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Node Processor Plugin API

Stable API

Classes on this page are marked @api and are guaranteed backward compatible in the 1.x release line. See the BC Policy for details.

The FlowDropNodeProcessor plugin system is the primary extension point for FlowDrop. Use these classes to create custom node types that appear in the visual workflow editor.

Overview

Class Type Description
FlowDropNodeProcessor final class Attribute for FlowDropNode plugins.
FlowDropNodeProcessorInterface interface Interface for FlowDropNodeProcessor plugins.
AbstractFlowDropNodeProcessor abstract class Abstract base class for FlowDropNode plugins.
NodeExecutorInterface interface Interface for node executors.
ConfigEditProviderInterface interface Interface for node processors that provide dynamic configuration editing.
ExecutionContextAwareInterface interface Interface for processors that need access to execution context.
TriggerNodeProcessorInterface interface Marker interface for trigger node processors.
FlowDropNodeProcessorPluginManager class Plugin manager for FlowDropNode plugins using attribute-based discovery.

FlowDropNodeProcessor (Attribute)

Namespace: Drupal\flowdrop\Attribute
Type: final class
Extends: Plugin
Source: src/Attribute/FlowDropNodeProcessor.php

Attribute for FlowDropNode plugins.

This attribute provides plugin discovery metadata for FlowDrop node processors. Parameters are defined via getParameterSchema() method, not in this attribute. Category, tags, and visual type are managed by the config entity, not by the plugin attribute.

Constructor Parameters

Parameter Type Default Description
$id string — The plugin ID.
$label TranslatableMarkup — The human-readable label.
$description string "" The component description.
$version string "1.0.0" The component version.
$deriver ?string NULL (optional) The deriver class.

FlowDropNodeProcessorInterface

Namespace: Drupal\flowdrop\Plugin\FlowDropNodeProcessor
Type: interface
Extends: NodeExecutorInterface
Source: src/Plugin/FlowDropNodeProcessor/FlowDropNodeProcessorInterface.php

Interface for FlowDropNodeProcessor plugins.

This interface defines the contract for node processor plugins in FlowDrop. Plugins must implement the Unified Parameter System via getParameterSchema().

Note: Visual type is managed by the config entity (FlowDropNodeType), not by the plugin. This allows site builders to choose the visual format.

Methods

getId(): string

Get the component ID.

getName(): string

Get the component name.

getDescription(): string

Get the component description.

getVersion(): string

Get the component version.

validateParams(array $params): ValidationResult

Validate parameters for the node.

Parameter Type Description
$params array The parameters to validate.

getOutputSchema(): array

Get the output schema for this node.

getParameterSchema(): array

Get the parameter schema for this node.

AbstractFlowDropNodeProcessor

Namespace: Drupal\flowdrop\Plugin\FlowDropNodeProcessor
Type: abstract class
Extends: PluginBase
Implements: FlowDropNodeProcessorInterface, ContainerFactoryPluginInterface
Source: src/Plugin/FlowDropNodeProcessor/AbstractFlowDropNodeProcessor.php

Abstract base class for FlowDropNode plugins.

This class provides common functionality for FlowDropNode plugins and implements default behavior for the FlowDropNodeProcessorInterface methods.

All plugins must implement: - getParameterSchema(): Define the data contract (types, defaults, constraints) - process(ParameterBagInterface $params): The main processing logic

LOGGING POLICY: - Routine logging (start, complete, input/output) is handled by the orchestration layer via ExecutionLogger. - Processors should ONLY log exceptional events worth flagging: - External service retries/failures - Fallback usage - Rate limits - Unexpected data shapes - For such exceptional logging, inject LoggerChannelFactoryInterface in the concrete processor that needs it.

Note: UI/workflow behavior (connectable, configurable, required) is controlled entirely by the config entity, not by the plugin schema.

Methods

getOutputSchema(): array

getParameterSchema(): array

Default implementation returns an empty schema. Subclasses should override this to define their parameters.

getId(): string

getName(): string

getDescription(): string

getVersion(): string

validateParams(array $params): ValidationResult

NodeExecutorInterface

Namespace: Drupal\flowdrop\Plugin\FlowDropNodeProcessor
Type: interface
Source: src/Plugin/FlowDropNodeProcessor/NodeExecutorInterface.php

Interface for node executors.

This interface defines the contract for node processors that execute workflow nodes using the Unified Parameter System.

Methods

process(ParameterBagInterface $params): array

Execute a node with resolved parameters.

Parameter Type Description
$params ParameterBagInterface The resolved parameters (merged from config, workflow values, and inputs).

Throws: Exception

ConfigEditProviderInterface

Namespace: Drupal\flowdrop\Plugin\FlowDropNodeProcessor
Type: interface
Source: src/Plugin/FlowDropNodeProcessor/ConfigEditProviderInterface.php

Interface for node processors that provide dynamic configuration editing.

Implement this interface on your FlowDropNodeProcessor plugin to indicate that the node supports dynamic configuration editing. This allows:

  • Dynamic schema fetching from REST endpoints at runtime
  • External edit links to admin forms or third-party configuration UIs
  • API endpoints for CRUD operations on configuration entities

When a plugin implements this interface, the FlowDrop frontend will use the provided configuration to render appropriate UI controls for editing the node's configuration.

Example implementation:

Methods

getConfigEdit(): ConfigEdit

Get the configuration edit options for this node processor.

ExecutionContextAwareInterface

Namespace: Drupal\flowdrop\Plugin\FlowDropNodeProcessor
Type: interface
Source: src/Plugin/FlowDropNodeProcessor/ExecutionContextAwareInterface.php

Interface for processors that need access to execution context.

Implement this interface when your processor needs access to: - Initial workflow data (trigger payload, input data) - Workflow, pipeline, or execution identifiers - Execution metadata.

The runtime will automatically inject the ExecutionContextDTO before calling execute() on processors that implement this interface.

Example usage:

Methods

setExecutionContext(ExecutionContextDTO $context): void

Sets the execution context for this processor.

Parameter Type Description
$context ExecutionContextDTO The execution context containing workflow data and identifiers.

TriggerNodeProcessorInterface

Namespace: Drupal\flowdrop\Plugin\FlowDropNodeProcessor
Type: interface
Source: src/Plugin/FlowDropNodeProcessor/TriggerNodeProcessorInterface.php

Marker interface for trigger node processors.

Processors that implement this interface are considered trigger nodes, which can initiate workflow executions. When a workflow is triggered by an event, only the trigger node that fired the event should be executed, while all other trigger nodes in the workflow should be excluded.

This interface is intentionally empty. It serves as a type marker used by JobGenerationService::isTriggerNodeProcessor() to identify trigger nodes during job generation — trigger nodes are excluded from the pipeline unless they are the specific trigger that fired the workflow.

Using instanceof/is_subclass_of checks with this marker interface provides compile-time safety that attribute-based detection would not.

FlowDropNodeProcessorPluginManager

Namespace: Drupal\flowdrop\Service
Type: class
Extends: DefaultPluginManager
Source: src/Service/FlowDropNodeProcessorPluginManager.php

Plugin manager for FlowDropNode plugins using attribute-based discovery.

This manager automatically namespaces plugin IDs with their provider module to prevent ID collisions when multiple modules define plugins with the same base ID. For example, a plugin with id: "chat_model" from module flowdrop_ai_provider becomes flowdrop_ai_provider:chat_model.

The namespacing format is: {provider}:{original_id}

Supports plugin derivers via DerivativeDiscoveryDecorator, enabling modules to dynamically generate multiple plugin instances from a single base plugin. Derivative plugins (e.g., tool_api:entity_save) are also namespaced with their provider to ensure uniqueness across modules.

Constants

Constant Value Description
NAMESPACE_SEPARATOR ":" The separator used between provider and plugin ID.

Methods

processDefinition(array<string,mixed> $definition, string $plugin_id): void

Processes plugin definitions to add provider-based namespacing.

This method prefixes each plugin ID with its provider module name, ensuring unique IDs across all contributing modules. The original (non-prefixed) ID is preserved in the 'original_id' property.

For derivative plugins (e.g., tool_api:entity_save), the full composite ID is namespaced with the provider to ensure unique IDs across modules. The derivative's ":" separator is distinct from the provider namespace.

Parameter Type Description
$definition array<string,mixed> The plugin definition to process.
$plugin_id string The plugin ID.

protected findDefinitions(): array

Re-keys definitions by their namespaced IDs after processing.

buildNamespacedId(string $provider, string $originalId): string

Builds a namespaced plugin ID from provider and original ID.

Parameter Type Description
$provider string The provider module name.
$originalId string The original plugin ID.

isNamespaced(string $pluginId): bool

Checks if a plugin ID contains a namespace separator.

Parameter Type Description
$pluginId string The plugin ID to check.

isProviderNamespaced(string $pluginId, string $provider): bool

Checks if a plugin ID is already namespaced with a specific provider.

Parameter Type Description
$pluginId string The plugin ID to check.
$provider string The provider module name to check for.

getProviderFromNamespacedId(string $pluginId): ?string

Extracts the provider from a namespaced plugin ID.

Parameter Type Description
$pluginId string The namespaced plugin ID.

getOriginalIdFromNamespacedId(string $pluginId): string

Extracts the original ID from a namespaced plugin ID.

Parameter Type Description
$pluginId string The namespaced plugin ID.

See Also

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