Watch the diff change of the kubernetes resource

k8s-watch-diff.sh

#!/bin/bash

# Define the resource and namespace to be monitored
RESOURCE_TYPE=$1  # Can be replaced with other resource types, such as deployments, services, etc.
NAMESPACE=$2   # Can be replaced with the actual namespace
RESOURCE_NAME=$3  # If a specific resource name is specified, only monitor that resource; leave empty to monitor all resources of that type

# Get the initial resource YAML
PREVIOUS_YAML=$(kubectl get $RESOURCE_TYPE $RESOURCE_NAME -n $NAMESPACE -o yaml)$'\n'

echo "Start monitoring changes in $RESOURCE_TYPE $RESOURCE_NAME resources..."

kubectl get $RESOURCE_TYPE $RESOURCE_NAME -n $NAMESPACE -o yaml -w | while true; do
  CURRENT_YAML=""
  while IFS= read -r -t 3 line; do
    if [[ $line == "---" ]]; then
      break
    fi
    CURRENT_YAML+="$line"$'\n'
  done

  if [ -n "$CURRENT_YAML" ]; then
    if [ "$CURRENT_YAML" != "$PREVIOUS_YAML" ]; then
      echo "Detected changes in $RESOURCE_TYPE $RESOURCE_NAME resource:"
      sdiff -s <(echo "$PREVIOUS_YAML") <(echo "$CURRENT_YAML")
      PREVIOUS_YAML=$CURRENT_YAML
    fi
  fi
done

Usage:

./k8s-watch-diff.sh deploy default hello

watch the deployment hello in namespace default changes and output the diff.