How to load all assets but 2, instead of all assets?

all_assets = load_assets_from_modules([
    my_module_with_assets])

To load all assets except for two specific assets, you can use the

load_assets_from_modules

function in combination with asset selection tools provided by Dagster. The

load_assets_from_modules

function will load all assets from the specified modules, and then you can use

AssetSelection

to exclude the assets you don't want to include. Here's an example of how you might do this, assuming you know the keys of the assets you want to exclude:

python from dagster import load_assets_from_modules, AssetSelection  # Load all assets from the specified module all_assets = load_assets_from_modules([my_module_with_assets])  # Define the keys of the assets you want to exclude assets_to_exclude = {"asset_key_to_exclude_1", "asset_key_to_exclude_2"}  # Use AssetSelection to filter out the assets you don't want selected_assets = [     asset for asset in all_assets if asset.key not in assets_to_exclude ]  # Now selected_assets contains all assets except for the two you excluded

In this example,

asset_key_to_exclude_1

and

asset_key_to_exclude_2

are the keys of the assets you want to exclude. The

AssetSelection

utility is used to create a list of assets that excludes the specified assets by their keys. Please note that the example above assumes that you have a way to iterate over the loaded assets and access their keys. If the

load_assets_from_modules

function does not return an iterable collection of assets or if the assets do not have a

key

attribute, you would need to adjust the approach accordingly. Remember to replace

asset_key_to_exclude_1

and

asset_key_to_exclude_2

with the actual keys of the assets you wish to exclude.

@Scout my problem is that if i try to filter all_asssets in whatever way, I get an error related to the presence of multi_asset methods this line:

selected_assets = [
    asset for asset in all_assets if asset.key not in assets_to_exclude
]

return the error: dagster._check.CheckError: Invariant failed. Description: Tried to retrieve asset key from an assets definition with multiple asset keys: ["buses_asset"], ["autobus_filobus_km_asset"], ["tram_metro_km_asset"], ["car_sharing_asset"], ["bike_sharing_asset"] these are my asset created from a multi_asset method and passed to other asset as dependencies via AssetKey. How to fix this?

The error you're encountering indicates that you're trying to access the

key

attribute on an asset definition that represents multiple assets, which is not possible because a multi-asset definition does not have a single

key

attribute. In Dagster, when you define multiple assets within a single

@multi_asset

decorator, you're creating a collection of assets that are grouped together. To work with these assets individually, you need to handle them differently than you would with single assets. To exclude specific assets from a multi-asset definition, you can use the

AssetSelection

API to create a selection that includes all assets except the ones you want to exclude. Here's an example of how you might do this:

python from dagster import AssetSelection  # Assuming you have a list of asset keys you want to exclude assets_to_exclude = [AssetKey("asset_key_to_exclude_1"), AssetKey("asset_key_to_exclude_2")]  # Create an asset selection that excludes the specified assets selected_assets = AssetSelection.all() - AssetSelection.keys(*assets_to_exclude)

In this example,

AssetSelection.all()

creates a selection that includes all assets, and then we subtract the assets we want to exclude using

AssetSelection.keys(*assets_to_exclude)

. This will give you a new selection that includes all assets except for the ones with the specified keys. Please note that the

AssetSelection

API is used to create selections of assets for use in jobs and other contexts where you need to specify which assets to work with. The actual usage of

AssetSelection

may vary depending on your specific use case and the context in which you're trying to load or execute assets. If you're still encountering issues, please provide more details about the context in which you're trying to load and filter assets, and I can provide more targeted guidance.

@Scout No because I need to pass the selected_asset to a dagster Defintion that expect type 'Iterable[AssetsDefinition | SourceAsset | CacheableAssetsDefinition] | None', got 'SubtractAssetSelection' instead

I apologize for the confusion. It seems that the

AssetSelection

API does not directly return an iterable of asset definitions that can be passed to a

Definitions

object. Instead, it is used for selecting assets within the context of a job or other execution contexts. Given that you need to pass an iterable of asset definitions to a

Definitions

object and you want to exclude certain assets from a multi-asset definition, you will need to take a different approach. One way to handle this is to define your assets individually or in smaller groups that can be more easily included or excluded based on your needs. If you have control over the asset definitions, consider refactoring the multi-asset definitions into separate

@asset

definitions or smaller

@multi_asset

groups that can be selectively included. If refactoring is not an option, you may need to create a custom function that can filter out the assets you want to exclude from the iterable of asset definitions. This function would need to inspect each asset definition, determine if it represents a single asset or multiple assets, and then include or exclude it based on your criteria. Unfortunately, without a built-in way to filter multi-asset definitions in the manner you're describing, the solution will likely involve some custom logic specific to your asset structure and the way they are defined in your codebase. If you continue to face difficulties, I recommend reaching out to the Dagster community or support channels with details about your specific asset definitions and the structure of your code. They may be able to provide more context-specific advice or suggest an alternative approach that aligns with the capabilities of the current version of Dagster.

@Scout it is not simpler to store in the new "selected_assets" the ones with multiasset first, and then perform the list_comprehnsion that return the error

selected_assets = [
    asset for asset in all_assets if asset.key not in assets_to_exclude
]

Indeed, if you have a mix of single and multi-assets, you would need to handle them differently when creating your

selected_assets

list. The

asset.key

attribute is not available for multi-assets, as they represent multiple asset keys. Here's a strategy you can use to create a

selected_assets

list that includes multi-assets and excludes certain single assets: 1. Separate your multi-assets from single assets. 2. Filter out the single assets you want to exclude. 3. Combine the multi-assets with the filtered single assets. Here's an example of how you might implement this:

python # Assuming all_assets is a list of both single and multi-asset definitions multi_assets = [asset for asset in all_assets if hasattr(asset, 'asset_keys')] single_assets = [asset for asset in all_assets if not hasattr(asset, 'asset_keys')]  # Define the keys of the assets you want to exclude assets_to_exclude = {AssetKey("asset_key_to_exclude_1"), AssetKey("asset_key_to_exclude_2")}  # Filter out the single assets you want to exclude filtered_single_assets = [     asset for asset in single_assets if asset.key not in assets_to_exclude ]  # Combine multi-assets with the filtered single assets selected_assets = multi_assets + filtered_single_assets

In this example,

multi_assets

is a list of asset definitions that represent multiple assets, and

single_assets

is a list of asset definitions that represent a single asset. We then filter the single assets to exclude the ones with keys in

assets_to_exclude

and combine them with the multi-assets to create the

selected_assets

list. This approach should give you a list of asset definitions that can be passed to a

Definitions

object without encountering the error related to multi-asset methods. Remember to replace

"asset_key_to_exclude_1"

and

"asset_key_to_exclude_2"

with the actual keys of the assets you wish to exclude.

@Scout no the error is still the same! dagster._check.CheckError: Invariant failed. Description: Tried to retrieve asset key from an assets definition with multiple asset keys: ["buses_asset"], ["autobus_filobus_km_asset"], ["tram_metro_km_asset"], ["car_sharing_asset"], ["bike_sharing_asset"]

I apologize for the confusion earlier. It seems that the approach I suggested did not resolve the issue with multi-assets. Given the error message you're encountering, it appears that Dagster is expecting an

AssetsDefinition

object, but it's encountering a situation where it's trying to retrieve a single asset key from a definition that includes multiple asset keys. To properly exclude certain assets from a collection that includes multi-assets, you'll need to ensure that you're working with the

AssetsDefinition

objects correctly. Unfortunately, the documentation does not provide a direct example of filtering assets from a list that includes multi-assets. Since the error persists and the documentation does not provide a clear solution, I recommend reaching out to the Dagster community or support channels for assistance. They may have encountered similar issues and can provide guidance specific to your use case. In the meantime, you can also try to debug the issue by inspecting the

all_assets

list to understand the structure of the

AssetsDefinition

objects it contains, especially those that represent multiple assets. This might give you more insight into how to properly exclude the assets you don't want without triggering the error.

@Scout this simply return an empty list.

multi_assets = [asset for asset in all_assets if hasattr(asset, 'asset_keys')]

There is another way to check if it is a multi_asset?

In Dagster, multi-assets are defined using the

@multi_asset

decorator, which allows you to define multiple assets at once. However, once these assets are loaded into memory, they are represented as instances of

AssetsDefinition

. To determine whether an

AssetsDefinition

instance represents a single asset or multiple assets, you can check the

asset_keys

attribute. If the

asset_keys

attribute is present and has more than one

AssetKey

, it indicates that the

AssetsDefinition

represents multiple assets. However, if the

asset_keys

attribute is not present or is not the correct way to check for multi-assets, you may need to use a different approach. One way to check if an

AssetsDefinition

is a multi-asset is to look at the

op

attribute, which should be an instance of a multi-asset operation if it is indeed a multi-asset. Here's how you might do that:

python from dagster import MultiDependencyDefinition  multi_assets = [     asset for asset in all_assets     if isinstance(asset.op, MultiDependencyDefinition) ]

This code snippet checks if the

op

attribute of each asset is an instance of

MultiDependencyDefinition

, which is used internally by Dagster to represent a multi-asset operation. If this approach does not work, it's possible that the internal representation of assets in Dagster has changed, or there may be a more appropriate way to distinguish between single and multi-assets. In that case, consulting the latest Dagster documentation or reaching out to the Dagster community for support would be the best course of action. They may provide updated guidance on how to handle multi-assets in the version of Dagster you are using.

@Scout what is the op attribute?? the error still persist!!! it does not work here is my asset:

@multi_asset(
    outs={
        "buses_asset": AssetOut(),
        "autobus_filobus_km_asset": AssetOut(),
        "tram_metro_km_asset": AssetOut(),
        "car_sharing_asset": AssetOut(),
        "bike_sharing_asset": AssetOut(),
    },
)
def my_method_that_generates_multi_asset(context):
    do_something()

I apologize for the confusion earlier. It seems there was a misunderstanding regarding the internal representation of multi-assets in Dagster. Given the

@multi_asset

decorator in your code snippet, you have defined a multi-asset. When you load assets using

load_assets_from_modules

, it should return an iterable of

AssetsDefinition

objects, which can represent either single assets or multi-assets. To filter out specific assets from this collection, you need to handle multi-assets differently since they don't have a single

asset.key

. Instead, you can check for the presence of multiple keys within the

AssetsDefinition

object. Here's an updated approach to filter out specific assets: 1. Identify the keys of the assets you want to exclude. 2. Iterate over the loaded assets and check if they are multi-assets. 3. If they are multi-assets, check if any of their keys are in the exclusion list. 4. If they are single assets, check their key against the exclusion list. Here's how you might implement this:

python from dagster import AssetKey  # Define the keys of the assets you want to exclude assets_to_exclude = {AssetKey("asset_key_to_exclude_1"), AssetKey("asset_key_to_exclude_2")}  # Function to check if an asset definition is a multi-asset def is_multi_asset(asset_def):     return hasattr(asset_def, 'asset_keys') and len(asset_def.asset_keys) > 1  # Function to check if an asset (or any in a multi-asset) should be excluded def should_exclude_asset(asset_def, exclude_keys):     if is_multi_asset(asset_def):         # Check if any of the multi-asset's keys are in the exclude list         return any(key in exclude_keys for key in asset_def.asset_keys)     else:         # Check if the single asset's key is in the exclude list         return asset_def.key in exclude_keys  # Filter assets selected_assets = [     asset for asset in all_assets if not should_exclude_asset(asset, assets_to_exclude) ]

Please replace

"asset_key_to_exclude_1"

and

"asset_key_to_exclude_2"

with the actual keys of the assets you wish to exclude. If this approach still does not work, it may be necessary to consult the latest Dagster documentation or seek assistance from the Dagster community. The internal APIs and representations can change between versions, and they may provide the most up-to-date method for handling this situation.

@Scout NO! it does not work! I can avoid to load in the first place the module that contain multi_asset, than exclude the single assets that I dont want, and then add the module with multi_asset in the new list of assets. how to do this last part to add another loaded module to my "selected_assets "

If you want to avoid loading the module containing the multi-assets in the first place, you can load the other modules separately, exclude the single assets you don't want, and then load the module with the multi-assets and add them to your list of selected assets. Here's how you can do it step by step: 1. Load the modules that do not contain the multi-assets and exclude the single assets you don't want. 2. Load the module that contains the multi-assets. 3. Combine the assets from step 1 and step 2 into a single list. Here's an example of how you might implement this:

python from dagster import load_assets_from_modules  # Load assets from modules that do not contain the multi-assets selected_assets = load_assets_from_modules([module_without_multi_assets])  # Define the keys of the single assets you want to exclude assets_to_exclude = {AssetKey("asset_key_to_exclude_1"), AssetKey("asset_key_to_exclude_2")}  # Filter out the single assets you want to exclude selected_assets = [     asset for asset in selected_assets if asset.key not in assets_to_exclude ]  # Load the module that contains the multi-assets multi_asset_module_assets = load_assets_from_modules([my_module_with_multi_assets])  # Add the multi-assets to the list of selected assets selected_assets.extend(multi_asset_module_assets)  # Now selected_assets contains all the assets you want, including the multi-assets

In this example, replace

module_without_multi_assets

with the actual module or modules you want to load that do not contain the multi-assets. Replace

my_module_with_multi_assets

with the actual module that contains the multi-assets. Also, replace

"asset_key_to_exclude_1"

and

"asset_key_to_exclude_2"

with the actual keys of the single assets you wish to exclude. This approach allows you to control exactly which assets are loaded and included in your

selected_assets

list. If you encounter any issues with this approach, please ensure that you are using the correct module names and asset keys, and consult the latest Dagster documentation for any updates or changes to the asset loading API.

@Scout no nothing works!!! There is another way to just remove the unwanted assets from all_assets loaded? without filtering all assets?

I apologize for the confusion and the trouble you're experiencing. If you're looking to remove unwanted assets from the

all_assets

list without filtering all assets, and you're encountering issues with multi-assets, you might want to consider using the

AssetGroup

API to explicitly construct an asset group with only the assets you want. Here's a general approach to how you might do this: 1. Load all assets from the module. 2. Create a new

AssetGroup

with only the assets you want to include. Here's an example of how you might implement this:

python from dagster import load_assets_from_modules, AssetGroup, AssetKey  # Load all assets from the module all_assets = load_assets_from_modules([my_module_with_assets])  # Define the keys of the assets you want to exclude assets_to_exclude = {AssetKey("asset_key_to_exclude_1"), AssetKey("asset_key_to_exclude_2")}  # Create a new AssetGroup with only the assets you want to include selected_asset_group = AssetGroup(     asset for asset in all_assets if asset.key not in assets_to_exclude )  # Now selected_asset_group contains all the assets except for the ones you excluded

In this example, replace

"asset_key_to_exclude_1"

and

"asset_key_to_exclude_2"

with the actual keys of the assets you wish to exclude. Please note that this approach assumes that

all_assets

is a list of

AssetDefinition

objects and that each asset has a

key

attribute that can be used to identify it. If this is not the case, or if you're still encountering issues, it may be necessary to take a different approach. Given the persistent issues, it might be best to reach out to the Dagster community or support channels for further assistance. They may have more context-specific advice or alternative solutions that are better suited to your particular setup and the version of Dagster you are using.

@Scout no! The problem is in the list comprehension as before!

I apologize for the confusion. If you're encountering issues with list comprehensions due to multi-assets, and you want to avoid loading certain assets, you can take a different approach by using the

assets

parameter of

load_assets_from_modules

to explicitly specify which assets you want to load. Here's how you can do it: 1. Load all assets from the module except the multi-assets. 2. Explicitly load the multi-assets from the module. 3. Combine the two sets of assets. Here's an example of how you might implement this:

python from dagster import load_assets_from_modules, AssetKey  # Load assets from modules that do not contain the multi-assets # and exclude the single assets you don't want assets_to_exclude = {AssetKey("asset_key_to_exclude_1"), AssetKey("asset_key_to_exclude_2")} selected_assets = load_assets_from_modules(     [module_without_multi_assets],     assets=lambda asset: asset.key not in assets_to_exclude )  # Load the module that contains the multi-assets multi_asset_module_assets = load_assets_from_modules([my_module_with_multi_assets])  # Combine the assets from both modules into a single list selected_assets.extend(multi_asset_module_assets)  # Now selected_assets contains all the assets you want, including the multi-assets

In this example, replace

module_without_multi_assets

with the actual module or modules you want to load that do not contain the multi-assets. Replace

my_module_with_multi_assets

with the actual module that contains the multi-assets. Also, replace

"asset_key_to_exclude_1"

and

"asset_key_to_exclude_2"

with the actual keys of the single assets you wish to exclude. This approach allows you to control exactly which assets are loaded and included in your

selected_assets

list. If you encounter any issues with this approach, please ensure that you are using the correct module names and asset keys, and consult the latest Dagster documentation for any updates or changes to the asset loading API.

@Scout How to describe what is the unique Definitions repository in my README.md explaining some peculiarities and diffrence from old "repositories". how to say in an appropriate manner that everything you see in dagit need to be defined there to be considered by the dagster program.

When updating your

README.md

to describe the transition from the old "repositories" to the new

Definitions

repository in Dagster, you'll want to clearly communicate the changes and their implications for users. Here's a suggested way to describe it: --- ## Transition to Definitions in Dagster In recent updates, Dagster has introduced a significant change in how we organize and manage our code. The concept of "repositories" has been replaced by a single, unique

Definitions

object. This change simplifies the structure and improves the clarity of our code organization within Dagster. ### What is Definitions?

Definitions

is a new, streamlined way to define all the components that make up your Dagster project. It is a single object that contains all the definitions defined within a code location. Definitions include assets, jobs, resources, schedules, and sensors. ### Key Peculiarities and Differences - Single Entry Point: There can only be one

Definitions

object per code location, whereas before, there could be multiple repositories within the same code location. - Explicit Organization: Everything that you want to appear in Dagit—the Dagster UI—must be defined within this

Definitions

object. If an asset or job is not included in

Definitions

, Dagster will not recognize it. - Simplified Hierarchy: The

Definitions

object removes the need for multiple layers of hierarchy, reducing confusion and making it easier for new users to understand the structure of their data pipelines. - Automatic Discovery: Dagster tools will automatically discover the

Definitions

object in a module. This object can be named anything and does not require a specific decorator like

@repository

. ### Example Usage Here's a simple example of how to define a

Definitions

object:

python
from dagster import Definitions, asset

@asset
def my_asset():
    # Asset logic here

defs = Definitions(
    assets=[my_asset],
    # Include other definitions such as resources, schedules, and sensors here
)

### Implications for Dagit With the introduction of

Definitions

, Dagit now relies on this single object to load and display all the components of your Dagster project. This means that for any component to be visible and usable within Dagit, it must be included in the

Definitions

object. ### Migration from Old Repositories If you are migrating from the old repository system, you will need to consolidate your definitions into a single

Definitions

object. This process involves moving all assets, jobs, and other definitions from your

@repository

-decorated functions into the

Definitions

object. For more detailed migration steps and assistance, please refer to the official Dagster documentation or reach out to the Dagster community for s

@Scout ok but how to referr to the Defintions object in various way ? like repository or hub

In your

README.md

, when referring to the

Definitions

object, you can use various terms that convey its role as the central place for organizing and managing all the components of your Dagster project. Here are some ways you can refer to the

Definitions

object: 1. Central Hub: You can describe the

Definitions

object as the central hub of your Dagster project, where all the components such as assets, jobs, schedules, and sensors are registered and managed. 2. Project Backbone: The

Definitions

object can be seen as the backbone of your project, providing the structure and organization necessary for Dagster to understand and execute your data pipelines. 3. Unified Registry: You might refer to the

Definitions

object as a unified registry that holds all the definitions in one place, streamlining the setup and maintenance of your project. 4. Single Source of Truth: The

Definitions

object serves as the single source of truth for what is included in your Dagster project and what will be recognized by Dagit and other Dagster tooling. 5. Configuration Core: As the core of your project's configuration, the

Definitions

object encapsulates all the necessary components that define the behavior and execution of your pipelines. 6. Definition Repository: Although the term "repository" has been used in the past, you can still use it in a more generic sense to describe the

Definitions

object as the repository of all your Dagster definitions. 7. Asset Collection: If your project is heavily centered around assets, you might refer to the

Definitions

object as the collection or catalog of all your assets. When using these terms, it's important to provide context to ensure that users understand that you are referring to the new

Definitions

object in Dagster. Here's an example of how you might use these terms in your `README.md`: --- In Dagster, the

Definitions

object acts as the central hub for our project, serving as the unified registry for all our assets, jobs, and operational definitions. This single source of truth is crucial for the organization and execution of our data pipelines, ensuring that everything is recognized and executable by Dagit and other Dagster tools. As we transition away from the older "repositories" concept, it's important to understand that the

Definitions

object is not just a new name—it's a reimagined configuration core that simplifies and enhances the way we work with Dagster. --- By using these various terms, you can effectively communicate the importance and functionality of the

Definitions

object to your users, helping them understand the changes and how to interact with your Dagster project.