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Caching Task Outputs

Some task types support caching, which saves task outputs for reuse in subsequent task executions. This feature can be configured in the task configuration.

To cache task output:

  1. In your Orkes Conductor cluster, go to Definitions > Workflow and select a workflow.
  2. In the visual workflow editor, select a task.
  3. Turn on the Cache output toggle and enter the ttlInSecond and key. Refer to Configuration for more information on the parameters.

Configuring cache output in UI.

Configuration​

Configure the following parameters to enable task caching.

ParameterDescriptionRequired/ Optional
cacheConfig. ttlInSecondThe time to live in seconds, which is the duration for the output to be cached.Required.
cacheConfig. keyThe cache key is a unique identifier for the cached output and must be constructed exclusively from the task’s input parameters.

It can be a string concatenation that contains the task’s input keys, such as ${uri}-${method} or re_${uri}_${method}.		Required.

Example

Here is a straightforward example of task caching using the task’s input keys, url and mediaType.

// workflow definition
{
  ...
  "tasks": [
    {
      "name": "get_document",
      "taskReferenceName": "get_document_ref",
      "inputParameters": {
        "url": "${workflow.input.url}",
        "mediaType": "application/pdf"
      },
      "type": "GET_DOCUMENT",
      "cacheConfig": {
        "key": "${url}-${mediaType}",
        "ttlInSecond": 60
      }
    }
  ],
  "inputParameters": [
    "url"
  ],
  "outputParameters": {},
  "schemaVersion": 2
}

In advanced cases where other parameters (such as workflow inputs or global variables) must be included in the cacheConfig.key, you must pass these parameters into the task’s inputParameters first.

{
  ...
  "tasks": [
    {
      "name": "get_document",
      "taskReferenceName": "get_document_ref",
      "inputParameters": {
        "url": "${workflow.input.url}",
        "mediaType": "application/pdf",
        "id": "${workflow.input.userId}"
      },
      "type": "GET_DOCUMENT",
      "cacheConfig": {
        "key": "${url}-${id}",
        "ttlInSecond": 60
      }
    }
  ],
  "inputParameters": [
    "url",
    "userId"
  ],
  "outputParameters": {},
  "schemaVersion": 2
}

Example of passing as a variable through the Set Variable task:

// workflow definition
{
  ...
  "tasks": [
    {
      "name": "set_variable",
      "taskReferenceName": "set_variable_ref",
      "type": "SET_VARIABLE",
      "inputParameters": {
        "region": "${workflow.input.location}"
      }
    },
    {
      "name": "http",
      "taskReferenceName": "http_ref",
      "inputParameters": {
        "uri": "https://orkes-api-tester.orkesconductor.com/api",
        "method": "GET",
        "accept": "application/json",
        "contentType": "application/json",
        "encode": true,
        "body": {
          "cacheKey": "${workflow.variables.region}",
          "someUnrelated": "Some-val-qvw4g"
        }
      },
      "type": "HTTP",
      "cacheConfig": {
        "key": "re_${body.cacheKey}",
        "ttlInSecond": 60
      }
    }
  ],
  "inputParameters": [
    "location"
  ],
  "outputParameters": {},
  "schemaVersion": 2
}

Task behavior with caching​

Before a task is scheduled, the server checks if there is cached output for the given task definition name by matching the cache key. If a match is found, the task is not scheduled, and the cached output is used to complete it.

If no cached output is found, the task is scheduled as usual. When the task is completed successfully, the output is cached against the cache key for the duration specified.

Supported tasks​

Caching is currently supported for the following task types: