conductor-python 1.0.4

Netflix Conductor Python SDK

Conductor Python

Software Development Kit for Netflix Conductor, written on and providing support for Python.

Quick Guide

In case you have already set up Conductor and got it running, you can quickly onboard to it with these steps:

1. Install Conductor Python SDK from pypi:

   $ python3 -m pip install conductor-python
   

2. Run Conductor Python SDK:

   $ python3 -m conductor.client
   

Custom worker

In order to create a custom python worker, it should inherit from WorkerInterface and instantiate a TaskHandler object.

Here is an example:

• Worker:
  • Details:

    from conductor.client.worker.worker_interface import WorkerInterface
    import multiprocessing
    import socket
    
    
    class SimplePythonWorker(WorkerInterface):
        def get_task_definition_name(self):
            return 'simple_python_worker'
    
        def execute(self, task_result):
            task_result.add_output_data('hostname', socket.gethostname())
            task_result.add_output_data('cpu_cores', multiprocessing.cpu_count())
            return task_result
    
        def get_polling_interval(self):
            return 3
    

    • Name: simple_python_worker
    • Input: None
    • Output: [hostname, cpu_cores]
    • Polling Interval: 3s
• Main:

  from conductor.client.automator.task_handler import TaskHandler
  from conductor.client.worker.simple_python_worker import SimplePythonWorker
  
  
  def main():
      workers = [SimplePythonWorker()] * 1
      with TaskHandler(workers) as parallel_task_handler:
          parallel_task_handler.start()
  
  
  if __name__ == '__main__':
      main()
  

  • Single worker within TaskHandler

Full installation guide

Set up Conductor

1. Clone Netflix Conductor repository: https://github.com/Netflix/conductor

   $ git clone https://github.com/Netflix/conductor.git
   

2. Start Conductor server by running this command at the repo root folder (/conductor):

   $ ./gradlew bootRun
   

3. Start Conductor UI by running this command at the UI folder (/conductor/ui):

   $ yarn install
   $ yarn run start
   

You should be able to access:

• Conductor API:
  • http://localhost:8080/swagger-ui/index.html
• Conductor UI:
  • http://localhost:5000

Run

Create new task

You need to define a Task within Conductor that your Python Worker is capable of running.

Make a POST request to /metadata/taskdefs endpoint at your conductor server.

• URL example: http://localhost:8080/api/metadata/taskdefs
• Task Definition example:

  [
    {
      "name": "simple_python_worker",
      "description": "Simple Python Worker",
      "retryCount": 3,
      "retryLogic": "FIXED",
      "retryDelaySeconds": 10,
      "timeoutSeconds": 300,
      "timeoutPolicy": "TIME_OUT_WF",
      "responseTimeoutSeconds": 180,
      "ownerEmail": "[e-mail]"
    }
  ]
  

• Command example:

  $ curl -X 'POST' \
      'http://localhost:8080/api/metadata/taskdefs' \
      -H 'accept: */*' \
      -H 'Content-Type: application/json' \
      -d '[
      {
        "name": "simple_python_worker",
        "description": "Simple Python Worker",
        "retryCount": 3,
        "retryLogic": "FIXED",
        "retryDelaySeconds": 10,
        "timeoutSeconds": 300,
        "timeoutPolicy": "TIME_OUT_WF",
        "responseTimeoutSeconds": 180,
        "ownerEmail": "[e-mail]"
      }
    ]'
  

Create new workflow

You need to define a Workflow within Conductor that contains the Task you had just defined.

Make a POST request to /metadata/workflow endpoint at your conductor server.

• URL example: http://localhost:8080/api/metadata/workflow
• Workflow Definition example:

  {
    "createTime": 1634021619147,
    "updateTime": 1630694890267,
    "name": "simple_workflow_with_python_worker",
    "description": "Simple Workflow with Python Worker",
    "version": 1,
    "tasks": [
      {
        "name": "simple_python_worker",
        "taskReferenceName": "simple_python_worker_ref_1",
        "inputParameters": {},
        "type": "SIMPLE"
      }
    ],
    "inputParameters": [],
    "outputParameters": {
      "workerOutput": "${simple_python_worker_ref_1.output}"
    },
    "schemaVersion": 2,
    "restartable": true,
    "ownerEmail": "[e-mail]",
    "timeoutPolicy": "ALERT_ONLY",
    "timeoutSeconds": 0
  }
  

• Command example:

  $ curl -X 'POST' \
      'http://localhost:8080/api/metadata/workflow' \
      -H 'accept: */*' \
      -H 'Content-Type: application/json' \
      -d '{
      "createTime": 1634021619147,
      "updateTime": 1630694890267,
      "name": "simple_workflow_with_python_worker",
      "description": "Simple Workflow with Python Worker",
      "version": 1,
      "tasks": [
        {
          "name": "simple_python_worker",
          "taskReferenceName": "simple_python_worker_ref_1",
          "inputParameters": {},
          "type": "SIMPLE"
        }
      ],
      "inputParameters": [],
      "outputParameters": {
        "workerOutput": "${simple_python_worker_ref_1.output}"
      },
      "schemaVersion": 2,
      "restartable": true,
      "ownerEmail": "[e-mail]",
      "timeoutPolicy": "ALERT_ONLY",
      "timeoutSeconds": 0
    }'
  

Start new workflow

Now that you have defined a Task and a Workflow within Conductor, you should be able to run it.

Make a POST request to /workflow/{name} endpoint at your conductor server.

• URL example: http://localhost:8080/api/workflow/simple_workflow_with_python_worker
  • Priority should be empty
  • Request body should be empty, like: {}
• Command example:

  $ curl -X 'POST' \
      'http://localhost:8080/api/workflow/simple_workflow_with_python_worker' \
      -H 'accept: text/plain' \
      -H 'Content-Type: application/json' \
      -d '{}'
  

• Create a bunch of workflows:

  $ export CREATE_WORKFLOW_SHORTCUT="curl -X 'POST' \
      'http://localhost:8080/api/workflow/simple_workflow_with_python_worker' \
      -H 'accept: text/plain' \
      -H 'Content-Type: application/json' \
      -d '{}' \
      -s"
  
  $ for idx in {1..100}; do \
      echo "Creating workflow ${idx}"; \
      workflow_id=$(eval "${CREATE_WORKFLOW_SHORTCUT}"); \
      echo "workflow_id=${workflow_id}"; \
    done
  

  • Expected output example:

    Creating workflow 1
    workflow_id=6dd2c86b-5ce6-487a-9a65-632139da1345
    Creating workflow 2
    workflow_id=b0ddfdcf-0c4a-4fd3-892c-97fc38c46d63
    ...
    

You should receive a Workflow ID at the Response body

• Workflow ID example: 8ff0bc06-4413-4c94-b27a-b3210412a914

See workflow execution

Now you must be able to see its execution through the UI.

• URL:
  • prefix: http://localhost:5001/execution
  • suffix: ${workflow_id}
• Example: http://localhost:5001/execution/8ff0bc06-4413-4c94-b27a-b3210412a914