Rocoto Example - TerrenceMcGuinness-NOAA/global-workflow GitHub Wiki

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The code in

rocoto.py

is responsible for generating a Rocoto XML workflow file from your workflow configuration defined using the CROW framework. Here's how the code works:

1. Imports and Dependencies:
   • The code imports essential modules and classes needed for workflow definition and manipulation.
   • Key imports include classes like Suite, Task, Family, and various dependency classes such as AndDependency, OrDependency, and NotDependency.
   • It also imports the

simplify

function from crow.metascheduler.algebra to handle logical dependency simplification.

2. Custom Exceptions:

   • The code defines custom exception classes:

RocotoConfigError

: General exception for Rocoto configuration errors. -

SelfReferentialDependency

: Indicates a self-referential dependency error in the workflow.

3. Constants and Mappings:

_KEY_WARNINGS

: A dictionary to map potential misspelled keys to suggestions. -

_REQUIRED_KEYS

: Specifies required configuration keys and their descriptions. -

_ROCOTO_STATE_MAP

: Maps internal state constants (

COMPLETED

,

FAILED

,

RUNNING

) to Rocoto's expected state strings (SUCCEEDED, DEAD,

RUNNING

). -

_ROCOTO_DEP_TAG

: Maps dependency types to Rocoto XML tags (and, or, not). -

_ZERO_DT

: Represents a zero

timedelta

for time comparisons.

4. **Function

has_conditions

**: - The

has_conditions

function checks if a given item (such as a task or dependency) meets certain conditions: - It checks if the item has a 'Complete' dependency. - It checks if the item's alarm name matches a specified test alarm name. - This function is used internally to determine how to represent dependencies and conditions when generating the Rocoto XML elements.

5. Workflow Translation to Rocoto XML:
   • Workflow Representation:
     • In your workflow, you define jobs, tasks, families, and their dependencies using CROW's configuration classes.
     • These classes capture the logical structure and dependencies of your workflow.
   • Conversion Process:
     • The

rocoto.py

code traverses the workflow configuration and converts it into Rocoto-compatible XML. - It handles tasks, families, cycles, and dependencies, mapping them to Rocoto's XML schema. - Logical dependencies are simplified using the

simplify

function to optimize the workflow execution logic. - Handling Dependencies: - Dependencies such as AND, OR, and NOT are mapped using the

_ROCOTO_DEP_TAG

dictionary. - State dependencies (e.g., task completion) are converted using the

_ROCOTO_STATE_MAP

.

6. Classes and Functions:

   • ToRocoto Class:
     • Although not fully shown in your excerpt, this class likely encapsulates methods to generate the Rocoto XML elements from the workflow configuration.
     • It would manage the overall conversion process, building the XML tree and writing it to a file.
   • to_rocoto Function:
     • Acts as an entry point to initiate the conversion.
     • It would take the workflow configuration and output the Rocoto XML workflow.

7. Generating the Rocoto Workflow File:

   • The final Rocoto XML file generated by this code defines your workflow in a format that Rocoto can execute.
   • This file includes definitions for cycles, tasks, dependencies, and resources.

In Summary:

• The

rocoto.py

code transforms your workflow configuration defined using CROW into a Rocoto-compatible XML file.

• It ensures that tasks and their dependencies are correctly represented, allowing Rocoto to schedule and execute them according to your specifications.
• By handling complex dependencies and workflow structures, it enables seamless integration between your configuration and Rocoto's execution engine.

Related Components:

• Workflow Configuration Classes: Suite, Task, Family
• Dependency Handling: Logical dependencies like AndDependency, OrDependency, and their simplification using simplify

Example Usage:

Suppose you have defined your workflow using CROW's configuration classes:

from crow.config import Suite, Task, Family, AndDependency

# Define tasks and dependencies
task_a = Task(name='TaskA')
task_b = Task(name='TaskB', dependencies=AndDependency(task_a))
suite = Suite(name='MyWorkflow', tasks=[task_a, task_b])

# Convert to Rocoto XML
from crow.rocoto import to_rocoto
rocoto_xml = to_rocoto(suite)

Using the to_rocoto function, your workflow is converted into a Rocoto XML file that can be executed by Rocoto to manage the tasks' scheduling and execution based on the defined dependencies.

Final Notes:

• This integration allows you to define complex workflows programmatically and leverage Rocoto's capabilities for high-throughput job scheduling.
• The

rocoto.py

module is a critical bridge between your workflow definitions and the execution layer provided by Rocoto.

Let me know if you need further clarification or assistance with specific parts of the code!