rally/doc/source/plugins/implementation/sla_plugin.rst
Boris Pavlovic 01289aa081 Improve Rally Logging (part 2)
- Remove translations

  Nobody is using translations for Rally and I don't think that
  anybody is going to use it. Target auditory for Rally are
  developers/operators which usually know well english.
  For me this looks like waste of resources, performance
  degradation (cause we are calling _()), complexity
  (+1 thing that you need to know)

- Pass to log already formatted strings

  It's very bad because in case of wrong formatting, it
  doesn't fail instead just writes errors to the logs,
  as well information about trace is lost, so it's super
  hard to fix it

  Log wrapper doesn't allow to use LOG anymore for
  formatting strings

  All places are fixed

- Improve logging of exceptions

LOG.exception() already logs exception, which means it's bad idea to
pass str(e) to it. Instead we should provide clear description of what
happend. Improved few places to write warnings or exceptions in case
of different level of logs. In few places just use LOG.exception

- Part of log messages were improved and simplified

Depends-On: If23d874e8b73de12ba2b8c4e028a55543af6381b
Change-Id: Ibc1e1f4f554649d14b8fe4801557b83922ecefe3
2017-10-05 22:57:39 +00:00

2.9 KiB

SLA as a plugin

Let's create an SLA (success criterion) plugin that checks whether the range of the observed performance measurements does not exceed the allowed maximum value.

Creation

Inherit a class for your plugin from the base SLA class and implement its API (the add_iteration(iteration), the details() method):

from rally.task import sla

@sla.configure(name="max_duration_range")
class MaxDurationRange(sla.SLA):
    """Maximum allowed duration range in seconds."""

    CONFIG_SCHEMA = {
        "type": "number",
        "minimum": 0.0,
    }

    def __init__(self, criterion_value):
        super(MaxDurationRange, self).__init__(criterion_value)
        self._min = 0
        self._max = 0

    def add_iteration(self, iteration):
        # Skipping failed iterations (that raised exceptions)
        if iteration.get("error"):
            return self.success   # This field is defined in base class

        # Updating _min and _max values
        self._max = max(self._max, iteration["duration"])
        self._min = min(self._min, iteration["duration"])

        # Updating successfulness based on new max and min values
        self.success = self._max - self._min <= self.criterion_value
        return self.success

    def details(self):
        return ("%s - Maximum allowed duration range: %.2f%% <= %.2f%%"
                 % (self.status(), self._max - self._min, self.criterion_value))

Usage

The new plugin can be used by specifying it in SLA section. Like below:

{
    "Dummy.dummy": [
        {
            "args": {
                "sleep": 0.01
            },
            "runner": {
                "type": "constant",
                "times": 5,
                "concurrency": 1
            },
            "context": {
                "users": {
                    "tenants": 1,
                    "users_per_tenant": 1
                }
            },
            "sla": {
                "max_duration_range": 2.5
            }
        }
    ]
}