Merge pull request #10 from breml/fix-formatting-multiline-string

Fix formatting multiline string

Author: breml

ast/ast_helper.go

@@ -3,9 +3,17 @@ package ast
 import (
 	"bytes"
 	"fmt"
+	"regexp"
 	"strings"
 )
 
+// This regular expression splits the config into indentable chunks that are:
+// * empty line
+// * line of comment
+// * line without any quotes
+// * line(s) with quoted strings, which are kept together to form a single "line of configuration"
+var linesRe = regexp.MustCompile(`(\n|\s*//[^\n]*\n|[^'"\n]*\n|([^"'\n]*("(\\"|[^"])*"|'(\\'|[^'])*')[^"'\n]*)*\n)`)
+
 func prefix(in string, emptyNewline bool) string {
 	if len(in) == 0 {
 		if emptyNewline {
@@ -16,13 +24,13 @@ func prefix(in string, emptyNewline bool) string {
 
 	var s bytes.Buffer
 	s.WriteString("\n")
-	lines := strings.Split(strings.TrimRight(in, "\n"), "\n")
+	lines := linesRe.FindAllString(strings.TrimRight(in, "\n")+"\n", -1)
 	for _, l := range lines {
-		if len(l) == 0 {
+		if len(strings.TrimLeft(l, " \n")) == 0 {
 			s.WriteString("\n")
 			continue
 		}
-		s.WriteString(fmt.Sprintln("  " + l))
+		s.WriteString(fmt.Sprint("  " + l))
 	}
 	return s.String()
 }

ast/ast_helper_test.go

@@ -0,0 +1,122 @@
+package ast
+
+import "testing"
+
+func TestPrefix(t *testing.T) {
+	tt := []struct {
+		name         string
+		input        string
+		emptyNewline bool
+
+		want string
+	}{
+		{
+			name: "empty string",
+		},
+		{
+			name:         `empty string with empty newline`,
+			emptyNewline: true,
+
+			want: "\n",
+		},
+		{
+			name: "simple attribute",
+			input: `value => 3.1415
+`,
+
+			want: `
+  value => 3.1415
+`,
+		},
+		{
+			name: "simple attribute with comment",
+			input: `// comment
+value => 3.1415
+`,
+
+			want: `
+  // comment
+  value => 3.1415
+`,
+		},
+		{
+			name: "block",
+			input: `add_field {
+  // comment
+  value => 3.1415
+}
+
+add_tag => [ "foobar" ]
+`,
+
+			want: `
+  add_field {
+    // comment
+    value => 3.1415
+  }
+
+  add_tag => [ "foobar" ]
+`,
+		},
+		{
+			name: "attribute with multiline string attribute",
+			input: `value => "string
+with multiple
+lines"
+othervalue => 3.1415
+`,
+
+			want: `
+  value => "string
+with multiple
+lines"
+  othervalue => 3.1415
+`,
+		},
+		{
+			name: "attribute with multiline string attribute (single quote)",
+			input: `value => 'string
+with multiple
+lines'
+othervalue => 3.1415
+`,
+
+			want: `
+  value => 'string
+with multiple
+lines'
+  othervalue => 3.1415
+`,
+		},
+		{
+			name: "comment with double and single quote",
+			input: `// comment with " and '
+othervalue => 3.1415
+`,
+
+			want: `
+  // comment with " and '
+  othervalue => 3.1415
+`,
+		},
+		{
+			name: "array with multiple string types",
+			input: `value => [ "string", 'string', string ]
+`,
+
+			want: `
+  value => [ "string", 'string', string ]
+`,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			got := prefix(tc.input, tc.emptyNewline)
+
+			if tc.want != got {
+				t.Errorf("want %q, got %q", tc.want, got)
+			}
+		})
+	}
+}

logstash_config_test.go

@@ -368,6 +368,19 @@ output {}
     }
   }
 }
+`,
+		},
+		{
+			name: "multiline string",
+			input: `filter {
+  mutate {
+    add_field => {
+      "largeint" => "a string
+with multiple
+lines"
+    }
+  }
+}
 `,
 		},
 	}