JSON Log Line (Single-Line Object) in GO
Match a single-line JSON object — typical of structured logging from services like slog, Bunyan, or Pino.
Try it in the GO tester →Pattern
regexGO
^\{(?:[^{}]|\{[^{}]*\})*\}$Go (RE2) code
goGo
package main
import (
"fmt"
"regexp"
)
func main() {
re := regexp.MustCompile(`^\{(?:[^{}]|\{[^{}]*\})*\}$`)
input := `{"level":"info","msg":"started","port":8080}`
for _, match := range re.FindAllString(input, -1) {
fmt.Println(match)
}
}Uses `regexp.MustCompile` (panics on bad patterns at startup) and `FindAllString` for all matches.
How the pattern works
^\{ anchors to an opening brace at start. (?:[^{}]|\{[^{}]*\})* matches any non-brace chars or one level of nested braces (so `{"a":{"b":1}}` matches but deeper nesting may not). \}$ anchors to the closing brace at end. Quick filter for log-line shape; pair with JSON.parse to validate fully.
Examples
Input
{"level":"info","msg":"started","port":8080}Matches
{"level":"info","msg":"started","port":8080}
Input
{"event":"login","user":{"id":42}}Matches
{"event":"login","user":{"id":42}}
Input
plain text log lineNo match
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