Stage Implementation Details

In order to create a staged script, you need to create your own class that extends the StagedScript base class.

from staged_script import StagedScript

class MyScript(StagedScript):
    ...

You can then define a method as a conceptual stage by using the StagedScript.stage() decorator.

from staged_script import StagedScript

class MyScript(StagedScript):

    @StagedScript.stage("stage-name", "Stage heading")
    def do_the_thing(self) -> None:
        ...

The do_the_thing() method defines what actually gets run during the Stage Body from The Conceptual Stage. The decorator handles automatically running methods for all the other phases of the stage.

Each phase has a default implementation provided by the StagedScript class. As a subclass developer, you can either use the default implementation as-is, or you can override or extend it in your subclasses. Additionally, phase implementations can be customized on a stage-by-stage basis, in case certain things need to be done for some, but not all, stages. Because of this added flexibility, the complete stage control flow diagram is as follows (where the nodes in the graph are referring to method names, and STAGE_NAME would be replaced with the name of the stage you’re customizing):

%%{init: {"theme": "neutral"}}%% flowchart TD classDef style_plain fill:#ddd,stroke:#999 classDef style_pre_stage fill:#fbb,stroke:#b77 classDef style_begin_stage fill:#ede,stroke:#a9a classDef style_end_stage fill:#dfe,stroke:#9ba classDef style_post_stage fill:#fdc,stroke:#b98 classDef style_skip_stage fill:#def,stroke:#9ab classDef style_retry_stage fill:#ffc,stroke:#bb8 linkStyle default color:#000 entry[stage decorator entry]:::style_plain pre_q{{_run_pre_stage_actions_STAGE_NAME exists?}}:::style_pre_stage pre_custom(_run_pre_stage_actions_STAGE_NAME):::style_pre_stage pre(_run_pre_stage_actions):::style_pre_stage begin_q{{_begin_stage_STAGE_NAME exists?}}:::style_begin_stage begin_custom(_begin_stage_STAGE_NAME):::style_begin_stage begin(_begin_stage):::style_begin_stage execute_q{{execute stage?}}:::style_plain run(run stage method):::style_plain skip_q{{_skip_stage_STAGE_NAME exists?}}:::style_skip_stage skip_custom(_skip_stage_STAGE_NAME):::style_skip_stage skip(_skip_stage):::style_skip_stage end_q{{_end_stage_STAGE_NAME exists?}}:::style_end_stage end_custom(_end_stage_STAGE_NAME):::style_end_stage end_stage(_end_stage):::style_end_stage retry_q{{retry stage?}}:::style_retry_stage retry_error_q{{retry error?}}:::style_retry_stage retry_error_handler_q{{_handle_stage_retry_error_STAGE_NAME exists?}}:::style_retry_stage handle_retry_error_custom(_handle_stage_retry_error_STAGE_NAME):::style_retry_stage handle_retry_error(_handle_stage_retry_error):::style_retry_stage retry_actions_q{{_prepare_to_retry_stage_STAGE_NAME exists?}}:::style_retry_stage retry_actions_custom(_prepare_to_retry_stage_STAGE_NAME):::style_retry_stage retry_actions(_prepare_to_retry_stage):::style_retry_stage post_q{{_run_post_stage_actions_STAGE_NAME exists?}}:::style_post_stage post_custom(_run_post_stage_actions_STAGE_NAME):::style_post_stage post(_run_post_stage_actions):::style_post_stage exit[stage decorator exit]:::style_plain entry --> pre_q pre_q -- Yes --> pre_custom pre_q -- No --> pre pre_custom --> begin_q pre --> begin_q begin_q -- Yes --> begin_custom begin_q -- No --> begin begin_custom --> execute_q begin --> execute_q execute_q -- Yes --> run execute_q -- No --> skip_q skip_q -- Yes --> skip_custom skip_q -- No --> skip run --> end_q skip_custom --> end_q skip --> end_q end_q -- Yes --> end_custom end_q -- No --> end_stage end_custom --> retry_q end_stage --> retry_q retry_q -- No --> retry_error_q retry_error_q -- Yes --> retry_error_handler_q retry_error_handler_q -- Yes --> handle_retry_error_custom retry_error_handler_q -- No --> handle_retry_error handle_retry_error_custom --> post_q handle_retry_error --> post_q retry_error_q -- No --> post_q post_q -- Yes --> post_custom post_q -- No --> post post_custom --> exit post --> exit retry_q -- Yes --> retry_actions_q retry_actions_q -- Yes --> retry_actions_custom retry_actions_q -- No --> retry_actions retry_actions_custom --> begin_q retry_actions --> begin_q

Note

You can zoom and pan in the image above.