Add CLI tool and release automation

.github/workflows/ci.yml

@@ -105,3 +105,6 @@ jobs:
 
     - name: Build
       run: go build -v ./...
+
+    - name: Build CLI binary
+      run: go build -v -o configdiff ./cmd/configdiff

.github/workflows/release.yml

@@ -0,0 +1,47 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+  packages: write
+
+jobs:
+  goreleaser:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Fetch all tags
+        run: git fetch --force --tags
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.22'
+          cache: true
+
+      - name: Run tests
+        run: go test -v ./...
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v6
+        with:
+          distribution: goreleaser
+          version: latest
+          args: release --clean
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          HOMEBREW_TAP_GITHUB_TOKEN: ${{ secrets.HOMEBREW_TAP_GITHUB_TOKEN }}
+
+      - name: Upload assets
+        uses: actions/upload-artifact@v4
+        with:
+          name: release-artifacts
+          path: dist/*

.gitignore

@@ -30,3 +30,4 @@ go.work
 # Build artifacts
 dist/
 build/
+/configdiff

.goreleaser.yml

@@ -0,0 +1,115 @@
+version: 2
+
+before:
+  hooks:
+    - go mod tidy
+    - go test ./...
+
+builds:
+  - id: configdiff
+    main: ./cmd/configdiff
+    binary: configdiff
+    env:
+      - CGO_ENABLED=0
+    goos:
+      - linux
+      - darwin
+      - windows
+    goarch:
+      - amd64
+      - arm64
+      - arm
+    goarm:
+      - "6"
+      - "7"
+    ignore:
+      - goos: windows
+        goarch: arm
+      - goos: windows
+        goarch: arm64
+    ldflags:
+      - -s -w
+      - -X main.version={{.Version}}
+      - -X main.commit={{.Commit}}
+      - -X main.date={{.Date}}
+      - -X main.builtBy=goreleaser
+
+archives:
+  - id: default
+    format: tar.gz
+    name_template: >-
+      {{ .ProjectName }}_
+      {{- .Version }}_
+      {{- .Os }}_
+      {{- if eq .Arch "amd64" }}x86_64
+      {{- else if eq .Arch "386" }}i386
+      {{- else }}{{ .Arch }}{{ end }}
+      {{- if .Arm }}v{{ .Arm }}{{ end }}
+    format_overrides:
+      - goos: windows
+        format: zip
+    files:
+      - README.md
+      - LICENSE
+      - CONTRIBUTING.md
+
+checksum:
+  name_template: "checksums.txt"
+
+snapshot:
+  version_template: "{{ incpatch .Version }}-next"
+
+changelog:
+  sort: asc
+  use: github
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+      - "^chore:"
+      - Merge pull request
+      - Merge branch
+  groups:
+    - title: Features
+      regexp: "^.*feat[(\\w)]*:+.*$"
+      order: 0
+    - title: "Bug fixes"
+      regexp: "^.*fix[(\\w)]*:+.*$"
+      order: 1
+    - title: "Enhancements"
+      regexp: "^.*enhance[(\\w)]*:+.*$"
+      order: 2
+    - title: Others
+      order: 999
+
+release:
+  github:
+    owner: pfrederiksen
+    name: configdiff
+  draft: false
+  prerelease: auto
+  mode: replace
+  header: |
+    ## configdiff {{ .Tag }} ({{ .Date }})
+
+    Install with Homebrew:
+    ```bash
+    brew install pfrederiksen/tap/configdiff
+    ```
+
+    Or download binaries directly from the assets below.
+
+brews:
+  - name: configdiff
+    repository:
+      owner: pfrederiksen
+      name: homebrew-tap
+      token: "{{ .Env.HOMEBREW_TAP_GITHUB_TOKEN }}"
+    directory: Formula
+    homepage: https://github.com/pfrederiksen/configdiff
+    description: "Semantic, human-grade diffs for YAML/JSON/HCL configuration files"
+    license: MIT
+    test: |
+      system "#{bin}/configdiff version"
+    install: |
+      bin.install "configdiff"

README.md

@@ -16,12 +16,52 @@ Perfect for GitOps reviews, CI checks, configuration drift detection, and any sc
 
 ## Installation
 
+### CLI Tool
+
+```bash
+# Homebrew (macOS/Linux)
+brew install pfrederiksen/tap/configdiff
+
+# Or download binaries from GitHub releases
+# https://github.com/pfrederiksen/configdiff/releases
+```
+
+### Go Library
+
 ```bash
 go get github.com/pfrederiksen/configdiff
 ```
 
 ## Quick Start
 
+### CLI Usage
+
+```bash
+# Basic comparison
+configdiff old.yaml new.yaml
+
+# Compare with stdin
+kubectl get deploy myapp -o yaml | configdiff old.yaml -
+
+# Different output formats
+configdiff old.yaml new.yaml -o compact
+configdiff old.yaml new.yaml -o json
+configdiff old.yaml new.yaml -o patch
+
+# Ignore specific paths
+configdiff old.yaml new.yaml -i /metadata/generation -i /status/*
+
+# Array-as-set comparison
+configdiff old.yaml new.yaml --array-key /spec/containers=name
+
+# Exit code mode for CI
+if configdiff old.yaml new.yaml --exit-code; then
+  echo "No changes detected"
+fi
+```
+
+### Library Usage
+
 ```go
 package main
 
@@ -67,6 +107,48 @@ env: production
 }
 ```
 
+## CLI Reference
+
+### Flags
+
+```
+Format Options:
+  -f, --format string          Input format (yaml, json, auto) (default "auto")
+      --old-format string      Old file format override
+      --new-format string      New file format override
+
+Diff Options:
+  -i, --ignore strings         Paths to ignore (can be repeated)
+      --array-key strings      Array paths to key fields (format: path=key)
+      --numeric-strings        Coerce numeric strings to numbers
+      --bool-strings           Coerce bool strings to booleans
+      --stable-order           Sort output deterministically (default true)
+
+Output Options:
+  -o, --output string          Output format (report, compact, json, patch) (default "report")
+      --no-color               Disable colored output
+      --max-value-length int   Truncate values longer than N chars (default 80)
+  -q, --quiet                  Quiet mode (no output)
+      --exit-code              Exit with code 1 if differences found
+
+Other:
+  -h, --help                   Help for configdiff
+  -v, --version                Version information
+```
+
+### Output Formats
+
+- **report** (default): Detailed human-friendly report with values
+- **compact**: Summary with paths only
+- **json**: JSON-serialized changes array
+- **patch**: JSON Patch (RFC 6902) format
+
+### Exit Codes
+
+- `0`: Success (no differences, or differences displayed)
+- `1`: Differences found (when using `--exit-code`)
+- `1`: Error occurred
+
 ## Features
 
 ### Normalized Tree Representation
@@ -425,11 +507,88 @@ type Options struct {
 
 ## Use Cases
 
-- **GitOps Reviews**: Understand exactly what changed in infrastructure configs
-- **CI/CD Checks**: Validate configuration changes before deployment
-- **Drift Detection**: Compare actual vs desired state in deployed systems
-- **Configuration Management**: Track changes across environments
-- **Multi-Format Comparison**: Compare YAML and JSON representations of the same config
+### Kubernetes Deployment Reviews
+
+```bash
+# Compare deployed config vs source
+kubectl get deployment myapp -o yaml > deployed.yaml
+configdiff deploy/myapp.yaml deployed.yaml -i /metadata/generation -i /status/*
+
+# Review Helm chart changes
+helm template myapp ./chart --values prod.yaml > new.yaml
+configdiff current-prod.yaml new.yaml --array-key /spec/template/spec/containers=name
+```
+
+### GitOps Pull Request Validation
+
+```bash
+# In CI pipeline - fail if unexpected changes
+git show main:config/production.yaml > old.yaml
+configdiff old.yaml config/production.yaml \
+  -i /metadata/annotations/last-modified \
+  --exit-code || echo "Configuration changes detected"
+```
+
+### Infrastructure Drift Detection
+
+```bash
+# Compare actual vs desired state
+terraform show -json > actual.json
+configdiff desired-state.json actual.json \
+  -o compact \
+  --ignore /timestamps/* \
+  --ignore /metadata/id
+```
+
+### Configuration Management
+
+```bash
+# Compare configs across environments
+configdiff config/staging.yaml config/production.yaml \
+  --array-key /services=name \
+  --array-key /databases=host
+
+# Cross-format validation (YAML source, JSON API)
+curl -s https://api.example.com/config > api-config.json
+configdiff local-config.yaml api-config.json \
+  --numeric-strings \
+  --bool-strings
+```
+
+### CI/CD Integration
+
+```yaml
+# GitHub Actions example
+- name: Validate config changes
+  run: |
+    configdiff old-config.yaml new-config.yaml --exit-code
+  continue-on-error: false
+
+# Only specific paths allowed to change
+- name: Check for unexpected changes
+  run: |
+    if configdiff base.yaml new.yaml -i /version -i /timestamp --quiet --exit-code; then
+      echo "Only version and timestamp changed - OK"
+    else
+      echo "Unexpected changes detected - review required"
+      exit 1
+    fi
+```
+
+### Docker Compose Migration
+
+```bash
+# Compare v2 vs v3 compose files
+configdiff docker-compose-v2.yaml docker-compose-v3.yaml \
+  --array-key /services=name \
+  -o report
+```
+
+**Key Benefits:**
+- Semantic understanding of configuration structure
+- Filter out noise (timestamps, auto-generated fields)
+- CI-friendly exit codes for automation
+- Multiple output formats for different use cases
 
 ## Testing