feat(kubernetes): Add styling based on current context (#4550)

* feat(kubernetes): Add styling based on current context

Add an ability to customize the configuration of the kubernetes module style, based on the current context.

A new variable is added to the config section, called environments, which is a list of possible customizations. Each such customization is an object with a context_pattern regex, which matches context name, and an optional style and icon that will override the global configuration, if the currently used context matched the context_pattern.

Based on multiple attempts to add per-context styling and symbols to the kubernetes module.

- https://github.com/starship/starship/pull/1568 by @lht https://github.com/lht -> base
- https://github.com/starship/starship/pull/614 by @nomaed https://github.com/nomaed -> naming, symbol, some tests

Rebased and combined by @jankatins

Contains the following squasched commits

- Rename to contexts and move aliases into contexts
- Move deprecated functions to a submodule
- Cleanup: ignore None-valued KubeCtxComponents
- Add regex func + clean up matching-context search
- Placate paper clip

Closes: https://github.com/starship/starship/issues/570

Co-authored-by: =?UTF-8?q?Boris=20Aranovic=CC=8C?= <nomaed@gmail.com>
Co-authored-by: Jan Katins <jasc@gmx.net>
Co-authored-by: Kevin Song <chips@ksong.dev>

* refactor(kubernetes): Remove options and use clearer names

* test(kubernetes): Handle duplicated contexts right

* refactor(kubernetes): Cleaner user matching

* fix(kubernetes): Only show warning in case of problems

* feat(kubernetes): Add back alias replacements

* refactor(kubernetes): Cleanup rust usage

---------

Co-authored-by: Haitao Li <lihaitao@gmail.com>
Co-authored-by: =?UTF-8?q?Boris=20Aranovic=CC=8C?= <nomaed@gmail.com>
Co-authored-by: Kevin Song <chips@ksong.dev>
Co-authored-by: David Knaack <davidkna@users.noreply.github.com>

1 files changed, 58 insertions, 26 deletions

diff --git a/docs/config/README.md b/docs/config/README.md
index 80d6ed377..2b171535b 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -2470,7 +2470,8 @@ kotlin_binary = 'kotlinc'
 Displays the current [Kubernetes context](https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig/#context) name and, if set, the namespace, user and cluster from the kubeconfig file.
 The namespace needs to be set in the kubeconfig file, this can be done via
 `kubectl config set-context starship-context --namespace astronaut`.
-Similarly the user and cluster can be set with `kubectl config set-context starship-context --user starship-user` and `kubectl config set-context starship-context --cluster starship-cluster`.
+Similarly, the user and cluster can be set with `kubectl config set-context starship-context --user starship-user`
+and `kubectl config set-context starship-context --cluster starship-cluster`.
 If the `$KUBECONFIG` env var is set the module will use that if not it will use the `~/.kube/config`.
 
 ::: tip
@@ -2486,18 +2487,45 @@ case the module will only be active in directories that match those conditions.
 
 ### Options
 
+::: warning
+
+The `context_aliases` and `user_aliases` options are deprecated. Use `contexts` and the corresponding `context_alias`
+and `user_alias` options instead.
+
+:::
+
 | Option              | Default                                            | Description                                                           |
 | ------------------- | -------------------------------------------------- | --------------------------------------------------------------------- |
 | `symbol`            | `'☸ '`                                             | A format string representing the symbol displayed before the Cluster. |
 | `format`            | `'[$symbol$context( \($namespace\))]($style) in '` | The format for the module.                                            |
 | `style`             | `'cyan bold'`                                      | The style for the module.                                             |
-| `context_aliases`   | `{}`                                               | Table of context aliases to display.                                  |
-| `user_aliases`      | `{}`                                               | Table of user aliases to display.                                     |
+| `context_aliases`*  | `{}`                                               | Table of context aliases to display.                                  |
+| `user_aliases`*     | `{}`                                               | Table of user aliases to display.                                     |
 | `detect_extensions` | `[]`                                               | Which extensions should trigger this module.                          |
 | `detect_files`      | `[]`                                               | Which filenames should trigger this module.                           |
 | `detect_folders`    | `[]`                                               | Which folders should trigger this modules.                            |
+| `contexts`          | `[]`                                               | Customized styles and symbols for specific contexts.                  |
 | `disabled`          | `true`                                             | Disables the `kubernetes` module.                                     |
 
+*: This option is deprecated, please add `contexts` with the corresponding `context_alias` and `user_alias` options instead.
+
+To customize the style of the module for specific environments, use the following configuration as
+part of the `contexts` list:
+
+| Variable          | Description                                                                              |
+| ----------------- | ---------------------------------------------------------------------------------------- |
+| `context_pattern` | **Required** Regular expression to match current Kubernetes context name.                |
+| `user_pattern`    | Regular expression to match current Kubernetes user name.                                |
+| `context_alias`   | Context alias to display instead of the full context name.                               |
+| `user_alias`      | User alias to display instead of the full user name.                                     |
+| `style`           | The style for the module when using this context. If not set, will use module's style.   |
+| `symbol`          | The symbol for the module when using this context. If not set, will use module's symbol. |
+
+Note that all regular expression are anchored with `^<pattern>$` and so must match the whole string. The `*_pattern`
+regular expressions may contain capture groups, which can be referenced in the corresponding alias via `$name` and `$N`
+(see example below and the
+[rust Regex::replace() documentation](https://docs.rs/regex/latest/regex/struct.Regex.html#method.replace)).
+
 ### Variables
 
 | Variable  | Example              | Description                              |
@@ -2519,13 +2547,9 @@ case the module will only be active in directories that match those conditions.
 [kubernetes]
 format = 'on [⛵ ($user on )($cluster in )$context \($namespace\)](dimmed green) '
 disabled = false
-[kubernetes.context_aliases]
-'dev.local.cluster.k8s' = 'dev'
-'.*/openshift-cluster/.*' = 'openshift'
-'gke_.*_(?P<var_cluster>[\w-]+)' = 'gke-$var_cluster'
-[kubernetes.user_aliases]
-'dev.local.cluster.k8s' = 'dev'
-'root/.*' = 'root'
+contexts = [
+  { context_pattern = "dev.local.cluster.k8s", style = "green", symbol = "💔 " },
+]
 ```
 
 Only show the module in directories that contain a `k8s` file.
@@ -2538,29 +2562,37 @@ disabled = false
 detect_files = ['k8s']
 ```
 
-#### Regex Matching
+#### Kubernetes Context specific config
 
-Additional to simple aliasing, `context_aliases` and `user_aliases` also supports
-extended matching and renaming using regular expressions.
-
-The regular expression must match on the entire kube context,
-capture groups can be referenced using `$name` and `$N` in the replacement.
-This is more explained in the [regex crate](https://docs.rs/regex/1.5.4/regex/struct.Regex.html#method.replace) documentation.
-
-Long and automatically generated cluster names can be identified
-and shortened using regular expressions:
+The `contexts` configuration option is used to customise what the current Kubernetes context name looks
+like (style and symbol) if the name matches the defined regular expression.
 
 ```toml
-[kubernetes.context_aliases]
-# OpenShift contexts carry the namespace and user in the kube context: `namespace/name/user`:
-'.*/openshift-cluster/.*' = 'openshift'
-# Or better, to rename every OpenShift cluster at once:
-'.*/(?P<var_cluster>[\w-]+)/.*' = '$var_cluster'
+# ~/.config/starship.toml
 
+[[kubernetes.contexts]]
+# "bold red" style + default symbol when Kubernetes current context name equals "production" *and* the current user
+# equals "admin_user"
+context_pattern = "production"
+user_pattern = "admin_user"
+style = "bold red"
+context_alias = "prod"
+user_alias = "admin"
+
+[[kubernetes.contexts]]
+# "green" style + a different symbol when Kubernetes current context name contains openshift
+context_pattern = ".*openshift.*"
+style = "green"
+symbol = "💔 "
+context_alias = "openshift"
+
+[[kubernetes.contexts]]
+# Using capture groups
 # Contexts from GKE, AWS and other cloud providers usually carry additional information, like the region/zone.
 # The following entry matches on the GKE format (`gke_projectname_zone_cluster-name`)
 # and renames every matching kube context into a more readable format (`gke-cluster-name`):
-'gke_.*_(?P<var_cluster>[\w-]+)' = 'gke-$var_cluster'
+context_pattern = "gke_.*_(?P<cluster>[\\w-]+)"
+context_alias = "gke-$cluster"
 ```
 
 ## Line Break