@financialforcedev/orizuru-transport-kafka
Version:
Kafka transport layer for the orizuru package
77 lines (65 loc) • 2.75 kB
JavaScript
/**
* Copyright (c) 2017, FinancialForce.com, inc
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the FinancialForce.com, inc nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**/
;
const
_ = require('lodash'),
Kafka = require('no-kafka'),
validateHandler = (handler) => () => {
if (!_.isFunction(handler)) {
throw new Error('Handler is not a Function.');
}
},
handlerWrapper = (handler, consumer) => (messageSet, topic, partition) => {
return messageSet.reduce((chain, record) => {
return chain
.then(() => handler(record.message.value))
.then(() => consumer.commitOffset({
topic: topic,
partition: partition,
offset: record.offset
}));
}, Promise.resolve());
},
createConsumer = (eventName, config) => () => {
return new Kafka.GroupConsumer(Object.assign({
groupId: eventName,
startingOffset: Kafka.EARLIEST_OFFSET
}, config));
},
initialiseConsumer = (eventName, handler) => (consumer) => {
return consumer.init([{
subscriptions: [eventName],
handler: handlerWrapper(handler, consumer)
}]);
};
module.exports = {
subscribe: ({ eventName, handler, config }) => {
return Promise.resolve()
.then(validateHandler(handler))
.then(createConsumer(eventName, config))
.then(initialiseConsumer(eventName, handler));
}
};