feat: add sample cli and build worrkflow

Author: evilmonkeyinc

.github/workflows/release-build.yaml

@@ -0,0 +1,34 @@
+name: Release Build
+on: 
+  release:
+    types: [created]
+jobs:
+  releases-matrix:
+    name: Release Go Binary
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goos: [linux, windows, darwin]
+        goarch: ["386", amd64, arm64]
+        goversion: ["1.16", "1.17"]
+        exclude:  
+          - goarch: "386"
+            goos: darwin 
+          - goarch: "386"
+            goos: windows
+          - goarch: arm64
+            goos: windows 
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set BUILD_VERSION env
+      run: echo "RELEASE_TAG=${GITHUB_REF/refs\/tags\//}" >> $GITHUB_ENV
+    - uses: wangyoucao577/[email protected]
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        goos: ${{ matrix.goos }}
+        goarch: ${{ matrix.goarch }}
+        goversion: ${{ matrix.goversion }}
+        project_path: "./cmd/"
+        binary_name: "jsonpath"
+        ldflags: -X "main.Command=jsonpath" main.Version=${{ env.RELEASE_TAG }}" -X "main.OS=${{ matrix.goos }}" -X main.Arch=${{ matrix.goos }}
+

cmd/main.go

@@ -0,0 +1,168 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/evilmonkeyinc/jsonpath"
+)
+
+var (
+	// Arch build identifier
+	Arch string = ""
+	// Command is the expected name of the build
+	Command string = "jsonpath"
+	// OS build identifier
+	OS string = ""
+	// Version build identifier
+	Version string = "dev"
+
+	errSelectorNotSpecified error = fmt.Errorf("selector not specified. expected -selector option or passed as argument")
+	errJSONDataNotSpecified error = fmt.Errorf("json data not specified. expected -jsondata, or -input options or passed as argument")
+)
+
+const (
+	cmdHelp    string = "help"
+	cmdVersion string = "version"
+)
+
+func main() {
+	flagset := flag.NewFlagSet("", flag.ContinueOnError)
+	selectorPtr := flagset.String("selector", "", "a valid JSONPath selector")
+	jsondataPtr := flagset.String("jsondata", "", "the json data to parse)")
+	inputPtr := flagset.String("input", "", "optional path to a file that includes the json data to query")
+	outputPtr := flagset.String("output", "", "optional path to a file that the result ")
+
+	if err := flagset.Parse(os.Args[1:]); err != nil {
+		if !errors.Is(err, flag.ErrHelp) {
+			outputError(errSelectorNotSpecified)
+			return
+		}
+		printHelp(flagset)
+		return
+	}
+
+	args := flagset.Args()
+	firstArg := ""
+	if len(args) > 0 {
+		firstArg = args[0]
+	}
+
+	switch firstArg {
+	case cmdHelp:
+		printHelp(flagset)
+		break
+	case cmdVersion:
+		fmt.Printf("version %s %s/%s\n", Version, OS, Arch)
+		break
+	default:
+		nextArg := 0
+
+		selector := *selectorPtr
+		if selector == "" && len(args) > nextArg {
+			selector = args[nextArg]
+			nextArg++
+		}
+
+		if selector == "" {
+			outputError(errSelectorNotSpecified)
+			return
+		}
+
+		compiled, err := jsonpath.Compile(selector)
+		if err != nil {
+			outputError(err)
+			return
+		}
+
+		jsondata := *jsondataPtr
+		if jsondata == "" && len(args) > nextArg {
+			jsondata = args[nextArg]
+			nextArg++
+		}
+
+		if jsondata == "" && *inputPtr != "" {
+			bytes, err := loadFileContents(*inputPtr)
+			if err != nil {
+				outputError(err)
+				return
+			}
+			jsondata = string(bytes)
+		}
+		if jsondata == "" {
+			outputError(errJSONDataNotSpecified)
+			return
+		}
+
+		result, err := compiled.QueryString(jsondata)
+		if err != nil {
+			outputError(err)
+			return
+		}
+
+		jsonOutput, err := json.Marshal(result)
+		if err != nil {
+			outputError(err)
+			return
+		}
+
+		if *outputPtr != "" {
+			if err := saveFileContents(*outputPtr, jsonOutput); err != nil {
+				outputError(err)
+			}
+			os.Exit(0)
+			return
+		}
+
+		fmt.Printf("%s\n", string(jsonOutput))
+		break
+	}
+	os.Exit(0)
+}
+
+func printHelp(flagset *flag.FlagSet) {
+	fmt.Printf("%s is a tool for querying json data using a JSONPath selector\n\n", Command)
+	fmt.Printf("Usage:\n\n")
+	fmt.Printf("  %s '[selector]' '[jsondata]'\n", Command)
+	fmt.Printf("\nExample:\n\n")
+	fmt.Printf(`  %s '$[*].key' '[{"key":"show this"},{"key":"and this"},{"other":"but not this"}]'`+"\n", Command)
+	fmt.Printf(`  > ["show this","and this"]` + "\n")
+	fmt.Printf("\nOptions:\n\n")
+	flagset.PrintDefaults()
+	os.Exit(0)
+}
+
+func outputError(err error) {
+	fmt.Printf("failed: %s\n", err.Error())
+	os.Exit(1)
+}
+
+func loadFileContents(filename string) ([]byte, error) {
+	jsonFile, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer jsonFile.Close()
+	byteValue, err := ioutil.ReadAll(jsonFile)
+	if err != nil {
+		return nil, err
+	}
+	return byteValue, nil
+}
+
+func saveFileContents(filename string, content []byte) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	if _, err = file.Write(content); err != nil {
+		return err
+	}
+	return nil
+}