Setting up the Development Environment

The following sections provide instructions for setting up your development environment for the botoflow.

Prerequisites

To develop applications that use the botoflow, you will need:

• A working Python 2.7 or 3.4+ environment.
• BotoCore (and it's dependencies).
• Dill (required for multiprocessing executor).
• Botoflow.
• An active AWS account signed up for Simple Workflow Service.
• An IAM user with privileges in SWF is needed. Please refer to Amazon IAM SWF for more details, but the inline policy for an existing user could be:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": [
        "swf:*"
      ],
      "Effect": "Allow",
      "Resource": "*"
    }
  ]
}

• Add a SWF domain in your AWS account. This is possible with awscli:

$ aws swf register-domain \
          --name helloworld \
          --description "Helloworld domain" \
          --workflow-execution-retention-period-in-days 7 \
          --region us-east-1

Note: Workflows Types and Activities Types will be automatically registered when initializing a workflow_worker and a activity_worker so there is no need to pre-register these resources.

Developing a Workflow

After you have set up the development environment and configured the AWS account you can start developing workflows with the botoflow. The typical steps involved in developing a workflow are as follows:

1. Define activity and workflow contracts. First, analyze your application requirements and identify the workflow and activities that are needed to fulfill them. For example, in a media processing use case, you may need to download a file, process it, and upload the processed file to an Amazon Simple Storage Service (S3) bucket. For this application, you may define a file processing workflow and activities to download the file, perform processing on it, upload the processed file, and delete files from the local disk.
2. Implement activities and workflows. The workflow implementation provides the business logic, while each activity implements a single logical processing step in the application. The workflow implementation calls the activities.
3. Implement host programs for activity and workflow implementations. After you have implemented your workflow and activities, you need to create host programs. A host program is responsible for getting tasks from Amazon SWF and dispatching them to the appropriate implementation method. AWS Flow Framework provides worker classes that make implementing these host programs trivial.
4. Test your workflow. TODO: botoflow does not yet provide nice testing facilities
5. Deploy the workers. You can now deploy your workers as desired - for example, you can deploy them to instances in the cloud or in your own data centers. Once deployed, the workers start polling Amazon SWF for tasks.
6. Start executions. You can start an execution of your workflow from any program using the workflow definition. You can also use the Amazon SWF console to start and view workflow executions in your Amazon SWF account.

Examples

• Helloworld: examples/helloworld