dynamic background color for custom prompt element in Powerlevel9k

Question

I am using the awesome Powerlevel9k theme for my Zsh.

I defined a custom kubecontext element to show my kubernetes cluster (context) and namespace (see code below).

While I conditionally set the foreground color through the color variable I would like to set the background color instead to be able to better see when I work on the production cluster. Is that somehow possible with Powerlevel9k? All I could find is that I can set the background color of the prompt element statically with POWERLEVEL9K_CUSTOM_KUBECONTEXT_BACKGROUND='075'

# Kubernetes Current Context/Namespace
custom_prompt_kubecontext() {
  local kubectl_version="$(kubectl version --client 2>/dev/null)"

  if [[ -n "$kubectl_version" ]]; then
    # Get the current Kuberenetes context
    local cur_ctx=$(kubectl config view -o=jsonpath='{.current-context}')
    cur_namespace="$(kubectl config view -o=jsonpath="{.contexts[?(@.name==\"${cur_ctx}\")].context.namespace}")"
    # If the namespace comes back empty set it default.
    if [[ -z "${cur_namespace}" ]]; then
      cur_namespace="default"
    fi

    local k8s_final_text="$cur_ctx/$cur_namespace"

    local color='%F{black}'
    [[ $cur_ctx == "prod" ]] && color='%F{196}'
    echo -n "%{$color%}\U2388  $k8s_final_text%{%f%}" # \U2388 is Kubernetes Icon

    #"$1_prompt_segment" "$0" "$2" "magenta" "black" "$k8s_final_text" "KUBERNETES_ICON"
  fi
}

POWERLEVEL9K_CUSTOM_KUBECONTEXT="custom_prompt_kubecontext"

# Powerlevel9k configuration
POWERLEVEL9K_LEFT_PROMPT_ELEMENTS=(context dir vcs custom_kubecontext)

Here is a screenshot of the current setup in action:

Answer 1

Disclaimer: I'm the author of powerlevel10k.

No, this is not possible in powerlevel9k. It is, however, possible in powerlevel10k. Powerlevel10k is backward compatible with powerlevel9k configuration, meaning that you won't have to change any POWERLEVEL9K parameters if you decide to switch.

Powerlevel10k has several advantages over its predecessor:

1. It's over 10 times faster.
2. It has a builtin configuration wizard. Type p10k configure to access it.
3. It has many new features. One of them is relevant to you. The builtin kubecontext supports context classes that allow you to style this prompt segment differently depending on which kubernetes context is currently active. Here's the excerpt from the configuration that p10k configure generates:

# Kubernetes context classes for the purpose of using different colors, icons and expansions with
# different contexts.
#
# POWERLEVEL9K_KUBECONTEXT_CLASSES is an array with even number of elements. The first element
# in each pair defines a pattern against which the current kubernetes context gets matched.
# More specifically, it's P9K_CONTENT prior to the application of context expansion (see below)
# that gets matched. If you unset all POWERLEVEL9K_KUBECONTEXT_*CONTENT_EXPANSION parameters,
# you'll see this value in your prompt. The second element of each pair in
# POWERLEVEL9K_KUBECONTEXT_CLASSES defines the context class. Patterns are tried in order. The
# first match wins.
#
# For example, given these settings:
#
#   typeset -g POWERLEVEL9K_KUBECONTEXT_CLASSES=(
#     '*prod*'  PROD
#     '*test*'  TEST
#     '*'       DEFAULT)
#
# If your current kubernetes context is "deathray-testing/default", its class is TEST
# because "deathray-testing/default" doesn't match the pattern '*prod*' but does match '*test*'.
#
# You can define different colors, icons and content expansions for different classes:
#
#   typeset -g POWERLEVEL9K_KUBECONTEXT_TEST_FOREGROUND=0
#   typeset -g POWERLEVEL9K_KUBECONTEXT_TEST_BACKGROUND=2
#   typeset -g POWERLEVEL9K_KUBECONTEXT_TEST_VISUAL_IDENTIFIER_EXPANSION='⭐'
#   typeset -g POWERLEVEL9K_KUBECONTEXT_TEST_CONTENT_EXPANSION='> ${P9K_CONTENT} <'
typeset -g POWERLEVEL9K_KUBECONTEXT_CLASSES=(
    # '*prod*'  PROD    # These values are examples that are unlikely
    # '*test*'  TEST    # to match your needs. Customize them as needed.
    '*'       DEFAULT)
typeset -g POWERLEVEL9K_KUBECONTEXT_DEFAULT_FOREGROUND=7
typeset -g POWERLEVEL9K_KUBECONTEXT_DEFAULT_BACKGROUND=5
typeset -g POWERLEVEL9K_KUBECONTEXT_DEFAULT_VISUAL_IDENTIFIER_EXPANSION='⎈'

You can also customize the text content of kubecontext. You'll find more info in ~/.p10k.zsh once you run p10k configure. Oh, and kubecontext is about 1000 times faster in powerlevel10k.