log stack traces

internal/engine.cm

@@ -324,6 +324,7 @@ var log_config = null
 var channel_sinks = {}
 var wildcard_sinks = []
 var warned_channels = {}
+var log_stack_enabled = false
 
 function log(name, args) {
   var msg = args[0]
@@ -476,15 +477,27 @@ function load_log_config() {
     }
   }
   build_sink_routing()
+  log_stack_enabled = log_config.stack == true
 }
 
 function pretty_format(rec) {
   var aid = text(rec.actor_id, 0, 5)
   var src = ""
+  var ev = null
+  var out = null
+  var i = 0
+  var fr = null
   if (rec.source && rec.source.file)
     src = rec.source.file + ":" + text(rec.source.line)
-  var ev = is_text(rec.event) ? rec.event : json.encode(rec.event, false)
-  return `[${aid}] [${rec.channel}] ${src} ${ev}\n`
+  ev = is_text(rec.event) ? rec.event : json.encode(rec.event, false)
+  out = `[${aid}] [${rec.channel}] ${src} ${ev}\n`
+  if (rec.stack && length(rec.stack) > 0) {
+    for (i = 0; i < length(rec.stack); i = i + 1) {
+      fr = rec.stack[i]
+      out = out + `    at ${fr.fn} (${fr.file}:${text(fr.line)}:${text(fr.col)})\n`
+    }
+  }
+  return out
 }
 
 function bare_format(rec) {
@@ -523,6 +536,9 @@ load_log_config()
 log = function(name, args) {
   var sinks = channel_sinks[name]
   var event = args[0]
+  var caller = null
+  var stack = null
+  var rec = null
 
   if (!sinks && length(wildcard_sinks) == 0) {
     if (!warned_channels[name]) {
@@ -532,14 +548,16 @@ log = function(name, args) {
     return
   }
 
-  var caller = caller_info(2)
-  var rec = {
+  caller = caller_info(2)
+  if (log_stack_enabled) stack = os.stack(1)
+  rec = {
     actor_id: _cell.id,
     timestamp: time.number(),
     channel: name,
     event: event,
     source: caller
   }
+  if (stack) rec.stack = stack
 
   if (sinks) arrfor(sinks, function(sink) { dispatch_to_sink(sink, rec) })
   arrfor(wildcard_sinks, function(sink) { dispatch_to_sink(sink, rec) })