Include real OS info in metrics. (#10425)

calculated a hashed user ID from either auth user id or API key
Also correctly populates OS.

These will make our metrics more useful and powerful for analysis.

codex-rs/utils/string/src/lib.rs

@@ -36,3 +36,46 @@ pub fn take_last_bytes_at_char_boundary(s: &str, maxb: usize) -> &str {
     }
     &s[start..]
 }
+
+/// Sanitize a tag value to comply with metric tag validation rules:
+/// only ASCII alphanumeric, '.', '_', '-', and '/' are allowed.
+pub fn sanitize_metric_tag_value(value: &str) -> String {
+    const MAX_LEN: usize = 256;
+    let sanitized: String = value
+        .chars()
+        .map(|ch| {
+            if ch.is_ascii_alphanumeric() || matches!(ch, '.' | '_' | '-' | '/') {
+                ch
+            } else {
+                '_'
+            }
+        })
+        .collect();
+    let trimmed = sanitized.trim_matches('_');
+    if trimmed.is_empty() || trimmed.chars().all(|ch| !ch.is_ascii_alphanumeric()) {
+        return "unspecified".to_string();
+    }
+    if trimmed.len() <= MAX_LEN {
+        trimmed.to_string()
+    } else {
+        trimmed[..MAX_LEN].to_string()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::sanitize_metric_tag_value;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn sanitize_metric_tag_value_trims_and_fills_unspecified() {
+        let msg = "///";
+        assert_eq!(sanitize_metric_tag_value(msg), "unspecified");
+    }
+
+    #[test]
+    fn sanitize_metric_tag_value_replaces_invalid_chars() {
+        let msg = "bad value!";
+        assert_eq!(sanitize_metric_tag_value(msg), "bad_value");
+    }
+}