Community contributed system tasks

Published Artifacts

Group: com.netflix.conductor

Published Artifact	Description
conductor-task	Community contributed tasks

Note: If you are using condutor-contribs as a dependency, the task module is already included, you do not need to include it separately.

JsonJQTransform

JSON_JQ_TRANSFORM_TASK is a System task that allows processing of JSON data that is supplied to the task, by using the popular JQ processing tool’s query expression language.

"type" : "JSON_JQ_TRANSFORM_TASK"

Check the JQ Manual, and the JQ Playground for more information on JQ

Use Cases

JSON is a popular format of choice for data-interchange. It is widely used in web and server applications, document storage, API I/O etc. It’s also used within Conductor to define workflow and task definitions and passing data and state between tasks and workflows. This makes a tool like JQ a natural fit for processing task related data. Some common usages within Conductor includes, working with HTTP task, JOIN tasks or standalone tasks that try to transform data from the output of one task to the input of another.

Configuration

Here is an example of a JSON_JQ_TRANSFORM task. The inputParameters attribute is expected to have a value object that has the following

1. A list of key value pair objects denoted key1/value1, key2/value2 in the example below. Note the key1/value1 are arbitrary names used in this example.

2. A key with the name queryExpression, whose value is a JQ expression. The expression will operate on the value of the inputParameters attribute. In the example below, the inputParameters has 2 inner objects named by attributes key1 and key2, each of which has an object that is named value1 and value2. They have an associated array of strings as values, "a", "b" and "c", "d". The expression key3: (.key1.value1 + .key2.value2) concats the 2 string arrays into a single array against an attribute named key3

{
  "name": "jq_example_task",
  "taskReferenceName": "my_jq_example_task",
  "type": "JSON_JQ_TRANSFORM",
  "inputParameters": {
    "key1": {
      "value1": [
        "a",
        "b"
      ]
    },
    "key2": {
      "value2": [
        "c",
        "d"
      ]
    },
    "queryExpression": "{ key3: (.key1.value1 + .key2.value2) }"
  }
}

The execution of this example task above will provide the following output. The resultList attribute stores the full list of the queryExpression result. The result attribute stores the first element of the resultList. An optional error attribute along with a string message will be returned if there was an error processing the query expression.

{
  "result": {
    "key3": [
      "a",
      "b",
      "c",
      "d"
    ]
  },
  "resultList": [
    {
      "key3": [
        "a",
        "b",
        "c",
        "d"
      ]
    }
  ]
}

Input Configuration

Attribute	Description
name	Task Name. A unique name that is descriptive of the task function
taskReferenceName	Task Reference Name. A unique reference to this task. There can be multiple references of a task within the same workflow definition
type	Task Type. In this case, JSON_JQ_TRANSFORM
inputParameters	The input parameters that will be supplied to this task. The parameters will be a JSON object of atleast 2 attributes, one of which will be called queryExpression. The others are user named attributes. These attributes will be accessible by the JQ query processor
inputParameters/user-defined-key(s)	User defined key(s) along with values.
inputParameters/queryExpression	A JQ query expression

Output Configuration

Attribute	Description
result	The first results returned by the JQ expression
resultList	A List of results returned by the JQ expression
error	An optional error message, indicating that the JQ query failed processing

Kafka Publish Task

A Kafka Publish task is used to push messages to another microservice via Kafka.

"type" : "KAFKA_PUBLISH"

Examples

Sample Task

{
  "name": "call_kafka",
  "taskReferenceName": "call_kafka",
  "inputParameters": {
    "kafka_request": {
      "topic": "userTopic",
      "value": "Message to publish",
      "bootStrapServers": "localhost:9092",
      "headers": {
    "x-Auth":"Auth-key"    
      },
      "key": "123",
      "keySerializer": "org.apache.kafka.common.serialization.IntegerSerializer"
    }
  },
  "type": "KAFKA_PUBLISH"
}

The task expects an input parameter named "kafka_request" as part of the task's input with the following details:

1. "bootStrapServers" - bootStrapServers for connecting to given kafka.
2. "key" - Key to be published.
3. "keySerializer" - Serializer used for serializing the key published to kafka. One of the following can be set : a. org.apache.kafka.common.serialization.IntegerSerializer b. org.apache.kafka.common.serialization.LongSerializer c. org.apache.kafka.common.serialization.StringSerializer. Default is String serializer.
4. "value" - Value published to kafka
5. "requestTimeoutMs" - Request timeout while publishing to kafka. If this value is not given the value is read from the property kafka.publish.request.timeout.ms. If the property is not set the value defaults to 100 ms.
6. "maxBlockMs" - maxBlockMs while publishing to kafka. If this value is not given the value is read from the property kafka.publish.max.block.ms. If the property is not set the value defaults to 500 ms.
7. "headers" - A map of additional kafka headers to be sent along with the request.
8. "topic" - Topic to publish.

The producer created in the kafka task is cached. By default the cache size is 10 and expiry time is 120000 ms. To change the defaults following can be modified kafka.publish.producer.cache.size, kafka.publish.producer.cache.time.ms respectively.

Kafka Task Output

Task status transitions to COMPLETED.

The task is marked as FAILED if the message could not be published to the Kafka queue.