span.py 文件源码

def set_metric(self, key, value):
        # This method sets a numeric tag value for the given key. It acts
        # like `set_meta()` and it simply add a tag without further processing.

        # FIXME[matt] we could push this check to serialization time as well.
        # only permit types that are commonly serializable (don't use
        # isinstance so that we convert unserializable types like numpy
        # numbers)
        if type(value) not in numeric_types:
            try:
                value = float(value)
            except (ValueError, TypeError):
                log.debug("ignoring not number metric %s:%s", key, value)
                return

        # don't allow nan or inf
        if math.isnan(value) or math.isinf(value):
            log.debug("ignoring not real metric %s:%s", key, value)
            return

        self.metrics[key] = value