illumos gate

From the Joyent bug report:

Now that we're emitting debug log messages from bunyan, et al, as JSON strings it would be helpful to be able to format and predicate on the contents of these objects.

In order for this to work from within DTrace, a probe context-safe bespoke JSON parser must be written and hooked up to a DTrace subroutine; viz. {{json()}}. The {{json()}} subroutine will work like this:

bunyan*:::log-*
{
  this->str = copyinstr(arg0);
  this->component = json(this->str, "component");
}

bunyan*:::log-*
/this->component == "wuzzle"/
{
  this->wuzzle = json(this->str, "wuzzles[0]");
  this->method = json(this->str, "req.method");
  printf("Method: %s! First wuzzle was: %s\\n", this->method, this->wuzzle);
}

In addition, in order to be able to aggregate on integer values extracted from JSON strings, we will need a {{strtoll()}}.