Package com.microsoft.azure.functions.annotation

Annotation Type KafkaOutput

@Target(PARAMETER)
@Retention(RUNTIME)
public @interface KafkaOutput

Place this on a parameter whose value would be published to Kafka. The parameter type should be OutputBinding<T>, where T could be one of:

• Any native Java types such as int, String, byte[]
• Any POJO type

The following example shows a Java function that produce a message to the Kafka cluster, using event provided in the body of an HTTP Post request.

 @FunctionName("kafkaInupt-Java")

 public String input(
    @HttpTrigger(name = "request", methods = {HttpMethod.POST}, authLevel = AuthorizationLevel.ANONYMOUS)
     final String message,
    @KafkaOutput(name = "event", topic = "users", brokerList="broker:29092") OutputBinding<String< output,
    final ExecutionContext context) {
     context.getLogger().info("Message:" + message);
     output.setValue(message);
     return "{ \"id\": \"" + System.currentTimeMillis() + "\", \"description\": \"" + message + "\" }";
 }
 

Since:

1.4.0

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
java.lang.String	brokerList	Defines the BrokerList.
java.lang.String	name	The variable name used in function.json.
java.lang.String	topic	Defines the Topic.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
com.microsoft.azure.functions.BrokerAuthenticationMode	authenticationMode	SASL mechanism to use for authentication.
java.lang.String	avroSchema	Avro schema for generic record serialization default ""
int	batchSize	Defines the maximum number of messages batched in one MessageSet.
java.lang.String	dataType	Defines how Functions runtime should treat the parameter value.
boolean	enableIdempotence	When set to `true`, the producer will ensure that messages are successfully produced exactly once and in the original produce order.
int	lingerMs	linger.MS property provides the time between batches of messages being sent to cluster.
int	maxMessageBytes	Defines the maximum transmit message size.
int	maxRetries	How many times to retry sending a failing Message.
int	messageTimeoutMs	Local message timeout.
java.lang.String	password	SASL password with the PLAIN and SASL-SCRAM-..
com.microsoft.azure.functions.BrokerProtocol	protocol	Gets or sets the security protocol used to communicate with brokers default is PLAINTEXT
int	requestTimeoutMs	The ack timeout of the producer request in milliseconds.
java.lang.String	schemaRegistryPassword	Password for the Avro Schema Registry default ""
java.lang.String	schemaRegistryUrl	URL for the Avro Schema Registry default ""
java.lang.String	schemaRegistryUsername	Username for the Avro Schema Registry default ""
java.lang.String	sslCaLocation	Path to CA certificate file for verifying the broker's certificate.
java.lang.String	sslCertificateLocation	Path to client's certificate.
java.lang.String	sslKeyLocation	Path to client's private key (PEM) used for authentication.
java.lang.String	sslKeyPassword	Password for client's certificate.
java.lang.String	username	SASL username with the PLAIN and SASL-SCRAM-..

Element Detail

name

java.lang.String name

The variable name used in function.json.

Returns:

The variable name used in function.json.

topic

java.lang.String topic

Defines the Topic.

Returns:

The topic name.

brokerList

java.lang.String brokerList

Defines the BrokerList.

Returns:

The brokerList name string.

dataType

java.lang.String dataType

Defines how Functions runtime should treat the parameter value. Possible values are:

• "" or string: treat it as a string whose value is serialized from the parameter
• binary: treat it as a binary data whose value comes from for example OutputBinding<byte[]<

Returns:

The dataType which will be used by the Functions runtime.

Default:

""

maxMessageBytes

int maxMessageBytes

Defines the maximum transmit message size. Default: 1MB

Returns:

The maximum trnasmit message size.

Default:

1000012

batchSize

int batchSize

Defines the maximum number of messages batched in one MessageSet. default: 10000

Returns:

The maximum number of messages batched in one MessageSet.

Default:

10000

enableIdempotence

boolean enableIdempotence

When set to `true`, the producer will ensure that messages are successfully produced exactly once and in the original produce order. default: false

Returns:

whether idempotence is enabled.

Default:

false

messageTimeoutMs

int messageTimeoutMs

Local message timeout. This value is only enforced locally and limits the time a produced message waits for successful delivery. A time of 0 is infinite. This is the maximum time used to deliver a message (including retries). Delivery error occurs when either the retry count or the message timeout are exceeded. default: 300000

Returns:

The local message timeout.

Default:

300000

requestTimeoutMs

int requestTimeoutMs

The ack timeout of the producer request in milliseconds. default: 5000

Returns:

The ack timeout of the producer request in milliseconds.

Default:

5000

maxRetries

int maxRetries

How many times to retry sending a failing Message. **Note:** default: 2 Retrying may cause reordering unless EnableIdempotence is set to true.

Returns:

The number of the max retries.

See Also:

enableIdempotence()

Default:

2

authenticationMode

com.microsoft.azure.functions.BrokerAuthenticationMode authenticationMode

SASL mechanism to use for authentication. Default: PLAIN

Returns:

The SASL mechanism.

Default:

com.microsoft.azure.functions.BrokerAuthenticationMode.NOTSET

username

java.lang.String username

SASL username with the PLAIN and SASL-SCRAM-.. mechanisms Default: ""

Returns:

The SASL username.

Default:

""

password

java.lang.String password

SASL password with the PLAIN and SASL-SCRAM-.. mechanisms Default is plaintext security.protocol in librdkafka

Returns:

The SASL password.

Default:

""

protocol

com.microsoft.azure.functions.BrokerProtocol protocol

Gets or sets the security protocol used to communicate with brokers default is PLAINTEXT

Returns:

The protocol.

Default:

com.microsoft.azure.functions.BrokerProtocol.NOTSET

sslKeyLocation

java.lang.String sslKeyLocation

Path to client's private key (PEM) used for authentication. Default "" ssl.key.location in librdkafka

Returns:

The ssl key location.

Default:

""

sslCaLocation

java.lang.String sslCaLocation

Path to CA certificate file for verifying the broker's certificate. ssl.ca.location in librdkafka

Returns:

The ssl ca location.

Default:

""

sslCertificateLocation

java.lang.String sslCertificateLocation

Path to client's certificate. ssl.certificate.location in librdkafka

Returns:

The ssl certificate location.

Default:

""

sslKeyPassword

java.lang.String sslKeyPassword

Password for client's certificate. ssl.key.password in librdkafka

Returns:

The ssl key password.

Default:

""

lingerMs

int lingerMs

linger.MS property provides the time between batches of messages being sent to cluster. Larger value allows more batching that results in high throughput.

Returns:

value of linger.ms property.

Default:

5

avroSchema

java.lang.String avroSchema

Avro schema for generic record serialization default ""

Returns:

the avro schema

Default:

""

schemaRegistryUrl

java.lang.String schemaRegistryUrl

URL for the Avro Schema Registry default ""

Returns:

the avro schema registry url

Default:

""

schemaRegistryUsername

java.lang.String schemaRegistryUsername

Username for the Avro Schema Registry default ""

Returns:

the avro schema registry username

Default:

""

schemaRegistryPassword

java.lang.String schemaRegistryPassword

Password for the Avro Schema Registry default ""

Returns:

the avro schema registry password

Default:

""