[pkg/stanza] key_value_parser: Allow values that contain the delimiter string

.chloggen/stanza-allow-delimiter-in-value.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: pkg/stanza
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Allow `key_value_parser` to parse values that contain the delimiter string.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [29629]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

pkg/stanza/operator/parser/keyvalue/keyvalue.go

@@ -106,7 +106,7 @@ func (kv *Parser) parser(input string, delimiter string) (map[string]any, error)
 
 	var err error
 	for _, raw := range kv.pairSplitFunc(input) {
-		m := strings.Split(raw, delimiter)
+		m := strings.SplitN(raw, delimiter, 2)
 		if len(m) != 2 {
 			e := fmt.Errorf("expected '%s' to split by '%s' into two items, got %d", raw, delimiter, len(m))
 			err = multierr.Append(err, e)

pkg/stanza/operator/parser/keyvalue/keyvalue_test.go

@@ -488,15 +488,50 @@ key=value`,
 			false,
 		},
 		{
-			"invalid-pair",
+			"value-contains-delimiter",
 			func(kv *Config) {},
 			&entry.Entry{
 				Body: `test=text=abc`,
 			},
 			&entry.Entry{
+				Attributes: map[string]any{
+					"test": "text=abc",
+				},
 				Body: `test=text=abc`,
 			},
-			true,
+			false,
+			false,
+		},
+		{
+			"quoted-value-contains-delimiter",
+			func(kv *Config) {},
+			&entry.Entry{
+				Body: `msg="Message successfully sent at 2023-12-04 06:47:31.204222276 +0000 UTC m=+5115.932279346"`,
+			},
+			&entry.Entry{
+				Attributes: map[string]any{
+					"msg": `Message successfully sent at 2023-12-04 06:47:31.204222276 +0000 UTC m=+5115.932279346`,
+				},
+				Body: `msg="Message successfully sent at 2023-12-04 06:47:31.204222276 +0000 UTC m=+5115.932279346"`,
+			},
+			false,
+			false,
+		},
+		{
+			"multiple-values-contain-delimiter",
+			func(kv *Config) {},
+			&entry.Entry{
+				Body: `one=1=i two="2=ii" three=3=iii`,
+			},
+			&entry.Entry{
+				Attributes: map[string]any{
+					"one":   "1=i",
+					"two":   "2=ii",
+					"three": "3=iii",
+				},
+				Body: `one=1=i two="2=ii" three=3=iii`,
+			},
+			false,
 			false,
 		},
 		{