Usage¶

Cli¶

Run the command line prefect-yaml with the specified configuration file.

For example, the following YAML configuration is located in examples/simple_config.yaml.

metadata:
  output:
    directory: .output

task:
  task_a:
    caller: math:fabs
    parameters:
      - -9.0
    output:
      format: json
  task_b:
    caller: math:sqrt
    parameters:
      - !data task_a
    output:
      directory: null
  task_c:
    caller: math:fsum
    parameters:
      - [!data task_b, 1]

Run the following command to generate all the task outputs to the directory .output in the running directory.

prefect-yaml -c examples/simple_config.yaml

The output directory contains all the task outputs in the specified format.

% tree .output
.output
├── task_a.json
└── task_c.pickle

0 directories, 2 files

The expected behavior is to

run task_a to dump the value fabs(-9.0) to the output directory in JSON format,
run task_b to get the value sqrt(9.0) (from the output of task_a)
run task_c to dump the value fsum([3.0, 1.0]) to the output directory in pickle format.

As the output directory in task_b is overridden as null, the output of task_b is passed to task_c in memory. Also, the output format in task_c is not specified so it is dumped in default format (pickle).

For further details, please see the section configuration in the documentation.

Prefect Deployment¶

It also supports running the flow via prefect deployment.

First build the deployment configuration via command

prefect deployment build prefect_yaml.deployment:prefect_yaml_flow -n prefect_yaml_flow -q regular -i process

Then apply the prefect deployment with its deployment configuration. For example, the above command exports the configuration in default name prefect_yaml_flow-deployment.yaml

prefect deployment apply prefect_yaml_flow-deployment.yaml

For further information about deployment YAML, please refer to prefect official page.