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Change the 2nd argument of round to toNearest.

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This is more useful if you want get a multiple of 2 or 5, while
still working for .001.
This commit is contained in:
Brian Brazil 2015-02-05 16:06:35 +00:00
parent 82613527f3
commit 60271d58bf
3 changed files with 43 additions and 29 deletions
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6
rules/ast/ast.go
View file

@ -31,14 +31,16 @@ import (
var (
stalenessDelta = flag.Duration("query.staleness-delta", 300*time.Second, "Staleness delta allowance during expression evaluations.")
queryTimeout = flag.Duration("query.timeout", 2*time.Minute, "Maximum time a query may take before being aborted.")
queryTimeout = flag.Duration("query.timeout", 2*time.Minute, "Maximum time a query may take before being aborted.")
)
type queryTimeoutError struct {
timeoutAfter time.Duration
}
func (e queryTimeoutError) Error() string { return fmt.Sprintf("query timeout after %v", e.timeoutAfter) }
func (e queryTimeoutError) Error() string {
return fmt.Sprintf("query timeout after %v", e.timeoutAfter)
}
// ----------------------------------------------------------------------------
// Raw data value types.

22
rules/ast/functions.go
View file

@ -291,28 +291,22 @@ func dropCommonLabelsImpl(timestamp clientmodel.Timestamp, args []Node) interfac
return vector
}
// === round(vector VectorNode) Vector ===
// === round(vector VectorNode, toNearest=1 Scalar) Vector ===
func roundImpl(timestamp clientmodel.Timestamp, args []Node) interface{} {
// round returns a number rounded to nearest integer.
// Ties are solved by rounding towards the even integer.
round := func(n float64) float64 {
if n-math.Floor(n) == 0.5 && int64(n)%2 == 0 {
n += math.Copysign(0.5, -n)
}
return math.Copysign(math.Floor(math.Abs(n)+0.5), n)
}
places := float64(0)
// round returns a number rounded to toNearest.
// Ties are solved by rounding up.
toNearest := float64(1)
if len(args) >= 2 {
places = float64(args[1].(ScalarNode).Eval(timestamp))
toNearest = float64(args[1].(ScalarNode).Eval(timestamp))
}
pow := math.Pow(10, places)
// Invert as it seems to cause fewer floating point accuracy issues.
toNearestInverse := 1.0 / toNearest
n := args[0].(VectorNode)
vector := n.Eval(timestamp)
for _, el := range vector {
el.Metric.Delete(clientmodel.MetricNameLabel)
el.Value = clientmodel.SampleValue(round(pow*float64(el.Value)) / pow)
el.Value = clientmodel.SampleValue(math.Floor(float64(el.Value)*toNearestInverse+0.5) / toNearestInverse)
}
return vector
}

44
rules/rules_test.go
View file

@ -527,16 +527,16 @@ func TestExpressions(t *testing.T) {
{ // Round should correctly handle negative numbers.
expr: `round(-1 * (0.004 * http_requests{group="production",job="api-server"}))`,
output: []string{
`{group="production", instance="0", job="api-server"} => -0 @[%v]`,
`{group="production", instance="0", job="api-server"} => 0 @[%v]`,
`{group="production", instance="1", job="api-server"} => -1 @[%v]`,
},
fullRanges: 0,
intervalRanges: 2,
},
{ // Round should round half to even.
{ // Round should round half up.
expr: `round(0.005 * http_requests{group="production",job="api-server"})`,
output: []string{
`{group="production", instance="0", job="api-server"} => 0 @[%v]`,
`{group="production", instance="0", job="api-server"} => 1 @[%v]`,
`{group="production", instance="1", job="api-server"} => 1 @[%v]`,
},
fullRanges: 0,
@ -551,7 +551,7 @@ func TestExpressions(t *testing.T) {
fullRanges: 0,
intervalRanges: 2,
},
{ // Round should round half to even.
{
expr: `round(1 + 0.005 * http_requests{group="production",job="api-server"})`,
output: []string{
`{group="production", instance="0", job="api-server"} => 2 @[%v]`,
@ -563,23 +563,23 @@ func TestExpressions(t *testing.T) {
{
expr: `round(-1 * (1 + 0.005 * http_requests{group="production",job="api-server"}))`,
output: []string{
`{group="production", instance="0", job="api-server"} => -2 @[%v]`,
`{group="production", instance="0", job="api-server"} => -1 @[%v]`,
`{group="production", instance="1", job="api-server"} => -2 @[%v]`,
},
fullRanges: 0,
intervalRanges: 2,
},
{ // Round should accept a number of decimal places to round to.
expr: `round(0.0005 * http_requests{group="production",job="api-server"}, 1)`,
{ // Round should accept the number to round nearest to.
expr: `round(0.0005 * http_requests{group="production",job="api-server"}, 0.1)`,
output: []string{
`{group="production", instance="0", job="api-server"} => 0 @[%v]`,
`{group="production", instance="0", job="api-server"} => 0.1 @[%v]`,
`{group="production", instance="1", job="api-server"} => 0.1 @[%v]`,
},
fullRanges: 0,
intervalRanges: 2,
},
{ // Round should look at last decimal place parity.
expr: `round(2.1 + 0.0005 * http_requests{group="production",job="api-server"}, 1)`,
{
expr: `round(2.1 + 0.0005 * http_requests{group="production",job="api-server"}, 0.1)`,
output: []string{
`{group="production", instance="0", job="api-server"} => 2.2 @[%v]`,
`{group="production", instance="1", job="api-server"} => 2.2 @[%v]`,
@ -588,16 +588,16 @@ func TestExpressions(t *testing.T) {
intervalRanges: 2,
},
{
expr: `round(5.2 + 0.0005 * http_requests{group="production",job="api-server"}, 1)`,
expr: `round(5.2 + 0.0005 * http_requests{group="production",job="api-server"}, 0.1)`,
output: []string{
`{group="production", instance="0", job="api-server"} => 5.2 @[%v]`,
`{group="production", instance="0", job="api-server"} => 5.3 @[%v]`,
`{group="production", instance="1", job="api-server"} => 5.3 @[%v]`,
},
fullRanges: 0,
intervalRanges: 2,
},
{ // Round should work correctly with negative numbers and multiple decimal places.
expr: `round(-1 * (5.2 + 0.0005 * http_requests{group="production",job="api-server"}), 1)`,
expr: `round(-1 * (5.2 + 0.0005 * http_requests{group="production",job="api-server"}), 0.1)`,
output: []string{
`{group="production", instance="0", job="api-server"} => -5.2 @[%v]`,
`{group="production", instance="1", job="api-server"} => -5.3 @[%v]`,
@ -605,6 +605,24 @@ func TestExpressions(t *testing.T) {
fullRanges: 0,
intervalRanges: 2,
},
{ // Round should work correctly with big toNearests.
expr: `round(0.025 * http_requests{group="production",job="api-server"}, 5)`,
output: []string{
`{group="production", instance="0", job="api-server"} => 5 @[%v]`,
`{group="production", instance="1", job="api-server"} => 5 @[%v]`,
},
fullRanges: 0,
intervalRanges: 2,
},
{
expr: `round(0.045 * http_requests{group="production",job="api-server"}, 5)`,
output: []string{
`{group="production", instance="0", job="api-server"} => 5 @[%v]`,
`{group="production", instance="1", job="api-server"} => 10 @[%v]`,
},
fullRanges: 0,
intervalRanges: 2,
},
{
expr: `avg_over_time(http_requests{group="production",job="api-server"}[1h])`,
output: []string{