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prefect_kubernetes.credentials

Module for defining Kubernetes credential handling and client generation.

KubernetesClusterConfig

Bases: Block

Stores configuration for interaction with Kubernetes clusters.

See from_file for creation.

Attributes:

Name Type Description
config Dict

The entire loaded YAML contents of a kubectl config file
context_name str

The name of the kubectl context to use
Example

Load a saved Kubernetes cluster config: 

from prefect_kubernetes.credentials import import KubernetesClusterConfig

cluster_config_block = KubernetesClusterConfig.load("BLOCK_NAME")

Source code in prefect_kubernetes/credentials.py 
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class KubernetesClusterConfig(Block):
    """
    Stores configuration for interaction with Kubernetes clusters.

    See `from_file` for creation.

    Attributes:
        config: The entire loaded YAML contents of a kubectl config file
        context_name: The name of the kubectl context to use

    Example:
        Load a saved Kubernetes cluster config:
        ```python
        from prefect_kubernetes.credentials import import KubernetesClusterConfig

        cluster_config_block = KubernetesClusterConfig.load("BLOCK_NAME")
        ```
    """

    _block_type_name = "Kubernetes Cluster Config"
    _logo_url = "https://cdn.sanity.io/images/3ugk85nk/production/2d0b896006ad463b49c28aaac14f31e00e32cfab-250x250.png"
    _documentation_url = "https://prefecthq.github.io/prefect-kubernetes/credentials/#prefect_kubernetes.credentials.KubernetesClusterConfig"  # noqa
    config: Dict = Field(
        default=..., description="The entire contents of a kubectl config file."
    )
    context_name: str = Field(
        default=..., description="The name of the kubectl context to use."
    )

    @validator("config", pre=True)
    def parse_yaml_config(cls, value):
        if isinstance(value, str):
            return yaml.safe_load(value)
        return value

    @classmethod
    def from_file(cls: Type[Self], path: Path = None, context_name: str = None) -> Self:
        """
        Create a cluster config from the a Kubernetes config file.

        By default, the current context in the default Kubernetes config file will be
        used.

        An alternative file or context may be specified.

        The entire config file will be loaded and stored.
        """

        path = Path(path or config.kube_config.KUBE_CONFIG_DEFAULT_LOCATION)
        path = path.expanduser().resolve()

        # Determine the context
        (
            existing_contexts,
            current_context,
        ) = config.kube_config.list_kube_config_contexts(config_file=str(path))
        context_names = {ctx["name"] for ctx in existing_contexts}
        if context_name:
            if context_name not in context_names:
                raise ValueError(
                    f"Context {context_name!r} not found. "
                    f"Specify one of: {listrepr(context_names, sep=', ')}."
                )
        else:
            context_name = current_context["name"]

        # Load the entire config file
        config_file_contents = path.read_text()
        config_dict = yaml.safe_load(config_file_contents)

        return cls(config=config_dict, context_name=context_name)

    def get_api_client(self) -> "ApiClient":
        """
        Returns a Kubernetes API client for this cluster config.
        """
        return config.kube_config.new_client_from_config_dict(
            config_dict=self.config, context=self.context_name
        )

    def configure_client(self) -> None:
        """
        Activates this cluster configuration by loading the configuration into the
        Kubernetes Python client. After calling this, Kubernetes API clients can use
        this config's context.
        """
        config.kube_config.load_kube_config_from_dict(
            config_dict=self.config, context=self.context_name
        )

configure_client

Activates this cluster configuration by loading the configuration into the Kubernetes Python client. After calling this, Kubernetes API clients can use this config's context.

Source code in prefect_kubernetes/credentials.py 
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def configure_client(self) -> None:
    """
    Activates this cluster configuration by loading the configuration into the
    Kubernetes Python client. After calling this, Kubernetes API clients can use
    this config's context.
    """
    config.kube_config.load_kube_config_from_dict(
        config_dict=self.config, context=self.context_name
    )

from_file classmethod

Create a cluster config from the a Kubernetes config file.

By default, the current context in the default Kubernetes config file will be used.

An alternative file or context may be specified.

The entire config file will be loaded and stored.

Source code in prefect_kubernetes/credentials.py 
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@classmethod
def from_file(cls: Type[Self], path: Path = None, context_name: str = None) -> Self:
    """
    Create a cluster config from the a Kubernetes config file.

    By default, the current context in the default Kubernetes config file will be
    used.

    An alternative file or context may be specified.

    The entire config file will be loaded and stored.
    """

    path = Path(path or config.kube_config.KUBE_CONFIG_DEFAULT_LOCATION)
    path = path.expanduser().resolve()

    # Determine the context
    (
        existing_contexts,
        current_context,
    ) = config.kube_config.list_kube_config_contexts(config_file=str(path))
    context_names = {ctx["name"] for ctx in existing_contexts}
    if context_name:
        if context_name not in context_names:
            raise ValueError(
                f"Context {context_name!r} not found. "
                f"Specify one of: {listrepr(context_names, sep=', ')}."
            )
    else:
        context_name = current_context["name"]

    # Load the entire config file
    config_file_contents = path.read_text()
    config_dict = yaml.safe_load(config_file_contents)

    return cls(config=config_dict, context_name=context_name)

get_api_client

Returns a Kubernetes API client for this cluster config.

Source code in prefect_kubernetes/credentials.py 
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def get_api_client(self) -> "ApiClient":
    """
    Returns a Kubernetes API client for this cluster config.
    """
    return config.kube_config.new_client_from_config_dict(
        config_dict=self.config, context=self.context_name
    )

KubernetesCredentials

Bases: Block

Credentials block for generating configured Kubernetes API clients.

Attributes:

Name Type Description
cluster_config Optional[KubernetesClusterConfig]

A KubernetesClusterConfig block holding a JSON kube config for a specific kubernetes context.
Example

Load stored Kubernetes credentials: 

from prefect_kubernetes.credentials import KubernetesCredentials

kubernetes_credentials = KubernetesCredentials.load("BLOCK_NAME")

Source code in prefect_kubernetes/credentials.py 
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class KubernetesCredentials(Block):
    """Credentials block for generating configured Kubernetes API clients.

    Attributes:
        cluster_config: A `KubernetesClusterConfig` block holding a JSON kube
            config for a specific kubernetes context.

    Example:
        Load stored Kubernetes credentials:
        ```python
        from prefect_kubernetes.credentials import KubernetesCredentials

        kubernetes_credentials = KubernetesCredentials.load("BLOCK_NAME")
        ```
    """

    _block_type_name = "Kubernetes Credentials"
    _logo_url = "https://cdn.sanity.io/images/3ugk85nk/production/2d0b896006ad463b49c28aaac14f31e00e32cfab-250x250.png"  # noqa
    _documentation_url = "https://prefecthq.github.io/prefect-kubernetes/credentials/#prefect_kubernetes.credentials.KubernetesCredentials"  # noqa

    cluster_config: Optional[KubernetesClusterConfig] = None

    @contextmanager
    def get_client(
        self,
        client_type: Literal["apps", "batch", "core", "custom_objects"],
        configuration: Optional[Configuration] = None,
    ) -> Generator[KubernetesClient, None, None]:
        """Convenience method for retrieving a Kubernetes API client for deployment resources.

        Args:
            client_type: The resource-specific type of Kubernetes client to retrieve.

        Yields:
            An authenticated, resource-specific Kubernetes API client.

        Example:
            ```python
            from prefect_kubernetes.credentials import KubernetesCredentials

            with KubernetesCredentials.get_client("core") as core_v1_client:
                for pod in core_v1_client.list_namespaced_pod():
                    print(pod.metadata.name)
            ```
        """
        client_config = configuration or Configuration()

        with ApiClient(configuration=client_config) as generic_client:
            try:
                yield self.get_resource_specific_client(client_type)
            finally:
                generic_client.rest_client.pool_manager.clear()

    def get_resource_specific_client(
        self,
        client_type: str,
    ) -> Union[AppsV1Api, BatchV1Api, CoreV1Api]:
        """
        Utility function for configuring a generic Kubernetes client.
        It will attempt to connect to a Kubernetes cluster in three steps with
        the first successful connection attempt becoming the mode of communication with
        a cluster:

        1. It will first attempt to use a `KubernetesCredentials` block's
        `cluster_config` to configure a client using
        `KubernetesClusterConfig.configure_client`.

        2. Attempt in-cluster connection (will only work when running on a pod).

        3. Attempt out-of-cluster connection using the default location for a
        kube config file.

        Args:
            client_type: The Kubernetes API client type for interacting with specific
                Kubernetes resources.

        Returns:
            KubernetesClient: An authenticated, resource-specific Kubernetes Client.

        Raises:
            ValueError: If `client_type` is not a valid Kubernetes API client type.
        """

        if self.cluster_config:
            self.cluster_config.configure_client()
        else:
            try:
                config.load_incluster_config()
            except ConfigException:
                config.load_kube_config()

        try:
            return K8S_CLIENT_TYPES[client_type]()
        except KeyError:
            raise ValueError(
                f"Invalid client type provided '{client_type}'."
                f" Must be one of {listrepr(K8S_CLIENT_TYPES.keys())}."
            )

get_client

Convenience method for retrieving a Kubernetes API client for deployment resources.

Parameters:

Name Type Description Default
client_type Literal['apps', 'batch', 'core', 'custom_objects']

The resource-specific type of Kubernetes client to retrieve.

 required

Yields:

Type Description
KubernetesClient

An authenticated, resource-specific Kubernetes API client.
Example 
from prefect_kubernetes.credentials import KubernetesCredentials

with KubernetesCredentials.get_client("core") as core_v1_client:
    for pod in core_v1_client.list_namespaced_pod():
        print(pod.metadata.name)
Source code in prefect_kubernetes/credentials.py 
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@contextmanager
def get_client(
    self,
    client_type: Literal["apps", "batch", "core", "custom_objects"],
    configuration: Optional[Configuration] = None,
) -> Generator[KubernetesClient, None, None]:
    """Convenience method for retrieving a Kubernetes API client for deployment resources.

    Args:
        client_type: The resource-specific type of Kubernetes client to retrieve.

    Yields:
        An authenticated, resource-specific Kubernetes API client.

    Example:
        ```python
        from prefect_kubernetes.credentials import KubernetesCredentials

        with KubernetesCredentials.get_client("core") as core_v1_client:
            for pod in core_v1_client.list_namespaced_pod():
                print(pod.metadata.name)
        ```
    """
    client_config = configuration or Configuration()

    with ApiClient(configuration=client_config) as generic_client:
        try:
            yield self.get_resource_specific_client(client_type)
        finally:
            generic_client.rest_client.pool_manager.clear()

get_resource_specific_client

Utility function for configuring a generic Kubernetes client. It will attempt to connect to a Kubernetes cluster in three steps with the first successful connection attempt becoming the mode of communication with a cluster:

  1. It will first attempt to use a KubernetesCredentials block's cluster_config to configure a client using KubernetesClusterConfig.configure_client.

  2. Attempt in-cluster connection (will only work when running on a pod).

  3. Attempt out-of-cluster connection using the default location for a kube config file.

Parameters:

Name Type Description Default
client_type str

The Kubernetes API client type for interacting with specific Kubernetes resources.

 required

Returns:

Name Type Description
KubernetesClient Union[AppsV1Api, BatchV1Api, CoreV1Api]

An authenticated, resource-specific Kubernetes Client.

Raises:

Type Description
ValueError

If client_type is not a valid Kubernetes API client type.
Source code in prefect_kubernetes/credentials.py 
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def get_resource_specific_client(
    self,
    client_type: str,
) -> Union[AppsV1Api, BatchV1Api, CoreV1Api]:
    """
    Utility function for configuring a generic Kubernetes client.
    It will attempt to connect to a Kubernetes cluster in three steps with
    the first successful connection attempt becoming the mode of communication with
    a cluster:

    1. It will first attempt to use a `KubernetesCredentials` block's
    `cluster_config` to configure a client using
    `KubernetesClusterConfig.configure_client`.

    2. Attempt in-cluster connection (will only work when running on a pod).

    3. Attempt out-of-cluster connection using the default location for a
    kube config file.

    Args:
        client_type: The Kubernetes API client type for interacting with specific
            Kubernetes resources.

    Returns:
        KubernetesClient: An authenticated, resource-specific Kubernetes Client.

    Raises:
        ValueError: If `client_type` is not a valid Kubernetes API client type.
    """

    if self.cluster_config:
        self.cluster_config.configure_client()
    else:
        try:
            config.load_incluster_config()
        except ConfigException:
            config.load_kube_config()

    try:
        return K8S_CLIENT_TYPES[client_type]()
    except KeyError:
        raise ValueError(
            f"Invalid client type provided '{client_type}'."
            f" Must be one of {listrepr(K8S_CLIENT_TYPES.keys())}."
        )
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