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Execution Engine Changelog

Below you can find the changelog for Execution Engine.

Execution Engine v1.2.0 | inference v0.23.0

  • The video_metadata kind has been deprecated, and we strongly recommend discontinuing its use for building blocks moving forward. As an alternative, the image kind has been extended to support the same metadata as video_metadata kind, which can now be provided optionally. This update is non-breaking for existing blocks, but some older blocks that produce images may become incompatible with future video processing blocks.
Potential blocks incompatibility

As previously mentioned, adding video_metadata as an optional field to the internal representation of image kind (WorkflowImageData class) may introduce some friction between existing blocks that output the image kind and future video processing blocks that rely on video_metadata being part of image representation.

The issue arises because, while we can provide default values for video_metadata in image without explicitly copying them from the input, any non-default metadata that was added upstream may be lost. This can lead to downstream blocks that depend on the video_metadata not functioning as expected.

We've updated all existing roboflow_core blocks to account for this, but blocks created before this change in external repositories may cause issues in workflows where their output images are used by video processing blocks.

  • While the deprecated video_metadata kind is still available for use, it will be fully removed in Execution Engine version v2.0.0.

Breaking change planned - Execution Engine v2.0.0

video_metadata kind got deprecated and will be removed in v2.0.0

  • As a result of the changes mentioned above, the internal representation of the image kind has been updated to include a new video_metadata property. This property can be optionally set in the constructor; if not provided, a default value with reasonable defaults will be used. To simplify metadata manipulation within blocks, we have introduced two new class methods: WorkflowImageData.copy_and_replace(...) and WorkflowImageData.create_crop(...). For more details, refer to the updated WoorkflowImageData usage guide.

Execution Engine v1.3.0 | inference v0.27.0

  • Introduced the change that let each kind have serializer and deserializer defined. The change decouples Workflows plugins with Execution Engine and make it possible to integrate the ecosystem with external systems that require data transfer through the wire. Blocks bundling page was updated to reflect that change.

  • Kinds defined in roboflow_core plugin were provided with suitable serializers and deserializers

  • Workflows Compiler and Execution Engine were enhanced to support batch-oriented inputs of any kind, contrary to versions prior v1.3.0, which could only take image and video_metadata kinds as batch-oriented inputs (as a result of unfortunate and not-needed coupling of kind to internal data format introduced at the level of Execution Engine). As a result of the change:

    • new input type was introduced: WorkflowBatchInput should be used from now on to denote batch-oriented inputs (and clearly separate them from WorkflowParameters). WorkflowBatchInput let users define both kind of the data and it's dimensionality. New input type is effectively a superset of all previous batch-oriented inputs: WorkflowImage and WorkflowVideoMetadata, which remain supported, but will be removed in Execution Engine v2. We advise adjusting to the new input format, yet the requirement is not strict at the moment - as Execution Engine requires now explicit definition of input data kind to select data deserializer properly. This may not be the case in the future, as in most cases batch-oriented data kind may be inferred by compiler (yet this feature is not implemented for now).

    • new selector type annotation was introduced - named simply Selector(...). Selector(...) is supposed to replace StepOutputSelector, WorkflowImageSelector, StepOutputImageSelector, WorkflowVideoMetadataSelector and WorkflowParameterSelector in block manifests, letting developers express that specific step manifest property is able to hold either selector of specific kind. Mentioned old annotation types should be assumed deprecated, we advise to migrate into Selector(...).

    • as a result of simplification in the selectors type annotations, the old selector will no longer be providing the information on which parameter of blocks' run(...) method is shipped by Execution Engine wrapped into Batch[X] container. Instead of old selectors type annotations and block_manifest.accepts_batch_input() method, we propose the switch into two methods explicitly defining the parameters that are expected to be fed with batch-oriented data (block_manifest.get_parameters_accepting_batches()) and parameters capable of taking both batches and scalar values (block_manifest.get_parameters_accepting_batches_and_scalars()). Return value of block_manifest.accepts_batch_input() is built upon the results of two new methods. The change is non-breaking, as any existing block which was capable of processing batches must have implemented block_manifest.accepts_batch_input() method returning True and use appropriate selector type annotation which indicated batch-oriented data.

  • As a result of the changes, it is now possible to split any arbitrary workflows into multiple ones executing subsets of steps, enabling building such tools as debuggers.

Breaking change planned - Execution Engine v2.0.0

  • WorkflowImage and WorkflowVideoMetadata inputs will be removed from Workflows ecosystem.

  • StepOutputSelector,WorkflowImageSelector,StepOutputImageSelector,WorkflowVideoMetadataSelectorandWorkflowParameterSelector` type annotations used in block manifests will be removed from Workflows ecosystem.

Migration guide

Kinds' serializers and deserializers

Creating your Workflows plugin you may introduce custom serializers and deserializers for Workflows kinds. To achieve that end, simply place the following dictionaries in the main module of the plugin (the same where you place load_blocks(...) function):

from typing import Any

def serialize_kind(value: Any) -> Any:
  # place here the code that will be used to
  # transform internal Workflows data representation into 
  # the external one (that can be sent through the wire in JSON, using
  # default JSON encoder for Python).
  pass


def deserialize_kind(parameter_name: str, value: Any) -> Any:
  # place here the code that will be used to decode 
  # data sent through the wire into the Execution Engine
  # and transform it into proper internal Workflows data representation
  # which is understood by the blocks.
  pass


KINDS_SERIALIZERS = {
    "name_of_the_kind": serialize_kind,
}
KINDS_DESERIALIZERS = {
    "name_of_the_kind": deserialize_kind,
}
New type annotation for selectors - blocks without Batch[X] inputs

Blocks manifest may optionally be updated to use Selector in the following way:

from typing import Union
from inference.core.workflows.prototypes.block import WorkflowBlockManifest
from inference.core.workflows.execution_engine.entities.types import (
    INSTANCE_SEGMENTATION_PREDICTION_KIND,
    OBJECT_DETECTION_PREDICTION_KIND,
    FLOAT_KIND,
    WorkflowImageSelector,
    StepOutputImageSelector,
    StepOutputSelector,
    WorkflowParameterSelector,
)


class BlockManifest(WorkflowBlockManifest):

    reference_image: Union[WorkflowImageSelector, StepOutputImageSelector]
    predictions: StepOutputSelector(
        kind=[
            OBJECT_DETECTION_PREDICTION_KIND,
            INSTANCE_SEGMENTATION_PREDICTION_KIND,
        ]
    )
    confidence: WorkflowParameterSelector(kind=[FLOAT_KIND]) 

should just be changed into:

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from inference.core.workflows.prototypes.block import WorkflowBlockManifest
from inference.core.workflows.execution_engine.entities.types import (
    INSTANCE_SEGMENTATION_PREDICTION_KIND,
    OBJECT_DETECTION_PREDICTION_KIND,
    FLOAT_KIND,
    IMAGE_KIND,
    Selector,
)


class BlockManifest(WorkflowBlockManifest):
    reference_image: Selector(kind=[IMAGE_KIND])
    predictions: Selector(
        kind=[
            OBJECT_DETECTION_PREDICTION_KIND,
            INSTANCE_SEGMENTATION_PREDICTION_KIND,
        ]
    )
    confidence: Selector(kind=[FLOAT_KIND]) 
New type annotation for selectors - blocks with Batch[X] inputs

Blocks manifest may optionally be updated to use Selector in the following way:

from typing import Union
from inference.core.workflows.prototypes.block import WorkflowBlockManifest
from inference.core.workflows.execution_engine.entities.types import (
    INSTANCE_SEGMENTATION_PREDICTION_KIND,
    OBJECT_DETECTION_PREDICTION_KIND,
    FLOAT_KIND,
    WorkflowImageSelector,
    StepOutputImageSelector,
    StepOutputSelector,
    WorkflowParameterSelector,
)


class BlockManifest(WorkflowBlockManifest):

    reference_image: Union[WorkflowImageSelector, StepOutputImageSelector]
    predictions: StepOutputSelector(
        kind=[
            OBJECT_DETECTION_PREDICTION_KIND,
            INSTANCE_SEGMENTATION_PREDICTION_KIND,
        ]
    )
    data: Dict[str, Union[StepOutputSelector(), WorkflowParameterSelector()]]
    confidence: WorkflowParameterSelector(kind=[FLOAT_KIND]) 

    @classmethod
    def accepts_batch_input(cls) -> bool:
        return True

should be changed into:

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from inference.core.workflows.prototypes.block import WorkflowBlockManifest
from inference.core.workflows.execution_engine.entities.types import (
    INSTANCE_SEGMENTATION_PREDICTION_KIND,
    OBJECT_DETECTION_PREDICTION_KIND,
    FLOAT_KIND,
    IMAGE_KIND,
    Selector,
)


class BlockManifest(WorkflowBlockManifest):
    reference_image: Selector(kind=[IMAGE_KIND])
    predictions: Selector(
        kind=[
            OBJECT_DETECTION_PREDICTION_KIND,
            INSTANCE_SEGMENTATION_PREDICTION_KIND,
        ]
    )
    data: Dict[str, Selector()]
    confidence: Selector(kind=[FLOAT_KIND]) 

    @classmethod
    def get_parameters_accepting_batches(cls)W -> List[str]:
        return ["predictions"]

    @classmethod
    def get_parameters_accepting_batches_and_scalars(cls) -> List[str]:
        return ["data"]

Please point out that:

  • the data property in the original example was able to accept both batches of data and scalar values due to selector of batch-orienetd data (StepOutputSelector) and scalar data (WorkflowParameterSelector). Now the same is manifested by Selector(...) type annotation and return value from get_parameters_accepting_batches_and_scalars(...) method.
New inputs in Workflows definitions

Anyone that used either WorkflowImage or WorkflowVideoMetadata inputs in their Workflows definition may optionally migrate into WorkflowBatchInput. The transition is illustrated below:

{
  "inputs": [
    {"type": "WorkflowImage", "name": "image"},
    {"type": "WorkflowVideoMetadata", "name": "video_metadata"}
  ]
}

should be changed into:

{
  "inputs": [
    {
      "type": "WorkflowBatchInput",
      "name": "image",
      "kind": ["image"]
    },
    {
      "type": "WorkflowBatchInput",
      "name": "video_metadata",
      "kind": ["video_metadata"]
    }
  ]
}

Leaving kind field empty may prevent some data - like images - from being deserialized properly.

Note

If you do not like the way how data is serialized in roboflow_core plugin, feel free to alter the serialization methods for kinds, simply registering the function in your plugin and loading it to the Execution Engine - the serializer/deserializer defined as the last one will be in use.

Execution Engine v1.4.0 | inference v0.29.0

  • Added new kind - secret to represent credentials. No action needed for existing blocks, yet it is expected that over time blocks developers should use this kind, whenever block is to accept secret value as parameter.

  • Fixed issue with results serialization introduced in v1.3.0 - by mistake, Execution Engine was not serializing non-batch oriented outputs.

  • Fixed Execution Engine bug with preparing inputs for steps. For non-SIMD steps before, while collecting inputs in runtime, WorkflowBlockManifest.accepts_empty_input() method result was being ignored - causing the bug when one non-SIMD step was feeding empty values to downstream blocks. Additionally, in the light of changes made in v1.3.0, thanks to which non-SIMD blocks can easily feed inputs for downstream SIMD steps - it is needed to check if upstream non-SIMD block yielded non-empty results (as SIMD block may not accept empty results). This check was added. No action needed for existing blocks, but this fix may fix previously broken Workflows.