Add parent span names to TraceLogger

Signed-off-by: Eliza Weisman <eliza@buoyant.io>

tokio-trace-log/src/lib.rs

@@ -153,13 +153,13 @@ pub struct TraceLogger {
  current: tokio_trace_subscriber::CurrentSpanPerThread,
 }
 
-#[derive(Default)]
 pub struct TraceLoggerBuilder {
  log_span_closes: bool,
  log_enters: bool,
  log_exits: bool,
  log_ids: bool,
  parent_fields: bool,
+ log_parent: bool,
 }
 
 // ===== impl LogTracer =====
@@ -241,11 +241,29 @@ impl TraceLoggerBuilder {
  Self { log_ids, ..self }
  }
 
+ pub fn with_parent_names(self, log_parent: bool) -> Self {
+ Self { log_parent, ..self }
+ }
+
+
  pub fn finish(self) -> TraceLogger {
  TraceLogger::from_builder(self)
  }
 }
 
+impl Default for TraceLoggerBuilder {
+ fn default() -> Self {
+ TraceLoggerBuilder {
+ log_span_closes: false,
+ parent_fields: true,
+ log_exits: false,
+ log_ids: false,
+ log_parent: true,
+ log_enters: false,
+ }
+ }
+}
+
 struct SpanLineBuilder {
  parent: Option<Id>,
  ref_count: usize,
@@ -423,20 +441,34 @@ impl Subscriber for TraceLogger {
  let logger = log::logger();
  if logger.enabled(&log_meta) {
  let spans = self.spans.lock().unwrap();
- let current_fields = self.current.id()
+ let current = self.current.id()
  .and_then(|id| {
  spans.get(&id)
+ });
+ let (current_fields, parent) = current
+ .map(|span| {
+ let fields = span.fields.as_ref();
+ let parent = if self.settings.log_parent {
+ Some(span.name)
+ } else {
+ None
+ };
+ (fields, parent)
  })
- .map(|span| span.fields.as_ref())
- .unwrap_or("");
+ .unwrap_or(("", None));
  logger.log(
  &log::Record::builder()
  .metadata(log_meta)
  .target(meta.target)
  .module_path(meta.module_path.as_ref().map(|&p| p))
  .file(meta.file.as_ref().map(|&f| f))
  .line(meta.line)
- .args(format_args!("{}{}", LogEvent(event), current_fields))
+ .args(format_args!("{}{}{}{}",
+ parent.unwrap_or(""),
+ if parent.is_some() { ": " } else { "" },
+ LogEvent(event),
+ current_fields,
+ ))
  .build(),
  );