feat(logs): implement timestamp stripping in log message rendering

Author: tobimadehin

internal/cli/commands/log_format.go

@@ -0,0 +1,28 @@
+package commands
+
+import "regexp"
+
+// leadingTimestampPatterns are anchored to the start of the string.
+// Order matters: more specific patterns (PHP bracket, ISO 8601) are tried first.
+var leadingTimestampPatterns = []*regexp.Regexp{
+	// PHP built-in server / Apache ErrorLog: [Sat Jun 13 09:14:57 2026] or [Sat Jun  3 09:14:57 2026]
+	regexp.MustCompile(`^\[\w{3} \w{3}\s+\d{1,2} \d{2}:\d{2}:\d{2} \d{4}\]\s*`),
+	// ISO 8601: 2026-06-13T09:14:57Z  2026-06-13T09:14:57.123Z  2026-06-13T09:14:57+00:00
+	regexp.MustCompile(`^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|[+-]\d{2}:?\d{2})?\s*`),
+	// Date with space separator: 2026-06-13 09:14:57  2026-06-13 09:14:57.123
+	regexp.MustCompile(`^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}(?:\.\d+)?\s*`),
+	// nginx / Go stdlib: 2026/06/13 09:14:57
+	regexp.MustCompile(`^\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2}\s*`),
+}
+
+// stripMessageTimestamp removes a leading timestamp from a log message, returning
+// the remainder. If no known timestamp pattern is found at the start of the string,
+// the original message is returned unchanged.
+func stripMessageTimestamp(message string) string {
+	for _, re := range leadingTimestampPatterns {
+		if loc := re.FindStringIndex(message); loc != nil {
+			return message[loc[1]:]
+		}
+	}
+	return message
+}

internal/cli/commands/log_format_test.go

@@ -0,0 +1,117 @@
+package commands
+
+import "testing"
+
+func TestStripMessageTimestamp(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		// PHP built-in server / Apache ErrorLog
+		{
+			name:  "PHP bracket timestamp two-digit day",
+			input: "[Sat Jun 13 09:14:57 2026] 172.17.0.1:46058 GET /",
+			want:  "172.17.0.1:46058 GET /",
+		},
+		{
+			name:  "PHP bracket timestamp single-digit day space-padded",
+			input: "[Sat Jun  3 09:14:57 2026] 172.17.0.1:46058 Accepted",
+			want:  "172.17.0.1:46058 Accepted",
+		},
+		{
+			name:  "PHP bracket timestamp is entire message",
+			input: "[Sat Jun 13 09:14:57 2026]",
+			want:  "",
+		},
+
+		// ISO 8601
+		{
+			name:  "ISO 8601 with Z suffix",
+			input: "2026-06-13T09:14:57Z GET /api/users 200",
+			want:  "GET /api/users 200",
+		},
+		{
+			name:  "ISO 8601 with milliseconds and Z suffix",
+			input: "2026-06-13T09:14:57.123Z user login succeeded",
+			want:  "user login succeeded",
+		},
+		{
+			name:  "ISO 8601 with numeric timezone offset",
+			input: "2026-06-13T09:14:57+00:00 connection established",
+			want:  "connection established",
+		},
+		{
+			name:  "ISO 8601 with no timezone indicator",
+			input: "2026-06-13T09:14:57 starting worker",
+			want:  "starting worker",
+		},
+
+		// Date with space separator
+		{
+			name:  "date-space-time timestamp",
+			input: "2026-06-13 09:14:57 [error] upstream timeout",
+			want:  "[error] upstream timeout",
+		},
+		{
+			name:  "date-space-time with milliseconds",
+			input: "2026-06-13 09:14:57.456 queue flushed",
+			want:  "queue flushed",
+		},
+
+		// nginx / Go stdlib
+		{
+			name:  "nginx slash-separated timestamp",
+			input: "2026/06/13 09:14:57 [error] connect() failed",
+			want:  "[error] connect() failed",
+		},
+
+		// Must NOT be stripped
+		{
+			name:  "Apache combined log — timestamp follows IP, not at start",
+			input: `172.17.0.1 - - [13/Jun/2026:09:14:57 +0000] "GET / HTTP/1.1" 200 -`,
+			want:  `172.17.0.1 - - [13/Jun/2026:09:14:57 +0000] "GET / HTTP/1.1" 200 -`,
+		},
+		{
+			name:  "plain message with no timestamp",
+			input: "user logged in successfully",
+			want:  "user logged in successfully",
+		},
+		{
+			name:  "date only, no time component",
+			input: "2026-06-13 scheduled maintenance window",
+			want:  "2026-06-13 scheduled maintenance window",
+		},
+		{
+			name:  "partial timestamp lookalike",
+			input: "2026-06-13T09 partial",
+			want:  "2026-06-13T09 partial",
+		},
+
+		// Edge cases
+		{
+			name:  "empty string",
+			input: "",
+			want:  "",
+		},
+		{
+			name:  "whitespace only",
+			input: "   ",
+			want:  "   ",
+		},
+		{
+			name:  "trailing whitespace after timestamp is trimmed",
+			input: "2026/06/13 09:14:57   spaced message",
+			want:  "spaced message",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := stripMessageTimestamp(tt.input)
+			if got != tt.want {
+				t.Errorf("stripMessageTimestamp(%q)\n  got  %q\n  want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}

internal/cli/commands/logs.go

@@ -170,7 +170,7 @@ func printLogChunk(chunk client.LogChunk) {
 	fmt.Printf("%s%s%s  %s[%s]%s  %s%s%s\n",
 		colorGray, ts, colorReset,
 		sourceColor, chunk.Source, colorReset,
-		levelColor, chunk.Message, colorReset,
+		levelColor, stripMessageTimestamp(chunk.Message), colorReset,
 	)
 }