HTTP to Kafka (Deprecated)

The HTTP to Kafka origin listens on an HTTP endpoint and writes the contents of all authorized HTTP POST requests directly to Kafka. However, the HTTP to Kafka origin is now deprecated and will be removed in a future release. We recommend using the HTTP Server origin that can use multiple threads to enable parallel processing of data from multiple HTTP clients.

Use the HTTP to Kafka origin to write large volumes of HTTP POST requests immediately to Kafka without additional processing. To perform processing, you can create a separate pipeline with a Kafka Consumer origin that reads from the Kafka topic.

If you need to process data before writing it to Kafka or need to write to a destination system other than Kafka, use the HTTP Server origin.

You can configure multiple HTTP clients to send data to the HTTP to Kafka origin. Just complete the necessary prerequisites before you configure the origin. Here is an example of the architecture for using the HTTP to Kafka origin:

When you configure HTTP to Kafka, you specify the listening port, Kafka configuration information, maximum message size, and the application ID. You can also configure SSL/TLS properties, including default transport protocols and cipher suites.

You can add Kafka configuration properties and enable Kafka security as needed.

Tip: Data Collector provides several HTTP origins to address different needs. For a quick comparison chart to help you choose the right one, see Comparing HTTP Origins.

Prerequisites

Before you run a pipeline with the HTTP to Kafka origin, configure the following prerequisites:

Configure HTTP clients to send data to the HTTP to Kafka listening port

When you configure the origin, you define a listening port number where the origin listens for data.

To pass data to the pipeline, configure each HTTP client to send data to a URL that includes the listening port number.

Use the following format for the URL:

<http | https>://<sdc_hostname>:<listening_port>/

The URL includes the following components:

<http | https> - Use https for secure HTTP connections.
<sdc_hostname> - The Data Collector host name.
<listening_port> - The port number where the origin listens for data.

For example: https://localhost:8000/

Include the application ID in request headers

When you configure the origin, you define an application ID. All messages sent to the HTTP to Kafka origin must include the application ID in the request header.

Add the following information to the request header for all HTTP POST requests that you want the origin to process:

X-SDC-APPLICATION-ID: <applicationID>

For example:

X-SDC-APPLICATION-ID: sdc_http2kafka

Pipeline Configuration

When you use an HTTP to Kafka origin in a pipeline, connect the origin to a Trash destination.

The HTTP to Kafka origin writes records directly to Kafka. The origin does not pass records to its output port, so you cannot perform additional processing or write the data to other destination systems.

However, since a pipeline requires a destination, you should connect the origin to the Trash destination to satisfy pipeline validation requirements.

A pipeline with the HTTP to Kafka origin should look like this:

Kafka Maximum Message Size

Configure the Kafka maximum message size in the origin in relationship to the equivalent Kafka cluster property. The origin property should be equal to or less than the Kafka cluster property.

The HTTP to Kafka origin writes the contents of each HTTP POST request to Kafka as a single message. So the maximum message size configured in the origin determines the maximum size of the HTTP request and limits the size of messages written to Kafka.

To ensure all messages are written to Kafka, set the origin property to equal to or less than the Kafka cluster property. Attempts to write messages larger than the specified Kafka cluster property fail, returning an HTTP 500 error to the originating HTTP client.

For example, if the Kafka cluster allows a maximum message size of 2 MB, configure the Maximum Message Size property in the origin to 2 MB or less to avoid HTTP 500 errors for larger messages.

By default, the maximum message size in a Kafka cluster is 1 MB, as defined by the message.max.bytes property.

Kafka Security

You can configure the HTTP to Kafka origin to connect securely to Kafka through SSL/TLS, Kerberos, or both. For more information about the methods and details on how to configure each method, see Security in Kafka Stages.

Configuring an HTTP to Kafka Origin

Configure an HTTP to Kafka origin to write high volumes of HTTP POST requests directly to Kafka.

In the Properties panel, on the General tab, configure the following properties:

General Property	Description
Name	Stage name.
Description	Optional description.
Stage Library	Library version that you want to use.
On Record Error	Error record handling for the stage: Discard - Discards the record. Send to Error - Sends the record to the pipeline for error handling. Stop Pipeline - Stops the pipeline. Not valid for cluster pipelines.

On the Kafka tab, configure the following properties:

Kafka Property	Description
Connection	Existing connection that defines the information required to connect to an external system. To connect to an external system, you can select an existing connection that contains the details, or you can directly enter the details in the pipeline. When you select an existing connection, Pipeline Designer hides other properties so that you cannot directly enter connection details in the pipeline.
Broker URI	Comma-separated list of connection strings for the Kafka brokers. Use the following format for each broker: `<host>:<port>`. To ensure a pipeline can connect to Kafka in case a specified broker goes down, list as many brokers as possible.
Topic	Kafka topic to read.
Max Message Size (KB)	Maximum size of the message to be written to Kafka. To avoid HTTP 500 errors, configure this property to equal to or less than the equivalent Kafka cluster property.
Kafka Configuration	Additional Kafka configuration properties to use. Using simple or bulk edit mode, click the Add icon to add properties. Define the Kafka property name and value. Use the property names and values as expected by Kafka.
Kafka Message Key	Passes message key values stored in a record header attribute to Kafka as message keys. Enter an expression that specifies the attribute where the message keys are stored. To pass string message keys stored in an attribute, use: `${record:attribute('<message key attribute name>'}` To pass Avro message keys stored in an attribute, use: `${avro:decode(record:attribute('avroKeySchema'),base64:decodeBytes(record:attribute('<messsage key attribute name')))}` For more information, about working with Kafka message keys, see Kafka Message Keys.

On the Security tab, configure the security properties to enable the stage to securely connect to Kafka.

For information about the security options and additional steps required to enable security, see Security in Kafka Stages.

On the HTTP tab, configure the following properties:

HTTP Property	Description
HTTP Listening Port	Listening port for the HTTP to Kafka origin. The port number must be included in the URL that the HTTP client uses to pass data. For more information, see Prerequisites.
Application ID	Application ID used to pass requests to the HTTP to Kafka origin. The Application ID must be included in the header of the HTTP POST request. For more information, see Prerequisites.
Max Concurrent Requests	Maximum number of HTTP clients allowed to send messages to the origin at one time. If the origin reaches the configured maximum and receives additional requests from different clients, it processes those requests as slots become available.
Application ID in URL	Enables reading the application ID from the URL. Use when HTTP clients include the application ID in the URL query parameter instead of in the request header.

To use SSL/TLS, click the TLS tab and configure the following properties:

TLS Property	Description
Use TLS	Enables the use of TLS.
Use Remote Keystore	Enables loading the contents of the keystore from a remote credential store or from values entered in the stage properties. For more information, see Remote Keystore and Truststore.
Private Key	Private key used in the remote keystore. Enter a credential function that returns the key or enter the contents of the key.
Certificate Chain	Each PEM certificate used in the remote keystore. Enter a credential function that returns the certificate or enter the contents of the certificate. Using simple or bulk edit mode, click the Add icon to add additional certificates.
Keystore File	Path to the local keystore file. Enter an absolute path to the file or a path relative to the Data Collector resources directory: $SDC_RESOURCES. For more information about environment variables, see Data Collector Environment Configuration in the Data Collector documentation. By default, no keystore is used.
Keystore Type	Type of keystore to use. Use one of the following types: Java Keystore File (JKS) PKCS #12 (p12 file) Default is Java Keystore File (JKS).
Keystore Password	Password to the keystore file. A password is optional, but recommended. Tip: To secure sensitive information such as passwords, you can use runtime resources or credential stores. For more information about credential stores, see Credential Stores in the Data Collector documentation.
Keystore Key Algorithm	Algorithm to manage the keystore. Default is SunX509.
Use Default Protocols	Uses the default TLSv1.2 transport layer security (TLS) protocol. To use a different protocol, clear this option.
Transport Protocols	TLS protocols to use. To use a protocol other than the default TLSv1.2, click the Add icon and enter the protocol name. You can use simple or bulk edit mode to add protocols. Note: Older protocols are not as secure as TLSv1.2.
Use Default Cipher Suites	Uses a default cipher suite for the SSL/TLS handshake. To use a different cipher suite, clear this option.
Cipher Suites	Cipher suites to use. To use a cipher suite that is not a part of the default set, click the Add icon and enter the name of the cipher suite. You can use simple or bulk edit mode to add cipher suites. Enter the Java Secure Socket Extension (JSSE) name for the additional cipher suites that you want to use.