yaml-parse,yamlutils: Support multiple documents in a single yaml input

https://yaml.org/spec/1.2-old/spec.html#id2800401

yaml-parse/go.mod

@@ -2,7 +2,7 @@ module github.com/DavidGamba/dgtools/yaml-parse
 
 require (
 	github.com/DavidGamba/dgtools/yamlutils v0.0.0
-	github.com/DavidGamba/go-getoptions v0.23.0
+	github.com/DavidGamba/go-getoptions v0.25.3
 )
 
 replace github.com/DavidGamba/dgtools => ../

yaml-parse/go.sum

@@ -1,7 +1,5 @@
-github.com/DavidGamba/go-getoptions v0.21.0 h1:nVyFTaDSacJ1Sb3kRB4RgxNkGhf+b8khQ0M/ldihwS0=
-github.com/DavidGamba/go-getoptions v0.21.0/go.mod h1:wYjd1McJbGzBFD61+lahGR+5A8QGA1aBnRZmfkBLy5A=
-github.com/DavidGamba/go-getoptions v0.23.0 h1:j8q36PvconcXzKphnnOmmUcKGpcpHfbaAZ/FD0qwdd0=
-github.com/DavidGamba/go-getoptions v0.23.0/go.mod h1:qLaLSYeQ8sUVOfKuu5JT5qKKS3OCwyhkYSJnoG+ggmo=
+github.com/DavidGamba/go-getoptions v0.25.3 h1:lSPcMkwWvVZU05C+Uz4DKnKN5wz4bcD1QvJ/QHCRexo=
+github.com/DavidGamba/go-getoptions v0.25.3/go.mod h1:qLaLSYeQ8sUVOfKuu5JT5qKKS3OCwyhkYSJnoG+ggmo=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=

yaml-parse/main.go

@@ -33,7 +33,7 @@ func program(args []string) int {
 	opt := getoptions.New()
 	opt.Self("", `Parses YAML input passed from file or piped to STDIN and filters it by key or index.
 
-    Source: https://github.com/DavidGamba/dgtools`)
+         Source: https://github.com/DavidGamba/dgtools`)
 	opt.Bool("help", false, opt.Alias("?"))
 	opt.Bool("debug", false)
 	opt.Bool("version", false, opt.Alias("V"))
@@ -46,6 +46,7 @@ func program(args []string) int {
 		opt.Description(`Key or index to descend to.
 Multiple keys allow to descend further.
 Indexes are positive integers.`))
+	opt.IntOptional("document", 1, opt.Description("Document number"), opt.Alias("d"), opt.ArgName("number"))
 	_, err := opt.Parse(os.Args[1:])
 	if opt.Called("help") {
 		fmt.Println(opt.Help())
@@ -90,11 +91,11 @@ func realMain(opt *getoptions.GetOpt) error {
 	stdinIsDevice := (statStdin.Mode() & os.ModeDevice) != 0
 
 	var err error
-	var yml *yamlutils.YML
+	var ymlList []*yamlutils.YML
 	if !stdinIsDevice && !opt.Called("file") {
 		Logger.Printf("Reading from stdin\n")
 		reader := os.Stdin
-		yml, err = yamlutils.NewFromReader(reader)
+		ymlList, err = yamlutils.NewFromReader(reader)
 		if err != nil {
 			return fmt.Errorf("reading yaml from STDIN: %w", err)
 		}
@@ -103,13 +104,29 @@ func realMain(opt *getoptions.GetOpt) error {
 		if !opt.Called("file") {
 			return fmt.Errorf("missing argument '--file <file>'")
 		}
-		yml, err = yamlutils.NewFromFile(file)
+		ymlList, err = yamlutils.NewFromFile(file)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "ERROR: reading yaml file: %s\n", err)
 			os.Exit(1)
 		}
 	}
 
+	if !opt.Called("document") && len(ymlList) > 1 {
+		fmt.Fprintf(os.Stderr,
+			`WARNING: provided input contains %d YAML documents
+         specify '--document <number>' to remove this warning
+`, len(ymlList))
+	}
+
+	n := 0
+	if opt.Called("document") {
+		n = opt.Value("document").(int) - 1
+	}
+	if len(ymlList) < n+1 {
+		return fmt.Errorf("wrong document number: %d", n+1)
+	}
+	yml := ymlList[n]
+
 	if opt.Called("add") {
 		str, err := yml.AddString(xpath, add)
 		if err != nil {

yamlutils/yamlutils.go

@@ -12,12 +12,12 @@ Package yamlutils - Utilities to read yml files like if using xpath
 package yamlutils
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"log"
+	"os"
 	"strconv"
 	"strings"
 
@@ -39,33 +39,47 @@ type YML struct {
 	Tree interface{}
 }
 
-// NewFromFile returns a pointer to a YML object from a file.
-func NewFromFile(filename string) (*YML, error) {
-	data, err := ioutil.ReadFile(filename)
-	if err != nil {
-		return nil, err
-	}
-	var tree interface{}
-	err = yaml.Unmarshal(data, &tree)
-	if err != nil {
-		return nil, err
+// NewFromFile returns a list of pointers to a YML object from a file.
+//
+// Returns a list since YAML files can contain multiple documents:
+// https://yaml.org/spec/1.2-old/spec.html#id2800401
+func NewFromFile(filename string) ([]*YML, error) {
+	list := []*YML{}
+	fh, err := os.Open(filename)
+	decoder := yaml.NewDecoder(fh)
+	for {
+		var tree interface{}
+		err = decoder.Decode(&tree)
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				return nil, err
+			}
+			break
+		}
+		list = append(list, &YML{Tree: tree})
 	}
-	return &YML{Tree: tree}, nil
+	return list, nil
 }
 
-// NewFromReader returns a pointer to a YML object from an io.Reader.
-func NewFromReader(reader io.Reader) (*YML, error) {
-	var tree interface{}
-	buf := new(bytes.Buffer)
-	_, err := buf.ReadFrom(reader)
-	if err != nil {
-		return nil, err
-	}
-	err = yaml.Unmarshal(buf.Bytes(), &tree)
-	if err != nil {
-		return nil, err
+// NewFromReader returns a list of pointers to a YML object from an io.Reader.
+//
+// Returns a list since YAML files can contain multiple documents:
+// https://yaml.org/spec/1.2-old/spec.html#id2800401
+func NewFromReader(reader io.Reader) ([]*YML, error) {
+	list := []*YML{}
+	decoder := yaml.NewDecoder(reader)
+	for {
+		var tree interface{}
+		err := decoder.Decode(&tree)
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				return nil, err
+			}
+			break
+		}
+		list = append(list, &YML{Tree: tree})
 	}
-	return &YML{Tree: tree}, nil
+	return list, nil
 }
 
 // NewFromString - returns a pointer to a YML object from a string.