kubernetes-client / python

Retrieving Lists of Resources

The Kubernetes Python client offers methods for retrieving lists of resources. These methods are designed to be efficient and flexible, allowing you to retrieve specific sets of resources based on your needs.

Limiting the Number of Results

You can use the limit parameter to control the maximum number of items returned in a list operation.

Parameter: limit (int)

Description: Specifies the maximum number of responses to return for a list call. If more items exist, the server will set the continue field on the list metadata to a value that can be used with the same initial query to retrieve the next set of results. Setting a limit may return fewer than the requested amount of items (up to zero items) in the event all requested objects are filtered out. The continue field should only be used to determine whether more results are available. Servers may choose not to support the limit argument and will return all of the available results. If limit is specified and the continue field is empty, you can assume that no more results are available. This field is not supported if watch is true.

Example:

from kubernetes import client, config
          
          # Load the Kubernetes configuration
          config.load_kube_config()
          
          # Create an instance of the API client
          api = client.NetworkingV1Api()
          
          # Retrieve a list of Ingress resources with a limit of 5
          ingresses = api.list_namespaced_ingress(namespace="default", limit=5)
          
          # Print the number of Ingress resources retrieved
          print(f"Number of Ingress resources: {len(ingresses.items)}")

Source:

Pagination with _continue

The _continue parameter is used to retrieve the next set of results in a paginated list operation.

Parameter: _continue (str)

Description: Specifies the continuation token for paginated results.

Example:

from kubernetes import client, config
          
          # Load the Kubernetes configuration
          config.load_kube_config()
          
          # Create an instance of the API client
          api = client.NetworkingV1Api()
          
          # Retrieve the first page of Ingress resources
          ingresses = api.list_namespaced_ingress(namespace="default", limit=5)
          
          # Check if there are more results
          if ingresses.metadata.continue_:
              # Retrieve the next page of results using the continuation token
              next_page = api.list_namespaced_ingress(namespace="default", limit=5, _continue=ingresses.metadata.continue_)
          
              # Process the next page of results
              print(f"Number of Ingress resources on the next page: {len(next_page.items)}")

Source:

Filtering Resources

You can filter the list of resources using the field_selector and label_selector parameters.

Parameter: field_selector (str)

Description: A selector to restrict the list of returned objects by their fields. Defaults to everything.

Parameter: label_selector (str)

Description: A selector to restrict the list of returned objects by their labels. Defaults to everything.

Example:

from kubernetes import client, config
          
          # Load the Kubernetes configuration
          config.load_kube_config()
          
          # Create an instance of the API client
          api = client.NetworkingV1Api()
          
          # Retrieve a list of Ingress resources with a specific label
          ingresses = api.list_namespaced_ingress(namespace="default", label_selector="app=my-app")
          
          # Print the number of Ingress resources retrieved
          print(f"Number of Ingress resources with 'app=my-app' label: {len(ingresses.items)}")

Source:

Other Parameters

The list methods accept several other parameters to fine-tune your resource retrieval.

Parameter: resource_version (str)

Description: When specified with a watch call, shows changes that occur after that particular version of a resource. Defaults to changes from the beginning of history.

Parameter: resource_version_match (str)

Description: resourceVersionMatch determines how resourceVersion is applied to list calls. It is highly recommended to use resourceVersionMatch field for list calls with resourceVersion to ensure that you are seeing the latest state of the resources. Possible enum values: [“Include”, “Exact”, “None”]

Parameter: send_initial_events (bool)

Description: If true, returned list will include resource that matches the resourceVersion.

Parameter: timeout_seconds (int)

Description: Timeout for the list/watch call.

Parameter: watch (bool)

Description: Watch for changes to the described resources and return them as a stream of add, update, and remove notifications. Specify resourceVersion.

Source:

Accessing List Items

List methods return an object representing the list of resources. This object provides access to the individual items in the list.

Example:

from kubernetes import client, config
          
          # Load the Kubernetes configuration
          config.load_kube_config()
          
          # Create an instance of the API client
          api = client.NetworkingV1Api()
          
          # Retrieve a list of Ingress resources
          ingresses = api.list_namespaced_ingress(namespace="default")
          
          # Iterate over the list items
          for ingress in ingresses.items:
              # Print the name of each Ingress resource
              print(ingress.metadata.name)

Source:

Documentation

For detailed information on each parameter and available resource lists, refer to the documentation for the specific API client.

Example:


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