Stalk - Watch your Kubernetes Resources change

stalk is a command line tool to watch a given set of resources and print the diffs for every change.

Installation

You can download a binary for the latest release on GitHub or install stalk via Go:

go install go.xrstf.de/stalk@latest

Usage

Usage of ./stalk:
  -c, --context-lines int       Number of context lines to show in diffs (default 3)
  -w, --diff-by-line            Compare entire lines and do not highlight changes within words
  -h, --hide stringArray        Path expression to hide in output (can be given multiple times)
      --hide-managed            Do not show managed fields (default true)
  -j, --jsonpath string         JSON path expression to transform the output (applied before the --show paths)
      --kubeconfig string       Kubeconfig file to use (uses $KUBECONFIG by default)
  -l, --labels string           Label-selector as an alternative to specifying resource names
  -n, --namespace stringArray   Kubernetes namespace to watch resources in (supports glob expression) (can be given multiple times)
  -s, --show stringArray        Path expression to include in output (can be given multiple times) (applied before the --hide paths)
  -e, --show-empty              Do not hide changes which would produce no diff because of --hide/--show/--jsonpath
  -v, --verbose                 Enable more verbose output
  -V, --version                 Show version info and exit immediately

Examples

stalk -n kube-system deployments

Would watch all Deployments in the kube-system namespace. You can give the -n flag multiple times and it even supports glob expressions (e.g. -n 'kube-*').

stalk -n kube-system deployments,statefulsets,configmaps

Would also watch StatefulSets and ConfigMaps. Note that only a single namespace can be given.

stalk -n kube-system deployments,statefulsets,configmaps,clusterroles

You can include Cluster-wide resources.

stalk -n kube-system deployments --labels "key=value"

A label selector can be given. It will be applied to all given resource kinds.

stalk -n kube-system deployments kube-apiserver kube-controller-manager kube-scheduler

You can also list the resources you are interested in by name. You can give multiple names and they support glob expressions.

stalk -n kube-system deployments --hide-managed-fields=false

By default metadata.managedFields is hidden. You can disable that if you like.

stalk -n kube-system deployments --hide spec --hide metadata

Show only the status. You can combine --hide (-h) and --show (-s) as you like, but show expressions are always applied before hide expressions.

stalk -n kube-system deployments --show spec --hide spec.labels

This should the entire spec, except the labels.

stalk -n kube-system deployments --jsonpath "{.metadata.name}"

JSONPaths are also supported, but only a single one can be given and it's always applied first (before --show and --hide). If your JSONPath results in a scalar value (like {.metadata.name}), the --show and --hide rules are not applied anymore.

kubectl get deployments -o yaml --watch | stalk - --jsonpath "{.metadata.name}"

If you want, you can also pipe kubectl's output (a series of YAML documents) into stalk. Note that in this case filtering by label selector or resource name is not available, but all other formatting options work. You must use a single - argument to indicate reading from stdin.

License

MIT