> ## Documentation Index
> Fetch the complete documentation index at: https://docs.prophecy.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# View pipeline Python

> Understand how the pipeline.py file defines pipeline structure and execution order.

The `pipeline.py` file defines the structure of a pipeline as code. It acts as the code-based representation of the visual pipeline graph, allowing you to understand how steps are connected and executed.

Previous versions of this file used task-based structure; Prophecy now uses a graph-based model for this file. Instead of organizing logic by tasks, the pipeline is now defined as a set of processes connected through dependencies, which determine execution order.

## Overview

The `pipeline.py` file serves as the source of truth for generating the pipeline graph. It defines how pipeline steps relate to each other.

<Note>
  There is not always a one-to-one mapping between gems and nodes. Some gems may be grouped into an execution unit.
</Note>

In this model:

* Nodes (vertices) represent steps in the pipeline, such as data sources, transformations, models, or outputs.
* Edges represent dependencies between steps, indicating execution flow.

## How the pipeline is defined

The file defines pipelines using a declarative graph structure.

* Nodes are represented by `Process` objects.
* Edges (connections) are created using the `>>` operator.
* The graph structure is captured using context management.

For example:

```

source >> transform >> sink

```

defines the following execution flow:

```

source → transform → sink

```

### Example

The following snipped represents a pipeline that runs a transformation (`sales_by_region`) and then sends the results via email. The connection `transform >> email` shows that the email step depends on the transformation output. See [classes](#classes) for an explanation of classes.

```Python theme={null}
with Pipeline(args) as pipeline:
    transform = Process(
        name="sales_by_region",
        properties=ModelTransform(modelName="sales_by_region")
    )

    email = Process(
        name="send_report",
        properties=Email(subject="Sales रिपोर्ट", to="team@example.com")
    )

    transform >> email
```

## How to access the file

You can view the `pipeline.py` file in the [Project Browser](/data-analysis/development/studio/studio#project-browser/) while in [Code view](/data-analysis/development/studio/studio#visual-code-toggle).

1. Go to **Project**.
2. Select **Pipelines**.
3. Open the `.py` file listed under **Pipelines**.

## How to use this file

You can use the `pipeline.py` file to:

* Understand pipeline structure.
* Determine execution order based on dependencies.
* Inspect how processes are connected in the graph.

This file is informational and reflects how the pipeline is defined internally.

## How it differs from the previous model

Previously, pipelines were organized by tasks, and execution order could be inferred from the task structure.

In the current model:

* The structure is organized by process instead of task.
* Execution order is determined by the dependency graph between processes.
* The underlying execution logic has not changed.
* Only the representation has changed from task-based to graph-based.

## Relationship to the visual pipeline

The `pipeline.py` file is the code counterpart of the visual pipeline graph.

* It provides the structural definition used to render the graph.
* You can use it to understand how different steps are connected.
* It reflects execution flow through explicit dependencies.
* Gems generally map to processes.
* In some cases, multiple gems may be grouped into a single execution unit instead of a one-to-one mapping.

## CI/CD considerations

This file is not intended for CI/CD usage.

## Editing the file

You can edit the `pipeline.py` file directly, but we recommend using the Agent to modify it.

## Classes

| Class                  | What it Represents                                 | What to Look For                                                                                                                                                |
| ---------------------- | -------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **`Pipeline`**         | The overall pipeline definition                    | Wraps the entire pipeline. Everything inside defines the pipeline structure. Think of this as “the full workflow”                                               |
| **`PipelineArgs`**     | Basic metadata about the pipeline                  | `label`: pipeline name<br /><br />`version`: pipeline version<br /><br />Optional settings (such as `layout`)                                                   |
| **`Process`**          | A step in the pipeline (may combine multiple gems) | Each process is one operation (such as `Transform`, `Visualize`, or  `Email`).<br /><br /> `name` identifies the step- `properties` defines what the step does. |
| **Connections (`>>`)** | The flow of data between steps                     | `A >> B` means “A feeds into B.”<br /><br />Defines order and dependencies.<br /><br />Chains show the path data follows.                                       |