Add GitHub Actions workflow for building and releasing Go project

Author: Senk02

.github/workflows/build-and-release.yaml

@@ -0,0 +1,56 @@
+name: Build and Release Kdiff
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  release:
+    types: [published]
+
+permissions:
+  contents: write
+
+jobs:
+  build-and-compress:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Go environment
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.24.3'
+
+    - name: Run 'compress' target from Makefile
+      run: make compress
+
+    - name: Upload kdiff.tgz for release (as artifact)
+      uses: actions/upload-artifact@v4
+      with:
+        name: kdiff-linux-amd64
+        path: kdiff.tgz
+
+  create-github-release:
+    needs: build-and-compress
+    runs-on: ubuntu-latest
+
+    if: github.event_name == 'release' && github.event.action == 'published'
+
+    steps:
+    - name: Download kdiff.tgz artifact
+      uses: actions/download-artifact@v4
+      with:
+        name: kdiff-linux-amd64
+        path: .
+
+    - name: Create GitHub Release and Upload Asset
+      uses: softprops/action-gh-release@v1
+      with:
+        files: kdiff.tgz
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

LICENSE

@@ -0,0 +1,9 @@
+CORES := $(shell nproc)
+
+build:
+	CGO_ENABLED=0 GOMAXPROCS=$(CORES) go build -p $(CORES) -ldflags="-s -w" -o kdiff
+
+compress: build
+	tar -cvzf kdiff.tgz ./kdiff
+
+.PHONY: build compress

Makefile

@@ -0,0 +1,194 @@
+# 🚀 kdiff
+
+<div align="center">
+  
+![Go](https://img.shields.io/badge/go-%2300ADD8.svg?style=for-the-badge&logo=go&logoColor=white)
+![Kubernetes](https://img.shields.io/badge/kubernetes-%23326ce5.svg?style=for-the-badge&logo=kubernetes&logoColor=white)
+![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg?style=for-the-badge)
+
+**A pretty command-line tool to monitor Kubernetes pod resource usage vs requests**
+
+Compare actual CPU and memory usage against requested resources with color-coded output for easy identification of over/under-utilized pods.
+
+</div>
+
+## ✨ Features
+
+- 🎨 **Color-coded output** - Instantly identify resource utilization patterns
+- 📊 **Detailed comparison** - See requested vs actual CPU and memory usage
+- 🌐 **Multi-namespace support** - Check single namespace or all at once
+- 🎯 **Flexible filtering** - Show only CPU, memory, or both
+- ⚡ **Performance focused** - Fast scanning with progress indicators
+- 🔧 **Customizable thresholds** - Adjust color coding to your needs
+- 📈 **Usage percentage** - Clear percentage differences for easy analysis
+
+## 🎨 Color Legend
+
+- <span style="color: cyan">**Cyan**</span> - Very under-utilized (< -90% by default)
+- <span style="color: green">**Green**</span> - Under-utilized (-90% to -20% by default)
+- <span style="color: yellow">**Yellow**</span> - Well-utilized (-20% to 0% by default)
+- <span style="color: red">**Red**</span> - Over-utilized (> 0% by default)
+- <span style="color: magenta">**Magenta**</span> - No resource requests set
+
+## 🚀 Installation
+
+### Option 1: Download Pre-built Binary
+
+```bash
+# Download the latest release for your platform
+curl -L https://github.com/Senk02/kdiff/releases/latest/download/kdiff-linux-amd64 -o kdiff
+chmod +x kdiff
+sudo mv kdiff /usr/local/bin/
+```
+
+### Option 2: Build from Source
+
+```bash
+# Clone the repository
+git clone https://github.com/Senk02/kdiff.git
+cd kdiff
+
+# Build the binary
+make build
+
+sudo chmod +x kdiff
+
+# Optional: Install to PATH
+sudo mv kdiff /usr/local/bin/
+```
+
+## 📋 Prerequisites
+
+- Kubernetes cluster with `metrics-server` installed and running
+- Valid `kubeconfig` file (usually at `~/.kube/config`)
+- Go 1.19+ (if building from source)
+
+## 🔧 Usage
+
+### Basic Usage
+
+```bash
+# Check current namespace
+kdiff
+
+# Check specific namespace
+kdiff -n kube-system
+
+# Check all namespaces
+kdiff -a
+```
+
+### Advanced Options
+
+```bash
+# Show only CPU usage across all namespaces
+kdiff -a -o cpu
+
+# Show only memory usage in specific namespace
+kdiff -n production -o memory
+
+# Show only pods exceeding their requests
+kdiff -d
+
+# Ignore pods without resource requests set
+kdiff -i
+
+# Combine filters: only over-utilized pods with requests set
+kdiff -d -i
+
+# Use specific kubeconfig context
+kdiff --context my-cluster-context
+```
+
+### Custom Color Thresholds
+
+```bash
+# Customize when colors appear (values are percentages)
+kdiff --color-red 10 --color-yellow -10 --color-cyan -75
+
+# This means:
+# Red: > 10% over requests
+# Yellow: -10% to 10% of requests  
+# Green: -75% to -10% under requests
+# Cyan: < -75% under requests
+```
+
+## 📊 Example Output
+
+```
+Processing 3 running pods...
+Progress: 3/3 pods - Complete!
+
++------------------+------------------+-------------+--------------+----------------+-------------+---------------+
+|       POD        | REQUESTED MEMORY | USED MEMORY | MEMORY DIFF  | REQUESTED CPU | USED CPU    | CPU DIFF (%)  |
++------------------+------------------+-------------+--------------+----------------+-------------+---------------+
+| nginx-deployment | 128.0Mi          | 45.2Mi      | -64.69%      | 100m          | 23m         | -77.00%       |
+| api-server       | 512.0Mi          | 634.1Mi     | 23.85%       | 200m          | 156m        | -22.00%       |
+| database         | 1.0Gi            | 890.3Mi     | -13.18%      | 500m          | 520m        | 4.00%         |
++------------------+------------------+-------------+--------------+----------------+-------------+---------------+
+```
+
+## 🛠️ Command Line Options
+
+| Flag | Description |
+|------|-------------|
+| `-n <namespace>` | Specify namespace to check (defaults to current context) |
+| `-a` | Check all namespaces |
+| `-o <filter>` | Filter output to 'cpu' or 'memory' |
+| `-d` | Only show pods with usage over requests |
+| `-i, --ignore-unset` | Ignore pods without resource requests set |
+| `--context <context>` | Use specific kubeconfig context |
+| `-h` | Show help message |
+| `--color-red <float>` | Threshold for red color (default: 0.0) |
+| `--color-yellow <float>` | Threshold for yellow color (default: -20.0) |
+| `--color-cyan <float>` | Threshold for cyan color (default: -90.0) |
+
+## 🤝 Contributing
+
+Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.
+
+1. Fork the repository
+2. Create your feature branch (`git checkout -b feature/AmazingFeature`)
+3. Commit your changes (`git commit -m 'Add some AmazingFeature'`)
+4. Push to the branch (`git push origin feature/AmazingFeature`)
+5. Open a Pull Request
+
+## 📝 License
+
+This project is licensed under the GNU GPL V3 License - see the [LICENSE](LICENSE) file for details.
+
+## ☕ Support
+
+If you find this tool helpful, consider supporting the development:
+
+<div align="center">
+
+[![ko-fi](https://ko-fi.com/img/githubbutton_sm.svg)](https://ko-fi.com/senk0)
+
+</div>
+
+## 🐛 Troubleshooting
+
+### Common Issues
+
+**"Error connecting to metrics API"**
+- Ensure `metrics-server` is installed: `kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml`
+- Check if metrics-server pods are running: `kubectl get pods -n kube-system | grep metrics-server`
+
+**"No running pods found"**
+- Verify you're connected to the right cluster: `kubectl cluster-info`
+- Check if pods exist in the namespace: `kubectl get pods -n <namespace>`
+
+**"Error creating kubeconfig"**
+- Ensure your kubeconfig file exists and is valid: `kubectl config view`
+- Try specifying a different context: `kdiff --context <context-name>`
+
+---
+
+<div align="center">
+  
+**Made with ❤️ for the Kubernetes community**
+
+[Report Bug](https://github.com/Senk02/kdiff/issues) · [Request Feature](https://github.com/Senk02/kdiff/issues)
+
+</div>

README.md

@@ -0,0 +1,58 @@
+module github.com/Senk02/kdiff
+
+go 1.24.3
+
+require (
+	github.com/fatih/color v1.18.0
+	github.com/olekukonko/tablewriter v1.0.7
+	k8s.io/api v0.33.1
+	k8s.io/apimachinery v0.33.1
+	k8s.io/client-go v0.33.1
+	k8s.io/metrics v0.33.1
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/emicklei/go-restful/v3 v3.11.0 // indirect
+	github.com/fxamacker/cbor/v2 v2.7.0 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-openapi/jsonpointer v0.21.0 // indirect
+	github.com/go-openapi/jsonreference v0.20.2 // indirect
+	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/google/gnostic-models v0.6.9 // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/olekukonko/errors v0.0.0-20250405072817-4e6d85265da6 // indirect
+	github.com/olekukonko/ll v0.0.8 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/x448/float16 v0.8.4 // indirect
+	golang.org/x/net v0.38.0 // indirect
+	golang.org/x/oauth2 v0.27.0 // indirect
+	golang.org/x/sys v0.31.0 // indirect
+	golang.org/x/term v0.30.0 // indirect
+	golang.org/x/text v0.23.0 // indirect
+	golang.org/x/time v0.9.0 // indirect
+	google.golang.org/protobuf v1.36.5 // indirect
+	gopkg.in/evanphx/json-patch.v4 v4.12.0 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/klog/v2 v2.130.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20250318190949-c8a335a9a2ff // indirect
+	k8s.io/utils v0.0.0-20241104100929-3ea5e8cea738 // indirect
+	sigs.k8s.io/json v0.0.0-20241010143419-9aa6b5e7a4b3 // indirect
+	sigs.k8s.io/randfill v1.0.0 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.6.0 // indirect
+	sigs.k8s.io/yaml v1.4.0 // indirect
+)