kafka cache_server

The kafka cache_server binding supports proactive fetch of messages to keep the cache fresh in preparation for new consumers. This is enabled by configuring a list of bootstrap topics for the binding.

kafka_cache_server:
  type: kafka
  kind: cache_server
  options:
    bootstrap:
      - items-responses
  exit: kafka_client

Configuration (* required)

options

object

The cache_server specific options.

options:
  bootstrap:
    - items-requests
    - items-responses
  topics:
    - name: items-requests
      defaultOffset: live

options.bootstrap

array of string

Topics to bootstrap in cache server even when no clients.

options.topics

array of object

Topic configuration.

topics[].name

string

Topic name.

topics[].key

enum [ avro, double, float, int32, int64, json, protobuf, string ], object

Enforce validation for key

key.model*

enum [ avro, double, float, int32, int64, json, protobuf, string ]

A schema or type to validate the topic's key. Refer to the individual model docs for type specific implementation.

topics[].value

enum [ avro, double, float, int32, int64, json, protobuf, string ], object

Enforce validation for value

value.model*

enum [ avro, double, float, int32, int64, json, protobuf, string ]

A schema or type to validate the topic's value. Refer to the individual model docs for type specific implementation.

topics[].defaultOffset

enum [ live, historical ]

Fetch offset to use for new consumers

topics[].transforms

array

Extract key or value attributes from the typed Kafka message to apply to the Kafka message id or Kafka headers. The extract-key property must come before the extract-headers property if they both exist.

transforms:
  - extract-key: ${message.key.id}

transforms:
  - extract-headers:
      my-kafka-header: ${message.value.test}

transforms:
  - extract-key: ${message.value.id}
  - extract-headers:
      my-kafka-header: ${message.value.test}

transforms[].extract-key

string | Pattern: ^\\$\\{message\\.(key|value)\\.([A-Za-z_][A-Za-z0-9_]*)\\}$

Use a part of the Kafka message as the Kafka message key.

transforms[].extract-headers

object as map of named string properties | Pattern: ^\\$\\{message\\.(key|value)\\.([A-Za-z_][A-Za-z0-9_]*)\\}$

Use a part of the Kafka message as a Kafka message header.

routes*

array of object

Conditional kafka specific routes.

routes[].guarded

object as map of named array of string

List of roles required by each named guard to authorize this route.

routes:
  - guarded:
      my_guard:
        - read:items

routes[].when

array of object

List of conditions (any match) to match this route. Read more: When a route matches

when[].topic

string

Topic name pattern.

routes[].exit

string

Next binding when following this route.

exit: echo_server

exit

string

Default exit binding when no conditional routes are viable.

exit: echo_server

telemetry

object

Defines the desired telemetry for the binding.

telemetry.metrics

array

Telemetry metrics to track

telemetry:
  metrics:
    - stream.*