data.py 文件源码

def get_metric_data(target, start="-5min", end="now"):
    """
    Retrieves raw datapoints from a graphite target for a given period of time.

    :param target: A metric path string or a list of multiple metric paths
    :param start: A start time specification that Graphite will accept.
    :param end: An end time specification that Graphite will accept.

    :returns: A raw, response from Graphite. Normally a list of dicts that
              represent the names and datapoints of each matched target,
              like so::

                  [{'target': 'x', 'datapoints': [(value, timestamp), ...]}]

    """
    base = CONFIG.get("graphiteweb", "base")
    url = urljoin(base, "/render/")

    # What does Graphite accept of formats? Lets check if the parameters are
    # datetime objects and try to force a format then
    if isinstance(start, datetime):
        start = start.strftime('%H:%M%Y%m%d')
    if isinstance(end, datetime):
        end = end.strftime('%H:%M%Y%m%d')

    query = {
        'target': target,
        'from': start,
        'until': end,
        'format': 'json',
    }
    query = urlencode(query, True)

    _logger.debug("get_metric_data%r", (target, start, end))
    req = Request(url, data=query)
    try:
        response = urlopen(req)
        json_data = json.load(response)
        _logger.debug("get_metric_data: returning %d results", len(json_data))
        return json_data
    except HTTPError as err:
        _logger.error("Got a 500 error from graphite-web when fetching %s"
                      "with data %s", err.url, query)
        _logger.error("Graphite output: %s", err.fp.read())
        raise errors.GraphiteUnreachableError(
            "{0} is unreachable".format(base), err)
    except URLError as err:
        raise errors.GraphiteUnreachableError(
            "{0} is unreachable".format(base), err)
    except ValueError:
        # response could not be decoded
        return []
    finally:
        try:
            response.close()
        except NameError:
            pass