "name": "ErrorCodeResults", "type": "int16[]DescribeConfigsResult", "versions": "0+", "about": "The errorresults code,for or 0 if we were able to successfully describe the configurations." },each resource.", "fields": [ { "name": "ErrorMessageErrorCode", "type": "stringint16", "versions": "0+", "nullableVersions": "0+", "about": "The error messagecode, or null0 if we were able to successfully describe the configurations." }, { "name": "ResourceTypeErrorMessage", "type": "int8string", "versions": "0+", "nullableVersions": "0+", "about": "The resource typeerror message, or null if we were able to successfully describe the configurations." }, { "name": "ResourceNameResourceType", "type": "stringint8", "versions": "0+", "about": "The resource nametype." }, { "name": "ConfigsResourceName", "type": "[]DescribeConfigsResourceResultstring", "versions": "0+", "about": "EachThe listedresource configurationname.", "fields": [ }, { "name": "NameConfigs", "type": "string[]DescribeConfigsResourceResult", "versions": "0+", "about": "TheEach listed configuration name." },.", "fields": [ { "name": "ValueName", "type": "string", "versions": "0+", "nullableVersions": "0+", "about": "The configuration valuename." }, { "name": "ReadOnlyValue", "type": "boolstring", "versions": "0+", "nullableVersions": "0+", "about": "True if theThe configuration is read-onlyvalue." }, { "name": "IsDefaultReadOnly", "type": "bool", "versions": "0+", "about": "True if the configuration is not setread-only." }, // Note{ "name": the v0 default for this field that should be exposed to callers is // "IsDefault", "type": "bool", "versions": "0", "about": "True if the configuration is not set." }, // Note: the v0 default for this field that should be exposed to callers is // context-dependent. For example, if the resource is a broker, this should default to 4. // -1 is just a placeholder value. { "name": "ConfigSource", "type": "int8", "versions": "1+", "default": "-1", "ignorable": true, "about": "The configuration source." }, { "name": "IsSensitive", "type": "bool", "versions": "0+", "about": "True if this configuration is sensitive." }, { "name": "Synonyms", "type": "[]DescribeConfigsSynonym", "versions": "1+", "ignorable": true, "about": "The synonyms for this configuration key.", "fields": [ { "name": "Name", "type": "string", "versions": "1+", "about": "The synonym name." }, { "name": "Value", "type": "string", "versions": "1+", "nullableVersions": "0+", "about": "The synonym value." }, { "name": "Source", "type": "int8", "versions": "1+", "about": "The synonym source." } ]}, <--- Start of new Fields { "name": "ConfigValueType", "type": "int8", "versions": "3+", default": "0", "ignorable": true, <--- New Field "about": "The configuration data type."}, Type can be one of the following values - BOOLEAN, STRING, INT, SHORT, LONG, DOUBLE, LIST, CLASS, PASSWORD"}, { "name": "Documentation", "type": "{ "name": "Documentation", "type": "string", "versions": "3+", "nullableVersions": "0+", <--- New Field "about": "The configuration documentation." }, <---- End of new Fields ]} ]} ] } |
AdminClient Class
No new method will be added or updated to the AdminCient
class.
Proposed Changes
Under the proposed change, AdminClient.describeConfigs
response (DescribeConfigsResponse.ConfigEntry
) would include following new properties
Type: ConfigType -
This is an Enum of all the supported data type.
...
AbstractConfig Class
As part of this KIP, a new method will be added to AbstractConfig to return the documentation of the given Config
Code Block |
---|
public String documentationOf(String key) { |
...
|
...
ConfigDef.ConfigKey configKey = definition.configKeys().get(key); if (configKey == null) return null; return configKey.documentation; } |
Proposed Changes
Under the proposed change, response for AdminClient.describeConfigs
would include following new properties, which would be part of DescribeConfigsResponse.ConfigEntry
class.
Type: ConfigType -
This is an Enum of all the supported data type.
BOOLEAN, STRING, INT, SHORT, LONG, DOUBLE, LIST, CLASS, PASSWORD }Code Block ConfigType.Unknown
is for ensuring backward compatibility (explained is Compatibility section below)/
The above enum directly maps to the existingType
Enum as defined in ConfigDef.java belowCode Block /** * Data type Theof configconfiguration typesentry. */ public enum TypeConfigType { UNKNOWN, BOOLEAN, STRING, INT, SHORT, LONG, DOUBLE, LIST, CLASS, PASSWORD PASSWORD }
...
ConfigType.Unknown
is for ensuring backward compatibility (explained is Compatibility section below)
The values in above Enum is derived from existingType
Enum defined in ConfigDef.java belowCode Block /** * The config types */ public enum Type { BOOLEAN, STRING, INT, SHORT, LONG, DOUBLE, LIST, CLASS, PASSWORD }
2. Documentation: String
- field's documentation
DescribeConfigsResponse.ConfigEntry
with the above new fields
Code Block |
---|
public class ConfigEntry { |
...
DescribeConfigsResponse.ConfigEntry
Code Block |
---|
public class ConfigEntry { private final String name; private final String value; private final ConfigSource source; private final boolean isSensitive; private final boolean isReadOnly; private final List<ConfigSynonym>String synonymsname; private final String type; // This is the new property value; private final StringConfigSource documentationsource; // This is the new property ..... private final boolean isSensitive; private final boolean isReadOnly; private final List<ConfigSynonym> synonyms; ..... private final ConfigType type; // This is the new property private final String documentation; // This is the new property ..... |
Rest of the changes would be plumbing this new Rest of the changes would be plumbing this new property in AdminManager
class to be eventually consumed by AdminClient
class
...
Following example show how the response would look like in JSON format.
Note: Kafka uses binary protocol over TCP. ConfigType Enum is serialized as byte instead of string.
Code Block | ||
---|---|---|
Code Block | ||
| ||
{ "name": "offsets.topic.num.partitions", "value": "50", "source": "DEFAULT_CONFIG", "type": "INT", // <---- New Field "synonyms": [ { "name": "offsets.topic.num.partitions", "value": "50", "source": "DEFAULT_CONFIG" } ], "documentation": "The number of partitions for the offset commit topic (should not change after deployment)", // <---- New Field "isReadOnly": true, "isSensitive": false, } |
Compatibility, Deprecation, and Migration Plan
The proposed change is backward compatible in a sense that for same version of Kafka server and client response would include additional fields
For example, if one runs kafka-config.sh
bin/kafka-configs.sh --describe --entity-type brokers --bootstrap-server localhost:9092 --entity-name 0
the output would be as
Code Block |
---|
replication.quota.window.num=11 type=INT sensitive=false synonyms={} documentation=... |
...
Code Block |
---|
request.timeout.ms=30000 type=null sensitive=false synonyms={} documentation=null |
...
Default Behavior
By default, the `documentation` field will not be included in the response to describeConfigs
. This is to avoid the response from boating up as the value for documentation
field can be quite large.
Below example shows how client can include the new fields in the response
Code Block | ||
---|---|---|
| ||
KafkaAdminClient.describeConfigs(
resources,
new DescribeConfigsOptions()
.includeSynonyms(true)
.includeDocumentation(true)
) |
Compatibility, Deprecation, and Migration Plan
For backward compatibility we rely on existing schema versioning technique. Under this, client sends its version information in the request header. This in turn is used on the server to select the schema for that version.
Server version | Client version | Expected Behavior | |
---|---|---|---|
1 | X | X | Both Type and Documentation is visible to the client. |
2 | X | X-1 |
Not serialized as part of the response. |
3 | X-1 | X | IllegalArgumentException: Invalid version for API key... |
4 | X+1 | X | Both If version X+1 has new value in enum |
Rejected Alternatives
NA