Can update a yaml file from an instruction yaml file

README.md

@@ -1,7 +1,7 @@
 # yaml
-yaml command line tool written in go
+yaml is portable command line tool written in go
 
-Allows you to read (and soon update) yaml files given a yaml path. All in a lovely dependency free binary!
+Allows you to read and update yaml files from bash (or whatever). All in a lovely dependency free binary!
 
 [Download latest release](https://github.com/mikefarah/yaml/releases/latest)
 
@@ -12,7 +12,7 @@ go get github.com/mikefarah/yaml
 
 ## Read examples
 ```
-yaml <yaml file> <path>
+yaml r <yaml file> <path>
 ```
 
 ### Basic
@@ -23,10 +23,37 @@ b:
 ```
 then
 ```bash
-yaml sample.yaml b.c
+yaml r sample.yaml b.c
 ```
 will output the value of '2'.
 
+### Reading from STDIN
+Given a sample.yaml file of:
+```bash
+cat sample.yaml | yaml r - b.c
+```
+will output the value of '2'.
+
+### Splat
+Given a sample.yaml file of:
+```yaml
+---
+bob:
+  item1:
+    cats: bananas
+  item2:
+    cats: apples
+```
+then
+```bash
+yaml r sample.yaml bob.*.cats
+```
+will output
+```yaml
+- bananas
+- apples
+```
+
 ### Handling '.' in the yaml key
 Given a sample.yaml file of:
 ```yaml
@@ -35,7 +62,7 @@ b.x:
 ```
 then
 ```bash
-yaml sample.yaml \"b.x\".c
+yaml r sample.yaml \"b.x\".c
 ```
 will output the value of '2'.
 
@@ -52,11 +79,33 @@ b:
 ```
 then
 ```
-yaml sample.yaml b.e[1].name
+yaml r sample.yaml b.e[1].name
 ```
 will output 'sam'
 
-### Updating yaml
+### Array Splat
+e.g.: given a sample file of
+```yaml
+b:
+  e:
+    - name: fred
+      value: 3
+    - name: sam
+      value: 4
+```
+then
+```
+yaml r sample.yaml b.e[*].name
+```
+will output:
+```
+- fred
+- sam
+```
+
+## Update examples
+
+### Update to stdout
 Given a sample.yaml file of:
 ```yaml
 b:
@@ -64,10 +113,50 @@ b:
 ```
 then
 ```bash
-yaml w sample.yaml b.c 'cat'
+yaml w sample.yaml b.c cat
 ```
 will output:
 ```yaml
 b:
   c: cat
 ```
+
+### Updating yaml in-place
+Given a sample.yaml file of:
+```yaml
+b:
+  c: 2
+```
+then
+```bash
+yaml w -i sample.yaml b.c cat
+```
+will update the sample.yaml file so that the value of 'c' is cat.
+
+
+### Updating multiple values with a script
+Given a sample.yaml file of:
+```yaml
+b:
+  c: 2
+  e:
+    - name: Billy Bob
+```
+and a script update_instructions.yaml of:
+```yaml
+b.c: 3
+b.e[0].name: Howdy Partner
+```
+then
+
+```bash
+yaml -w -s update_instructions.yaml sample.yaml
+```
+will output:
+```yaml
+b:
+  c: 3
+  e:
+    - name: Howdy Partner
+```
+

data_navigator.go

@@ -2,38 +2,58 @@ package main
 
 import (
 	// "fmt"
-	"log"
 	"strconv"
 )
 
 func write(context map[interface{}]interface{}, head string, tail []string, value interface{}) {
-	// e.g. if updating a.b.c, we need to get the 'b' map...
-	toUpdate := readMap(context, head, tail[0:len(tail)-1]).(map[interface{}]interface{})
-	//  and then set the 'c' key.
-	key := (tail[len(tail)-1])
-	toUpdate[key] = value
+	if len(tail) == 0 {
+		context[head] = value
+	} else {
+		// e.g. if updating a.b.c, we need to get the 'b' map...
+		toUpdate := readMap(context, head, tail[0:len(tail)-1]).(map[interface{}]interface{})
+		//  and then set the 'c' key.
+		key := (tail[len(tail)-1])
+		toUpdate[key] = value
+	}
 }
 
 func readMap(context map[interface{}]interface{}, head string, tail []string) interface{} {
-	value := context[head]
-	if len(tail) > 0 {
-		return recurse(value, tail[0], tail[1:len(tail)])
+	if head == "*" {
+		return readMapSplat(context, tail)
 	}
-	return value
+	value := context[head]
+	return calculateValue(value, tail)
+}
+
+func readMapSplat(context map[interface{}]interface{}, tail []string) interface{} {
+	var newArray = make([]interface{}, len(context))
+	var i = 0
+	for _, value := range context {
+		if len(tail) > 0 {
+			newArray[i] = recurse(value, tail[0], tail[1:len(tail)])
+		} else {
+			newArray[i] = value
+		}
+		i++
+	}
+	return newArray
 }
 
 func recurse(value interface{}, head string, tail []string) interface{} {
 	switch value.(type) {
 	case []interface{}:
+		if head == "*" {
+			return readArraySplat(value.([]interface{}), tail)
+		}
 		index, err := strconv.ParseInt(head, 10, 64)
 		if err != nil {
-			log.Fatalf("Error accessing array: %v", err)
+			die("Error accessing array: %v", err)
 		}
 		return readArray(value.([]interface{}), index, tail)
-	case nil:
-		return nil
-	default:
+	case map[interface{}]interface{}:
 		return readMap(value.(map[interface{}]interface{}), head, tail)
+	default:
+		return nil
 	}
 }
 
@@ -43,6 +63,19 @@ func readArray(array []interface{}, head int64, tail []string) interface{} {
 	}
 
 	value := array[head]
+
+	return calculateValue(value, tail)
+}
+
+func readArraySplat(array []interface{}, tail []string) interface{} {
+	var newArray = make([]interface{}, len(array))
+	for index, value := range array {
+		newArray[index] = calculateValue(value, tail)
+	}
+	return newArray
+}
+
+func calculateValue(value interface{}, tail []string) interface{} {
 	if len(tail) > 0 {
 		return recurse(value, tail[0], tail[1:len(tail)])
 	}

data_navigator_test.go

@@ -4,59 +4,141 @@ import (
 	"fmt"
 	"gopkg.in/yaml.v2"
 	"os"
+	"sort"
 	"testing"
 )
 
-var rawData = `
-a: Easy!
-b:
-  c: 2
-  d: [3, 4]
-`
-
-var parsedData map[interface{}]interface{}
-
-func TestMain(m *testing.M) {
+func parseData(rawData string) map[interface{}]interface{} {
+	var parsedData map[interface{}]interface{}
 	err := yaml.Unmarshal([]byte(rawData), &parsedData)
 	if err != nil {
 		fmt.Println("Error parsing yaml: %v", err)
 		os.Exit(1)
 	}
-
-	os.Exit(m.Run())
+	return parsedData
 }
 
 func TestReadMap_simple(t *testing.T) {
-	assertResult(t, 2, readMap(parsedData, "b", []string{"c"}))
+	var data = parseData(`
+---
+b:
+  c: 2
+`)
+	assertResult(t, 2, readMap(data, "b", []string{"c"}))
+}
+
+func TestReadMap_splat(t *testing.T) {
+	var data = parseData(`
+---
+mapSplat:
+  item1: things
+  item2: whatever
+`)
+	var result = readMap(data, "mapSplat", []string{"*"}).([]interface{})
+	var actual = []string{result[0].(string), result[1].(string)}
+	sort.Strings(actual)
+	assertResult(t, "[things whatever]", fmt.Sprintf("%v", actual))
+}
+
+func TestReadMap_deep_splat(t *testing.T) {
+	var data = parseData(`
+---
+mapSplatDeep:
+  item1:
+    cats: bananas
+  item2:
+    cats: apples
+`)
+
+	var result = readMap(data, "mapSplatDeep", []string{"*", "cats"}).([]interface{})
+	var actual = []string{result[0].(string), result[1].(string)}
+	sort.Strings(actual)
+	assertResult(t, "[apples bananas]", fmt.Sprintf("%v", actual))
 }
 
 func TestReadMap_key_doesnt_exist(t *testing.T) {
-	assertResult(t, nil, readMap(parsedData, "b.x.f", []string{"c"}))
+	var data = parseData(`
+---
+b:
+  c: 2
+`)
+	assertResult(t, nil, readMap(data, "b.x.f", []string{"c"}))
+}
+
+func TestReadMap_recurse_against_string(t *testing.T) {
+	var data = parseData(`
+---
+a: cat
+`)
+	assertResult(t, nil, readMap(data, "a", []string{"b"}))
 }
 
 func TestReadMap_with_array(t *testing.T) {
-	assertResult(t, 4, readMap(parsedData, "b", []string{"d", "1"}))
+	var data = parseData(`
+---
+b:
+  d:
+    - 3
+    - 4
+`)
+	assertResult(t, 4, readMap(data, "b", []string{"d", "1"}))
 }
 
 func TestReadMap_with_array_out_of_bounds(t *testing.T) {
-	assertResult(t, nil, readMap(parsedData, "b", []string{"d", "3"}))
+	var data = parseData(`
+---
+b:
+  d:
+    - 3
+    - 4
+`)
+	assertResult(t, nil, readMap(data, "b", []string{"d", "3"}))
+}
+
+func TestReadMap_with_array_splat(t *testing.T) {
+	var data = parseData(`
+e:
+  -
+    name: Fred
+    thing: cat
+  -
+    name: Sam
+    thing: dog
+`)
+	assertResult(t, "[Fred Sam]", fmt.Sprintf("%v", readMap(data, "e", []string{"*", "name"})))
 }
 
 func TestWrite_simple(t *testing.T) {
+	var data = parseData(`
+b:
+  c: 2
+`)
 
-	write(parsedData, "b", []string{"c"}, "4")
+	write(data, "b", []string{"c"}, "4")
 
-	b := parsedData["b"].(map[interface{}]interface{})
+	b := data["b"].(map[interface{}]interface{})
 	assertResult(t, "4", b["c"].(string))
 }
 
+func TestWrite_with_no_tail(t *testing.T) {
+	var data = parseData(`
+b:
+  c: 2
+`)
+	write(data, "b", []string{}, "4")
+
+	b := data["b"]
+	assertResult(t, "4", fmt.Sprintf("%v", b))
+}
+
 func assertResult(t *testing.T, expectedValue interface{}, actualValue interface{}) {
 	if expectedValue != actualValue {
-		t.Error("Expected <", expectedValue, "> but got <", actualValue, ">")
+		t.Error("Expected <", expectedValue, "> but got <", actualValue, ">", fmt.Sprintf("%T", actualValue))
 	}
 }
 
 func assertResultWithContext(t *testing.T, expectedValue interface{}, actualValue interface{}, context interface{}) {
+
 	if expectedValue != actualValue {
 		t.Error(context)
 		t.Error(": expected <", expectedValue, "> but got <", actualValue, ">")

instruction_sample.yaml

@@ -0,0 +1,2 @@
+b.c: cat
+b.e[0].name: Mike Farah

precheckin.sh

@@ -6,7 +6,7 @@ go test
 
 # acceptance test
 go build
-X=$(./yaml sample.yaml b.c)
+X=$(./yaml r sample.yaml b.c)
 
 if [ $X != 2 ]
   then

sample2.yaml

@@ -1,4 +1,9 @@
 a: Easy! as one two three
 b:
-  c: 3
-  d: [3, 4]
+  c: things
+  d: whatever
+things:
+ thing1:
+  cat: 'fred'
+ thing2:
+  cat: 'sam'

yaml.go

@@ -2,69 +2,96 @@ package main
 
 import (
 	"fmt"
-	"github.com/codegangsta/cli"
+	"github.com/spf13/cobra"
 	"gopkg.in/yaml.v2"
 	"io/ioutil"
-	"log"
 	"os"
 	"strconv"
 	"strings"
 )
 
+var trimOutput = true
+var writeInplace = false
+var writeScript = ""
+
 func main() {
-	app := cli.NewApp()
-	app.Name = "yaml"
-	app.Usage = "command line tool for reading and writing yaml"
-	app.Commands = []cli.Command{
-		{
-			Name:    "read",
-			Aliases: []string{"r"},
-			Usage:   "read <filename> <path>\n\te.g.: yaml read sample.json a.b.c\n\t(default) reads a property from a given yaml file\n",
-			Action:  readProperty,
-		},
-		{
-			Name:    "write",
-			Aliases: []string{"w"},
-			Usage:   "write <filename> <path> <value>\n\te.g.: yaml write sample.json a.b.c 5\n\tupdates a property from a given yaml file, outputs to stdout\n",
-			Action:  writeProperty,
-		},
+	var cmdRead = &cobra.Command{
+		Use:     "read [yaml_file] [path]",
+		Aliases: []string{"r"},
+		Short:   "yaml r sample.yaml a.b.c",
+		Example: `
+yaml read things.yaml a.b.c
+yaml r - a.b.c (reads from stdin)
+yaml r things.yaml a.*.c
+yaml r things.yaml a.array[0].blah
+yaml r things.yaml a.array[*].blah
+			`,
+		Long: "Outputs the value of the given path in the yaml file to STDOUT",
+		Run:  readProperty,
 	}
-	app.Action = readProperty
-	app.Run(os.Args)
+
+	var cmdWrite = &cobra.Command{
+		Use:     "write [yaml_file] [path] [value]",
+		Aliases: []string{"w"},
+		Short:   "yaml w [--inplace/-i] sample.yaml a.b.c newValueForC",
+		Example: `
+yaml write things.yaml a.b.c cat
+yaml write --inplace things.yaml a.b.c cat
+yaml w -i things.yaml a.b.c cat
+			`,
+		Long: `Updates the yaml file w.r.t the given path and value.
+Outputs to STDOUT unless the inplace flag is used, in which case the file is updated instead.`,
+		Run: writeProperty,
+	}
+	cmdWrite.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
+	cmdWrite.PersistentFlags().StringVarP(&writeScript, "script", "s", "", "yaml script for updating yaml")
+
+	var rootCmd = &cobra.Command{Use: "yaml"}
+	rootCmd.PersistentFlags().BoolVarP(&trimOutput, "trim", "t", true, "trim yaml output")
+	rootCmd.AddCommand(cmdRead, cmdWrite)
+	rootCmd.Execute()
 }
 
-func readProperty(c *cli.Context) {
-
+func readProperty(cmd *cobra.Command, args []string) {
 	var parsedData map[interface{}]interface{}
 
-	readYaml(c, &parsedData)
+	readYaml(args[0], &parsedData)
 
-	if len(c.Args()) == 1 {
+	if len(args) == 1 {
 		printYaml(parsedData)
 		os.Exit(0)
 	}
 
-	var paths = parsePath(c.Args()[1])
+	var paths = parsePath(args[1])
 
 	printYaml(readMap(parsedData, paths[0], paths[1:len(paths)]))
 }
 
-func writeProperty(c *cli.Context) {
-	var parsedData map[interface{}]interface{}
-	readYaml(c, &parsedData)
-
-	if len(c.Args()) < 3 {
-		log.Fatalf("Must provide <filename> <path_to_update> <value>")
+func writeProperty(cmd *cobra.Command, args []string) {
+	var writeCommands map[string]interface{}
+	if writeScript != "" {
+		readYaml(writeScript, &writeCommands)
+	} else if len(args) < 3 {
+		die("Must provide <filename> <path_to_update> <value>")
+	} else {
+		writeCommands[args[1]] = parseValue(args[2])
 	}
 
-	var paths = parsePath(c.Args()[1])
+	var parsedData map[interface{}]interface{}
+	readYaml(args[0], &parsedData)
 
-	write(parsedData, paths[0], paths[1:len(paths)], getValue(c.Args()[2]))
+	for path, value := range writeCommands {
+		var paths = parsePath(path)
+		write(parsedData, paths[0], paths[1:len(paths)], value)
+	}
 
-	printYaml(parsedData)
+	if writeInplace {
+		ioutil.WriteFile(args[0], []byte(yamlToString(parsedData)), 0644)
+	} else {
+		printYaml(parsedData)
+	}
 }
-
-func getValue(argument string) interface{} {
+func parseValue(argument string) interface{} {
 	var value, err interface{}
 	var inQuotes = argument[0] == '"'
 	if !inQuotes {
@@ -82,32 +109,58 @@ func getValue(argument string) interface{} {
 }
 
 func printYaml(context interface{}) {
+	fmt.Println(yamlToString(context))
+}
+
+func yamlToString(context interface{}) string {
 	out, err := yaml.Marshal(context)
 	if err != nil {
-		log.Fatalf("error printing yaml: %v", err)
+		die("error printing yaml: %v", err)
 	}
 	outStr := string(out)
 	// trim the trailing new line as it's easier for a script to add
 	// it in if required than to remove it
-	fmt.Println(strings.Trim(outStr, "\n "))
+	if trimOutput {
+		return strings.Trim(outStr, "\n ")
+	}
+	return outStr
 }
 
-func readYaml(c *cli.Context, parsedData *map[interface{}]interface{}) {
-	if len(c.Args()) == 0 {
-		log.Fatalf("Must provide filename")
+func readYaml(filename string, parsedData interface{}) {
+	if filename == "" {
+		die("Must provide filename")
 	}
-	var rawData = readFile(c.Args()[0])
 
-	err := yaml.Unmarshal([]byte(rawData), &parsedData)
-	if err != nil {
-		log.Fatalf("error: %v", err)
+	var rawData []byte
+	if filename == "-" {
+		rawData = readStdin()
+	} else {
+		rawData = readFile(filename)
 	}
+
+	err := yaml.Unmarshal([]byte(rawData), parsedData)
+	if err != nil {
+		die("error: %v", err)
+	}
+}
+
+func readStdin() []byte {
+	bytes, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		die("error reading stdin", err)
+	}
+	return bytes
 }
 
 func readFile(filename string) []byte {
 	var rawData, readError = ioutil.ReadFile(filename)
 	if readError != nil {
-		log.Fatalf("error: %v", readError)
+		die("error: %v", readError)
 	}
 	return rawData
 }
+
+func die(message ...interface{}) {
+	fmt.Println(message)
+	os.Exit(1)
+}

yaml_test.go

@@ -4,7 +4,7 @@ import (
 	"testing"
 )
 
-var getValueTests = []struct {
+var parseValueTests = []struct {
 	argument        string
 	expectedResult  interface{}
 	testDescription string
@@ -15,8 +15,8 @@ var getValueTests = []struct {
 	{"\"3.4\"", "3.4", "number as string"},
 }
 
-func TestGetValue(t *testing.T) {
-	for _, tt := range getValueTests {
-		assertResultWithContext(t, tt.expectedResult, getValue(tt.argument), tt.testDescription)
+func TestParseValue(t *testing.T) {
+	for _, tt := range parseValueTests {
+		assertResultWithContext(t, tt.expectedResult, parseValue(tt.argument), tt.testDescription)
 	}
 }