AGX: Standardizing Execution Layer Nomenclature

In the ever-evolving world of distributed systems and workflow management, clear and consistent terminology is paramount. This article delves into the recent efforts to align AGX's nomenclature with the authoritative standards defined in docs/EXECUTION-LAYERS.md. This alignment is not merely a cosmetic change; it's a fundamental step towards clarifying the roles and interactions between different components, particularly AGX, AGQ, and AGW, and refining how execution requests are submitted and managed. We'll explore the nuances of this transition, focusing on the plan.submit and action.submit verbs and the adoption of a five-layer model: Task, Plan, Job, Action, and Workflow.

Understanding the Five-Layer Execution Model

The cornerstone of this nomenclature update is the adoption of a standardized five-layer model. This model provides a clear hierarchy for understanding the execution process. At the most granular level, we have Tasks. A Task represents the smallest, indivisible unit of work that can be executed. Think of it as a single command or a specific operation. Building upon Tasks, we have Plans. A Plan is a collection of Tasks, defining a specific sequence or dependency graph for their execution. It’s the blueprint for a particular type of work. Moving up the hierarchy, a Job represents the actual execution of a Plan. When a Plan is submitted for execution, it becomes a Job. This is where the concept of submission truly comes into play. AGX defines Plans and Actions, and then submits them to AGQ. AGQ, in turn, manages the execution of these Plans as Jobs, distributing them across available workers on AGW. An Action, in this new model, is a higher-level concept that can encompass the definition and submission of one or more Jobs based on a common Plan. This is particularly useful when you need to run the same Plan with different inputs, effectively creating a fan-out of Jobs. Finally, a Workflow represents a collection of Actions, defining a broader orchestration of work, potentially spanning multiple Plans and Actions. By adopting this structured model, we ensure that each component has a well-defined responsibility and that the flow of execution is easily traceable from the initial request to the final execution.

This five-layer model is critical for achieving clarity and maintainability within the AGX ecosystem. Previously, terms like 'Job' might have been used ambiguously, leading to confusion about whether it referred to the definition of work or its actual execution. The new model explicitly separates these concepts. A Plan is the definition, the recipe, while a Job is the instance of that recipe being cooked. This distinction is crucial for understanding how AGX interacts with AGQ and AGW. AGX, acting as the orchestrator and client, defines Plans and Actions. It then submits these to AGQ using specific verbs. The core requirement is to align these submission verbs with the established nomenclature. For plan.submit, AGX will send a single Job envelope, representing the execution of a specific Plan. For action.submit, AGX can define an Action that will result in the fan-out of multiple Jobs. This is invaluable for batch processing scenarios where the same Plan needs to be executed with a variety of different inputs. AGX defines the overarching Action, and AGQ is responsible for creating and managing the individual Jobs that stem from it. AGW, the execution engine, then treats these Jobs as the execution of a Plan, with each worker typically handling one Job at a time. Within a Job, the individual steps are executed as Tasks. This clear delineation of responsibilities ensures that each component plays its part effectively and that the overall workflow is robust and predictable. The goal is to ensure that AGX client and CLI help documentation accurately reflect these canonical names, moving away from ambiguous or outdated terms and providing users with a consistent understanding of the system's capabilities. This not only simplifies onboarding for new users but also reduces the cognitive load for experienced ones, fostering a more productive development environment. Furthermore, the ability for AGX to monitor Jobs across multiple AGWs is a key requirement, ensuring that the system provides visibility into the status of all submitted work, regardless of where it is being executed. This comprehensive approach to nomenclature and submission semantics is vital for the scalability and reliability of the AGX platform.

Refining Submission Verbs: plan.submit vs. action.submit

One of the most significant aspects of this nomenclature alignment involves the refinement of submission verbs. The goal is to introduce clear, distinct semantics for submitting execution requests, moving from a potentially monolithic approach to a more flexible and powerful one. The two primary verbs we are focusing on are plan.submit and action.submit. Understanding the difference and the intended use case for each is crucial for effectively leveraging AGX's capabilities. The plan.submit verb is intended for scenarios where you want to execute a specific Plan once. It represents a straightforward request to AGQ to instantiate and run a Job based on a predefined Plan. This is akin to saying, "Execute this specific recipe now." The 'current job envelope' mentioned in the requirements refers to the structure of the submission for this verb, where AGX sends the necessary information for AGQ to create and manage a single Job derived directly from the specified Plan. This is the foundational submission method for executing individual workflows or tasks defined by a Plan.

In contrast, the action.submit verb is designed for more complex, batch-oriented scenarios. It allows AGX to define an Action that, when submitted, results in the creation of multiple Jobs. This is achieved by taking a single Plan and applying it to a set of different inputs. Think of it as saying, "Execute this recipe multiple times, each time with a different set of ingredients." AGX defines the Action, which encapsulates the Plan and the variations in inputs. AGX then submits this Action to AGQ, which is responsible for the 'fan-out' – creating a separate Job for each input variation. This is incredibly powerful for tasks like batch data processing, parallel simulations, or any situation where the same logical operation needs to be performed on a large dataset or collection of parameters. The action.submit verb simplifies the submission process for these scenarios, as AGX doesn't need to individually submit each Job. Instead, it defines the overarching Action, and AGQ handles the creation and management of the resulting individual Jobs. This not only reduces the burden on the AGX client but also allows for more efficient communication with AGQ. Crucially, the specific RESP (Representational State Transfer) verbs and the associated schemas for these submissions need to be confirmed with AGQ to ensure seamless integration. This collaborative confirmation ensures that both systems understand and correctly process the submitted requests, maintaining the integrity and efficiency of the execution pipeline. The clarity brought by these distinct submission verbs ensures that users can accurately express their intent, whether it's a single execution of a Plan or a multi-instance execution driven by an Action.

Updating Terminology and Documentation

Beyond the core submission mechanics, a critical component of this alignment effort is ensuring that all client-facing elements accurately reflect the new nomenclature. This means updating not only the internal code paths within AGX but also its public interface, including the CLI (Command Line Interface) and all associated help documentation and user guides. The goal is to eliminate ambiguity and provide a consistent, canonical set of terms that users can rely on. The old terminology, which may have been less precise or conflated different concepts (e.g., using 'Job' to refer to both a Plan definition and its execution instance), needs to be phased out. In its place, we will use the standardized terms from the five-layer model: Task, Plan, Job, Action, and Workflow. Specifically, what was previously referred to as a 'job' in the context of submission envelopes will now be clearly understood as a Job (the execution instance of a Plan), and the concept of grouping multiple Job submissions under a single logical unit will be represented by an Action. This systematic update ensures that users interacting with AGX through its client or CLI will encounter consistent language. For instance, CLI commands and help messages will use terms like plan submit or action submit (or their programmatic equivalents), and the output and descriptions will refer to Plans, Jobs, and Actions as defined in the EXECUTION-LAYERS.md document. This consistency extends to the internal workings of AGX, where code paths, variable names, and internal data structures will be refactored to use the canonical terms. This internal alignment is vital for maintainability and for preventing the reintroduction of old ambiguities. Furthermore, comprehensive documentation is key. The README files and any specific AGENTS documentation within the AGX project will be updated to explicitly define the new schema and naming conventions. Critically, these documents will include clear links to docs/EXECUTION-LAYERS.md, serving as the single source of truth for the execution layer model. This approach not only standardizes AGX's internal representation but also educates users on the broader ecosystem's execution model, fostering a shared understanding. By diligently updating all these aspects, we aim to create a more intuitive and user-friendly experience, reducing the learning curve and enhancing the overall usability of the AGX platform.

Implementing and Testing the New Semantics

To ensure that the newly defined nomenclature and submission semantics are not just theoretical but are fully functional and robust, a rigorous implementation and testing phase is essential. This phase involves translating the conceptual changes into concrete code within AGX and then verifying their correct operation through comprehensive test suites. The core requirement here is to ensure that the AGX submission flow seamlessly integrates the new verbs, specifically plan.submit and the newly supported action.submit. This means that when a user invokes the submission functionality, AGX correctly interprets their intent and translates it into the appropriate request to AGQ, adhering to the refined schemas and naming conventions. For action.submit, the implementation must handle the logic of defining an Action that can fan-out to multiple Jobs based on provided input variations. AGX needs to correctly package this Action definition and submit it to AGQ, which will then be responsible for instantiating the individual Jobs. The reverse process, monitoring the status of these Jobs across potentially multiple AGWs, also needs to be implemented and tested. This involves AGX receiving and processing status updates for all the Jobs initiated by an Action and presenting this information clearly to the user.

Beyond the submission and monitoring aspects, the updated AGQ client is a critical dependency. The requirements state that the AGQ client must also be updated to reflect the agreed-upon RESP verbs and schemas. This ensures that the communication channel between AGX and AGQ is perfectly synchronized. Therefore, the implementation effort must include or coordinate with the necessary updates in AGQ. Testing is not an afterthought; it's an integral part of the development process. Comprehensive test cases will be developed to cover all facets of the new submission paths. This includes unit tests for individual components, integration tests to verify the interaction between AGX and AGQ, and end-to-end tests that simulate real-world usage scenarios. These tests will specifically target the new naming conventions and the payloads associated with plan.submit and action.submit, ensuring that they conform to the requirements and the EXECUTION-LAYERS.md specification. Acceptance criteria clearly outline that the CLI help and documentation must reflect the canonical nomenclature and the responsibilities of AGX, AGQ, and AGW. Therefore, tests will also be designed to validate these documentation updates, ensuring accuracy and clarity for end-users. By diligently implementing these changes and backing them with a robust testing strategy, we can confidently introduce the new nomenclature and submission semantics, paving the way for a more standardized and efficient execution layer within the AGX ecosystem. For more insights into workflow orchestration best practices, consider exploring resources from ** **The Apache Airflow Documentation.